Solar and batteries question again (1 Viewer)

[Mags52]

About 15 months ago we had a problem with our batteries and eventually paid out for two new ones. We now have a repeat of the problem. We have more or less decided to have another solar panel and an MPPT controller fitted but still confused about what has been going wrong.
Our current set up is a 120 solar panel and the cheapest controller known to man. This set up was put in by a main dealer but not by us. They charged the last owner £800 for doing this and for the life of me I can't understand how it cost so much when the controller can be bought online for about £10 (or less).
Anyway here is the sorry tale. The batteries, despite the fact that we have driven all the way to Portugal and been on hook up for 10 weeks out of the last 20, have begun to fail again. We can't be off hook up for more than two nights without driving for miles. The reading, once the sun goes in, is at 12.6 and if we use the blown air heating in the evening it falls quite rapidly and recovers to about 12.2. If we put the blown air heating on the next morning we get a drastic fall in the batteries to 11 so we turn it off and put the oven on instead. This is clearly a problem and we have stopped trying to run it in the mornings.
The Sargent controller is EC200 that only delivers 13.6 maximum.
We've found an English speaking solar guy who has given us some advice. He suggested putting as many panels as the roof will take, upgrade to MPPT controller and then wait and see if the batteries recover. The ones we bought are AGM GreenPower batteries that he says are pretty good and should still have plenty of life in them.
Whilst we are happy to go ahead with getting more solar so that we're not always reliant on hook up I'm still bewildered by the fact that the batteries have declined in this way. We're not heavy users of 12v power, for most of this trip we've used no heating, all our lights are now LED and we don't watch the TV when not on hookup. We've driven 3,500 miles so you would expect that the combination of all that driving, the weeks on hook up and the solar panel would have kept the batteries in some kind of decent condition.
I think we're probably looking at shelling out for another pair of batteries but I'm worried that there is a hidden fault somewhere that we have no way of knowing about.
What do you think?
Mags

 

[Derbyshire wanderer]

If I have read the above correctly then you are never charging the batteries properly due to the charge voltage being too low.
IF? the batteries have not been over discharged and are basically recoverable they will need a maintenance recovery like what a CTEK charger will do.
Also the solar controller is adding to the problem.
Change the controller to a decent MPPT unit like a Victron and set the charge regime suitable for the battery needs.
Its is difficult to be exact with the above unless the existing system is tested properly to see if there is a more basic fault.
Hope this helps

 

[Boringfrog]

One 120 watt panel should be enough for your needs and in Portugal should be giving you a good charge during the day, sounds like something's not working properly, what is the battery readings when in full sun?

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[Mags52]

One 120 watt panel should be enough for your needs and in Portugal should be giving you a good charge during the day, sounds like something's not working properly, what is the battery readings when in full sun?

13.7 in full sun
Mags

 

[Kevan]

Batteries should still be in good condition at that age, if you are not on EHU and using your blow air heating this will cause a large draw on batteries, but it sounds to me as if the solar panel is not replacing that loss from your battery, i would first check what your solar panel is putting in with a multi meter, i think it could be your charge controller is naf.

 

[Mags52]

We've arranged to borrow a good charger - not sure what type but it's from the solar guy and he says it will give us a bigger voltage than the usual chargers. Hoping that boosting them to full charge will give them a fighting chance once the new controller is in place.

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[laurieash]

The sun is lower this time of year, so you might not be getting full charge as well it's been clowdy the past few days.
Is the panel flat to the roof.

 

[Boringfrog]

13.7 in full sun
Mags

If you're getting 13.7 volts during the day and they're dropping to 11 volts pretty quickly I would say new batteries needed, are both properly wired up?

 

[Lenny HB]

With only 13.6v going into AGM's you are lucky they lasted 15 months. AGM's need to be taken up to 14.8v to get a full charge.
13.6v will not fully charge any type of battery but wet cells would last a bit longer.

Afraid to say your AGM's have had it, your best option is to replace the batteries don't buy AGM's and get a new multi-stage charger. And an MPPT regulator that can be set for different battery types.

The factory fit Banner AGM's on our Hymer failed after 18 months as they were only getting charged to 14.2v. I replaced them with Gel's (need a charger with the correct regime for Gel's)

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[Allanm]

If it's any help, we have a 120watt panel and use a Victron MPPT 75/15 controller with just one 110ah battery. We have been without hook up for 3 weeks now and the battery is fully charged every day just with the panel and a few miles driving most days.
We will be replacing the single battery with a twin 110ah setup shortly, though I am not sure we will need it really.
We have older flourescent tube lights, water pump and charge iPads/iPhones daily, but no tv.

 

[Mags52]

With only 13.6v going into AGM's you are lucky they lasted 15 months. AGM's need to be taken up to 14.8v to get a full charge.
13.6v will not fully charge any type of battery but wet cells would last a bit longer.

Afraid to say your AGM's have had it, your best option is to replace the batteries don't buy AGM's and get a new multi-stage charger. And an MPPT regulator that can be set for different battery types.

The factory fit Banner AGM's on our Hymer failed after 18 months as they were only getting charged to 14.2v. I replaced them with Gel's (need a charger with the correct regime for Gel's)

Does this mean we should change the Sargent module in the van to get better charging? That sounds expensive and a bit drastic. Is there another way to improve the charger?

 

[Lenny HB]

Does this mean we should change the Sargent module in the van to get better charging? That sounds expensive and a bit drastic. Is there another way to improve the charger?

Yes it will shorten the life of any battery you use it with.
Cheapest solution would be the disconnect the charger part and wire in a new charger like the CTEK and keep the existing distribution system. For a fully functioning system it would be better to replace the complete unit, not too expensive if you can do the work yourself but to pay someone could be costly.

Probably worth talking to Sargent they may be able to offer an upgrade.

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[iceclimber]

There are a number of things that could be wrong. I agree with LennyHB; your batteries are probably now knackered. For some reason your charger has not been giving out enough volts and so gradually the batts have been deteriorating .....
Your options appear to be:
1.) upgrade the Sargent to suit what size of batteries you will have in the future
2.) Add a CTEK to use as an auxiliary charger (will need to be done correctly) + you will probably need the 25A one, especially if you decide to go with more than one leisure battery.

The solar charging is a separate issue ..... again I agree with comments above. Ive taken my 'cheapy' regulator out and I am currently deciding on what MPPT unit to install. (Victor stuff is very good)