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Comment by duffpkg | Hacker News Reader

Lifepo4 (lithium iron phosphate) batteries for the home are pretty cheap as of today. Power storage for residential use in a 48v metal rackable linkable system with battery management system (BMS) is $89/kwh shipped/duty paid from reputable chinese suppliers CATL/Seplos etc. You have to wait for sea shipping, add $30/kwh if you want to buy it in the US today.

From the same suppliers sodium batteries are currently $130/kwh and about 26% less efficient in the same form factor. I look forward to this changing.

Due to rising power costs I moved one of my homes completely to solar and battery (lifepo4) and haven't had any problems. I can't imagine ever going back to the power company. Panels have gotten to the point of being ridiculously cheap. I have a lot of space. I purchased pallets of used panels for more or less the cost of transportation ($34 per panel 270w). They produce about 85% of their nominal rating.

I mention this because other comments mention costs that are much much higher.

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Sounds great, but are there actual businesses who will come to your home and do an install, or do you need to to become a mad-scientist electrician and DIY? I got quotes on getting an LG system a few years ago and it was 4X these prices (also for me a problem is that my 'ancient' panels from 2013 use a single inverter instead of microinverters, so if I touch the system I have to replace it all). I keep hoping there will be a bunch of small businesses electrifying everything, I'd love to see - good, practical, safe - EV conversions driving around too, but it just doesn't seem to be materializing.

All of the quotes and interactions I had with the local solar installers were reminiscent of the used car lot if not outright fraud. I was able to do what was permissible myself and a regular licensed electrician did the rest. The equipment is UL listed. There was some learning curve but I found the diysolarforum.com to be a pretty good resource to learn what I didn't know. I ran the whole setup standalone for about 6 months before switching the house over to it. The only problem that happened was a loose battery cable connection which the BMS and inverter alerted to and handled correctly.

What voltage are you running your solar strings at? I was wondering what would happen if the loose cable was a cable from the solar panels instead of the low voltage battery.

The panel strings are at ~500v so there are safety, fusing and grounding considerations. Pretty common electrical equipment and cable is rated for use at 600v. There are special locking water resistant connectors for solar panels called MC4.

Are the hybrid inverters you are using be able to detect arc faults (in series) from the strings? Running 500V DC is probably by far the most dangerous thing in your setup, fortunately your solar panels are mounted on the groud.

If you want a DIY-friendly option, it's best to look towards DC optimizers. They are installed on each panel and they provide a steady 48V output. They also do MPPT tracking on the panel level, so you get the best possible performance if you have some shading.

Unlike microinverters that are notoriously unreliable, DC optimizers so far have excellent long-term reliability.

Are you suggesting using a DC Optimizer from your solar panels to charge 48V batteries directly? This would be interesting. It's the first I've heard of optimizers being used for anything other than prior to an inverter.

You absolutely can do that. You still need a charging controller and a BMS, obviously. But you can avoid the AC round-tripping.

Nice, the 48V batteries I have already have BMS's...any suggestion for a nominal 48V DC optimizer and charge controller?

Tigo is known to work. I've heard that SolarEdge DC Optimizers don't work without a SolarEdge inverter connected to them.

This approach may vary by country. Not a single sparky in Australia will sign off on someone else's solar/battery install.

Isn't there a distinction between the house wiring and the solar/battery stuff?

P.S. I've never heard of sparky being used as slang for an electrician, sounds very aussie.

> P.S. I've never heard of sparky being used as slang for an electrician, sounds very aussie.

When I moved into a new house in Australia I asked the real estate agent if I could extend the fence, and he said I'd need a cheapie to do that.

I said ok but scratched my head as to why it needs to be cheap, only to find out later what he actually said was chippy, slang for a carpenter.

Yeah, it's all fun and games until you're at Macca's and someone says, "Oi, can you pass me a chippy?" and they get real confused when you go find a carpenter.

Maccas is nz, maccies is Aus

It's definitely Maccas in AU. Maccies must be a UK thing.

Chippies are also known as "wood butchers" apparently. Amused me ;)

Next you’ll need a roofie

Why, though? Is there some kind of requirement that only fully trained carpenters can build fences?

Just about everything in Australia needs a license to do. Even down to network cabling.

The rule is - if it's going inside the wall, only a licenced electrician can do it. Yes it also extends to things like speaker or HDMI cables. It's mad.

Mad, indeed. It's hard to imagine those rules are followed, especially for speaker wires and HDMI cables.

HDMI cables? Sounds like protectionism. Invent rules to make yourself more work.

Aren't there power delivery versions of HDMI?

I can understand requiring a license for any power wires behind walls.

I could also see the possibility that it's just an old law that doesn't consider data-only cables which don't have the safety issues that wires carrying power do.

It's definitely an old law that never took data cables into account, but the current interpretation is that any cable that carries electrical current has to be installed and certified by an electrician.

While HDMI can provide a tiny bit of power and there are active cables for signal boosting, HDMI was never meant for power delivery. You might be mixing it with HDMI with Ethetnet.

