Like a lot of people I recently developed trouble with the temperature warning light flashing on on Multiplus 24/3000/70. When charging the batteries (2 x 240 ah lead acid) from about 75% charged the input amps (according to my BMV712 ) are about 50 amps and the unit displays "Bulk". After about 2 minutes the battery warning light flashes on and the charge drops to zero. A few seconds later the temp warning light goes off, the charge slowly returns to 50 amps. A minute later the temperature light flashes again, charging drops to zero, temp light stops flashing, and charge creeps back up to 50 amps. It will keep doing this until the unit switches to "absorption", delivering about 30 amps, which stops the temp light coming on. The pattern happens regardless of whether it is switched to inverter on or charging only. I have tried it having rested the machine overnight. I am in north Netherlands at the moment so ambient temps not a problem. I have removed the unit from the cupboard and put a fan against it, but no change. I charge with a 7kva generator, with a stable sine wave. The system has worked well till now.
We are cruising and hoping the unit does not need to be sent away for repair.