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Comment by donquichotte | Hacker News Reader

The kit consists of a 100W Pmax solar panel and a 420Wh [edited: this falsley said 420Ah before] deep cycle lead acid battery. The battery is pretty heavy and in the picture the setup is mounted on a car.

Let's keep in mind that a car alternator has 0.5-2kW and you need to burn <0.1l of gas to charge that battery once with the alternator. I'm not sure its worth all the extra equipment and cost to go full solar.

Edit: The solar panel probably gets you 360Wh to 900Wh per day, depending on how sunny the region you live in is. This is not enough to run a household refrigerator, but enough to charge your phones or laptops and some lights.

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Optimizing for cost is not always the top priority.

For example, when you're camping or at another event with lots of people around. There's nothing quite as abominable as a fleet of autos chugging along in a loud cacophony.

> There's nothing quite as abominable as a fleet of autos chugging along in a loud cacophony.

If you have been to burning man you know there are things way more abominable.

That said, I agree cost is not the priority. Convenience is.

We have that battery in our camping gear for my wife's CPAP machine. It weighs 23 pounds. It's not hatefully heavy to deal with.

We started camping w/ a battery this summer and I'm definitely going to add solar charging. For me, the allure is to have the battery charging silently, and while we're away from the campsite.

Try this battery instead, if you want something lighter and more portable:

https://smile.amazon.com/gp/product/B01M3S00H0/ref=oh_aui_de...

I used it while camping for the eclipse, and only had to charge it once every few days, and that was with charging all sorts of other devices as well.

The "BOM" lists a 35 Ah / 12 V battery, which is reasonable. A 420 Ah battery is (a) a boutique item (b) should weight around 120-140 kg (c) does not fit into a toolbox (d) costs significantly more than 299 $.

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From a professional standpoint I'd nag about

> the battery is laid into the tool tray. Plenty of extra space in this toolbox, which protects the system from dust and the sun.

A closed box is not a good place to keep actively cooled electronics; less so when it's a black box in the sun.

You can get passively cooled 150W inverters, but yeah, a black box outside in the desert may not be ideal. You can eliminate most of the radiant and some of the convective heating with a beach towel on the box and an umbrella+emergency blanket above it. (I mean, we are talking burning man, after all)

If you seal your box in a humid environment, the cool night temps can cause condensation, so ventilation of the box would be useful to prevent this (as well as provide for active or passive cooling of electronics) or throw in some silica gel packs.

The box is mostly to prevent dust ingress which is arguably a bigger problem than heat or condensation on the playa.

Thats not true.

If you suppose a 12V 420Ah battery, its capacity will be of 5kWh. That would require at least 0.5l of fuel. But with a typical efficiency of 30%, it will require 1.6l, and not 0.1l.

My mistake, I meant 420Wh. Thanks.

This is a teeny setup, but it is also easy to scale up. This setup gives you everything you need to get started and you can add or replace parts to get more capacity and current. With the project box and a folding shopping cart you could haul two larger batteries and several panels.

If you have money, you can buy integrated solutions like the Xantrex XPower Powerpack 1500 + regulator + solar panels.

I have a "plan" (we'll see where it goes when I get to it) to do something like this on my Jeep for camping. Except, instead of an external battery, my plan is to get either an Optima or Odyssey hybrid battery (maybe two, if I can fit them under the hood), that can be used for cranking and deep-cycling.

So for $200 you can keep your devices churning while not connected to grid? That sounds pretty nice if you like longer road trips and mainly visit places with a lot of Sun light.

I think that's the main goal (charging phone+tablet+laptop). He's talking about that in one of the other posts on the site.

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