Solar Panel Wiring (1 Viewer)

May 7, 2013
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On our 2nd MH now a AutoTrail Savannah which we're absolutely delighted with
Just about to order a Solar kit which amounts only to a single panel,controller ,inverter and a MC4 connector
My question is a simple one I think but that could be my senility kicking in!

Do I really need a joint in the 6 mm solar panel cable to the controller as the length is less than 2 metres?
Look forward to your advice.
Thanks Ian
 

tonka

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As above, a lot could depend on how much cable is on the solar panel. Most do only have a short piece....
On past jobs I have cut off the MC4, passing the original cable through the roof gland and then used a connection block once inside to extend the cable down to the controller. Every job is different and will depend on where you are siteing everything.

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Aug 6, 2013
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You do need a convenient method of disconnecting the panel. Most controllers don't like being disconnected from the battery when the panel is still connected.
 
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Lenny HB

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2m sounds a short run, where are you monting the regulator?
The regulator needs to be as close to the battery as possible, size of cable depends on the size of panel, length of run and what loses you are prepared to accept. For a 2m run even 4mm sq cable would be well over the top.
 
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IanF
May 7, 2013
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You do need a convenient method of disconnecting the panel. Most controllers don't like being disconnected from the battery when the panel is still connected.

Thank you I didn't know that
Ian

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IanF
May 7, 2013
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On our 2nd MH now a AutoTrail Savannah which we're absolutely delighted with
2m sounds a short run, where are you monting the regulator?
The regulator needs to be as close to the battery as possible, size of cable depends on the size of panel, length of run and what loses you are prepared to accept. For a 2m run even 4mm sq cable would be well over the top.
Regulator is being mounted about 3 feet off floor behind drivers seat with the leisure batteries on floor immediately below it
Ian
 
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Apr 12, 2010
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I would not be too concerned about "loss" due to longer cables, its miniscule. Use thick cables to the controller, and to the battery. My cables are the orange ones like on a lawn mower, and are about 5 mtrs long. Batteries are always fully charged even in the winter.
Phil
 
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Voyger1010

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Do I really need a joint in the 6 mm solar panel cable to the controller as the length is less than 2 metres?
answer No you don't especially if it's 6mm, as for needing to disconnect the controller had mine for 3 years on last van, never disconnected it once "why would you unless you had a major problem with it" Lots of technical advice on Google if you want to convince yourself. happy motor-homing.

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Lenny HB

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I have 2 x 100 watt panels with a 5 m cable run, I used 4mm cable when panels are producing their max in high summer the loss amounts to 5%, 9.5 amps of a possible 10 amps, in winter panels are only producing a couple of amps loss is only 2% I can live with losing 80ma.
 
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Jul 5, 2013
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as for needing to disconnect the controller had mine for 3 years on last van, never disconnected it once "why would you unless you had a major problem with it" .

The problem comes when you disconnect the solar regulator from the battery(ies) as Tonyidle stated. You would need to do that if, for example, you wanted to work on the 12V system or if you wanted to replace the battery. I have a Schaudt Electroblok and solar regulator and the instructions are clear that the load to the regulator from the panels must be off before you disconnect the batteries. I have solved it by fitting an in-line fuse on the positive feed just before the regulator and it is then a simple job of pulling the fuse.
 
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IanF
May 7, 2013
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On our 2nd MH now a AutoTrail Savannah which we're absolutely delighted with
The problem comes when you disconnect the solar regulator from the battery(ies) as Tonyidle stated. You would need to do that if, for example, you wanted to work on the 12V system or if you wanted to replace the battery. I have a Schaudt Electroblok and solar regulator and the instructions are clear that the load to the regulator from the panels must be off before you disconnect the batteries. I have solved it by fitting an in-line fuse on the positive feed just before the regulator and it is then a simple job of pulling the fuse.
Thank you for this really helpful and informative response
Ian

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Voyger1010

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I have solved it by fitting an in-line fuse
Absolutely correct, but some people choose to install a fuse to the -ve cable or a blocking diode to prevent overnight discharge, but with most modern controllers, this is not entirely necessary. In addition you could always cover the panels with a blanket to make sure they don't see the daylight, lots of different ways to work on the 12v system if you need to, without needing a joint in the cable.
 
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Aug 6, 2013
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answer No you don't especially if it's 6mm, as for needing to disconnect the controller had mine for 3 years on last van, never disconnected it once "why would you unless you had a major problem with it" Lots of technical advice on Google if you want to convince yourself. happy motor-homing.
Perhaps if you needed to replace the leisure battery?
 
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