Solar and 2 batteries (1 Viewer)

[The Whittys]

Hi all

I have an Autotrail Imala 715 that has a solar panel fitted. Not sure of the voltage etc as it was fitted when i bought it.

I recently had a 2nd 110 amp battery fitted with the proper link cable fitted by Brownhills.

I was just wondering if anyone knew how to check if my panel was charging both batteries. Its just if i dont hook up then i lose charge quite quickly. I know its not sunny at the moment but 2 x 110 batteries only last 3 days.

Any advice appreciated

Cheers

 

[Derbyshire wanderer]

It depends on the load for how long they will last.
If the 2 batteries are connected together the panel will be trying to charge them both but in the present uk weather the solar will be close to nothing.
You can work out the loading if you know the wattage of what you are using.
Every 12 watts will draw 1 amp so 120w is 10 amps etc.
Your 2 batteries have a combined 220ah capacity but effectively can only go to half capacity before being considered as flat i.e. 110ah.
So a 110 watt load will take 10 hours to flatten your batteries.
This is a simplified reply as other factors will determine the real available power till flat.
Don't forget that taking the batteries too low will ruin them.

 

[TerryL]

Firstly, don't ask Brownhills! My experience with their "electricians" leaves a little to be desired.

How old is the original battery? The advice is usually to fit two of the same type, size and age. If your old battery is failing it will drag the new one down - not saying that's your problem but the symptoms are the same.

At this time of year unless you've got a huge solar panel you're not going to get much out of it in the UK, sunny or not; the sun is too low. Does your solar regulator give any indications? Presumably the batteries charge okay on hookup? We've got a similar setup, 100watt panel, and I would expect to get 6/7 days in the UK this time of year with normal use - but depends on what you call normal. Couple of days ago while transiting France we needed to leave the heating on all night and we'd have been lucky to get 3 days (I've also got a B2B charger which boosts the charge whilst driving).

There'll be someone else far more expert than me come along shortly but if you're unsure of how to use a test meter you'll maybe need professional help. Sorry can't help more, just a few ideas.

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[andy63]

If your batteries have been paralleled then they effectively become one...
If it was mine I'd be looking to see if they just added another battery and left the original connections for power and charging to the original battery... that would not be ideal but would have been a quick fit..
Ideally your positive of take an solar charging wires should come off the positive on one of the two batteries and the negative be taken off the second battery...
That arrangement helps ensure the batteries are sharing the load as effectively as you can...
Worth a look...
Andy.

 

[The Whittys]

Hi. Both batteries where fitted brand new by Brownhills in Sept so they should be ok.

The controller is only a basic one that just shows a light that says charge i have been looking at swapping it for MPTT?

Will have to work out my draw.

Cheers

 

[The Whittys]

If your batteries have been paralleled then they effectively become one...
If it was mine I'd be looking to see if they just added another battery and left the original connections for power and charging to the original battery... that would not be ideal but would have been a quick fit..
Ideally your positive of take an solar charging wires should come off the positive on one of the two batteries and the negative be taken off the second battery...
That arrangement helps ensure the batteries are sharing the load as effectively as you can...
Worth a look...
Andy.

They fitted a link cable and said thats all i needed. They didn't take any wires off the original

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[andy63]

They fitted a link cable and said thats all i needed. They didn't take any wires off the original

I'm most probably not explaining very clearly..
There's a lot written about it.. I'll try and add a link and it will explain what I'm trying to say..
https://caravanchronicles.com/guides/how-to-connect-two-batteries-in-parallel/
Sounds like they have just added a 2nd battery and left connections to the original... that would not surprise me but it's not what's recommended. ..
Have a read of the link and then check the wiring..
Andy.

 

[laurieash]

Do brown hill still fit banners if so check levels in batteries as mine were in need of a ltre

 

[The Whittys]

Do brown hill still fit banners if so check levels in batteries as mine were in need of a ltre

Yes they were Banner 110s

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[The Whittys]

I'm most probably not explaining very clearly..
There's a lot written about it.. I'll try and add a link and it will explain what I'm trying to say..
https://caravanchronicles.com/guides/how-to-connect-two-batteries-in-parallel/
Sounds like they have just added a 2nd battery and left connections to the original... that would not surprise me but it's not what's recommended. ..
Have a read of the link and then check the wiring..
Andy.

Will check wiring tomorrow thanks

 

[laurieash]

The link cable will be the one supplied by sargent.
They cost about 25 pounds and they just plug into the harness so you can not get it wrong.

 

[The Whittys]

The link cable will be the one supplied by sargent.
They cost about 25 pounds and they just plug into the harness so you can not get it wrong.

Yeah thats what they did but cant find out if that cable enables the solar panel to charge the 2nd battery.

Thanks

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[Lenny HB]

Seem to rember a thread on hear about AT cables not up to the job.
@Jaws should be able to advise.

Banner batteries! If you are lucky you may get more than a year out of them.

 

[Jaws]

The cables that Sargent use are, in my opinion, not really up to the job if you are using anything that will either charge or discharge the batteries at anything more than 10 amps.. and even that must be very close to the absolute limit..

However, as to the question re charging both batteries, yes they will both be charged as believe it or not the two wires coming from the control box and going to the batteries are joined inside the control box..

I altered mine because I did not like how it was originally done.
I put both the +ve wires from the control box together and ran to one battery and then did the same with the -ve wires. I then joined the batteries together using some serious wire ( actually some cheap jumper cable I cut up. )