I have two solar charge controllers each with their own solar array feeding my boat house lead acid batteries in parallel. They are both set to the default 14.4V Absorption and 13.8V Float voltages.
When I look at the levels on the smart shunt through VRM the voltage recorded is always about 0.1 to 0.15V lower during respective charge phases. I just wonder whether the "error" is in the chargers meaning my batteries never actually get fully charged, or if it's in the smart shunt. There does not appear to be any offset calibration in any of the devices to get them all reading teh same against a calibrated voltmeter. The one solar charger seems to fall back to the lower charging phase slightly before the other and I get that there will be some difference between them but I wasn't expecting 0.15 volt difference between them and the shunt.
Any thoughts?
