12v electrics dilemma

Hi. When I bought my boat in May, I changed it from 240v to 12v. It did have one very small solar panel. I employed a marine electrician and he installed 2 x 260 watt solar panels, 2 agm batteries, Enerdrive MPPT, inverter & installed a couple of plugs & USB ports all up costing $7,000Aus
On Tuesday, my Waeco fridge freezer stopped working. The volts had dropped to 11.6. I disconnected it. We’d had a few cloudy days but I don’t watch tv or use much power except for a light & phone charging.
The next day didn’t improve. I phoned the electrician & he asked me to turn the switches off on the enerdrive & turn back on. It showed e4 which is no power coming through. He came Thursday to look at it & the solar wasn’t coming through. After he left, I lost power to the radio, saloon lights & deck light. The lights working in v berth, midship cabin & head were working.
Does this mean there are 2 systems operating? He is very busy & i’m Not sure when he will be available. I will call Enerdrive tomorrow for assistance as it’s not working. At the moment i’m On a friend’s jetty & using their power to charge batteries. Any advice will be greatly appreciated. Sue

Are your lights LED or incandescent? Incandescent can use a lot of power. So can a fridge/freezer. You have 520w of solar that will charge your batts at that rate on a clear day for a few hours, but with low sun or clouds the input to the system will be much less.

Maybe there is a fault in his wiring causing no charge. But maybe you are using more watt hours than the solar is capable of providing over a normal day.

You need to get familiar with the term watt hours on such a system.

The lights are LED. I would’ve thought I could run a 50l chest fridge with 100amps per day? I live in a normally very sunny climate on the Gold Coast in Australia. Maybe it is the wiring. Thanks

"I would’ve thought I could run a 50l chest fridge with 100amps per day?"


Fine with endless sunny days .

You should investigate a SOC meter . State of Charge , like a gas gauge for your battery bank.

Not nearly enough battery capacity, to start. You also cannot allow them to be completely discharged, 12.2 Minimum on FLA and pretty close to that for AGM.

Sorry, not much help.

Using the existing wiring presents the problem of overloaded wires.

An amp at 240V ( V x A = W ) is 240 Watts.

240W divided by 12V is 20 amps ! .

The wire installed to power the electrics may be WAY to thin.

No power coming in from the solar panels could be a blown fuse. All solar panels should have a fuse. Even on cloudy days solar panels will produce a small amount of electrical current.


If somethings work and others not, while the batteries are essentially dead, leads me in two directions, blown fuse for things that are not working or too little power, and that there's a possibility that the things that are working may be wired into the engine start battery.