BMS Battery types

[kilowatt]

I am considering buying a battery from BMS battery but am very confused over the different battery materials being used between different size packs. I am looking at the 36 volt 20 amp they came out with back in October 09 that uses 40 pieces 6665143 type cells. The pack is called a LiNiCoMn204 type; is this any good? Then I notice that the 36 volt 12 amp uses 12 pieces Lifepo4 which I assume is the pouch type batteries. I plan to watch the forums until the end of Jan and then decide; any help explaining this mix and match of cell types by amp rating and what is best would be helpful.

Thanks,

Kilowatt

[deacon]

Let me be the first to admit that I am lost when it comes to this technology. I have heard that there are some real mysteries surrounding the new lithium battery types. Some manufacturers say their batteries are superior to others using the same chemistry. I still use sla because they are so much simpler. I know there are a lot of drawbacks to them, but I'm just not comfortable dropping half a grand on batteries that seem to be a hang of hair and piece of bone construction. \\

Sorry I can't be of more help.

You might want to also try the visforvolt forum

[kilowatt]

Deacon,

Thanks, and I am also thinking that going back to SLA is best. I spenT $400 for a lifepo4 that uses 26650 cells (cheap) and am now having problems. I have a bad cell in one of the parallel groups but with the welded straps and such, its too big a project to repair. Another problem is we don't have a good US supplier. I hope I get some more replies.

Kilowatt

[deacon]

the guys on Visforvolt have a lot more experience with this technology than most of us here I think.

[kilowatt]

Thanks,

Kilowatt

[TheE]

I found this on Wikipedia regarding the LiNiCoMn batteries:

High power cathode using lithium nickel manganese cobalt (NMC)

Imara Corporation[52], based in Menlo Park, CA is commercializing a new materials-agnostic technology first applied on an NMC material which has the effect of lowering impedance and extending cycle life. These high power-capable cells have high energy density relative to other high power cells in the market.[53][unreliable source?] The batteries are being deployed in power tools, outdoor power equipment and hybrid vehicles; Sony and Sanyo use NMC and NCA blended with LMO (spinel) for high-powered applications. NMC has a significant safety advantage over cobalt oxide and 50% greater energy density than FePO4, but suffers from a poor cycle life.

Nissan Motor Co. has nearly completed development of a lithium-ion battery using a lithium nickel manganese cobalt oxide cathode (NMC). The new system, which will reportedly offer almost double the capacity of Nissan/AESC’s current manganese spinel cell.[54]

I've used basic LiPos in the past, but never as e-bike batteries. If they're anything similar, you get a rediculous amount of power for a given weight...just make sure you use the proper charger and keep them away from anything flammable (while charging).

[deacon]

I saw a TV documentary showing just how they Lipos are made. They look pretty simple and forthright until they get to the balance thing. Drain and charge equality seems to be and issue. If the special circuit is working they should last almost forever or so they say.

The best feature for me would be he even distribution of drain. With Sla i have great power for the first quarter of the charge but then it goes down dramatically until the power output is minuscule.

[kilowatt]

Thanks Deacon,

I also got a very informative reply from Dogman on Endless-sphere under battery technology on how to calculate my battery needs and the importance of the C-Rate. I'll let everyone know how this works out this Spring.

Kilowatt

[deacon]

please do those of us in Ebikes are always on the look out for 1st hand information. Too much of the information out there is hype by the manufacturers.

[kilowatt]

To close this out I have decided to go back to SLA batteries until the Lion prices come down and we get some US suppliers. I found some 12 volt 18 amp SLA batteries that weigh the same as the 12 amp type just a different shape so that should get me around town with amps to spare. Thanks all for your assistance.

Kilowatt