Annoying electrical problem (1 Viewer)

[MikeandCarolyn]

Since we had 2nd leisure battery installed (2 x 110Ah new ones) We dont seem to achieve higher than 85% charge when using just the solar panels-with just one battery we used to see 105% all the time.
I (a novice with a multi meter) have been poking around and can't find any reasons for this.
What would be the symptoms if the wrong size cables had been used to connect the 2 batteries ? There is a cable run of about 2.5 mtrs-so what size cable should have been used ? How would I detect this with a Multi Meter ?
Mike.

 

[hilldweller]

It's not cable size or length. All a very small cable would do is delay the time to full charge.

Put your meter across the batteries on charge and write down the voltages.

Same again at night off charge.

Give us the numbers.

Make sure your meter is on DC volts, some meters set on AC volts will give the wrong reading when measuring DC volts.

Worst case is the self discharge of the two batteries is enough to prevent the solar panel hitting peak voltage. Sounds unlikely if the single old battery was performing OK.

 

[Wildman]

Have a play with the calculator below Mike
http://www.solar-wind.co.uk/cable-sizing-DC-cables.html

I have a pair of 110 amp/hr batteries charged only by an 80W solar panel, they are normally fully charged 13.8V by lunchtime following the previous evenings use for 4 hours by the TV.

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