Leisure batteries wired wrongly/differently

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Ally

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Subject:

Re: Leisure batteries wired wrongly/differently

· Posted: 15.02.2017 · #41

Quote by kabundi

Ally

Think about putting the two solar panels in series rather than parallel. This means that you will get a much higher voltage (double) from the solars. In the winter you will get sufficient voltage to charge your batteries even in poorish weather. As an example I have today an input voltage to the solar controller of 35Volts.

The downside is you need a high input voltage controller to accept the nominal 24volt (2x12 in series) from the solars. The input voltage from the 2 solars in mid summer could well be around 60volts.

I have a Tracer 2210RN MPPT controller with a maximum input voltage of 100 volts.

Just looking at my regulator manual, it is a PCM-3012.

Maximum Solar Module Open Circuit = 50 V

Maximum Solar Module power = 300 w

Maximum current = 18 A

So I am assuming the important one in your description is the 50 v?

Ally

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Re: Leisure batteries wired wrongly/differently

· Posted: 15.02.2017 · #42

Quote by kabundi

http://www.12voltplanet.co.uk/…rgers.html

That was a great explanation.

They link to this video also:

kabundi

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Subject:

Re: Leisure batteries wired wrongly/differently

· Posted: 15.02.2017 · #43

Quote by Douzeper

Quote by kabundi

Yes the 50V is the critical value.

There is also MPPT Range @ Operating Voltage 15 V ~ 33 V @ 12 V in your manual. Not sure what this means, but suggests that if the input voltage is over 33V then the controller does not operate correctly????

For your solar panels do you have the specification sheet? If so what value do they quote for Voc. See attached link for explanation

https://www.altestore.com/blog…lar-panel/

If your Voc is 23volts on each panel, or above, (23x2+10% = 50volts) you will not be able to use your controller with two panels in series. The 10% is MY safety allowance.

kabundi

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Subject:

Re: Leisure batteries wired wrongly/differently

· Posted: 15.02.2017 · #44

Quote by kabundi

In the winter you will get sufficient voltage to charge your batteries even in poorish weather. As an example I have today an input voltage to the solar controller of 35V

.

Just checked at 1730 today where it is after lighting up time.

Input voltage to MPPT controller was 18V.

Output Voltage to Battery was 12.9V.

Output Current to battery was 0.1A

This shows that charging can take place in poor light with the correct setup.

Davy

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Re: Leisure batteries wired wrongly/differently

· Posted: 15.02.2017 · #45

A bit off topic but my 4Kw panels on the house will generate a few watts from the streetlight across the road. Couldn't believe it, but we had just had the panels fitted before we moved in so there was nothing drawing power !

Davy

Ally

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Re: Leisure batteries wired wrongly/differently

· Posted: 16.02.2017 · #46

Quote by TeamRienza

Before I fitted the extra panel I ran a meter on it to make sure it was working, it was in our porch up against a wall, as soon as I turned it round the voltage went up a lot, was quite surprised at how sensitive it was to light.

Ally

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Subject:

Re: Leisure batteries wired wrongly/differently

· Posted: 16.02.2017 · #47

Quote by kabundi

For your solar panels do you have the specification sheet? If so what value do they quote for Voc. See attached link for explanation

That's the problem I had, no spec for the first one so I took a chance. Ordered one that looked like the same panel, same design, same pattern on it etc. Before fixing it down I connected it all up to make sure everything seemed to be doing what it was meant too.

Seems to be working great.

killiand

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Re: Leisure batteries wired wrongly/differently

· Posted: 16.02.2017 · #48

so far.. I think I actually know less about the electrical set up in the motorhome, than I did before this and the other leisure battery posts!!

Serious amount of homework to be done...

Ally

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Re: Leisure batteries wired wrongly/differently

· Posted: 16.02.2017 · #49

Quote by killiand

so far.. I think I actually know less about the electrical set up in the motorhome, than I did before this and the other leisure battery posts!!

Serious amount of homework to be done...

Well don't be taking anything technical from my posts, I'm making it up as I go along with the help of more knowledgeable members on MHC.

kabundi

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Subject:

Re: Leisure batteries wired wrongly/differently

· Posted: 16.02.2017 · #50

Quote by Douzeper

Quote by kabundi

For your solar panels do you have the specification sheet? If so what value do they quote for Voc. See attached link for explanation

Do you have the Voc for the new panel

Ally

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Subject:

Re: Leisure batteries wired wrongly/differently

· Posted: 16.02.2017 · #51

Quote by kabundi

Do you have the Voc for the new panel

Voc:21.06v

kabundi

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Re: Leisure batteries wired wrongly/differently

· Posted: 16.02.2017 · #52

You should be OK then to wire the two panels in series.

If you want to try it then do following:-

Put a blanket over each of the two solar panels to keep light from them.

Disconnect the two solar panels from the controller and from each other.

Connect a digital voltmeter to the output cabling from the first panel.

Remove the blanket from the first panel

Measure and record the voltage Voc1*

Replace the blanket and disconnect the meter.

Repeat for the second panel to obtain Voc2*

Voc1 = Voc1* x 21.06/Voc2*

Voc2 = 21.06volts

Add Voc1 + Voc2, if less than 45/46volts then your existing controller should be OK for two panels in series.

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