Wiring up solar panels

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Cappen Boidseye

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I have just recieved from Amazon, a 130w flexible solar panel. It cam with the appropriate clever metal box which controls charge rates etc. There are diagrams showing the panel, the battery, the load and the clever box. Great so far. However, I have the added complication of the alternator to consider, as well as the fact that the domestic batteries and the starter battery are on their own respective breakers.

I seek guidance from the great and the wise; how do I plumb the panel in to my boat? I don't see a need to top up the starter battery, it always seems to be well charged, so it is only the domestics I want to top up with the panel (BM1 battery monitor also installed by the way).

The diagrams just show the panel wired into a set of terminals, the battery wired into the centre terminals and the load wired into it's own terminals.
 
Cappen Boidseye said:
I have just recieved from Amazon, a 130w flexible solar panel. It cam with the appropriate clever metal box which controls charge rates etc. There are diagrams showing the panel, the battery, the load and the clever box. Great so far. However, I have the added complication of the alternator to consider, as well as the fact that the domestic batteries and the starter battery are on their own respective breakers.

I seek guidance from the great and the wise; how do I plumb the panel in to my boat? I don't see a need to top up the starter battery, it always seems to be well charged, so it is only the domestics I want to top up with the panel (BM1 battery monitor also installed by the way).

The diagrams just show the panel wired into a set of terminals, the battery wired into the centre terminals and the load wired into it's own terminals.
Click to expand...

Wire the panel to the controller.

Wire the controller output to the domestic battery positive, incorporating a suitable fuse as close as practicable to the battery, and to the end of the BM1 shunt that is NOT the end connected to the battery negative.
The panel will then charge the domestic battery and it will be monitored by the BM1

Ignore the 'load' terminals unless you want to use whatever features they offer. Sometimes they can be used to supply an appliance such as a fridge which you would want switched off before it runs the battery flat. Sometimes they are intened to switch lights on at dusk and off at dawn.
 
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OK you can ignore the Load terminals on the controller. They are for use with something like a fridge where low voltage battery will cut off the load. If you want to sue this feature you disconnect your fridge (or perhaps bilge pump) from its present supply and connect to the clever box. If not then no connection to the load terminals.
The solar panel connects to the approriate terminals and the battery terminals go direct to the battery terminals. If the "box" is remote from the batterey then a fuse in the positive line to the battery is desirable. This will protect that wiring from battery to box which could find a short circuit one to the other and so start a fire. If you are confident these wires won't be shorted (check the terminals at the box, if the wiring is short and not touching anything that will burn if the wiring gets red hot then you may omit the fuse. Thhe fuse rating should be 10 amps or more as should the current rating of the wire. Note the box will contain a didoe so current can not flow from the battery to any fault in the panel or wiring so only the batteery to box wiring is of concern the panel itself can only genrate 6 amps so can not cause a fire.. good luck olewill
 
Without knowing what clever box you have it's difficult to answer but on my boat the panel is wired through a not so clever box straight to the battery. The alternator is ignored; it just charges in parallel with the solar panel.

Just check that your clever box is not one of the regulators which are designed for street lights. They are intended to switch the load (i.e the light) on only at night leaving the panel to charge the battery during the day. Not much help if you want to use your electrics during the day. It's not a irretrievable problem but does affect how you wire it up. The paperwork should make it clear.
 
Cappen Boidseye said:
Thanks guys, battery contacts in parallel with the alternator etc. it is.
Click to expand...

But note the correct connection of the negative is as I describe above in post #2 , not directly to the battery negative, or the battery monitor will not register the current from the solar panel

Now to find a weatherproof 10 amp connector to take the currents out of the panel and into the boat.
Click to expand...
Personally for a solar panel I have used a cable gland , or are you intending to make the solar panel a removable item.
 
The panel is flexible, backed with adhesive film, I intend to stick it to the boat roof and leave it there until it needs replaced, so a through deck connector was the first thing I thought of, hadn't even considered just gunking up a hole. I will look at the connectors suggested.
 
Cappen Boidseye said:
The panel is flexible, backed with adhesive film, I intend to stick it to the boat roof and leave it there until it needs replaced, so a through deck connector was the first thing I thought of, hadn't even considered just gunking up a hole. I will look at the connectors suggested.
Click to expand...

No point what so ever in having any form of plug and socket then.

My first panel in fact had the cable exit on the back. It just went through a hole sealed with silicone.

New panel has the cable connected to a junction box on one edge. With this one the cable goes through a cable gland.

This type of cable gland will make a neat, nearly flush installation. not expensive either. I wish Id known about them when I fitted my current solar panel

170067.jpg
... http://www.force4.co.uk/9695/Index-Marine-Side-Entry-Cable-Gland-for-2-7mm-Cable.html
 
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A quick "further to";
Assuming the panel will fit in either orientation, what do you reckon will be the best position to attach the panel to the cabin roof of my boat, I am hoping the panel will go either fore and aft, along the port side of the cabin roof, central would be good but I think the hatch is going to prevent that. In this position the panel will be fairly flat, just angled slightly to port and will be to port of the boom when it is at rest.
My other idea is to have the panel attached to the cabin roof just aft of the mast and running side to side across the boat, as long as the panel isn't too long it would sit over the curve of the cabin roof.
I can't actually check the panel measurements against the boat roof at the moment thanks to an errant knee so this is just some speculation and cogitation while hoping my knee gets better without surgery.
Any thoughts are welcome!
 
What RM says least amount of shadow.
My boat has a flat, sloping front to the cabin roof. That makes a very good spot with no shadows from mast and boom, just a little from the foresail reefing spar. Limits the size though.

You would probably have been better off with two smaller panels wired in parallel .Too late now!

Verl 27 ???
 
As the panel has an adhesive backing, could it be stuck to a sheet of plywood so that it could be more conveniently mounted and removed if required?
 
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