Float charge

HenrysCat

HenrysCat

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Hi all, been looking around but can't seem to find a definitive answer, I have a Renogy Voyager 20A PWM Solar Charge Controller connected to a small 20w panel, what I wan't to know, is it safe to leave it permanently connected to the battery on float charge (13.6v) without using the battery for any thing else, I am talking months here, or should I disconnect?
 
Might be OK if you can set the bulk voltage limit down to float, otherwise you risk overcharging every day as sun comes up and the controller sits at high voltage for a while before dropping down to float.
Though batteries can sit for a while untouched without a charge and be fine.
 
GHA, the Renogy has no settings except for battery type, I have selected AGM

srabande, it's a 12v Platinum leisure battery, 685L is the only marking on it.
 
I can't speak for solar power but I've had my battereis permanently connected to a mains Mastervolt charger for the 14 years I've had the boat. Since the engine start battery and both domestic batteries are the ones which were there when I bought it and they're still going strong, it seems to work.
 
RichardS said:
As the panel is connected to the battery through a charge controller, I'm not sure why the capacity of the battery would be a relevant factor? :unsure:

Richard
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Because the charge controller decides when to switch to float according to the current into the battery. A very small battery might be over charged before float occurred.
 
HenrysCat said:
Hi all, been looking around but can't seem to find a definitive answer, I have a Renogy Voyager 20A PWM Solar Charge Controller connected to a small 20w panel, what I wan't to know, is it safe to leave it permanently connected to the battery on float charge (13.6v) without using the battery for any thing else, I am talking months here, or should I disconnect?
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Personally I'm not comfortable with leaving any charger on and leaving things to their own devices for months. Same with leaving the battery disconnected, although that only risks the battery.
Personally it's been my experience that unless you have a Ctek maintenance charger made for the job, it's not a great plan to leave batteries with no oversight for long periods, although a great many people get away with it. YMMV.
 
For heavens sake, it's a 20w panel, max output about 1a. How the hell is that going to harm a 75ah battery ?

My engine battery is connected to the domestic bank when the engine is running, the solar controller is charging or the mains charger is on, been like it 4 years so far.
 
RichardS said:
Errrrr .... a 20W panel through a charge controller which manages to over-charge a battery. Just how small a lead-acid battery might that be? :unsure:

Richard
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Depends how many months you leave it. A few hours a day, times a lot of days, don't blame me if it's dried out at the end of it.
Likewise it should be OK disconnected for a couple of months, if it's a healthy battery to start with. But there's plenty of people who've found flat batteries after a 'few' months.
The best option might be to take it home and charge it once a month.
 
duncan99210 said:
My batteries are permanently linked to the solar panels. During the winter, the main switch is off, so no loads but the solar is still connected. Works fine for me, keeps the bank at 13.6v during the day. Just as well it’s set up that way as I’ve no idea when I’ll be able to get to Greece.....
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Through a regulator? Worth taking some care, even a small panel unregulated can push the voltage of a fully charged battery up too far >

 
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