A2B Metro- Lemon or worth putting time & $ into?

[EChris]

I'm Chris from Largo Fl. I've been a mechanic for over fifty years and have been pedalling a bike half that long. I've built a few kit bikes and purchased a couple used ones and got them going for a reasonable amount of time and money. Now the A2B Metro comes into the picture. Gen one upgraded. I'm almost sure the main and aux batteries haven't been replaced but with 25k miles, I'm not so sure. Both batteries take a charge but the main one depletes it's juice in a matter of a few blocks and I can't get the aux one to switch on. It tests 40 volts at cables but only 12volts at connector and drops to 3 volts when power button on case is switched on. I saw a Li-po replacement video on YouTube for the frame batt but was pretty vague. I'll keep looking for a cheaper approach than new or refurbished which has been in the $400-$500 range. It's nice to have a place with knowledgeable enthusiast's to bounce things of of. Any input will be greatly appreciated. Thanks guys, C.L.