Originally Posted by Anorak
Yes, that is the advantage of Lipo as well as energy density. A123 is LiFePo. Different chemistry.
li-po stands for lithium polymer, which is referring to how cells are constructed using gel polymer electrolyte without a hard casing inside a pouch. Li-po batteries can be built with lithium cobalt or lithium iron phosphate chemistry.
here's a clip of li-po (lithium cobalt) catching fire and exploding. lithium iron phosphate batteries can still overheat and puff up. but will not go into thermal runaway and explode.
All li-ion cells have very low internal resistance and will discharge at very high rates. this is why CCA ratings for li-ion cells means little. what's more important is how those same cells perform when cold. note this is when higher AH batteries have an advantage. necessary pre-heat cycles consumes energy.
A battery constructed with 4x A123 26650 cells has rating of 2.3AH ...during warm weather this little powerhouse will discharge at very high amp rates. and will deliver amazing performance.