solar panel install - deck connector or gland ?

[Delfini]

I am installing 2 x 100W solar panel from the port and starboard pushpit connected in series to deliver approx 18v at 12A (max) and wondering how to wire through the deck - I have been advised to use twin 2.5mm round tinned cable (about 7mm dia) and a couple of inline mc4 connectors to connect to the panel and have a preference for a 2 pin bulkhead connector but it would need to be rated 20A and waterproof - is there such a thing ?

The alternative is to take the cable through a deck gland at the base of the rail - but I don't really like the look of the ones I have seen

Any advice or experience of a similar project appreciated

 

[VicS]

Firstly you might like to look at these two links for alternatives to the conventional cable glands

http://www.indexmarine.co.uk/cable-glands.html

http://www.scanstrut.com/products/electrical-accessories

I wish I had known about the side entry glands when I installed my solar panel

Secondly, the cable x section required depends on the cable length as well as current in order to keep the volts drop within acceptable limits. I am not sure how you arrive at 18volts at 12 amps but taking those figures 2.5 mm² cable will only be suitable for a maximum cable run distance from solar panel to battery of about 11 feet. You may therefore need heavier cable .

 

[gregcope]

You may therefore need heavier cable .

Or, under deck, double up the 2.5mm2 or similar. I went with 2.5mm2 from panel to junction box, then 6mm2 to Regulator, and Reg->Batts. However I have recently seen a doubled up install that was quite neat.

 

[jonjo]

I am not sure how you arrive at 18volts at 12 amps but taking those figures

Hmm yes, good point.

What do you reckon he will see on the circuit up to the solar regulator, 36 volts at 5 or 6 amps max?

 

[Bobc]

I used a dry plug.

 

[stranded]

Wouldn't two 100w in series give you more like 36v at 5 and a bit amps?

 

[Delfini]

Wouldn't two 100w in series give you more like 36v at 5 and a bit amps?

yes sorry the two panels in series would give me 36v at 5 and a bit amps - it was late when I posted

@Bobc - What is a dry plug ?

 

[macd]

yes sorry the two panels in series would give me 36v at 5 and a bit amps - it was late when I posted

In which case the cable size you proposed may well be adequate, although that will depend on length of run.

 

[macd]

yes sorry the two panels in series would give me 36v at 5 and a bit amps - it was late when I posted

In which case the cable size you proposed may well be adequate, although that will depend on length of run.

 

[VicS]

yes sorry the two panels in series would give me 36v at 5 and a bit amps - it was late when I posted

@Bobc - What is a dry plug ?

In which case 2.5mm² will be suitable for a cable run of up to about 47 ft

You may be able to use lighter cable if the distance is less. 1.5mm² will be Ok up to about 28ft.


bobc means a "Dri-Plug" They are rated at 10A. I have several on my boat but they do not seem to be as popular as they once were.

The preferred option now seems to be Bulgin Buccaneer plugs

 

[ghostlymoron]

The waterproofness of Bulgins is much better than Driplugs and the plastic used seems more durable. Dri plugs seem to go brittle after a while. I've got all sorts on my current boat.

 

[ghostlymoron]

PS I have a trailable boat so need to take the mast down every year.

 

[simonfraser]

PS I have a trailable boat so need to take the mast down every year.

your solar panel is fixed to the boom / mast ?

 

[ghostlymoron]

My solar is attached to the coach roof and has one of these http://www.indexmarine.co.uk/deck-glands-se-series.php
I have other plugs at the mast foot for VHF, steaming light and wind instrument. These need to be disconnected to allow the mast to be dropped.

your solar panel is fixed to the boom / mast ?

 

[PaulRainbow]

My solar is attached to the coach roof and has one of these http://www.indexmarine.co.uk/deck-glands-se-series.php
I have other plugs at the mast foot for VHF, steaming light and wind instrument. These need to be disconnected to allow the mast to be dropped.

If you will need to disconnect the solar panel annually then you'll be better off fitting a socket/plug. If not, i'd go with a gland.

 

[DannyB]

It's only 36 volts why not just drill a couple of holes and stick a couple of brass studs through with washers and nuts both sides. The panel cable bolts to the top of the stud and the regulator cable bolts to the bottom with ring crimps. Keep the studs far enough apart so there's no risk of accidentally shorting them out. If you can get copper screwed rod, even better.

 

[ghostlymoron]

I thought I'd made it clear that the panel doesn't need annual disconnecting so has a deck gland whereas the vhf, mast light and wind instrument do so are fitted with plugs.

If you will need to disconnect the solar panel annually then you'll be better off fitting a socket/plug. If not, i'd go with a gland.

 

[Delfini]

Thanks all - I think I will go with a Dri or Bulgin plug/socket arrangement - mostly (having now considered further) so I don't get left with a deck gland with no cable in it since I will be using the solar for upcoming passage to Canaries and St Lucia (and back in 2017) and then on and off as plans dictate