MPPT solar charger positioning?

Submitted: Tuesday, Apr 22, 2014 at 10:56
ThreadID: 107401 Views:1463 Replies:3 FollowUps:5
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Hi all

Recently I purchased a 220w solar kit from Bit_deals on Ebay. He(?) was recommended to me by various other forum members and I have to say, I'm really happy with the shipping time, price and product. Would recommend to others.

Here is my question. The solar panel comes with a MPPT charger siliconed to the panels and then a 8m lead with alligator clips that are meant to be run to the battery.

Is it worth peeling off the MPPT from the solar panel, extending the cables and remounting it right near the battery to reduce the 8m of voltage drop?

Regards,

Damien
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Reply By: Ross M - Tuesday, Apr 22, 2014 at 11:39

Tuesday, Apr 22, 2014 at 11:39
You won't alter the voltage drop which is present in the line, but by having the MPPT near/close to the battery, it will receive the energy and make the switching process more efficient.
It will then sense the actual voltage of the battery and supply and regulate accordingly and not have a length of resistance/wire to slightly reduce the output given to the battery.
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Follow Up By: John and Regina M - Tuesday, Apr 22, 2014 at 14:34

Tuesday, Apr 22, 2014 at 14:34
And you will void the warranty.
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Reply By: Whirlwinder - Tuesday, Apr 22, 2014 at 15:16

Tuesday, Apr 22, 2014 at 15:16
Damien,
I too bought a folding solar panel set from them and it works a treat BUT you need to pop rivet the hinges and clips and maybe tidy up the leg hinge points a bit.
I connected a 50 amp Anderson plug to the output regulator and have another one on the fridge battery in the front. I have a 10 m 50 amp Anderson lead and so i can connect to either the front or the rear socket. Gives better options for keeping the L/c in the shade and the panel in the sun.
Ian
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Follow Up By: neimad19 - Tuesday, Apr 22, 2014 at 15:37

Tuesday, Apr 22, 2014 at 15:37
Thanks for the heads up on the hardware upgrade.

So you didn't bother with trying to relocate the regulator closer to the battery?

Does the solar panel off set the Ah usage of the fridge?
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Follow Up By: Whirlwinder - Tuesday, Apr 22, 2014 at 15:55

Tuesday, Apr 22, 2014 at 15:55
I have a 80 litre Waeco and the nominal 140 watt panel (actually more like 110-120 watt) easily keeps up even on a not perfect day.
I should have told you I bought from ABR Sidewinder a digital volt, amps and watt meter as well which I fitted with Anderson plugs. I connect it between the solar panel 10 metre cable and the battery. It shows the amp hours going in to the battery at that instant and also the total since you connected it. I regularly get around 7-8 amp/hours. great value at about $45 + 2 anderson plugs. It will also read the amps going out of the battery if you turn it end for end. Handy to check what the fridge etc is actually pulling.
Don't you just love Anderson plugs.
Ian
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Reply By: Member - Bruce C (NSW) - Wednesday, Apr 23, 2014 at 09:03

Wednesday, Apr 23, 2014 at 09:03
Hi Damien,

Locating the regulator closer to the battery is a good idea, however,........

While I have never removed a fixed regulator from one of Bit Deals solar panels to have any firm knowledge of the procedure, I would advise against trying to remove the fixed reg unless you have had a lot of experience doing so.

I think you might/could end up damaging the panel.

I would leave the existing reg in place and get another one and locate it where you want, then bypass the existing reg with the utmost care.

It may be a lot cheaper in the long run.

Use anderson plugs for main connections everywhere and in this way your options open up.

Cheers, Bruce.
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Follow Up By: Member - John and Val - Wednesday, Apr 23, 2014 at 11:56

Wednesday, Apr 23, 2014 at 11:56
Hi Damien,

I agree with Bruce. There is quite some risk of doing permanent damage if you try to remove the existing regulator from the panel. If practicable, I'd aim to get to the input side of that regulator, disconnect it and attach your cable at those points. MPPT controllers are now affordable and work much better close to the battery. (Controllers monitor battery voltage and aim to maintain the correct charging voltage. If there is a significant voltage drop between controller and battery, as there is when they are separated by a long cable, the controller is unlikely to fully charge the battery.)

A bit of an aside - flexible panels are light and thin so good to carry, but can't be free standing like solid panels. Solid panels are big and heavy. Has anyone had a go at mounting flexible panels on a light, thin backing such as say 3mm sheet plastic/perspex or similar? This would be light and easy to handle, yet can be easily deployed for maximum sun capture.

Cheers

John
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Follow Up By: Member - Rowdy6032 (WA) - Wednesday, Apr 23, 2014 at 18:59

Wednesday, Apr 23, 2014 at 18:59
Hi

I have removed the regulator from the Bit Deals 140 panel. It wasn't really a problem. I just used an old fishing knife with a very flexible blade. Most of the sealant is around the edges with a blob or two under the regulator. Just slid the blade around the edges and under the unit to remove it.

The regulator and panel was fine.

I then used the regulator near the battery and it worked fine, couldn't really tell if it made any difference.

As the regulator was only a cheapie I have recently replaced it with a Victron MPPT 70/15. Don't know how much difference it will make but in theory all should be good.

Regards
Rowdy
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