Sparky=electrician is common in the US too. I had previously thought of it as meaning a radio operator e.g. on a ship.

in Spain we call them “chispas”, which literally means sparks. An electrician is someone who knows the home electrical wiring stuff, while a chispas is someone who is skilled in repairing home appliances.

We use sparky in the UK for an electrician too.

> P.S. I've never heard of sparky being used as slang for an electrician, sounds very aussie.

I'm surprised to find out it's aussie slang; I always thought it was slang local to South Africa :-/

We say the chippie in the UK too.

We also use sparkie for electrician.

It's local to UK and more recent British colonies

ZA and AUS included. USA less so.

In the US, sparky is common slang electrician among the trades, but far loss-so for end customers who are looking to hire one.

It will, but I suspect this will get a lot easier everywhere as more of the problem gets packaged as units that you can just buy off the shelf (and the prices of such units come down).

I'm currently in a pickle in this regard, as my new house has solar on Net Metering, but no ATS or battery. While its nice to only pay the base connection fee, I still go dark when the line power does.

I'd love to add at the very least an ATS to keep my fridge and freezer going when the power goes out during the day, if not a battery but I have little to no documentation on the existing solar install, so i'm reaching out to the county to see if permits have any info. Fun times!

> All of the quotes and interactions I had with the local solar installers were reminiscent of the used car lot if not outright fraud.

I had exactly the same experience. They absolutely would not tell me the actual system cost, only how much I would save on my current bill per month. It felt exactly like a car salesman only talking about monthly payments, and it was horrible.

Yup. I’ve (US) also talked to a few local ones to just see if they had a couple panels I could buy off them for close to wholesale for a personal project - which if they were actually involved in installation would be trivial - and just got blank stares.

They were clearly just doing lead generation for some other company they had no direct connection with, and didn’t even have any idea who to talk to that could even answer my question.

I had way better luck just looking online and paying shipping, which is absurd given how they were presenting themselves.

So not even as good as a used car salesman on an actual car lot, more like door to door used car salesman.

These companies are the equivalent of people who received a free product to review and then post a referral link for it in the details. Of course, they glow about how amazing the product is and how you should drop everything and buy it.

Yeah. Talked to a couple of solar companies. They were utterly focused on costs vs utility costs and very opaque about how that was being modeled. And it was based on the rules back then--which of course could not hold. Net metering is a huge subsidy that is already being walked back.

The true value of solar or wind is the cost of the fuel it saves. Nothing more. Even if his numbers come true there's a big problem--bad weather could deplete your batteries. You want to turn to the electric company in that case? You are once again in the situation that the value is only the fuel.

I think solar credits works into things too. People trying to get a long-term revenue stream.

> do you need to to become a mad-scientist electrician and DIY?

I did my own a couple years ago, and it worked quite well on the first go. I got someone else to build the LiFePo4 battery pack (16 CATL cells for 48v with a JK BMS).

It was fairly easy to build. Mount panels on the roof, and wire everything (PV, battery, grid electricity if you want it, and the output) to the inverter. I added some extra steps to monitor usage and output, and a smart MCB. I also have a small shop that I can feed from solar power if the battery is almost charged and the sunset time hasn't reached yet.

See if you quotation is to export electricity to the grid. Those kinds of setups usually require a certified company to do the installation (to make sure the inverter syncs with the grid), but for off-grid setups, you can definitely DIY.

If your setup burns your house down, will insurance cover it?

You do not necessarily have to become all these things. There are whole communities around this sort of a thing - Will Prowse's DiY Solar Forum (https://diysolarforum.com/) is an awesome source for learning as an example.

The setup you describe - lacking microinverters - I think there are options there short of wholesale replacement [disclaimer: I, too, am a self-taught in this field, and so am likely wrong in non-trivial ways]

> but are there actual businesses who will come to your home and do an install, or do you need to to become a mad-scientist electrician and DIY?

A lot of the costs of a real install come from the permitting, doing proper upgrades (you might need a new electrical panel), the warranty, the labor, and other costs.

Every time I browse the DIY solar forums it feels like I see 1 person doing things by code for every 10 people cutting corners or playing loose with the rules. YMMV, but take the DIY cost estimates with a huge grain of salt.

Some people cold knocked on my dad's door and 3 weeks later he's got a wall of batteries in the garage. Rural Australia.

So yeah, there are businesses that'll do it.

In place where I live you do that and they will rip you off good time.

Better to DIY or at least do really good market research first.

Australia has become SO competitive for solar and battery installation you can actually be fairly safe nowadays just picking any old supplier that has >4.7* on google and there'll almost definitely be <10% price difference (that's the WA experience anyway).

Going with a door knocking sales rep for home batteries would be madness in most countries but chances are pretty good that in Australia you would get a perfectly decent product.

Despite what you get in Australia being pretty reliable, it's too expensive to justify quite yet. My 8kW solar is connected to a Fronius inverter, but until I find a less expensive option I can justify adding a battery.

A 13kWh system is over $AUD10k, and the ROI is on par with the expected lifespan of the battery.

