/diy/ - Do It Yourself

I've built a chink 1500w ebike recently, and I've soldered a battery for it so I'll answer.
Car batteries are not meant to be discharged deeply, using them for traction batteries will quickly destroy them. If you want lead acid, you can go for deep cycle batteries (like for boats) or sealed, mainly used for some backup systems (those will be more expensive per Wh). Both of those options will be very, very heavy which is not optimal for a bike.

>>1840575
It's not like it wouldn't work, but the two main issues you'd encounter, aside from the obvious weight, are longevity and charge times. As the other anon said, cheapo lead acids don't like being discharged rapidly or completely, expensive lead acids aren't much cheaper than lithium. And lead acids have to be charged much more slowly, a lithium ion bank can be charged in 2 hours without any problems if you have the right charger.

>>1840589
>>1840607
Welp, with your posts as a starting point I looked into charge cycles and the like and that basically killed the car battery plan. Thanks for bitchslapping me back to reality.

Guess I'll either just have to spend a good chunk of money on a large lithium battery or jury-rig one from cells stolen off of a bunch of those rental e-scooters that are littering the nearest big city.

>>1840650
Depending on how far you want to go, it shouldn't be that expensive. A 500Wh battery would be just over $100 with cheap-ish cells. If you later want more range, it's not hard to add more capacity. Of course it's better for batteries to be around 1C discharge, but 3C is still reasonable.

>>1840652
Are we talking weld-it-yourself or where are you getting that price?

>>1840723
The cost of individual cells, bought from China. Of course ready-made packs will be more expensive, but again if you buy from relatively reputable chinks, it's still around $100-$150.

>>1840765
>Relative reputable chinks
Damn, do you still believe in santa too?

Joking aside, got a link?

Don't buy cells from chinks, you can get great deals on salvaged cells domestically. https://batteryhookup.com/

>>1840824
If you're a burger, you can just buy from >>1840827
otherwise, I haven't bought any battery packs from chinks, but you can look at "most orders" ranking on aliexpress and read the feedback, also avoid the absolute cheapest deals, like there are listings for a 10Ah 48V pack at $75, those are definitely shit cells. There's another type at $100, that's a more believable price. Individual cells I buy from https://www.aliexpress.com/store/1890206 and they are always up to rated capacity.

>>1840650
car batteries have incredible amp hours though and should work if they'd be kept between 80-100% that would leave you with about 20 ah for each battery used though i have run my skateboard at 12v and can confirm that it's barely enough. kept me going at 7km/h max which would be fine for a bike equipped with pedals but i'd recommend running two of them
you have been holding on to your old car batteries right?

batteries have chips in them which work in tandem with the controller, they were both designed for working together. it stops the entire system overheating and various other functions.

>>1840575
Lead acid batteries are the worst for this. If you really want to do this on the cheap, assemble your own lithium battery. You can buy 18650 lithium cells relatively cheaply. I made my own ebike a couple of years ago. I seem to recall finding a pretty good 48v triangular lithium battery on aliexpress for 300-350ish

>>1842233
or you could use a battery pack that's already assembled from superior 18650 cells, it's a huge bonus that you can charge them normally and still use them in your tools. additionally the ryobi mowers have two of these wired in series which makes it ok to get 40v out of them.

>>1840575
if you can get used car batteries for free like I do you could make this project work
but you would need to build trike because weight
also stated Ah is absolute max, you could get maybe 50% of that max without permanent damage
keep in mind that used one will have lower capacity already so using free batteries you get max 40% usable Ah
Charging overnight/at work would work but you have to haul charger and extension with you too
After all that you need regular checks on batteries, so time and specialised testing equipment
And in end you ride on retarded unreliable vehicle that will cost more to build and maintain than factory ebike
When it finally packs in one towing back home will drain your pockets more than rabbi for bris

OP you are retarded. Just steal one of those scooters and replace the control board, or take the battery from one of those. Ideally you should replace the handle so it folds, maybe replace the wheels too since they suck. If you're too pussy to do it they're often trashed in cities. If you're open, an electric skateboard may be another thing to consider. What's the budget? Where the purpose? What's the range?