Electrical confusion?

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Location: Palmerston North

Re: Electrical confusion?

Postby nigsuz » Wed Sep 30, 2015 5:52 am


Thanks for the clear and precise advise. I appreciate the time you have put into your replies.

I will look into the float charge stuff a little more because when its sunny the solar controller just stays at 13.9V whereas an automotive smart charger will stop charging altogether.

One again the forum proves its worth.

Nigel & Suzanne.
Palmerston North.
2003 Hymer Nova 390.

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Location: Albany.

Re: Electrical confusion?

Postby Neddy » Wed Sep 30, 2015 8:10 am

A controller that switches to a fixed "Float" voltage when the battery is fully charged is better and "smarter" than a charger that switches off altogether or one that switches to a trickle charge.

The recommended Float voltage for your AGM battery is 13.6v - 13.8v.
Your controller is using 13.9 volts which is OK and in any case, I doubt that you are able to alter it.

Batteries commonly die from corrosion of their positive plates. Some corrosion is inevitable, but it is at its minimum when the battery is held at the correct Float voltage - commonly 13.7 volts. A float voltage higher
or lower than that increases the rate of corrosion. In other words, a battery held at the correct Float voltage will sustain considerably less corrosion than one that is disconnected altogether or one that is left on a trickle charge.

Set your solar controller Float voltage to 13.7v if you can, but if you are not able to, do not worry at all.
A 13.9v Float voltage is quite acceptable.


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