If sodium cells can bring the price down to $AUD100 it would indeed be a massive game changer.

Yep I agree - I will, however, be happy to install a battery if it doesn't save me money but does represent a carbon price of about $100/tonne

If you’re in NSW there’s a state government subsidy of $2800 later this year for home batteries.

If you're in the US, I don't think you need to pull a permit if it's not on your house. So you could build a small installation in your backyard and hook it up without too much trouble.

This channel on youtube is an excellent resource and explains everything for anyone one who is a DIYer.

https://www.youtube.com/@WillProwse

Make sure you have a good understanding of what your insurance company will and won't cover for DIY projects. Insurance companies can be skittish about unlicensed electrical work.

For something like this, a worst case scenario is an electrical fire during a drought or a kid gets electrocuted. If you do the work yourself, you're likely on the hook if something goes wrong, even if it's due to a faulty part and you have an umbrella policy that covers liability.

You might need to DIY, but "mad scientist" is doing a lot of work in your statement that I don't think applies. You just need to follow some very-thoroughly-detailed online tutorials. It's one of those things like baking, where as long as you're good at faithfully following directions, everything turns out great.

> I keep hoping there will be a bunch of small businesses electrifying everything

There are a few of these per large city; but they serve companies with large budgets for "becoming carbon negative", not residences trying to do things cost-effectively to lower their electric bills.

I really like the baking analogy! I've installed a set of 10 PV panels with full electric installation including optimizers myself, and in fact the hardest part is finding out which mechanical adaptor parts fits your type of roof, which screws to use etc. The rest is following recipes indeed.

I’ve followed the super cheap Chinese battery options for a while. It’s amazing how cheap they can be, but at the same time the number of early failure stories is alarmingly high. Getting a warranty exchange is hit or miss.

It feels a lot like gambling. You might get one that works for a thousand cycles without issues. You might get one that fails after a week. You might be able to get a warranty replacement, or you might spend hours every week trying to make progress on a warranty claim without any luck.

You’re right that there’s a lot of opportunity if you’re willing to buy used panels, Chinese batteries, and do all of your own work. However, the cost of equipment is falling while the costs of labor are rising, which is why professionally installed systems are still expensive.

There is a lot of information on this on the diysolarforum.com but if you purchase name brand cells, CATL/EVE from a good supplier these are the same ones used by all industry. They have a very good track record. I do not advocate buying from any random seller on aliexpress. There are not any mass market non-chinese batteries available for sale. Virtually all solar equipment of any fashion is chinese made.

That’s the forum I followed.

The failures often came from BMS or other parts, too. There’s a lot of focus on the cells, but people are buying whole packs with a BMS.

Then that’s more the issue with the BMS rather than the cells

Problems with the BMS can become problems with the cells very quickly.

Yeah, but I would just buy the cells and spend more on a BMS. Or you can just use a low voltage cutoff and an active balancer for a smaller setup

In many of the systems, the BMS and battery are one in the same.

This article blurs the lines between the cells and battery system, too.

The post you were replying to was specifically about cells, and if you’re going for economy, building your own packs are substantially cheaper than buying packs domestically. Also less fraught when you’ve DIYed to diagnose and fix when things go wrong

Also prone to average people setting themselves or their houses on fire, eh?

Depends on how scrupulous Average Person is being. There's codes for electrical and solar installations that can be followed, and it's best to stick to the letter, even if you're certain it doesn't apply. And after that, you should get it certified by a licensed professional, but would also need a licensed professional to hook it up to the grid

I think you’re misunderstanding what I’m trying to say.

I’m talking about assembling your own multi-kwh lithium battery assemblies (pre-BMS even).

One wrong poke with a screwdriver, and all sorts of entertainment is likely to ensue eh?

And they’re big enough, no portable fire extinguisher is going to make a dent either.

Sure, you're saying some people shouldn't DIY.

Where I live many people DIY as a great many people have mad skills (lots of FiFo workers making a good living from O&G installions and big mining projects).

They build their own houses, their own planes, off grid power systems, water proof EV's to drive across harbour floors, etc.

If you've got a big (shipping container sized) battery pack you need a big thermal blanket to cut off the oxygen or a wide enough fire break about it.

Speaking of DIY home builds, here's a good use of black builders plastic: https://www.youtube.com/watch?v=1ILbQHnHPnY

No, you’re talking about building structures.

I’m talking about assembling a bomb.

A 5kwh battery contains about 18MJ of energy, equivalent to 4.3KG of TNT. Short that out or puncture on of its component pouches, and it’s going to be very dramatic.

One of them requires a different degree of care than the other.

You're still making the same irresponsible and frankly silly generalisation about "average" people.

Most people, full stop, don't build houses, metal work shops, treat their own sewerage, build their own power systems, etc.

So "average" people just don't start fires or set off bombs because they're not doing anything that dangerous.

Of the people that do, say, build their own glass furnaces, annealing ovens, laying out gas lines and installing small truck sized propane tanks with more energy than a 5kwh battery .. easily less than half, well below the "average" number of people that do such things, have accidents.

