Solar Panel

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gary

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Jun 5, 2004
86
- - Sally Rose
Is there a simple "in line" meter which will tell me if my solar panel is actually sending current to my battery?

Thanx in advance.

gary
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,724
Canadian Sailcraft 36T Casco Bay, ME
twodzusfittings said:
Sunforce 7 Amp Charge Controller from Amazon $17.46 plus free shipping.
Click to expand
Not the best controller. "Shunting" controllers are cheap but very slow to top off batteries... Better to find an inexpensive PWM controller. That controller shuts off as soon as the batteries reach 14.2V it then waits for the battery voltage to decay to 13.0V before turning back on. This can waste a lot of time when you are trying to finish charging the batteries and the controller can spend much of the day disconnected/off.

This is much safer than no controller at all but still not a very good controller.

If you want to know the panels current just insert a DVM set to 10A into the pos or neg feed to the battery bank. Of course this assumes your panel is not capable of more than 10A...
 
Hugh Straub

Hugh Straub

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Dec 8, 2011
172
Hunter 23.5 New Orleans
I bought a cheap marine volt meter, cut a hole in the bottom of a small tupper ware bowl, and mounted the gauge in the hole. I wired the gauge to a male twelve volt cigarette lighter plug. I can easily check charging status of either my solar panel or my outboard alternator by simply plugging in the meter in the twelve volt socket. This arrangement works great and is stowed out of the way after one's curiosity is satisfied.

By the way, I read some time ago that a small solar panel doesn't need a a regulator. My panel is about the size of an ipad and I do not use a regulator. Its minimal output never the less has kept my battery fully charged and the process has not "boiled" off the battery acid. I have been told that regulators can reduce the charge getting from the panel to the battery, and with a small panel, the reduction my be counterproductive. I am not a solar panel expert by any means and I would be interested to read the views of those more knowledgable than I.

Kind regards

Hugh
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,724
Canadian Sailcraft 36T Casco Bay, ME
Hugh Straub said:
By the way, I read some time ago that a small solar panel doesn't need a a regulator. My panel is about the size of an ipad and I do not use a regulator.
Click to expand

The West Marine Advisor says up to 1.5% in amps of your banks 20 hour Ah rating. Other sources tout less than 10%, in wattage, of the banks 20 hour Ah capacity. The batteries in this video, being over charged, are at 0.32% and 0.56% of the West Marine advice and 9.6% and 5.5% of the 10% in watts advice.. Apply the data you find on the net carefully!!!

Keep in mind this takes time, weeks, to get to the point (unattended charging) but eventually the batteries can get full and the current has no where to go so the voltage climbs.

This 12W panel is not much bigger than an iPad.. Can you say cooked......;)

 
Chris14830

Chris14830

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Dec 1, 2007
74
-Hunter -23 Kenora, Ontario, Canada
Hi Gary, This a very interesting discussion on controllers, but to see the actual current from your panel you could buy something like this:
http://www.ebay.com/itm/15A-DC-AMP-METER-Analog-AMMETER-for-WIND-SOLAR-Power-/360586256918

I have not bought this myself. I have installed a shunt resistor in series with the negative post of my battery. It gives me a 1 millivolt reading for every amp going to and from my battery. I hook up my multimeter and can also figure out consumption of various things in the boat (I have shore power for charging).

I was on a large sailboat with a solar panel and ammeter in its circuit panel. It was very cool to watch the charging current with different panel angles while having cocktails!
-Chris
 
Hugh Straub

Hugh Straub

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Dec 8, 2011
172
Hunter 23.5 New Orleans
Maine Sail's video was very interesting indeed. I'd be grateful to know what exactly "cooked" means in terms of how one recognizes a severely damaged battery? Does the acid/ water solution in a lead acid battery boil away? Does the liquid level look normal but the battery just doesn't hold a charge? Sorry if these are dumb questions, but I really would like to understand.

Many thanks

Hugh
 
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