I have a bluesolar 75/15 controlling 200 watts of solar into a 550 AH battery bank.
It output rises to 16.5 volts in good sunlight. The voltage has been measured using 3 different meters. It was working fine last summer topping out at 14.4 volts for bulk charging. since then I have renewed the battery bank with 5 flooded lead acid batteries which involved disconnecting all the batteries from the output at once but with the solar panels still connected. What is wrong ?