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Discussion Starter #1
Hi guys,

I often have to leave the van idle for months at a time and am wondering what the best way to prolong the life of the leisure batteries is. I have 2 100ah batteries which are charged from a 100W roof mounted solar panel with controller (and via the van battery and heavy duty split charger when mobile).

Should I completely disconnect the batteries when leaving or is it ok to leave them as they are? They would be continuously topped up via solar panel but will this shorten their lifespan?

Cheers.T:
 

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I wouldn't go with the LED option as it's not enough of a draw to make a difference. Keeping the battery floated is by far the best way to keep it in good condition and as the other guy said a good cycle once in a while is good practice too. Re the discharge cycle I'm not talking about going crazy here, just load it up to about 20-30A for your system to give it a blast for a while, say 10 or 15 mins, then make sure you re-charge it properly after rather than just letting the PV panels trickle it in. You should be looking for a recharge period of around 10 x the dischard cycle i.e. 10 mins discharge = 100mins "propper" charge - like go for a drive or plug it in and let the mains charger do the work. If you do this every 3-4 months everything will be just lovely, again don't worry too much, but I would advise against leaving a battery without charging it for mare than 6 months. Also try to keep your batteries cool, below 20deg C , again be sensible here I'm not saying refrigerate them on hot days just that they don't like high temps and cooking them up for long periods will shorten their life.
 

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I wouldn't go with the LED option as it's not enough of a draw to make a difference. Keeping the battery floated is by far the best way to keep it in good condition and as the other guy said a good cycle once in a while is good practice too. Re the discharge cycle I'm not talking about going crazy here, just load it up to about 20-30A for your system to give it a blast for a while, say 10 or 15 mins, then make sure you re-charge it properly after rather than just letting the PV panels trickle it in. You should be looking for a recharge period of around 10 x the dischard cycle i.e. 10 mins discharge = 100mins "propper" charge - like go for a drive or plug it in and let the mains charger do the work. If you do this every 3-4 months everything will be just lovely, again don't worry too much, but I would advise against leaving a battery without charging it for mare than 6 months. Also try to keep your batteries cool, below 20deg C , again be sensible here I'm not saying refrigerate them on hot days just that they don't like high temps and cooking them up for long periods will shorten their life.
Thanks for the input. The thing is, I'm nowhere near the van when its left idle. You say recharge properly but I was lead to believe that solar panels (not a small trickle charger) do fully recharge batteries whereas split chargers only put 90% in?
 

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I ignore my two 110ah batteries in my caravan all winter, just disconnect them. They both give good service each spring and have enough power left move the caravan about with the mover etc without being recharged.
 

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Unless you have a whopping great big solar array on the roof of your van the best the you're going to get out of a PV panel over a UK winter is an amp or so, this will of course recharge the battery just fine over time but a good high current charge would be better. It's the act of passing a decent current through the plates in the cells of your battery that is the beneficial part. If you really want to go into this you can PM me all your specifics and I'll give you a proper opinion but like I said earlier if you leave the van for less then 6 months they'll be fine just left disconnected or on the PV panel, all the above is to keep them in tip top fighting condition but not an absolute necessity. I really wouldn't loose sleep over it.
If you would like me to go through your set up please let me know everything you can about it, makes model numbers of panel,regulator,battery split charge, cable sizes, cable distances between PV panel and regulator the reg to battery there cannot be too much info.
 

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Discussion Starter #8


You seem to know a lot about it. Thats the 100 W panel I have on the roof. When I turn the split charger off the only thing connected directly to the batteries is the head unit (rocker switch in dash). I leave the van at various airports in Portugal and Spain so its picking up quite a bit of sun. If its only for 4-6 weeks at a time maybe ill just leave the batteries connected but with split charger off.
 

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That will be just fine T: really it will, especially in sunnier Southern Europe. As part of my job I look after Europe's largest (at time of building) DC power installation... A constant 40000A at 50V! imagine two leisure centre sports halls full of batteries on racks 8 feet tall with me in the middle. These batteries are constantly floated then discharged for 30 mins every 3 months and we keep the batteries for 10 years before we change them.
 

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That will be just fine T: really it will, especially in sunnier Southern Europe. As part of my job I look after Europe's largest (at time of building) DC power installation... A constant 40000A at 50V! imagine two leisure centre sports halls full of batteries on racks 8 feet tall with me in the middle. These batteries are constantly floated then discharged for 30 mins every 3 months and we keep the batteries for 10 years before we change them.

Those batteries: are they normal leisure batteries or are they the expensive ones you find in small solar powered systems?
 
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