Bongo Solar

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Tony x
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Bongo Solar

Post by Tony x » Sat Nov 22, 2014 1:53 pm

Not sure which section of the forum this is best suited to....

I've finally finished adding the solar panels to our Bongo, We've had the two at the rear of the roof for a while but have added a third today. Total power is 190 watts in theory.

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The two larger panels are 80 watt from Titan Solar. The size of these is ideal and would still allow roof bars to be fitted if needed. These go to the more efficient MPPT controller below-

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The smaller panel is 30 watt and goes to this controller-

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The square switch by the MPPT controller switches the output of the 2 x 80 watt and 30 watt panels between the leisure and starter batteries. Usefully, it has an off position for when mucking about with the electrics.

A 300 watt pure sine wave inverter sits in the passenger foot well-

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With it's output here-

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A further modified sine wave, 300 watt inverter sits here-

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Voltmeter is here-

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and is switchable between batteries-

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The Bongo has a voltage sensitive split charger. Thus, another relay was added between the two batteries so that they can only connect to each other with the ignition on.

By my calculations, from the pair of 80 watt panels, I could get 50 watts 24/7 assuming 10 hours of solar power at 70 - 75% efficiency. This would half drain the 110 Ah leisure battery overnight (over 14 hours) and then recharge it in the daytime (10 hours) whilst running the 50 watt appliance.

Flat mounted solar panels get hotter than the frame mounted sort. This causes a loss of efficiency. However, for our needs, which are primarily to have reasonable power even in the winter, this isn't so much an issue, especially with the MPPT controller which I gather is particularly efficient with low light.
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Simon Jones
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Re: Bongo Solar

Post by Simon Jones » Sat Nov 22, 2014 3:21 pm

Very smart Tony. I'm looking into getting a 90 - 100w semi-flexible panel to bond onto the rear section of the roof. The plan is to get one with solder connections underneath so there will be no visible wiring and the then the cables will pass through the roof by the hinge with the existing wiring.
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Tony x
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Re: Bongo Solar

Post by Tony x » Sat Nov 22, 2014 5:39 pm

Simon
That would look good. I found such panels hard to come by but they do exist. I'd have settled for white wires and junction boxes but even these were pretty much not available.
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Simon Jones
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Re: Bongo Solar

Post by Simon Jones » Sat Nov 22, 2014 9:23 pm

I was looking around the motorhome show at the NEC and managed to find a camper with the right sort of panel and after chatting to the MD of the company, he said he could get one made to the shape / size to suit which he was quite happy to supply to me. The price for complete kit inc regulator was around £400 but I may just get the panel and source my own MPPT controller. There are cheaper options available but it was one of the better quality panels I've come across.
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Tony x
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Re: Bongo Solar

Post by Tony x » Sun Nov 23, 2014 9:48 pm

Simon,
I looked into controllers a fair bit and settled on this one:-
http://www.ebay.co.uk/itm/25A-300W-MPPT ... 20c01274f2
I went for a 20W version which is a tiny bit cheaper and, I would guess a bit more efficient than the 25W one in the link above.
You have to contact the ebayer to get the 20W version.
You have to be a bit careful. I was told some controllers marked as MPPT are the PWM type.
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Simon Jones
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Re: Bongo Solar

Post by Simon Jones » Sun Nov 23, 2014 9:55 pm

Thanks for the recommendation Tony. I'll contact the seller as the smaller 20A will be fine for my needs.
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