Sure, some people do watch Forged in Fire and have a go at knife making in a home built furnace, and then set fire to their barn | house | shed.

Most people don't try, and of those that do have a go most of them don't screw it up.

The point being, this:

> Also prone to average people setting themselves or their houses on fire, eh?

is just silly.

Average people don't attempt this, and of the people that do attempt such things most don't cock it up.

Perhaps your personal experience differs.

Maybe you can't dig your own septic system and fit it out without shit running back into your house.

Near as I can tell, you literally never even read my comment.

So seriously, WTF?

You’re doing on this weird rant, when I literally just said average people shouldn’t be assembling their own multi-kWh lithium battery packs unless they want to burn their houses down.

Which is, indeed, good advice. And pertinent to the discussion.

Where this bizarre tangent you keep going off on is not.

> average people shouldn’t be assembling their own multi-kWh lithium battery packs unless they want to burn their houses down

Average goofs shouldn't be assembling their own solar system and battery setups. Even an average person will apprise themselves of the know-how to proceed safely, and are legally obliged to do so. If average person is not interested in doing that, they'll call on a professional, and in some places, that is the only legal option. But perhaps there are contradictory stats out there to show that there's a real widespread phenomenon of well-meaning Average Joes and Janes that are burning down houses with DIY batteries.

Near as I can tell, you literally never even read my comment.

Consider that I explicitly stated:

* They build their own ... planes

* They build their own ... off grid power system(s)

* They ... water proof EV's to drive across harbour floors

and you responded that "No, you’re talking about building structures. I’m talking about assembling a bomb."

Let me remind you that aircraft are bombs, off grid power systems are bombs, water proof EV's with battery packs large enough to drive 7 km's underwater have the same issues you're talking about.

You apparently didn't pause to read the content of my comment before launching into a "Yes, but ..."

I've already linked to locally built ground effect plane (with builders plastic for wings), here's a locally built EV: https://www.abc.net.au/news/2023-07-30/nt-world-record-darwi...

Average people are quite capable of doing extraordinary things and not burning down their houses - you just have a low opinion of "average".

Idiots that can't read manuals and installation guides should avoid house grade battery packs, sure.

None of these people seem to meet any definition of population average I've ever seen or heard of.

If you counted them and put them on a distribution, how far off the bell curve do you think they'd be?

In fact, they seem rather extraordinary. If they seem average to you, I'd argue your sense of average is rather extraordinary too.

FUD.

This isn’t running a nuclear reactor it’s following some basic rules and common sense.

Lifepo4 is much more stable than you seem to think.

> One wrong poke with a screwdriver

I'm not sure where you're jamming the screwdriver, but certainly any wrenches/tools you use should be insulated if you're dealing with very high current and/or high voltage. Enclosures, insulated wires, conduits, terminal covers should be used to avoid short circuits. Also proper earthing and circuit isolation with RCBOs to protect from electric shock and overcurrents frying the wires/you, all which should be switched to the off position when you're poking your screwdriver, eh? ;)

> And they’re big enough, no portable fire extinguisher is going to make a dent either.

If you aren't doing basic safety things and somehow manage thermal runaway on LiFePo4 (pretty hard), you're probably going to melt some copper. Probably best not to put your battery assembly near flammable things, unless you want to see the world burn like this guy (though at low voltage/high current)

https://www.youtube.com/watch?v=ywaTX-nLm6Y

This is why at https://gouach.com we've built the first easy-to-repair, easy-to-swap-cell battery! We're launching a Kickstarter soon, stay tuned (on our newsletter!)

I buy that the bms aren't very good and are drastically hurting your system. Much lower key stakes, but I have an Andis Supra trimmer I rely on a lot, but it's charger has basically no low key mode: it will pump 10W+ power into these 2S cells forever. It's criminally bad battery management, will absolutely nuke the heck out of these high end cells, if you forget to pull it off the charger.

To me, the main thing is observability. Too many people trust their systems. We need to see how things are going. As the voltage converges to peak, we should be seeing the amps level out.

We can't just trust the machines, ever. We need to be observant. Ultimately I think we'd be able to review & get rid of bad equipment more effectively, but we should be in tune with what these systems are doing, should be aware that - oh hell - we are at peak voltage and still pushing power in, and we need to stop. These systems need to report what they are doing. Being blind consumers makes the economic system weaker; these systems should all report what they are doing.

This is why at https://gouach.com we've built the first easy-to-repair, easy-to-swap-cell battery! We're launching a Kickstarter soon, stay tuned (on our newsletter!)

> Due to rising power costs I moved one of my homes completely to solar and battery

Were you able to disconnect that home from the grid? Most places you're required to maintain a grid connection unless the home is in an exceptionally remote location.

While pricing tends to be usage-based, true costs tend to be dominated by the capital expense of building base-load capacity for the few days your home might need to run fully on grid power. So as long as you're connected to the grid, you're still forcing the utility to spend about the same amount of money even if you only use grid power a few days out of the year.

Yes. Totally disconnected, zero power bill. That home is in a jurisdiction where that is permissible.

