Small lithium

[emilevirus]

I'm looking to get https://goldentechnologies.ca/power-cha ... ider-envy/ Right now I have a chinese chair 17kg that I use to travel with 10ah lion. It's ok to go on flat surfaces but if you go uphills it doesn't have enough grip. So the Literider weighs 110lb but detachable into 30lb parts so I think it could be good. BUT it comes with 22ah lead crap. I'll be using it a few times a year and I don't want to be dealing with maintening batteries. The chinese chair I just charge the lion to 3.8v and forget about it. Next time I need to use it I have enough range. How should I replace these 22ah leads? 20Ah lifepo4 won't be enough right? 3C lion? I don't really like putting lion under my butt.

[Burgerman]

It only has a 40A controller so 80A peak across 2 motors for a few seconds at a time. Most of the time way less. So shouldnt be that hard to find some cells. You need to measure its battery area.

I wouldnt want lithium ions. Unless I could get off fast. Or pull the battery out and throw it fast...

[emilevirus]

So 2C lifepo4 cells with M6 studs should be good.

[shirley_hkg]

Panasonic LiFePO4 20Ah

20C rated.

[shirley_hkg]

A123 32113 cell.

4000 mAH @40C continuous.

[Burgerman]

All good examples. When you say, 2C is enough, then that isnt adequate information.


A 5Ah cell, thas 2C can do 10A. I wouldnt though... Half of that and you get sensible battery life.

A 30Ah 2C battery can do 60A max. If you believe the self claimed specs. C rating has no official set of rating criteria. So many silly figures are claimed to sell cells. So half it!

A 10C cell will likely be safe and live a long life at 5C so 10C makes sense if the pack is really 5C and 20Ah. So 100A capable all day long. Thats if its half that capacity you need to double the C rate for the same current capability.

There are 130 and 150C hobby packs. So 1Ah pack will drive that chair...

The reason that we use huge 230Ah cells normally is because they will fit and give huge range. And because even 1C means 240A capability. And they are 2C peak/pulse so all we need.

1C cells are smaller for a given Ah than say 3C or 10C ones.

So 1st job, mesure where it needs to fit.
2nd job, find a cell that allows you to maximise Ah whilest allowing a peak draw of around 80 to 100A even though 15 to 20 will be 95% of the day. That way it will last well. And have the best range while fitting the space. Remember that if you can fit more Ah then the required C rate is less.

[emilevirus]

Also when it's cold outside that 2C cell becomes 1C so I need atleast double or triple even. With 22Ah lead they claim 15 miles range which is more than I'll do in a day. 22Ah equals around 12Ah usable right? I don't want to maximize capacity here but minimize weight. So I think I could get away with 10Ah 10C?

[Burgerman]

I would be happier with maybe 15 or 20. But your choice.

Look on aliexpress. Many 12 or 24v life packs.

[emilevirus]

Well range claims are usually way off. My 17kg chair has about 7 miles range with 10ah battery. Now they claim 15 miles on a chair that weighs 4x more. That's nonsense.

[Burgerman]

I know. But I meant Ah.

[emilevirus]

Yeah my point is 10Ah would most likely be too little then. 15Ah would be fine I guess still 1/4 weight of lead.

[emilevirus]

What kills me is I'll probably pay more for a 15Ah than I paid for a 100Ah.