Andrew Bayly

Sounds totally like a pre-charge issue to me. I know that 1 x Pylontech US2000 won't start a Mutiplus 48/3000 without pre-charge, so there's a good chance that 1 x US3000 wouldn't start a Multiplus 48/5000 without pre-charge. It's not hard to rig up a pre-charge circuit. I used, I think, 2 x 10 Ohm, 10W ceramic resistors in parallel to give 5 Ohm, 20W. I then connected them in the positive line of a secondary power supply to the multi (I used 4mm^2 solar cable) and ran this through a 25A double pole DC breaker (the pre-charge switch). Just turn the pre-charge switch on a few seconds before closing the main battery fuse/switch ...and remember to then turn the pre-charge off again!