More Lifepo4 on ebay

[Beagle123]

This guy now has a store on ebay, and he's offering various Lifepo4 batteries:

http://stores.ebay.com/City-e-Cycle-Golden-Front

I wonder who manufactures his stuff?

 

[olaf-lampe]

They are not LiFePO because he uses only 13s to make a 48V pack. Also he claims capacity >60% after 800 cycles, which is unusual. But I like the connectors. Far better than pouches with soldered rip_off_ tabs

-Olaf

 

[dogman dan]

If I am looking at the right battery in his store, bms cuts out at 20 amps is nothing to cheer about. I don't know how to calculate it, but the c rate must be really low. Pings are supposed to go 1500 cycles at 1 c, and still be usable at 3000 cycles at 1 c. Clearly inferior cells if they go less than a thousand cycles. Somebody in china must be using factory reject cells so maybe he is the one. If so, this battery should sell for sub $300.

Ok i was looking at the Lifepo4. The other one is lipo. But even the Lifepo4 has a pretty poor test results for cycle life. The price difference betten this seller and Ping is not worth it.

 

[ZapPat]

[...] But I like the connectors. Far better than pouches with soldered rip_off_ tabs
-Olaf

The big cells do look nice, but remember that inside these "cells" there is probably the same prismatic type flat pouch cells that ping uses, the difference being that this builder packages them up in individual units of paralleled cell groups instead of making the whole thing one big block like ping's and others. Note that I'm not saying this vendor uses the same cells as ping, just the same type of cells.

One thing I wonder is the 13 cells to make up a 48V battery... it must be LiMnPO4 instead of LiFePO4 being used, no? The vendor does not specify either. At least this vendor does look better than others we've seen recently on ebay! But as dogman mentions, a 30A BMS cutout (this is what I read, dogman!) is not as good as ping's 40A for the same 20Ah pack.

 

[Jeremy Harris]

The big cells do look nice, but remember that inside these "cells" there is probably the same prismatic type flat pouch cells that ping uses, the difference being that this builder packages them up in individual units of paralleled cell groups instead of making the whole thing one big block like ping's and others. Note that I'm not saying this vendor uses the same cells as ping, just the same type of cells.

Very true. Those big Thundersky type cells, the ones with the big rectangular plastic cases, just have pouch cells inside, very similar to the Ping cells. Here's a few pictures of one that's been sawn open: http://www.flickr.com/photos/anachrocomputer/sets/72157604409956712/

Looking at those pictures shows clearly how the fragile tabs from each pouch cell are just simply bolted together either side of the blocks that form the terminal connections.

Jeremy

 

[dogman dan]

I was looking at first at the lifepo4 battery at the top of the page, and the specs for it. Later I realized the thread was talking about the 13 cell Lipo battery, with the big plastic case cells. I would rather have sla's than lipo anyway. Sorry if I caused even more confusion than usual with my blather. Either way they don't look like that much of a bargain.