About a year and half ago I became the first person AFAI&DK to test this out for Dave (@Inwo ). He had an old idea on sticking an extra battery between the contactor and the controller and it sounded interesting to me. As a bonus it’s also been a test of a mixed battery system as the GEM it’s installed in has 6 FLA mains and a 4s lifepo pack as the extra battery. It’s been rock solid. Seriously, it’s been flawless. I’ve put a bit shy of 4k miles on it since installing that pack.
Here’s the install and testing thread: