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post #11 of 31 (permalink) Old 28-10-2015, 22:53
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post #12 of 31 (permalink) Old 29-10-2015, 09:04 Thread Starter
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Originally Posted by WildThingsKev View Post
Is there a hint here that your 2 leisure batteries might be separated by more than the usual 30cm of cable? If so, then maybe over long, under sized wire has something to do with it. Perhaps one battery not fully charging and the 2 batteries then equalising post charge?

Just a thought.

Kev
Cables are not what Brunel would have fitted and the two batteries are probably 5m apart, so I can recable.
I do wonder if the second battery is necessary, as keeping one battery in a higher state of charge might suffice.

Jon
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post #13 of 31 (permalink) Old 29-10-2015, 09:13 Thread Starter
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Where in Dorset? Anywhere near Weymouth?

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post #14 of 31 (permalink) Old 29-10-2015, 09:15
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Quote:
Originally Posted by jonasw19 View Post
Cables are not what Brunel would have fitted and the two batteries are probably 5m apart, so I can recable.
I do wonder if the second battery is necessary, as keeping one battery in a higher state of charge might suffice.

Jon
I would always prefer to have more than one LB even if it didn't get used much.

5 meters seems a huge distance, or is that electrically rather than physical, you would need a fairly humpty cable in either case.

An absolute minimum of 25mm2 but I'd consider 50mm2

http://www.vehicle-wiring-products.e...-starter-cable
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post #15 of 31 (permalink) Old 29-10-2015, 09:31
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Quote:
Originally Posted by jonasw19 View Post
Cables are not what Brunel would have fitted and the two batteries are probably 5m apart, so I can recable.
I do wonder if the second battery is necessary, as keeping one battery in a higher state of charge might suffice.

Jon
In that case the wires between the batteries are probably fundamental to your problem. I think you will find that the second battery is not fully charging then after the charging completes the first battery trickle charges the second as they equalise.

Try measuring the terminal voltage on both batteries whilst charging (by engine would be best). After a decent run separate batteries and measure them again whilst not under load. Also measure them both immediately after a period of heavy use.

Could be more to it than that as I'm a bit puzzled why the mains charger is only outputting 2A, what is battery 1 voltage at this point? Use mulimeter and check callibration of panel.

Kev

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post #16 of 31 (permalink) Old 29-10-2015, 09:59 Thread Starter
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Kev I agree with you and nicholsong about calibrating the panel.
This thread has given me some useful homework. I can only get at one of the batteries easily, the other requires the front seat to be removed, so I will defer 'til end of November.
The battery charger output also surprised me, usually on ehu the charger runs at 8 or 9 amps dropping gradually, and if the batteries are quite "full", it drops back quickly to a base of 1 or 2 amps.
This time it never got above 2 amps. This could imply that the batteries were indeed fully charged or that the panel is giving misleading readings.
I have just reset the control panel and will see what happens.
Jon
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post #17 of 31 (permalink) Old 29-10-2015, 10:15 Thread Starter
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quote=Kev_n_Liz;1721138]I would always prefer to have more than one LB even if it didn't get used much.

5 meters seems a huge distance, or is that electrically rather than physical, you would need a fairly humpty cable in either case.

An absolute minimum of 25mm2 but I'd consider 50mm2

http://www.vehicle-wiring-products.e...-starter-cable[/quote]

Kev_n_Liz
Distance is about right as the second LB was abandoned in the back of the mh whilst the original is under passenger seat.
The loads are not great, 5 amps would be max, mostly less than 3A unless charging.

I do on occasions run a 350W inverter (with a 40W load) to charge a laptop. This is connected directly to the LB at the back with properly sized, short fused cables.
I appreciate that this will also require an equalising current from the first LB, however this has been done only 3 times in the last 6 weeks and the behaviours described seem independent to this.
Pondering
Jon
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post #18 of 31 (permalink) Old 29-10-2015, 17:35
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I agree, unless you are taking a lot of current - over 10 amps, then the vo;tage drop should be minimal. I often turn my fridge off if I need to put in a lot of charge, say after several days wild camping - the fridge takes 15 amps which could be going to the batteries. The fridge will stay cold all day quite happily
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post #19 of 31 (permalink) Old 31-10-2015, 20:42 Thread Starter
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Quote:
Originally Posted by WildThingsKev View Post
In that case the wires between the batteries are probably fundamental to your problem. I think you will find that the second battery is not fully charging then after the charging completes the first battery trickle charges the second as they equalise.

Try measuring the terminal voltage on both batteries whilst charging (by engine would be best). After a decent run separate batteries and measure them again whilst not under load. Also measure them both immediately after a period of heavy use.

Could be more to it than that as I'm a bit puzzled why the mains charger is only outputting 2A, what is battery 1 voltage at this point? Use mulimeter and check callibration of panel.

Kev
OK today was a bit too warm for cycling.

Measured the voltage with engine at tick over
Engine bat. 14.23v
Leisure bat1 14.07v
Leisure bat2 13.67v
So 0.4v lost in the wiring.

With just solar
Engine bat. 12.5v
Leisure bat1 12.5v
Leisure bat2 12.5v
The control panel gave 12.5v for both engine and Leisure batteries

After ruing engine on tick over for 10 min I switched off and put a small load on the inverter (est 3.5A max)
The voltmeter showed
Engine bat. 12.73v
Leisure bat1 12.49v
Leisure bat2 12.39v
The control panel gave 12.5v for engine and 12.3 for Leisure batteries
Conclusions
From the first set of readings there is indeed a voltage drop between the leisure batteries of 0.4v. So I should reduce that with larger wires (kev_n_Liz and WildthingsKev)
The control panel seems to report accurately (nicholsong)
My solar panel may be poor though new in August
The solar controller may not be brilliant.

What else could I do?

Jon
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post #20 of 31 (permalink) Old 31-10-2015, 20:53
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Clean the solar panel.
I thought my two panels were clean until I got up on the roof for the twelve monthly and gave the panels a good scrub.
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