How do you get through winter? I’m asking in good faith, I‘m using a PV installation myself and cannot see how I could realistically get off the grid.

Over provision the panels by a good margin and have them at a more southerly angle (for northern hemisphere). You can play around on nrel pvwatts to see what configuration produces the most even expected monthly output: https://pvwatts.nrel.gov/pvwatts.php

Most solar charge controllers allow a certain amount of PV overprovisioning.

In central/northern Europe in january solar goves 10% of the output of summer, and you need 3-4x power to heat compared to cooling down in summer.

It is often surprising that most of the US is south of most of Europe (the common reference is that Chicago and Rome are both 42N. The jet stream complicates the effect on overall climate, but latitude is pretty much the only thing that matters for solar power.)

Solar panels are mildly more efficient when colder, the same latitude in an area with similar cloud cover in north America is probably generally slightly better for solar than Europe because it is colder, not sure if it would ever be more than a rounding error though.

I’ve been in northern France for a couple weeks in a January and didn’t see the sun once…

Not really a thing in Toronto.

Solar panels don’t need sunshine they need light.

gonna have a lot lower performance in cloudy conditions

The difference between surface solar radiation levels in the US and Europe are wild[1], fully agree on the rounding error view. Anchorage seems to receive the same level of watts per area as Germany and Poland.

[1] https://1.bp.blogspot.com/-I5kzJIeV4Ds/VFSHUX3374I/AAAAAAAAA...

Amusing southern California is getting more watts per m2 then A lot of North Africa.

This is a good source, population by latitude.

http://www.statsmapsnpix.com/2021/11/world-population-by-lat...

It's missing the "most population in smallest (circular) area" view, as defined in https://en.wikipedia.org/wiki/Valeriepieris_circle .

Need a renewables feasibility index that accounts for the amount of solar, wind, hydro vs climate and typical weather. And bin plot population vs that.

Seems obvious that Norway, Washington State have lots of hydro. Places like Spain and California have lots of steady sun. Scotland, no sun in the winter but lots wind all the time. Those places renewables aren't problematic.

Northern Europe is much further from the equator than most of the rest of the world. To the point where rooftop solar stops being a great option. That said there’s a few ways to boost that 10%.

PS: Geothermal can also slash energy needed for heating. Ground sourced heat pumps are the only reasonable small scale solution, but in urban areas going a little deeper starts to make a lot of sense.

> To the point where rooftop solar stops being a great option.

Perhaps as a complete energy solution. But it is already the case today that a domestic rooftop solar in Europe (maybe not in the very north) has payback times <10 years. And that's without factoring in batteries which (as the OP describes) are rapidly approaching affordability.

Where in central Europe is it 10%? And you get extra in summer, the actual overprovisioning is when you compare to the equinoxes.

In southernmost Sweden, just above Germany, solar production is only 5% in December compared to June. In northernmost Sweden the sun doesn't even rise above the horizon for most of December.

This is a pretty late response, but even as "not too north" as Hamburg it gets close to 10%.

Hamburg is at 53.6 degrees North; Berlin is 52.5. Both are just farther north than Calgary, as a pretty reasonable comparison for the US.

To contrast, New York City is at 40.7 degrees, and Boston is at 42.3 degrees North.

This is in the american southwest so winters are very mild and the sun is still strong. Summer is the much more demanding part where AC is 90% of electricity use for the year. There would certainly be challenges in other locations but I think you could do the napkin math on it with panels being as cheap as they are. The solution to pretty much any deficit these days is to just add more panels. The biggest issue there is, is if you do not have sufficient space. My panels are ground mounted.

Right now?

Using an overprovisioned quantity of cheap cells is part of it.

Insulating and air sealing your home well is part of it.

Thermal mass approaches are part of it. Without cheap batteries, it's very possible to store a great many kwh in volumes of soil, water, or sand riddled with pipes and resistive heaters.

This year it has been pointed out that vertical bifacial solar panels radically outperform tilted arrays if snow is a possibility. Expect this to be the new normal at high latitudes as cell area is very cheap now.

In jurisdictions where that's not legal, can you realistically maintain a connection for just the cost of the customer fee and draw no other power? Or are there typically other roadblocks to installing solar in such places?

> Totally disconnected, zero power bill.

Great job! Over the last half a year my feelings about rooftop grid-connected solar (net energy metering, feed in tariff which are subsidised by the electricity bills of others) have changed somewhat, but going off-grid you've put in the investment to be energy independent.

When you say $89/kwh, are you talking about just cells, or assembled packs? I’m just about to buy a 5kw Lifepo4 server rack battery from EG4 for a diy project. It’s closer to $220/kwh

This is what I’m planning to buy, but you know something better I’d love to take a look. https://signaturesolar.com/eg4-lifepower4-lithium-battery-48...

It would be for the completed battery units with BMS. You would have to install the batteries into the battery cases. It is a bit tedious but it was otherwise straightforward. The batteries are extremely heavy.

