Hi, I recently upgraded my charging system to Victron Smart solar mppt chargers x 2 (100/15 & 100/30), Orion 30A B2B charger & 30A EHU charger. These charge my Fogstar Drift 300A Lithium battery. My query is with the mppt chargers, the 100/15 is connected to a mono 115w solar panel, the 100/30 to 2 x 140w poly panels. I have noticed that the 115w mppt setup switches to absorption & float while the 280w setup remains at bulk until the battery is around 98% full (amps). I have tried creating a VE.network but the resulting network reverted to the 115w setup so went into float well before the battery had got to the full amp capacity. My knowledge of voltages etc is very limited but I noticed that the 115w setup seems to detect the voltage of the battery as being much higher than the 240w setup. Can the settings be altered so both mppt setups harvest the maximum solar until the battery is full to its amp capacity? Fogstar recommend for Victron chargers 14.2v for absorption and 13.5v for float. I have attached screenshots of the Fogstar & Victron readouts.
Check the 12V cabling of the 100/15, both positive and negative, theres a bad/loose connection or some other contact resistance, possibly in a fuse or circuit breaker somewhere
Thanks, I’ll have a look at it
I’ve checked the wiring, fuses etc and there’s nothing obvious unfortunately 
Is there a difference in the length or size of the wires used by the two solar charge controllers? That much voltage difference is, as chrigu posted, usually a bad connection, bad crimp or bad component. If you have breakers/fuses between the solar charge controllers and the common busbar, switch the breakers/fuses to the other solar charge controller. Do a pull test on all your crimped connections.
Thanks for the advice, I’m heading to a rally on Thursday so I’ll have another look and if I can’t find anything myself I’m sure there’s a couple of the memberswho will be able to assist.