PRT-13813 Lithium Battery in Parallel

I was trying to look around and find out if it is possible to put 2 of the PRT-13813 1ah lithium battery packs in parallel to a PRT-14411 charger/booster. Really needing the form factor of the 1ah pack but need a little more capacity

It might work; I would sooner recommend using 2 individual boards, though (set-ups like this usually create imbalanced systems, and weird stuff happens unless you isolate)

Batteries in parallel can be a problem because the voltages are never the same. The one with the highest voltage tries to charge the other(s) which has losses and they all discharged much more quickly than if they were isolated.