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Comment by Goz3rr | Hacker News Reader

We already have standardized voltages, they're a defining feature of each chemistry. What Makita markets as 18V batteries and DeWalt calls 20V are actually the same battery with the same voltage range.

And regarding combining a 12V 1Ah pack and 80Ah pack together to create a 24V pack, you would end up with a 24V 1Ah pack, as by that time the first pack will have been emptied and you need to recharge it, while the other pack still has 79Ah remaining.

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Getting into FPV drones was super interesting because battery tech plays a huge part in the hobby. Rather than voltages, everything is normalized to number of LiPo cells in series, e.g. 1S, 2S, 4S.

Drone accessories also accept a super wide voltage range so they can be mostly powered by whatever battery packs you have laying around (excepting support for 6S, which is kinda rare).

However moving past drones, you'll start seeing other battery chemistries with different voltage ranges. Li-Ion can be discharged further than LiPo. LiFePO4 tops out at 3.6V, rather 4.2V. And so on.

This has me wondering how to engineer a circuit to have the 80Ah constantly charging/balancing with the 1Ah to maintain both the full voltage and capacity capabilities of both cells without shorting out the leads to the load. Of course, the peak power/current is still limited by the 1Ah cell. I guess the simple way is just put the cells in parallel and use a boost converter.

This whole strand of consideration serves no purpose since nowadays if a hardware designer wanted specific voltages they'd use a buck/boost converter with the effect that any battery can output any voltage at any current up to its total safe power output limit, with losses so minimal that they are negligible.

You use a battery controller that balances the cell voltages by doing either charge redistribution or plain current bypass.

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