Solar

rtboss1 said:
I have two 100w panels join to the control the output is 18v. However the batteries are only showing 11.7v. When I run the engine this goes up to 13.4v.
Ideas please
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Do you have a controller on the panels? If the battery are significantly discharged the controller might be in bulk mode and will be putting as much amps as possible into the batteries at a voltage which is only slightly higher than the battery voltage.

The alternator is not smart and will put out whatever voltage its regulator is set to.

Richard
 
RichardS said:
Do you have a controller on the panels? If the battery are significantly discharged the controller might be in bulk mode and will be putting as much amps as possible into the batteries at a voltage which is only slightly higher than the battery voltage.

The alternator is not smart and will put out whatever voltage its regulator is set to.

Richard
Click to expand...
Yes, theres a dual controller for both banks.each read the same.both green lights are solid.
 
rtboss1 said:
I have two 100w panels join to the control the output is 18v.
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Do you mean "I have two 100W panels joined to a controller"?
Is the "18V" their rating our their measured output? If the latter, where measured?


rtboss1 said:
However the batteries are only showing 11.7v.
Click to expand...
Measured how and where? 11.7V (from a rested battery) is pretty much flat, although I daresay yours are under some load.

rtboss1 said:
When I run the engine this goes up to 13.4v.
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Sounds like a pretty ancient alternator regulator. Modern ones usually reach 14.4V or so. 13.4V is going to take an age to fully charge your batteries, if it ever does.
 
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We had a smart charger fitted and it controls the charge level and can be set for different charging regimes for different types of battery such as lead acid ang gel which we had for house, deep cycle and engine start CCA.
 
rtboss1 said:
Yes, theres a dual controller for both banks.
Click to expand...

Often dual controllers favour one battery bank over the other, and sometimes only give a small charge to one bank, which would by design usually be the starter battery. Are you sure you have them the right way round? What voltage is the starter battery showing?

Above all: is this a new problem with an existing set-up which used to work? Or a new installation?
 
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Unfortunately for some mysterious reason solar panel controllers are not very reliable, at least compared to most electronics, so this is a likely culprit.

The easiest test is to bypass the controller and connect the solar panels direct to batteries. Ideally monitor the current, but this could be over the maximum permitted for many multimeters. A clamp on multimeter is ideal and has been mentioned this is a great troubleshooting tool to have available.

However, intelligently monitoring the voltage will be enough to tell you if the solar panels are working. You can compare how the voltage behaves with the solar panels directly connected to the batteries verses connected via the controller. My guess is controller is not working at all.

You can leave the solar panels directly connected to your batteries until you purchase a new controller providing you monitor the battery voltage and disconnect the panels when the voltage reaches 14.6v or so. Given the low state of your batteries this will take some time.
 
If your batteries are showing 11.7 amps at rest I'd be looking for new ones.

My rule of thumb is 12.7 volts equal fully charged. 12.2 volts empty, but I can start my 18hp engine on that.

If I leave the boat for a month then my fully charged batteries usually have 12.65 volts on my return.
 
Sandy said:
My rule of thumb is 12.7 volts equal fully charged. 12.2 volts empty, but I can start my 18hp engine on that.
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A reasonable working rule, granted that your 'empty' is about 50% charge, which is as low as most lead-acid batteries should be allowed to cycle. As I mentioned earlier, the OP's 11.7V is close to 100% discharged. They won't like sitting there for long, if they aren't already beyond recovery.
 
Disconnect one panel. Wire the other panel direct to the batteries.

THIS IS THE IMPORTANT BIT.

Arrange the panel so as it is at 45 degrees to the sun.

This will give you a 50w panel. [ For the solar pedants I know this is not exactly correct but who cares ]

You can leave this on forever but over 2 months it should bring the batteries up to near full charge.
 
Hi
I have the two flexible 100w panel on top of the bimini so very little shading .
I have wired both panels together +to + and -to - this goes to a 20A duel controller, input is about 19 v + When I checked before going home the controller was kaput, so I replaced it with what I could find a cheap mono controller.
As all my 3 batteries are Varta silver line 180ah. I wired and connected the controller to all three to keep them all topped up ,my friend who starts the boat once a week has told me the last time he tried it was sluggish to turn over.

What the hell is going wrong and as I need to buy a new duel controller which one is best

thanks
 
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