I have always had good experiences with signature solar. My inverters are EG4 and I am very happy with their product after trying A LOT of others. I think the primary reasons for the price difference is that you are purchasing US inventory (it's already here), it's preassembled and warrantied as a unit, they provide pretty decent support and their battery packs use 100ah cells instead of 280ah+ cells. So you are buying ~3x as many BMSs, connecting cable ($$$$) and cases for the same power.

Their rackable units are not light but can be moved by a capable person without too much fuss. A fully loaded 280ah unit in it's case is over 250lb so you really need a lift cart or such. The 280ah units and now maybe 320ah are more economical.

Do you know if these batteries be used as a replacement for batteries of a lead-acid UPS? I have a Tripp-Lite rack-mount UPS with an extension battery, but its battery has degraded and it can only sustain my computing load for 3-4 hours.

It'd be great to replace it with an LFP battery.

For that low a power need Anker and some others make ready to go units you can buy off of amazon that are pretty reasonable.

You can't use LFP batteries as a direct replacement in your UPS, no. The voltages and charge characteristics are different. What you can do is replace the UPS with a portable battery solution, like another poster suggested. I believe the Anker units are one of the few that can function as a UPS. Most sorta-can, but the key difference most of them lack is that they don't turn on automatically after fully discharging when the mains power comes back on. It's up to you if you need this particular feature.

Will Prowse on youtube I think has some videos comparing and contrasting the different units for this purpose.

Also, most of those power banks don’t switch between power sources fast enough to avoid causing problems.

That said, something I can confirm works on that front is getting one of those power banks, plugging the UPS in, and then plugging whatever into the UPS.

I had several days of uptime on Starlink that way, running it 10 hrs or so at a time on a battery bank, the remainder on a cheap generator.

The Anker units that are at minimum $600 per kWh? At that point we've completely lost the cheap factor.

I actually had a good experience replacing a lead-acid backup battery with an LFP battery in my garage door opener. I guess if the battery has an internal BMS and can accept charge at 52V, it might be enough?

They can be used to replace ups.the voltages are close enough with lfp cells. I've done it. So long as you have a bms, there is nothing to worry about

I have seen Na-ion replacements for lead-acid, the chemistry is forgiving enough for that. No idea how good are they.

There's some very significant additional costs of bus bars & holding racks, but holy heck man EVE LF280K batteries are amazing. Usually 300Ah cells/<$90. That's basically 1kWh of energy (~3.2V average ish).

Building a big 14s 14kWh serial pack is really not hard, albeit those small hardware costs (bus bars) can add up. Most people don't need that much energy, probably, but these cells are just epic, maybe go 24v if you want less. 8k cycle life makes them good for a much much much longer time than most cells.

Latest prices for highthium cells are $40/280ah

Current European/German prices for home storage of 2-10kwh are at 400-500 EUR per kwh.

https://geizhals.de/?cat=bmseswresp&sort=t&hloc=at&hloc=de&v...

So... about 30k for 60kwh to cover 30kwh daily use with solar charging, and probably another 10k for installation. Hmm yes super cheap, might impulse buy later.

Unlikely that you need more than 10kwh. You just want to cover morning and evening electricity consumption. During the day you recharge and consume directly.

Absolutely agree - I think people fall into a major fallacy with sizing their battery systems. Their power consumption probability* distribution is skewed, and they think their battery needs to be sized for 99% or 100% of their daily consumptions. This gives a drastically oversized battery.

Instead, a simple approach is to download the daily power consumption for a year and size the battery for about your 80th-90th percentile consumption. You tend to find the sizing is not that sensitive to whether you go for 80th or 90th percentile, and in any case the batteries come in standard sizes.

If you've sized your battery system economically, it should be empty a good proportion of the time, but that just doesn't "feel right" to consumers.

* Yes I mean frequency not probability but I didn't want to cause confusion with electrical frequency

Maintaining reliable access to off grid electricity and going net zero are very different applications requiring very different expenditures. Both are valid choices, but going net zero relies on a great deal of grid infrastructure investment and maintenance, and the understanding is that utilities in high home solar areas will rapidly de-emphasize per-kwh pricing in favor of per-month access pricing.

It depends on how many cloudy/winter days you want to be proof for right? There needs to be some backup capacity for when you won't be able to fully recharge for weeks on end.

Although I suppose it is cheaper to oversize solar and not the battery, but that's usually already maxed out and limited by roof space. Maybe a small wind turbine to compensate for stormy days...

> There needs to be some backup capacity

I think they're talking about the situation where you're still connected to the grid, in which case you don't need to handle the backup capacity.

> Hmm yes super cheap, might impulse buy later.

It's part of a house. Of course it's not an impulse buy. That's not a useful basis for comparison.

From that page: Pylontech 5 kWh for 1198€ - so 250€/kWh is also possible :-)

>I purchased pallets of used panels for more or less the cost of transportation ($34 per panel 270w)

For comparison, I've seen pallets of new 24 410w panels at 58€ per panel (transportation included), hopefully I'll see similar deals in the future when I will ready to jump into solar.

Edit: I'm mostly worried because I don't know how sustainable the industry is when you can buy solar panels at such dirt cheap prices.

