Solar panel-battery saver

[Newboy]

Just gone and tried to start my outboard and the batteries are as flat as a glass of week old cola .

 

I bought a solar panel before I went on holiday and thought that would top up the batteries while I was away (well, obviously not ).

 

So where did I go wrong? I left the battery switch on 'all' and with the panel plug into the cigarette lighter plug. The red led 'flashes' and I presumed it's working. I must admit the panel doesn't see any direct sunlight, but then it should still have worked.

 

 

[Afishionado]

I am not an electrical expert so others may come up with more esoteric answers but............

You may have a small leak to earth which has drained the battery. If leaving the boat for some time I would disconect the battery entierly from the boats system.

 

Also I do think that the more SUN light the better the panel will perform. Indirect light may not create enough power to break the battery's natural resistance to current flow.

 

Mad Mike

 

Ps What about a mains powered trickle charger on an extension lead?

[Bob F]

Ken,

 

I assume you were only on holiday for a couple of weeks or so. In which case, your batteries should not have gone flat, even without the solar panel running.

 

As Mike says, you may have a small leak to earth, but most probably you will find that something was accidently turned on.

 

Having said that, the solar panel will need to get direct sunlight to work efficiently. You never know, it might have been the flashing red led that ran down your batteries.

 

BF

[Newboy]

It was 4 weeks since I last started the outboard. All the electrics work, but just haven't got enough juice to turn the starter motor on the outboard. I think I'll just use my battery mate to charge the batteries once every other weeks just to be sure.

 

Before I had the solar panel I'd left the boat for about 3 weeks but without any problems. I did turn the batteries to off before that. To add insult to injury, to be able to connect the solar panel, I had to plug in the ciggie lighter plug which has a red light ......... maybe it's the light which drained the batteries.

[Bob F]

Ah, so the batteries weren't completely flat.

 

In which case, I think I know what the problem is. You mentioned that the panel is not in direct sunlight. Solar panels can actually drain a battery if they are not getting sufficient light. At night, for example, they will start drawing current from your battery.

 

Try to see if your solar panel has blocking diode fitted to it. Cheap ones may not have one fitted. They stop the current being drawn back into the solar panel.

 

BF

[Afishionado]

Well blow me down Bob.

I was going to make a joke about the solar panels glowing in the dark sorta reverse osmosis thing.

 

I never even thought that they could actualy do that without a blocking diode..

 

As the man said ........"you live and learn"

 

Mad Mike

[Adam F]

Kam - something is obviously not right. I leave my batts in the 'ON' position all the time, and leave the Solar Panel plugged in - I dont know whether the panel has much effect or not, but I have never had a problem with low batts.

 

The 100hp on Sweet Honey is a big old girl though - I suspect that she draws a lot when turning over from cold. My old 50hp did, and occasionally I would struggle - the new one however has no probs.

 

My panel is mounted in a clear PVC sleeve on the Tonneau cover, which means is is always facing more or less towards the sun.

 

Adam

[Newboy]

I keep mine in the wheel house, and where the boat is on the drive, it only see sunlight for a couple of hours in the afternoon. Maybe it's the lack of sunlight, I don't know, but I think I will plug in the charger once a week/2 weeks just to top up.

[Paul D]

Ken,

 

I think Bob's expanation is the most likely problem. You need to get a solar panel with a blocking diode ( or a blocking dioide for your solar panel ), since they will drain the battery when there is little/no sunlight

[Bob F]

Ken or Kam (which is it? you seem to use both names),

 

Again, you need to check if you have a blocking diode in line with the +ve lead.

Even if you move the panel into direct sunlight the panel will still draw power from your battery during the night. And with daylight hours being much shorter during the winter months, the situation will be worse.

 

If you don't have a blocking diode, go into Maplins and they will advise you on the type of diode you need and how to fit it. It will be less than

[Newboy]

Officially it's Kam, but I've been using Ken since I was a littling so it's both really.

 

I think I will try all the above and see if it improve, thanks everyone.

[sean]

To establish if your system is using power when everything is shut down. Disconnect the negative battery connection and put a small wattage bulb between the battery terminal and the disconnected negative connection. If the bulb is on you are drawing power, as long as you battery has some life in it.