Lead acid (LA) has a very attractive buy-in price, I think around $150/kWh. You see a lot of shoestring budget EV conversions using lead acid .. and many EVs in china too.
While LA is very recyclable, it has a number of very serious problems for EVs:
1. You do not want to discharge down to 0% SOC, even with deep cycle LA. It's best not to do this with lithium batteries either, but they'll typically bounce back just fine. 0% SOC on a LA battery is probably going to kill the battery.
So if you want ideally to keep above 50% SOC in daily usage, and absolutely never go below 20% SOC, then you need to buy 25% more battery than you would with lithium. Hurts weight, hurts price.
2. Cycle count is low - few hundred cycles, where each "cycle" is down to 50% SOC. Because of this, buy-in cost is low but operational cost is high due to the need to replace the battery every year or two.
3. Low capacity per volume and weight. Exacerbated by point #1 above.
4. Slow recharge times. Not a problem if you overnight charge, as most of us do currently. J1772 3-7kW would only be acceptable with a very large pack.
