I'm replacing a friends 24v/12ah lead acid battery with a 24v/20ah LifePO4 battery. I've never unwrapped a LifePO4. I have a LifePO4 battery in my bike and I feel sure the cells are stacked in sheets. I see LifePO4 batteries that appear to contain rows of cylinder shaped cells (cans?) beneath the wrapped cover. Power-wise is there any difference in the two different shapes of cells?
I run both Ping battery packs and Headway packs. I find the Headways are a bit saggier voltage-wise, and a bit heavier. The Headway packs are easier to maintain, as you can fairly easily take the whole pack apart and put in a new cell or plastic cell blocks or whatever - the modularity is good. The Ping batteries also have issues with heat production by the stock Signalab BMS from Ping, so that charging them in a cooler pack can overheat the bms. I haven't noticed this issue with the Headway pack BMS - much better heat dissipation with the big aluminum heatsink on the board. In fact I've replaced several Signalabs with the Headway bms, on the Ping packs. The Ping packs are a bit lighter and more compact. They are about the same pricewise for the same energy content. The Headways are supposedly rated at 3C continuous I believe whereas the Pings are 2C. I like both brands, with a slight edge to the Headways, for modularity, diagnostics and repair, and have assembled several packs from the raw cells and plastic blocks and connectors.
Thanks for your reply... Never had Headways and know nothing about them. Good to know they can be maintained easier. I am really hoping to see improvement in longevity of power for my friend's bike. Her 24v/12ah lead acid pack died rather quickly when riding. After charging the lead-acid, the bike speed would start out good but dropped quickly; and life-wise, they would not recharge after only approximately a years use. She did not ride her bike much... maybe 20 times, and recharged the lead acids after each use.... very disappointed. So really hoping the lifepo4 will have better results
Last edited by t44; 05-15-14 at 08:50 AM.
It will be no comparison between Lead-Acid and LiFP04. Lead acid suffers from the "Peukert effect", and voltage drops very rapidly across the discharge. The lithium has a very flat discharge curve until it shuts off. You'll never look back from the lithium. Most lead acid users probably want to save money, but eventually regret the whole experience, I think. Headways are pretty commonly available from various Chinese ebike vendors, with blue cell cans, joined together with metal connectors and screw terminals, and orange plastic cell holders which slot together. Not as light as the LiMn types that are more expensive and lighter, but easy to work on and very good lifespan. The Ping packs also last for several years typically, if they are well matched to the size of the motor and controller. Good luck.