Solar deck connector

stuartwineberg

stuartwineberg

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About to fit 120w rigid solar and want to be able to remove and fold it away so looking at the photonic unit. Don’t really want a deck gland with mc4 or Anderson plugs hanging out and would like to use a deck socket and plug. Short circuit current is 7.4amp open circuit voltage is about 22 and the cable is 4mm single core. Any reason I can’t use a bulgin 2 pin 10amp deck plug. I know I have to cover the panels before unplugging if I use this approach to remove arcing risk.. Not sure if the amperages are ok and whether the 4mm cable would fit the terminals
 
stuartwineberg said:
About to fit 120w rigid solar and want to be able to remove and fold it away so looking at the photonic unit. Don’t really want a deck gland with mc4 or Anderson plugs hanging out and would like to use a deck socket and plug. Short circuit current is 7.4amp open circuit voltage is about 22 and the cable is 4mm single core. Any reason I can’t use a bulgin 2 pin 10amp deck plug. I know I have to cover the panels before unplugging if I use this approach to remove arcing risk.. Not sure if the amperages are ok and whether the 4mm cable would fit the terminals
Click to expand...
I have fitted a pin deck plug for the same purpose. In my case it is out of harms ( ropes) way on the outside of the centre cockpit coaming . I had not considered arcing to be an issue so interested to learn more!
 
pcatterall said:
I have fitted a pin deck plug for the same purpose. In my case it is out of harms ( ropes) way on the outside of the centre cockpit coaming . I had not considered arcing to be an issue so interested to learn more!
Click to expand...
To answer your question, I understand that when you unplug a live socket there is a risk of arcing but with AC that tends to break. With DC the arc can persist and cause damage so you should cover panels before unplugging (I have to say I am just reciting what I have read, I am an electronics numpty). To help me please tell me what power your panels are, what sort of deck socket you used (including its amperage) and the size of cable it takes
Thanks
 
The Bulgin plug is designed to take round flex cable you can't use a pair of single cables. The cable fitted to your panels is also pretty stiff, thick and unwieldy. I would stick a small waterproof enclosure to the underside of the panel and join the two single cables to a 2-core flex.
 
If you have the solar panel connected through a circuit breaker and turn that off first there would be no current flowing and no possibility of arcing. I use a Bulgin 2-pin, but I have swapped the inserts so that the deck fitting has the male pins and the panel has the female receptacles.
 
PaulRainbow said:
The Bulgin plug is designed to take round flex cable you can't use a pair of single cables. The cable fitted to your panels is also pretty stiff, thick and unwieldy. I would stick a small waterproof enclosure to the underside of the panel and join the two single cables to a 2-core flex.
Click to expand...
Hi Paul
I was hoping you would pop up :) Apologies for some very potentially silly questions.. I understand solar cable is very thick and stiff but from what you have just said if I connect it at the panel to - say 13Amp marine grade tinned twin core to go to the deck socket and ditto inside the boat from the socket to the controller I wont have too much in the way of cable losses (about 5 metres total length) and any risk of overloading the cables. This could help a lot as I want ideally to use the victron controller but it only takes 2.5mm cable and the solar leads are 4mm meaning I had to consider moving to a less ideal tracer BN controller. As mentioned 120w panels, Short circuit current is 7.4amp open circuit voltage is about 22 volts. Thanks for your advice.
 
andygc said:
If you have the solar panel connected through a circuit breaker and turn that off first there would be no current flowing and no possibility of arcing. I use a Bulgin 2-pin, but I have swapped the inserts so that the deck fitting has the male pins and the panel has the female receptacles.
Click to expand...
Thank you, good point. Like the idea of swapping the inserts - presumably to remove risk of touching live pins attached to the panel. Its a folding panel so I think just folding it away will kill the current so I should be OK
 
stuartwineberg said:
Hi Paul
I was hoping you would pop up :) Apologies for some very potentially silly questions.. I understand solar cable is very thick and stiff but from what you have just said if I connect it at the panel to - say 13Amp marine grade tinned twin core to go to the deck socket and ditto inside the boat from the socket to the controller I wont have too much in the way of cable losses (about 5 metres total length) and any risk of overloading the cables. This could help a lot as I want ideally to use the victron controller but it only takes 2.5mm cable and the solar leads are 4mm meaning I had to consider moving to a less ideal tracer BN controller. As mentioned 120w panels, Short circuit current is 7.4amp open circuit voltage is about 22 volts. Thanks for your advice.
Click to expand...

2.5mm is borderline in terms of voltage drop, 4mm would be better. You can use 4mm from the panel to the plug and from the socket to the controller, at the controller you can splice a pair of short 2.5mm tails to fit into the controller terminals.
 
PaulRainbow said:
2.5mm is borderline in terms of voltage drop, 4mm would be better. You can use 4mm from the panel to the plug and from the socket to the controller, at the controller you can splice a pair of short 2.5mm tails to fit into the controller terminals.
Click to expand...
Thanks Paul, what would you use to splice 4mm to 2.5mm - would a simple butt crimp and heat shrink do it?
 
Just had a quick shufti at the DC arcing issue. Lots of info ( mainly from down under) and some horror stories about fires etc. The information available mainly related to systems with very high voltages ( typically 600)
When we come down to the sort of voltages we commonly use on yachts the cables would have to be very close to arc ( certainly not across the pins on a plug) There was an interesting video where an arc was formed ( 2 or 3mm separation) and sustained at 110 volts. Quite possibly we should think about damage to the kind of twin core cable some of us are considering.
Certainly an issue to be aware of?
 
dune16 said:
Oceanflex 2.5mm2 twin core says its good for 29amp. Would this be ok for 2 short (1.5m'ish) cables from 2 x 150w panels in series to bulgin deck sockets, the rest of the cable run below deck to controller will be 4mm2 cable?
Click to expand...

With boat wiring amps are rarely the issue, it's usually more a case of voltage drop. If the cables are only 1.5m, 2.5mm cable will be OK. It's also worth noting that if you double the voltage, you halve the voltage drop, so everything from the point you connect in series will have less voltage drop.
 
I have a single 35W solar panel which came with 3m of 2 core 2mm cable attached. This will lead eventually to a duo regulator. It is for trickle charging two batteries on a swinging mooring.
Ideally I want to be able to plug the solar panel cable into a deck/bulkhead fitted socket which is robust and waterproof (even though it will be in a relatively protected location), so I can unplug and remove the panel when not required. Most 2 pin sockets (e.g. Bulgin) seem to be specified for larger cable size (min 3.5mm). Can anyone recommend something appropriate - many thanks.
 
I’m not on the boat but I thought the bulgin were specced for max 3.5 not minimum. You can tighten the screws down to any size and use self amalgamating tape on the cable gland to get a waterproof seal
 
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