It’s not sustainable. Solar panel producers are going to be in big trouble in 8-10 years I think.

In the 8 to 10 years panels will be even cheaper. Probably half of today. The price trajectory is still falling.

>Probably half of today.

A 410W solar panel at 29€? I really doubt that honestly. Cheaper than plywood.

Efficiency going up is one way to reduce instillation costs which grid scale solar really cares about.

470W + even cheaper inverters seems likely.

This is not shade on the original comment. But I do find it funny when economists that extrapolate out to infinity.

Comely divorced from the real world materials and ecology.

Economies of scale baby. Another 10x more in production another 30% less in price.

>Economies of scale baby.

That's what they said about regular electric grid power too - that it "soon" would be so cheap as to be unmetered. That was half a century ago and it didn't pan out...

The reasons for this are entirely political. Technology, left to its own devices, would have followed the usual maturity curve on fission power, which would be universal, ubiquitous, abundant, and cheap.

Solar power has neither the geopolitical problems nor the squishy 'environmentalist' ick factor of fission. There's no reason not to expect another halving or two of PPP dollar per Watt to follow.

Thin-film solar panels will be much cheaper than that. They will be printed in huge quantities.

I can see why 8-10 years looks like a wall in terms of how much total solar we want.

However panels age which costs ~1% of capacity per year even before they need to be replaced, and global electricity demand tends to increase 2+%/year. So the more solar you install the more you need to install every year just to keep providing the same percentage of total electricity.

On top of this lower prices mean you it's still worthwhile even if a larger percentage of output gets wasted. Similarly, as storage gets cheaper (inflation adjusted) there's going to be more demand to cheaply charge it thus raising the demand for panels.

This is a controversial hypothesis that is merely from a idiot, being myself. I don't truly believe this but it something I have throught about.

Energy costs are THE driving force of prices. The cost of materials is essentially the energy it takes to squire/process/ship them. If energy was free, we would just dig up random patches of dirt and sift it for every material we wanted even in trace amounts. But its not because unfortunately, we are still primarily a fossil fuel economy for many reasons (legacy, price, chemical properties) and their cheap price relative to labour is acting as a subsidie to renewables pricing. So if the availability of fossil fuels deminishes it seemed logical that the price of inputs goes up and so too would renewable manufacturing. We would then see an inverted bell shaped curve on pricing over time. I have long suspected we would see this trend of lowering prices revert around the 2020s. So far I have been pleasantly wrong.

But fossil fuels like almost all minerals is fighting an uphill battle on availability and ore quality as we used the best stuff first. The US isnt fracking at the pace it is because they just wanted a laugh. It is due to the primary "conventional" stuff couldnt keep up. But that is a whole different issue.

If renewables were offsetting fossil fuel usage, this wouldnt be a problem but it is merely being added on top of it. Thus Jevons paradox in full swing. If we can over come that then this whole idea can be thrown in the recyling bin.

When we can make a solar panel with the outputs of a solar panel, then that is the escape velocity moment. And I don't just mean counting the joules and ignoring the energy fungability.

I am much more optimistic about this in the last few years but im not sure we are there yet. It is looking reasonable now.

there is a name for this "hypothesis" and other people have worked on the idea. it's called the "energy theory of value"

Core belief of Howard Scott's Technocracy Now movement,

> At the core of Scott's vision was "an energy theory of value". Since the basic measure common to the production of all goods and services was energy, he reasoned "that the sole scientific foundation for the monetary system was also energy", and that by using an energy metric instead of a monetary metric (energy certificates or 'energy accounting') a more efficient design of society could be made

https://en.wikipedia.org/wiki/Technocracy_movement

If nothing else it's a fascinating lens to view modernity through.

I've read some heretic economists that say that instead what orthodox economists claim that energy contributes 10% to GDP it's much higher closer to 100%. You get outside economics into accounting and as you chase the supply costs down you run into energy and scarce resources as the driver of cost.

Maybe 20 years ago I had the thought that ever never was enough supply of fossil fuels to lift the remaining 2/3rds of humanity out of poverty[1]. But there is enough solar and wind to give people a low energy middle class life. And the cost reduction since I think can do better than that.

[1] China I think burned half it's coal reserves in last 40 years. Modern China is basically built on coal. And much of the world doesn't have anything like that.

> China I think burned half it's coal reserves in last 40 years.

As a point of nomenclature isn't that always the case for any resource?

Given that "reserves" are drill tested known quantities that are tested, proven, modelled, and queued up for mining .. most reserves having been taken past "economic feasibility".

Hasn't the usual pattern in mining for some three thousand years since the oiriginal Rio Tinto Gold Mine been that reserves are mined and as they are exhausted, an exploration phase ramps up to prove inferred resources and raise them to reserve status?

eg: https://www.ga.gov.au/digital-publication/aimr2021/australia...

