Hacker News Reader

Comment by jxf | Hacker News Reader

The idea with really cheap batteries is that they don't need good energy density. You just swap them every so often and put the one you aren't using in the charging rack. You could even carry your own reserve energy with you!

View on HN

We used to have swappable batteries in virtually all of portable electronics. You could even get them in a rechargeable accumulator format. Virtually all of portable electronics has integrated batteries.

Yeah but AAs suck, and the newer more advanced batteries all have different voltages and require different charge circuitries so it’s hard to create a new standard for them.

It is always the case that custom configurations have advantages over other configurations. But standards give a good trade off between performance vs having a large ecosystem. Integrated batteries just add to the e-waste problem.

Why do you think AA suck ? It’s the chemistry, not the standard size, voltage or swappability right? 18650 and 21700 also have those assets. Some modern devices let you swap 18650.

My understanding is that it's a poor form factor for lithium ion - which operates at higher voltages, and thus needs an extra voltage regulator to step them down to 1.5V if you're packing them into the AA format (adding cost, reducing capacity, & introducing conversion losses.)

https://www.youtube.com/watch?v=uKYF1CXZPng

Every chemistry outputs a different voltage and requires different charge controllers. So sure we could have created a standard lithium size but it would have just locked us in to one chemistry again which will eventually be obsolete. 18650s are also too bulky for most applications. Usually you want flat rectangles. Another benefit of the proprietary batteries is they can completely fill the space available rather than being constrained by the standard.

Swappable proprietaries are still better than not swappable at all. For my previous phone I managed to order an external charger and several replacement batteries.

That and there's an incentive to try to lock customers into your particular battery ecosystem.

It’s all depends on device size and required capacity. AA is not a bad choice for many cases. And there are other replaceable batteries with higher capacity e.g. 18650.

Most modern devices have an integrated 3.7v Lithium battery so standardisation should be possible but I see no market forces for this - devices with short lifespan (limited by a non-replaceable battery) are more profitable.

The lifespan of the devices I own is generally limited by security patches not by batteries.

For me, this limitation applies only to my phone. I have plenty of other wireless devices and deliberately prefer devices that can use AA batteries. One reason is that I don't have to manage the multitudes of internal batteries as much and I need only 1 battery charger with batteries always ready to go. And obviously, battery going bad won't make my device useless (My DS4 controller's internal battery went bad in about a year. So I'm sticking with xbox controllers.)

How often do you receive security patches for your Bluetooth speaker? A cordless drill? Cordless vacuum cleaner? Cordless shaver? Sex toys...

I don't recall throwing one of those out because of the battery either.

That's true for smartphones (I had bad experience with Android from 2 big vendors which stopped updates around end of sales date) but many other battery powered devices don't need regular security patches.

My mother bought a flash light with non-rechargeable batteries. That type of product is basically destined to be thrown away on day one.

Li-ion cells are available in AA- and AAA-scaled sizes, e.g. 14500, 10440, plus fractional sizes that can be shorter or longer for the same diameter. If we wanted to not glue batteries into devices, we very well could, but that would make it harder to force purchase of a new device when the consumable component inside it fails.

I think very few manufacturers are optimizing for that. The move to integrated batteries for most portable electronics happened when the price of the battery plus charging ICs became lower than putting in a battery holder. Doing battery holder is currently simply more expensive, design is more complex putting it together is more complex. The cost are not intuitive, you can get 10+ microcontrollers for a price of a single physical on-off switch.

I agree that we could use standardized lithium-or-similar batteries in a ton of devices.

But please don't exactly match AA/AAA sizes. That will cause much more harm than good.

A circuit that accepts the voltage range of lithium ion is probably 90-100% of the way to accepting a range of cell chemistries. And you can put in a half cent identifier chip to say what the charging voltage is.

I don't think the technical difficulties are the problem here.

18650 are everywhere from hand tools, drones and vapes to Teslas and scooters. High energy per cell (up to 3600 mAh * 3.7V ~= 13Wh) and fairly cheap

Almost nothing lets you replace the cells individually though. They seal them in a pack which requires buying a replacement proprietary pack.

Chinese devices have standardized on taking 18650 "3.7V" cells for this purpose.

We might eventually get back there; maybe the EU will do for e.g. hand tool batteries what they have done for phone chargers and mandate an interchangeable standard.

Reply on news.ycombinator.com