Do turn your solar off while motoring?

[Lifeonalean]

Hi all, I recently installed a solar array on my boat and have found that when motoring, my mppt controllers throw a “battery overload” warning. I asked the guy I bought my solar system from and he said I was supposed to install a switch between the panels and the controllers and I need to turn the solar off anytime I am motoring. I did a lot of research when I was doing the install and I don’t remember seeing anything about turning it off when motoring. Are charge controllers really not capable of dealing with other charge sources? Why does it seem to work fine when I am on shore power?

[Reefmagnet]

News to me. Is it battery "overload" or battery "overvoltage"? Your alternator might not be regulating properly.

[Lifeonalean]

Originally Posted by Reefmagnet

News to me. Is it battery "overload" or battery "overvoltage"? Your alternator might not be regulating properly.

It said “battery overvoltage” and the monitors were showing 16 volts

[sailorboy1]

never turn mine off, the controller senses the alternator charge and just shuts down

[john61ct]

Should be no problem, but sounds like your alt VR is putting out too high a voltage

[motion30]

Dont turn mine of.... the controller's read the voltage and go into float. if you were getting 16 volts at your batteries something. probably need to test your alternator

[smac999]

if your gauge is showing 16v your alternators have problems and you need to get that looked at before you run then again. you will damage things.

[Uncle Bob]

Originally Posted by sailorboy1

never turn mine off, the controller senses the alternator charge and just shuts down

Ditto, never turned mine off in the six plus years it's been on the boat.

[chuckr]

Originally Posted by sailorboy1

never turn mine off, the controller senses the alternator charge and just shuts down

Agree with sailorboy - in 12 years of cruising never turned mine off - we are at 550w - kinda what the controller is for

[Pebbles]

16v is way too high. Your alternator regulator needs setting to your battery specs.
I switch my solar off when I'm on shore power. The reason being that most solar controllers will go into bulk charge for a set time (usually 3hr) every morning. This is putting unnecessary bulk charge into the batteries. They really only need a bulk once a month or so to stop sulphating. You need a specific DC switch that is designed for the DC current that could be following. In my case of used a 6 pole 20amp switch. I switch both positive and negative feeds. I have nearly a KW of solar though.

[piloto]

The whole idea of controllers is.... to control (the charging source GOING THROUGH THEM), thus you should not have to. Turn them off, they’ll simply terminate the charge source they control. What they’re doing is reading voltage on the battery side and showing “overcharge” as a condition, but it would simply be a reading, and the result would be to **** off the charge input that they control (at least that’s what the normal condition would be), so you really shouldn’t have to do any such switch install.

[Group9]

No expert here, but I agree, that sounds like an alternator problem that the MPPT is just reporting.

[belizesailor]

First, find a more knowledge vendor/tech. There is no need to install any switching mechanism for use when motoring. The controller for your solar panels will handle this automatically.

It sounds like to me you have an alternator regulator problem which is resulting in high voltage output from the alternator. 16V will bake your batteries. Fix the alternator regulator issue and your solar controller will stop throwing a warning.

[senormechanico]

Turning off the solar so the controller can't report an overvoltage is like putting a piece of black tape over your car's "check engine" light.

[Lifeonalean]

Thanks for the replies guys, when he told me that I had a hard time believing it because I thought that’s what the controller is for in the first place! Also I’ve never heard of anyone turning theirs off. Looks like I need to test my alternator. Although the alternator never had this problem before the solar was installed. Coincidence I guess?