I'm reposting my response to another thread in case it helps anyone: I had left my Enertia unplugged for two years and it wouldn't turn on. Took out the six batteries and they were dead, no blinking lights. I used a simple 12 volt trickle charger to wake up each one and each red light started blinking. I then used a Noco genius 2 and charged each one for a day or two up to 50 - 80% but when I put them back in the bike they wouldn’t keep their charge, dropping about 3% per day. I took the batteries out again and charged them individually again all the way to full. Then I connected all the positive terminals with four gauge wire and all the negatives the same. Then attached the positive charger clamp to the first positive terminal and the negative charging clamp to the last negative terminal and charged them all together. This got them all really close to each other on the multimeter readings, around 14 volts. Then I took off the charger and let them rest still parallel for a day and they balanced perfectly around 13 volts. Put them back in the bike and now it charges and runs fine.
