marrying batteries?

[Waddle]

I have recently purchased a couple of parallel dual 18650 regulated mods. I also have an Opus BT-C3100 battery charger which can tell me the internal resistance (IR) of the batteries. Now before anyone tells me I should buy new batteries, please understand that I already have about 20x 18650 batteries. I'd really rather not buy any more batteries at the moment unless I have absolutely have to.

What I'd like to do is find sets of similar IR rated batteries using my charger. Since I will be using them in parallel can anyone give me a good reason why this might be a bad idea?

 

[sonicbomb]

Marrying from new is ideal. But as long as they are the same chemistry and spec eg. CDR and mAh and are kept together and chargeed together from that point I don't think it's such a huge deal. As far as I know parallel or series makes no difference.
Perhaps @Mooch can chime in?

 

[Mooch]

For parallel, decently matched capacities and internal resistances is good to have to extend the vaping time you can get from them. This assumes both batteries can otherwise handle the current you'll be drawing from them.

Since they're in parallel they cannot diverge in voltage, like what can happen in series, so marrying is much less important.

 

[Waddle]

For parallel, decently matched capacities and internal resistances is good to have to extend the vaping time you can get from them. This assumes both batteries can otherwise handle the current you'll be drawing from them.

Since they're in parallel they cannot diverge in voltage, like what can happen in series, so marrying is much less important.

Thanks Mooch! They are in fact all Samsung INR18650 25r batteries. Some of them are a little old but the internal resistances are still quite low due to frequent rotation. Both the mods I bought are only 100w and I won't be running them over 50-60 watts.