Parallel Poly Li-Ion battery charging (Need help)

[Sci]

This may have been covered, but I haven't been able to find a thread about it. If you know of one please point me to it.

I've got 2 of these: Polymer Li-Ion battery Module, 3.7 V 2500mAh (9.25 Wh) - Prewired with PCB (IC).

What I would like to do is stack them(parallel-solder their leads together, +to+ -to-) and need to know if I can charge them at the same timeI(I bought their suggested charger). Also, am I right in thinking that this would result in a 3.7v 5000 mAh output?
I'm thinking of using them as a portable power pack(charge batteries or plug in my passthrough). I realize I could just build a NicoStick(& have), but I have these & want to use them.
I've already tried attaching an M401 atty to one of these & it powered it fine.

Any help is greatly appreciated.

 

[opuscroakus]

You want to be real careful with LiPo batteries. Your playing with something that is more volatile than the Li-Ion batteries we usually use. I would just stick to one of those packs.

 

[Sci]

Can you tell me more? They have protection circuits already attached & I have the recommended charger for them.

 

[me2cyclops]

you can charge them in parallel but you need to get something to keep them ballanced look for the astroflight blinky to see how they work

 

[Sci]

Ok, that's interesting. The astroflight blinky costs more than the batteries did. Are these batteries safe to use for vaping or charging other batteries individually?

One more question, I've got some regular Li-Ion 900 mAh single flat cells coming, can they safely be stacked(parallel) & used or should I just give up that idea & pull the set from a PCC that I dismantled? I want to make a NicoStick out of a 2x AA battery box that will last all day & then I can plug it in(USB) to charge it. I've got some USB chargers that I have dismantled also. I'm going to try to use the circuitry out of them.

Thanks for the help.