New system questions

[Smiddyt]

Hello, I just recently set up my system in middle Tennessee, (details below) and have some questions about the reading I am getting. Electricity was double the price of what I paid for my system. My charge controller seems to be all over the map on what I am getting in and what it is putting out. At night when it is cloudy I usually get 14v in, during the cloudy days I get 80 -96 volts in, 107 on sunny, and the battery voltage reads anywhere from 48.7 - 60.2. I did the SG test on my batteries after the system was online for a week (during the day) and the readings were 1.240 to 1.265 on the different batteries. It was 40 degrees at the time but had been in the single digits for the 2 days before. When I subtracted 0.016 for temperature I got 1.224-1.244 which the chart tells me means my batteries are at 75% charge. I took a volt meter reading on all of them and they all were at 7.2 or 7.1 volts. How can I be at 75% charge if I am reading 7.1 volts on a 6 volt battery? This weekend I will wire in a plug so I can hook up my generator to make sure I have a full charge because it has been cloudy for 4 days. So far all I am running is some led lights and TV/satellite DVR but hope to add a converter deep freeze soon for a refrigerator.

6 280 watt panels in 2 3 panels strings, Midnight Classic 150 charge controller, Magnum 4400w 48v Parallel Inverter, 8 Crown 6V Flooded - 395 AH L16 Batteries

Thanks

[emartin00]

Are you measuring the voltage when they are actively charging? If so, you are really reading the voltage that the charge controller is putting out.
I don't know a ton about off grid, so that's about all I got for ya.

[Mike90250]

Welcome.
In average conditions, you can expect 1344 watts from your panels. In a good 4 hour solar day, you could harvest 5 KWh or so, and you can use about half of that for your daily loads. (2,5KWh)


Charging at 59V, you could get 22 amps. That's about half of what I would want charging 400Ah of battery bank..
So, unless your daily loads are really lightweight, you can expect some problems being undercharged.


The way batteries charge, the BULK cycle takes them up to the ABSORB voltage, They are held in ABSORB for at least 2, and sometimes up to 4 hours, This gets them about 95% charged. FLOAT actually finishes charging them, But often, there is not enough sun to get through all stages, and batteries suffer. Then you must either reduce loads till they get charged, or run a generator in the morning to perform the BULK stage and let solar do the Absorb and float stages.

Your Classic controller is very adaptable and you need to get your recommended battery Mfg settings set into the controller, either via the front panel, or using the Local App and your computer.