Solar Panel on/off.?

[BASA47]

Sorry if this has been asked before. Installed a Solar Panel 2 years ago to keep both the leisure and cab batteries topped up, great in the summer but switch on my mains charger in the winter. Should I disconnect my solar source whilst doing this? Worried that doubling up the charge rate has damaged the leisure battery, which I have just replaced. I have a Intelligent MPPT solar controller as part of the setup.

 

[Two on Tour]

Your MPPT solar controller will only add charge to your battery if it is require, so leave it to let it do it's thing, it will be okay.

 

[funflair]

One panel shouldn't be any problem, you are right though that you shouldn't respect the charge rate your battery gets, the recommendation is usually 20% of the nominal capacity but again depends on the battery chemistry, how many and what size batteries and what size charger all comes into the equation.

 

[Richard n Ann]

Personally I would disconnect it, ours is in the garage over winter and I pull the fuse on the solar controller.
But in your case (if outside) I would at least disconnect the panel from the controller, otherwise imagine if the mains smart charger has finished charging over night so goes into 13.4v float mode, then the sun gets up and the solar controller starts bulk charging up to 14.4v, it will do this every morning, and it's totally unnecessary.

 

[Geo]

Is it not the case of when a battery is full it's full
neither controller or charger can put in more than full
Both should have overcharge protection built in Yes?

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[funflair]

Is it not the case of when a battery is full it's full
neither controller or charger can put in more than full
Both should have overcharge protection built in Yes?

But you can fill them up too quickly which is where the charge rate come in.

 

[Lenny HB]

Doesn't matter but why bother plugging it in when you have solar, I don't.

 

[JockandRita]

Doesn't matter but why bother plugging it in when you have solar, I don't.

I don't either.

Cheers,

Jock.

 

[BASA47]

Doesn't matter but why bother plugging it in when you have solar, I don't.

Well I do it because the solar panel is less effective in winter for obvious reasons and if left for long periods batteries will suffer. Hence my question do I turn off the solar, whilst using mains charger. The Van is left outside 365 days and as Richard and Ann reply that’s the concern I have.

 

[Richard n Ann]

The reason the manufacturers recommend 13.4/5v for long term maintenance rather than 13.8 is to reduce electrolyte loss. Taking a battery up to 14.4v every day when not being used seems unnecessary and may increase electrolyte loss.
I'm no battery expert, but that's what I'd do... err.. in fact that's what I do do

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[Raul]

Your mppt charger has a alogarithm to calculate the necessary re bulk if needed. It takes in account the state of charge at the beginning based on voltage, and it calculates the necessary time in absorb. Once that done drops into float. If any load brings the voltage low enough, below re bulk threshold, it will trigger re bulk and only stays up if you really discharged some; otherwise it will briefly switch back to float. If you have the right settings you should leave it alone. In winter you get very little to be of any concern of charge rate. A 100w in winter will yield 1-2 amp. Add that to your mains charger is nothing. It’s not the solar charger killed your previous battery. Also lower temperatures dictates higher voltage so the 13,8v for float in winter storage is not high. The self discharge is higher and efficiency, capacity are reduced at low temps. In summer yes. I would back down to 13,5-13,6v if temperatures are 25C plus.

 

[BASA47]

Thanks for that Raul

 

[Off da Grid]

Don’t bother with the mains charger unless we’re on a site in the later part of the year and the sun doesn’t show.

 

[The Wino]

We leave ours plugged into both as our cab battery isn't on the solar. I would have thought that the solar controller won't provide any charge when on hook up as the battery or charger would make it see no charge being required.

 

[PeteH]

Mine is currently off the EHU. It is sat showing 13.3v for the hab battery. And 13.2v for the chassis battery. The solar panel output circa 3pm was 14.8v and amps Zero. The panel only shows a current if the batteries drop below the threshold for a charge requirement. As it is stored at present no more than minor "ghost" demands are being serviced. Come winter the EHU is back on. To cover the heater I leave in to prevent frost.

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[movan]

. Oh no. Something else I don't understand to worry about.

 

[JockandRita]

We leave ours plugged into both as our cab battery isn't on the solar.

You might benefit from installing a BCM which provides up to a 4A charge to the cab batteries, when the leisure batteries don't require the charge available from solar. BCM12

Thy are very easy to install and connect.

Cheers,

Jock.

 

[The Wino]

You might benefit from installing a BCM which provides up to a 4A charge to the cab batteries, when the leisure batteries don't require the charge available from solar. BCM12

Thy are very easy to install and connect.

Cheers,

Jock.

Yes thought about it but as were now parked at home on ehu and when out and about seldom stay in one place more than a day can't decide if it's worth it. The installation looks really easy we have 2 big relays next to each other with a positive from one of the batteries to each.
I hadn't seen the one in your link but had seen the battery master and votronic one.