Second solar panel and regulator
Submitted: Saturday, Sep 18, 2010 at 21:03
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wombat1
I currently have 2x80 panels roof mounted and this is just under what I need for 100% self sufficiency (miserable multiple days excepted)
I have considered just adding another panel (120) to the roof and using existing built in 20 amp reg however I am now strongly considering the additional panel being a portable one to give flexibility
If I go down this route it will be easiest for the new portable panel having it own reg.as I will not have to break into the van wiring
Will this create any issues??
Reply By: oldtrack123 - Saturday, Sep 18, 2010 at 21:21
Saturday, Sep 18, 2010 at 21:21
Hi Wombat
Should be no problems.
Each regulator will do it's own thing.
Meaning switching points may not be the same on both
One may still be putting in amps when other has stopped
Just make sure you use a nice heavy lead on the portable panel & have the reg as near to battery as possible,NOT @ the panel !!
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Reply By: Mandrake's Solar Power- Saturday, Sep 18, 2010 at 23:06
Saturday, Sep 18, 2010 at 23:06
If your van has some kind of connection to the tow vehicle other than the 7 pin unit for lights etc ( ie an Anderson plug ) - Then you could simply plug a 100 watt kit into it ..
Alternatively you could switch reg that you currently have to an MPPT and gain an extra 20 - 30% input power from your 2X80s ?? that would be the equivalent of 200 watts ( roughly ) ...
Cheers
Steve
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430753
Reply By: Member - John and Val - Sunday, Sep 19, 2010 at 07:44
Sunday, Sep 19, 2010 at 07:44
Wombat,
Think I'd aim to add a connector to one of the existing panels so that you can plug the extra panel in there, simply wired in parallel with the existing ones. Mandrake makes a good point too - by fitting an MPPT controller (assuming that you don't already have one), you will pick up 20+% extra and get close to the rated power from your panels. If you do go for the extra panel, maybe consider fitting it in place of one of the present ones so that an 80W panel becomes the portable one? Swings and roundabouts - you'll get more hours but at a suboptimal orientation if mounted on the roof.
Cheers
John
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Follow Up By: Member - Boobook - Sunday, Sep 19, 2010 at 10:38
Sunday, Sep 19, 2010 at 10:38
I agree this is the right approach John.
If there is a portable panel, you can have a long wire run with voltage drop where it should be, before the regulator.
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Follow Up By: Member - John and Val - Sunday, Sep 19, 2010 at 14:57
Sunday, Sep 19, 2010 at 14:57
A further thought Wombat - We carry 2 panels on the roof rack, one on top of the other. The lower one slides into channels on the rack and that panel itself carries channels which the top panel slides into for transport. In this way the top one is always exposed to available sunlight. When camped, one or both are used as portables. Electrically, the top panel connects into the lower one which connects to the vehicle, with the controller close to the battery. Connections are all latching plugs, easily connected and disconnected. Short cables when travelling, longer ones when the panels are used as portables.
In your case, with roof area for 2 panels, it might be possible to carry your portable panel as we do, on top of one of the fixed ones - saves space, solves a storage problem, and allows it to do its work at every opportunity. Assuming your two 80W panels are the same size, should be fairly easy to do.
If your controller is a simple (non-MPPT) one and is mounted near the battery, you can afford to have fairly long cables, as Boobook says. If though you are using an MPPT controller, important that it be near the battery and best to minimise cable losses by using heavy cables and limiting cable length.
Cheers
John
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Reply By: Maîneÿ . . .- Sunday, Sep 19, 2010 at 11:44
Sunday, Sep 19, 2010 at 11:44
wombat1,
Use the 120w panel as the portable panel, reasoning is you already have the other two connected on the roof, so if there is room for a 3rd panel up there put it up there with them BUT… have it so it is removable quickly and easily to be used away from the others.
This way you still get the maximum current available (120w being higher than 80w) when your parked in the shade and have the 120w panel out in the sun.
(My system is set-up this way, however the portable panel has never been off the roof)
Connect it direct to the existing regulator, I would use a 'quick connection' plug like an Anderson plug (get a different color to the
grey ones so you don't get some helpful soul sticking the wrong cables together) so you don’t need any access to the solar regulator at all.
Use a thick 'extension lead' to eliminate any drop in power between the panel and the regulator.
Maîneÿ . . .
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