Next is more expensive - and still haven't figured out if Li polymers are always Li-Po4 batteries - $749
http://www.texaselectricbikes.com/catal ... -c-36.html
No! And the distinction is very important. Lithium polymer is the same lithium cobalt (LiCo) chemistry as in laptop/cell phone batteries (lithium ion a.k.a. Li-ion), but packaged into a polymer allowing cells of odd sizes, such as "prismatic" (rectangular). Lithium polymer carries all the risks, benefits, and concerns of lithium cobalt since it is lithium cobalt. Lithium phosphate (LiPO4) is a different chemistry, safer, longer-lived, lower energy density, higher power density. The a123 cells are the most common example of lithium phosphate. Lithium phosphate can also be packaged into a prismatic form. Lithium manganese (LiMn -- example: Emoli cells) is a third kind of common lithium chemistry that sits between LiPO4 and LiCo in most measures of performance.
More details --
Lithium ion and polymer:
Same here, are Li-Polymers Li-Po4? $ 460 for 10 ah with BMS.
https://2339072343.monstercommercesites ... rodID=3326
These are lithium polymer, not LiPO4. Besides the big tag saying "polymer", the voltage is a dead giveaway. Lithium polymer and lithium manganese cells are 3.7 and 3.8 volts nominal per cell respectively. Lithium phospate cells are 3.2-3.3 volts nominal.
If I was you, I'd check into Forsen's selection of lithium phosphate and lithium manganese packs:
Ypedal here has a thread of his tests of Forsen's LiMn pack.
If I remember correctly, Kokam also makes large LiPO4 cells.