Battery Protection, LiMn and LiFePo4's

[interestingfellow]

I've read around, and am still unclear about a couple pieces of info:

Does LiFeP04 require internal protection? What about LiMn? I'm under the impression that they do not have/require internal protection, but that they still need to be protected from over discharging (min volts and max current draw), as well as over charging???

The battery warning sticky doesn't clearly (IMHO) address the above two points clearly (or maybe I'm just slow).

And, is it safe(r)/ok to run 2 Cr2's or RCR123's in parallel (3.7v with x2 mah) to supply more current?

Thanks!

 

[jmanning]

The chemistry of LiFePO4 and LiMn are such that they will not vent with flame so they do not require protection circuits. I was also concerned about over-discharging and damaging these batteries but have found that the pv will stop producing vapor long before this happens. Chargers do not rely on the battery's protection circuit to cut off charging, so just make sure you take them off when charged or get a charger that properly shuts off when the battery is fully charged and does not do trickle charging after that point.

It is safe to run 2 batteries in parallel, and I actually built a 2x18650 mod this way. However, IMHO, it is not worth the increased size of the 2 batteries in parallel. I like a smaller mod, and just carry around an extra battery. When talking about the CR2 or RCR123 batteries, you might as well just go with a larger battery, a 14500, 17670, 18500, or 18650 for example, to get longer battery life. Just my 2 cents, there.

 

[interestingfellow]

Cool, and thanks!

The mod I"m designing is more for cool factor than performance, but I do want/need it to perform well. Space constraints means I'm gonna have to use a couple CR2's or CR123's for power, and.... it'll make sense when you see the finished prototype.

But thanks, sometimes I get caught up on the simple stupid stuff.