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Post Info TOPIC: Solar panels in the sun 24/7 is this okay for the batteries?
Pradokakadudavid


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Solar panels in the sun 24/7 is this okay for the batteries?
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Just wondering if it is okay to leave a caravan with its solar panels exposed whilst not using any power and if the constant charge is detrimental to the lithium batteries.

Also in the above scenario, should I drain some power from the batteries from time to time or is this not necessary?

Basically the caravan will  sit for several months at a time before being used about four times per year - at this stage anyway.

Any advice would be greatly appreciated.

Regards

David 



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Possum3


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Leave a radio on, day and night, in the van when not using. Small drain easily replenished daily.

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Peter_n_Margaret


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Lithium should not be left at full charge for long periods. Simply disconnect them, preferably when they are 50-75% charged.
Cheers,
Peter

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Phillipn


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Pradokakadudavid wrote:

Just wondering if it is okay to leave a caravan with its solar panels exposed whilst not using any power and if the constant charge is detrimental to the lithium batteries.

Also in the above scenario, should I drain some power from the batteries from time to time or is this not necessary?

Basically the caravan will  sit for several months at a time before being used about four times per year - at this stage anyway.

Any advice would be greatly appreciated.

Regards

David 

 Where on earth do you get sun 24/7 except for the north and south poles in summer????????

All jokes aside,  disconnect the panels or turn the regulator off. When I purchased  lithium batteries I was told not to charge the batteries when the  van is in a shed. Lithium batteries will hold their charge for many months and do not need constant charging.



-- Edited by Phillipn on Tuesday 26th of November 2019 09:31:12 PM

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Pradokakadudavid


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That's great advice thanks.

Regards

David



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Whenarewethere


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Maybe disconnect everything & connect a 20 watt solar panel making sure it has a diode.



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Mike Harding


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Do the same as is done on every lead acid standby system on the planet: put the battery on float charge.

A decent batter charger (solar panel controller) should do this automatically and it is the kindest thing you can do for your batteries.



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Peter_n_Margaret


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Whenarewethere wrote:

Maybe disconnect everything & connect a 20 watt solar panel making sure it has a diode.

 Not necessary, Lithiums are OK for at months without load or charge and are best stored well below full charge.

20W will have them full charged and that is not good for them. 

20W is also too big for keeping AGMs topped up. They will slowly loose liquid. 5W is plenty for AGMs.

Cheers,

Peter



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Pradokakadudavid


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Thanks Mike and apology for my ignorance.

Maybe some time in the distant future, I too will have some knowledge in the area lol.

I believe my Redarc BMS system has a "storage" mode which I am ignorantly presuming might be the same setting as the "float charge " setting you have referred to. 

 

??



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Mamil


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Pradokakadudavid wrote:

Thanks Mike and apology for my ignorance.

Maybe some time in the distant future, I too will have some knowledge in the area lol.

I believe my Redarc BMS system has a "storage" mode which I am ignorantly presuming might be the same setting as the "float charge " setting you have referred to. 

 

??

 Storage mode on the Redarc BMS switches off charging and allows the batteries to fall to approximately 90% SOC due to self-discharge or parasitic loads before the charger kicks in again and charges them up. This cycle of discharge and charge just repeats until you go out of storage mode and into Touring mode. Touring mode will keep the batteries in float. As others have said it's advised NOT to keep Lithium batteries on a constant float charge. Their self discharge rate is very low and are best left at about 50% SOC and disconnected, and like this will happily spend a year or more in storage without discharging.



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Mike Harding


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Pradokakadudavid wrote:

Thanks Mike and apology for my ignorance.

Please don't thank me 'cause I gave you incorrect information :(

I failed to correctly understand your post and wrote what is best for lead acid batteries rather than the lithiums you have.

I haven't done much professional work on lithium batteries so won't offer a suggestion but Terry in the solar forum has good knowledge of this chemistry.



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Pradokakadudavid


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Thanks Peter.

May I ask WHERE or at what position do you "disconnect" the lithium batteries?

Thanks.

David 



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Tinggu


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Just my two bob's worth but I believe that constant float is a good way to shorten a lead acid battery life. The dreaded sulphation. If in storage for a while best way is to have a timer that will once a week (say) run the fridge - or whatever - overnight and then the solar panels can recharge at leisure.
As for lithium agreed that best storage is somewhere between 60% and 75% and not fully charged. Happy to not cycle.



-- Edited by Tinggu on Saturday 30th of November 2019 05:03:00 PM

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