I have started to work on going RC with Piko’s key fob remote style RC kits. The question I am running into is working with batteries up until this point I have stuck with RC car style batteries which are basically shrink wrapped AA, AAA, or C cell batteries that are NiMh. I usually have added a charging socket so I don’t have to disassemble the entire locomotive to charge. But I am now working on some smaller British Gauge 1 tank locomotives (a1x Terrier) and the commercial battery packs are right at the top size I can tuck into the boiler and side tanks. Is there a way to string single batteries together AA or AAA to basically be able to charge them as a pack or would the difference in battery cell potential prevent this?