Solar Panels - wiring.

[Chris_Robb]

I am installing 2 x 85watt solar panels. Each will have their own pair of 6 sq mm cable, which should be more than adequate back to the regulator. However, I want to make them removable when the boat is left for longer periods (£1000 of panels sitting on a boat), so will I loose much current/voltage if I use deck plugs to unplug the units or is the loss so small as not to worry about?

I usually seal deck plugs with self amalgamating tape to try to ward off corrosion. The question assumes that I will keep the plugs corrosion free.

 

[nimbusgb]

Ouch! I installed 2 * 85 watt panels, £480 for both!

You would probably be better off fitting plugs and sockets right at the panels.
* There is already a connection to be made at the panel so soldering that one to a socket means that you wont be introducing another junction in the wiring.
* If you run the tails up inside any steelwork you wont have to reroute it each time.
* Carrying a 1 metre plus by 1.2 metre panel around is enough of a pain without 3 or 4 m of cable attached and long tails place loads on the junctions.

 

[alan]

I bought some waterproof plugs and sockets from Index Marine, and fitted the socket on the connector box that was already on the panel. The plug has a waterproof srew-on cap, so that when the panels are removed are just leave the plugs "taped" to the guard rails. The plugs and sockets were not cheap but seem to be waterpoof so far!! By the way I have Kyocera panels which have a large junction box on the rear, so fitting the sockets was no problem.

As for volts drop across the plug socket: this should not have any affect. The panels probably output around 17 to 20 volts, and then go to your regulator which drops it to around 14.4 volts or so. So a small drop at the plug/socket will not be a problem.

Alan.

 

[Anonymous]

They are big panels. I have 2 x 185W. I am an electronics engineer and even so underestimated the volts drop in the system, through the cable and controller so re-wired using 'alternator cable' (I forget the mm2). I wouldn't put any plug/socket in the circuit. If you MUST demount the panels consider using a good quality brass heavy 'chocolate block' suitable for 30A or so, tin the ends of all the wires and make up the joint each time, sealing with amalgamating tape. Cut the tape off with a sharp knife to demount. Any plug and socket will cause you grief and fail after a season.

 

[noelex]

Google Andeson plugs.
They come in several sizes. They have large silver plated contacts. I used them on the 80w solar panels on my previous boat with no problems.
If you are concerned leave a little extra length to the cable and renew the connectors if they show signs of corrosion, or if you are getting any voltage drop. They are not expensive.

 

[William_H]

Plugs and sockets in themselves should not be a problem of volt drop. Thet just need to have a large contact surface area, It is common on aircraft to plug in ground power for engine starting 1000 amps plus but they are big plugs.
For your solar panel you might look at the AMP crimp connector joiners like knife connector or handshake connector. Connecting each wire individually.
good luck olewill

 

[rogerdog]

I would use a deck fitting to take the cables inside, small loop in cable to guard against drips coming down the cables and then as already correctly stated (IMHO) brass terminals and tin the ends of the wire - very reliable - unlikely to to corrode and almost no voltage drop. (I used domestic electrical junction boxes on my wind gen when redone - and some Vaseline to help ward off corrosion)

PS agree with use heavier wire than expected to reduce power losses to a minimum.

 

[Chris_Robb]

Thanks all for those ideas, lots of help. So now to plan the job!