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Old 12-27-2013, 12:51 PM   #121 (permalink)
TurnNBurn
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Quote:
Originally Posted by Daox View Post
I'd highly suggest sticking with lithium. Their cycle life is rated around 3000 cycles under ideal circumstances. Under those circumstances you can use up to 80% DOD. With lead acid, you get at most 800 cycles at 50% DOD. So lets do some math:

65Ah lithium @ 80% DOD gives 52 usable Ah.
40Ah lead battery @ 50% DOD gives you 20 usable Ah. In order to get 52 usable Ah out of a lead acid battery, you actually need it to be 104Ah. That is a big battery, I know because I have four of them on my riding lawn mower.

Now, you have the same usable Ah, but you still have a battery that weighs a TON more, and is only going to last at most 1/4 as long as the lithium. Also, refurbished batteries won't have near the rated capacity of a new cell.
Thanks for the info. I understand the concept now, but I'm still confused as to what I should be looking for. I guess I don't understand the whole "40Ah isn't really 40Ah once it starts discharging" concept.

That and I'm just confused by browsing EValbum. I see people with 40Ah Lifepo4 batteries getting a 35 mile range and then I'll see other bikes using 70 Ah batteries getting 35 mile range. I do realize there's a lot of variables in play here, like sprocket size, controller, motor efficiency, etc... But is it really that complicated?

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