new solar panel working?

Hello everyone, I have just connected a 100 watt solar panel to our van. I have a small volt meter that tells you how much voltage is left in the Battery. (Don't know how accurate it is though). How can you tell IF the panel is doing the job and all the connections are OK?. The battery was 50% full when I checked it and connected the Panel. With full sunlight how long would it take to fill battery? Thanks johno
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Reply By: Iain M - Saturday, Apr 21, 2012 at 16:54

Saturday, Apr 21, 2012 at 16:54
Mate really roughly,
A 100watt panel will deliver just over 8amps if all the ducks are in a row.
A battery is at 50% state of charge, assume it is 100amp hour battery so half charged is 50 amp hours.
You are looking to put 50 amp hours into the battery to get 1005 SoC.
So 50 divide by 8 = 6.25 which is hours
That does not take into account and inefficiencies, poor performance from the panel, losses across conections or the regulator.
Might give you and idea for a start ing point.
Cheers
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Follow Up By: Ozhumvee - Saturday, Apr 21, 2012 at 18:12

Saturday, Apr 21, 2012 at 18:12
Remember too that in midsummer you typically only get 5 hours full sun per day at the latitude mid NSW so any further south you get less and further north you get a bit more. 5 hours is what the "spurts" reckon you should do your calcs on.
You do have regulator between the panel and battery don't you? especially if connected permanently.
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Reply By: Member - Kevin S (QLD) - Saturday, Apr 21, 2012 at 18:31

Saturday, Apr 21, 2012 at 18:31
jonno, what reading did your volt meter give you that indicated 50% rate of charge?
Kevin
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Follow Up By: johno59 - Sunday, Apr 22, 2012 at 10:01

Sunday, Apr 22, 2012 at 10:01
kevin, the reading was 12.22v. According to notes i got on the web this is app %50. would that be about correct? thanks johno
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Follow Up By: Member - Kevin S (QLD) - Monday, Apr 23, 2012 at 17:09

Monday, Apr 23, 2012 at 17:09
Looks about right to me. Thanks.

Kevin
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Reply By: Ross M - Saturday, Apr 21, 2012 at 21:25

Saturday, Apr 21, 2012 at 21:25
G'day Johno59

You have a solar panel on a c'van and unless it follows the sun you can only get an average of about 1/2 the panels output. It might peak sometimes but will rarely if ever give the 100watt output.
I work on a factor of half for the expected output.
So working on the above calculations, double it.
Someone asked about the regulator and if you also had one of these. It is essential to include one to save your battery, and an MPPT regulator will maximize charge to the battery.

When charging the system will get to 14v and above.

Ross M
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Follow Up By: johno59 - Sunday, Apr 22, 2012 at 07:47

Sunday, Apr 22, 2012 at 07:47
thanks everyone for your simple and and easy to understand replies. Yes it does have a regulator. i prably need to experiment now to see what i can do. Theres and old saying but true, KISS......................KEEP IT SIMPLE SUNSHINE111 THANKS JOHNO
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