Solar Regulators, Again

Submitted: Wednesday, Dec 23, 2015 at 21:29

ThreadID: 131191 Views:2307 Replies:4 FollowUps:14

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Member - Ross N (NSW)

I put my solar panels on my aux battery today test some reconnections I made and found that there was 17volts reading on my amp meter
This seems high.
The panels are 160's and have a controller which states 10 amps output at 12 volts
Any comments would be appreciated
Ross

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Reply By: Frank P (NSW) - Wednesday, Dec 23, 2015 at 21:42

Wednesday, Dec 23, 2015 at 21:42

17 volts on your amp meter? Maybe you meant multimeter.

Anyway, if the meter was in the volts configuration, where were you measuring the volts? Sounds like it was at the solar input to the regulator, in which case 17 volts would be about right.

If you did the same test at the battery connections to the regulator you would get a lower reading, maybe 12 to 14 volts or so depending on battery state of charge.

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Follow Up By: Allan B (Member, SunCoast) - Wednesday, Dec 23, 2015 at 22:56

Wednesday, Dec 23, 2015 at 22:56

..
Where's Mainey when you need him?? lol

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Follow Up By: Frank P (NSW) - Wednesday, Dec 23, 2015 at 23:33

Wednesday, Dec 23, 2015 at 23:33

A bit before my time, Allan.

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Follow Up By: Member - Ross N (NSW) - Thursday, Dec 24, 2015 at 05:00

Thursday, Dec 24, 2015 at 05:00

Sorry Frank, meant multimeter.
Voltage reading was at the battery with no load but solar panels connected via regulator
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Follow Up By: Allan B (Member, SunCoast) - Thursday, Dec 24, 2015 at 10:23

Thursday, Dec 24, 2015 at 10:23

You missed 'Mainey' Frank? Ahh, the best bit of entertainment this site ever had!
He was largely misunderstood and went off to another forum.
But he meant well.

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Follow Up By: Member - Boobook - Friday, Dec 25, 2015 at 12:15

Friday, Dec 25, 2015 at 12:15

Gezus Alan you just give me a xmas migrane.

And here is an irrelevant picture to prove it.

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Reply By: Member - Phil G (SA) - Wednesday, Dec 23, 2015 at 22:47

Wednesday, Dec 23, 2015 at 22:47

If your controller is a 12V/24V with automatic voltage detection, then you have to hook it up in the correct sequence:
Load first.
Battery 2nd - so the controller can tell whether it is a 12V or 24V battery
Solar Panels 3rd.

If you connect the solar panels before the battery, you will easily get 17V

Also I'm assuming your regulator is bigger than 10A - just the way it reads on your post.

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Follow Up By: Member - Phil G (SA) - Wednesday, Dec 23, 2015 at 22:49

Wednesday, Dec 23, 2015 at 22:49

Just to be clear, the regulator will think you have a 24V battery if you connect the solar panels before you hook up the battery.

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Reply By: Member - Phil G (SA) - Friday, Dec 25, 2015 at 01:01

Friday, Dec 25, 2015 at 01:01

Are you there Ross?

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Follow Up By: Member - Ross N (NSW) - Friday, Dec 25, 2015 at 10:17

Friday, Dec 25, 2015 at 10:17

Sorry PHIL, been a bit distracted.
Excuse my ignorance of things electrical but wouldn't the solar panel pump in more than
17V if it thought the battery was 24V.
I connected the solar panel with it's built in or attached regulator to the battery with alligator
Clips and within minutes the reading was 17V.
I don't understand how I could connect the solar panel after connecting the battery.
Merry Christmas
Ross

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Follow Up By: Member - Phil G (SA) - Friday, Dec 25, 2015 at 11:49

Friday, Dec 25, 2015 at 11:49

Merry Xmas Ross!
The solar panel might put out say 21V but as soon as it is connected to a battery, the battery accepts all the current from the panel and the voltage measured at the battery drops. If you hit a 12V battery with the 21V from the solar panel the battery will accept the current and will boil.

My caravan has a 12/24V solar regulator. I disconnected the battery to do something, then hooked up again and saw 17V on the gauges, which told me something was wrong. I disconnected the battery then read the manual and the fine print tells you that the battery must be connected to the regulator before the panels, otherwise this will happen.

What model regulator is yours?

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Follow Up By: Member - Ross N (NSW) - Friday, Dec 25, 2015 at 12:59

Friday, Dec 25, 2015 at 12:59

Phil G
thanks for your input.
My regulator looks to be a no name job
It is attached to the back of the panels & says "MPPT Solar Charge Controller 12/24V 10amp max
input/output"
Perhaps I should look for a manual amonst the thousands of other bits of gumph in my kit
What happened to the days when a sleeping bag, a small shovel to dig a hiphole & a billy was all
we needed
Ross

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Follow Up By: Member - Phil G (SA) - Friday, Dec 25, 2015 at 13:41

Friday, Dec 25, 2015 at 13:41

Ross, Its hard to answer your questions without good info about the controller. Did you say your panels were 160W? If so, a 10Amp controller is undersized. Your first post read as if you measured 10A coming out of the panels. Can you post a photo of the controller?

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Follow Up By: Member - Ross N (NSW) - Saturday, Dec 26, 2015 at 07:46

Saturday, Dec 26, 2015 at 07:46

Phil,
I am not in the same locality as my solar panels at the moment so can't do photo.
Ross

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Reply By: Rangiephil - Friday, Dec 25, 2015 at 10:53

Friday, Dec 25, 2015 at 10:53

I think Frank is assuming you have an MPPT regulator which should first be attached to the battery and it senses if it is 12v or 24V and tailors the output to match.

If you just have an attached regulator on the average Ebay set of panels , then it usually doesn't have this facility.
It sounds as if your regulator is crook if you had both terminals connected to a battery and you were measuring the volts across the terminals. The 10 amps is the maximum input that the regulator can handle. I don't know why but makers often refer to 12 volts when the maximum volts is usually 14+.

My MPPT regulator rarely goes over 14volts, and in fact will start to cycle on and off if it does.

I have a 120Watt cheapo panel set which is connected in series rather than parallel and I have a watt/volt etc meter from ABR attached between the battery and MPPT regulator which is sited at the battery, then through 2x8gauge 10 meter cables to the panels.
Regards Philip A

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Follow Up By: Member - Ross N (NSW) - Friday, Dec 25, 2015 at 11:28

Friday, Dec 25, 2015 at 11:28

Thanks Rangiephil,
My panel are Rich Solar which have been given a good wrap and have only had one outing but I guess you can be unlucky
I need some elect work done on my ute and camper so I will fit a proper set up and then hopefully do away with the generator altogether.
Ross

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