I feel your pain but a lot of us have faced the same kind of issues at one point or another. What I finally decided to do is standardize my battery setups and I have always liked the A123 cells since we had to harvest them from DeWalt cordless drill battery packs.

As I started getting into turbines, they all had LiPo batteries for the ECU so I had mixed batteries in the models and had to pull the ECU battery out to charge. A number of the battery suppliers will build you an A123 pack in whatever configuration you like and I did that with a couple of Warbird gassers where the packs had to be basically buried and not very big. So WrongWay built me some four cell A123 packs using the 1100 mah size batteries in a 2S2P configuration. So I put those in my first turbine but still had a LiPo ECU battery. Same deal for the next models until I finally said okay, I'm going to go all HV and get the same type batteries everywhere in the model. Then I decided on KingTech turbine without knowing they were restricted to three cell LiFe batteries.... UGH!

Long story shorter; since most of the turbines can now use the LiFe chemistry three cell batteries, all but one of the turbines have A123/LiFe batteries everywhere except for the one Behotec engine which still has a LiPo. Makes life easier for us old guys to have the same type batteries in the models.... lol