Everything society does is aimed at (locally) reducing entropy, and energy is the only way to do that.

https://en.m.wikipedia.org/wiki/Nicholas_Georgescu-Roegen

In 2011 solar panel producers were in trouble because China was flooding the market with panels sold below cost, which prompted a new set of tariffs. Those panels were around $1/watt in 2022 dollars. Since then, price per watt has apparently dropped _85%_.

It's an industry that's been driving down prices at an absolutely bonkers rate the entire time it's existed, and any time a company falls behind on that they're immediately in very deep trouble. I think it's basically impossible to make predictions about what an industry like that will be in 8-10 years.

Why tesla charges 5x for their Powerwall? I know their software is excellent, but I haven’t seen prices like that anywhere.

My guess: to throttle demand. Installers are generally in short supply and huge demand. So why not charge a premium?

Because there's value in a brand name, they are using more expensive batteries (or they were, I think just recently they started shipping LFP), and you're paying for the plug-and-play convenience.

Buying cells from CATL, adding a BMS, and putting all in a case is easy but still not trivial. Definitely not plug and play. You can absolutely get dirt cheap LFPs (like other people, I hang out on diysolarforum.com too), but it is not a competitor with the Powerwall unless you want something to tinker with or are simply too budget constrained to buy the brand name product.

I think OP mentioned battery rack (not cells) with BMS, not pure cells.

> Lifepo4 (lithium iron phosphate) batteries for the home are pretty cheap as of today. Power storage for residential use in a 48v metal rackable linkable system with battery management system (BMS) is $89/kwh shipped/duty paid from reputable chinese suppliers CATL/Seplos etc.

I'm probably not the only one wondering: does ordering from these Chinese suppliers require reaching out to them over email? I looked at both websites, and while Seplos asks to write in, CATL doesn't even have battery listings or sales contact information.

I'd love to order LiFePo4 batteries to put in some old UPSes of mine.

you can order through Alibaba, but there are so many suppliers and not all are reputable, so it's a good idea to search around on some of the solar forums for recommendations.

Yeah I think if you want to order from CATL directly, your chances for a reply are better if your order is worth some billions :-)

EVE cells are very famous in the DIY scene, you can get them via Alibaba/Aliexpress, or if you're in Europe from nkon.nl, they have a very good reputation.

89$/kWh seems way too low. If I'm mistaken please point out where I could buy them cause I'll gladly buy some. On well known Chinese market places the price is 5x to 10x that (I live in Europe)

Can you share places the I can get 1kwh if batteries for 89/kw shipped? I am waiting for a 14kw diy build set at 122/kw, that's the best I could find on Alibaba

What's a good cheap invertor vendor from china these days?

We are looking at ordering a lot of these systems in Ukraine to deal with russian attacks on power grid

Well, here, France, LFP batteries now cost MUCH MORE than just three years ago (final customer price) and... ~1000€ per kWh, while just 3 years ago they was a bit less than 700€ per kWh, the battery alone (with BMS etc) but we also need an inverter witch as well is not much more expensive and I talk about self-assembled systems, here legal, but not legal in large slice of the EU, because retail price of a complete installed system by some p.v. companies are so high that there is no economical reason to install them.

My system is 5kWp/8kWh @11.500€ three years ago, it would be now a bit different (400V batteries instead of 48V and a hybrid inverter instead of a p.v. string inverter AC coupled with a battery inverter) @~ the same price due to a single inverter and slightly cheaper p.v. modules (@~100€ for a 415Wp). If done by third parties the cheapest proposal back than was ~30.000€. At this prices given current electricity prices and local grid stability it's a nonsense, it's even cheaper a diesel generator.

I know prices in China are FAR lowers, and I've read also on far lower Thailand prices, but compared to local cost of life I can't quantify how much.

Well with the DIY route that's not a problem - nkon.nl is shipping to France as well, I guess? So there you can get EVE 280 Ah cells for about 100 €/kWh: https://www.nkon.nl/fr/rechargeable/lifepo4/prismatisch/eve-...

Unfortunately DIY is limited to what is certified in France, Victron MultiPlus are certified all, Quattro so far are not, the sole battery from this shop allowed for a grid-connected system are the Pylontech. Still MUCH cheaper than what I've found from French shops anyway so a big thanks :-)

This is why at https://gouach.com we've built the first easy-to-repair, easy-to-swap-cell battery! We're launching a Kickstarter soon, stay tuned (on our newsletter!)

How is this cheap? How much did you pay for the whole package?

That does not include the costs for inverters and other electrical system parts. I am not endorsing these vendors but I am happy with the result. My system paid for itself in less than 18 months. I have many years of experience buying from China in industry. I purchased batteries from Docan Power and BMS/battery housings from EEL Battery. My inverters are from EG4 and UL listed. You can see current pricing on their respective websites. I would say there is some learning curve for a complete novice. The diysolarforum.com is a good vendor neutral and honest resource for information.

> How is this cheap?

It's $900 + inverters for 10 kWh. A Tesla Powerwall 2 (14 kWh) is $10k (inverter included).

I doubt the inverters cost more than $1k.

> $89/kwh shipped/duty paid

Sorry what? Currently I'm happy to buy 5 kWh units for €1300.

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