Battery charger question

[blackrose]

I came home yesterday evening and heard my battery charger fan whirring away. When it gets a bit warm in the boat this usually happens, except it wasn't that warm. The charger is well vented.

 

Looking at the charger (Sterling 30 amp pro-digital, about 8 years old), I noticed that it was in bulk charging mode, so it was going through its full cycle. It's on 24/7 so this doesn't usually happen.

 

There were no 12v consumables left on, so what's caused my battery charger left on float charge, to go through a full charge cycle? I know it's supposed to happen if there is no 12v activity for a period of time (I think it's a week), but I live aboard.

Edited June 7, 2013 by blackrose

[Chris Pink]

Could be a faulty battery?

[Naughty Cal]

Beat me too it Chris.

 

The only time our charger (30amp Newmar) has ever done that was when the leisure battery had died. Coincidentally the starter died the same time so it was working overtime!!

[Chris Pink]

Clues will be a warm battery ( when the charger is on), bulging case, different terminal voltage when isolated (and rested a little), different SG readings on a hydrometer.

Incidentally it's probably a good place to add that I don't believe it's a good idea to leave high current battery chargers on unattended for exactly this reason, though I realise many disagree.

[BargeeSpud]

I concur, same happened with my Sterling Pro, turned out to be knackered batteries.

[blackrose]

Knackered batteries eh?

 

The charger went back onto float shortly after I got home last night and stayed on float all night. I will see what it's doing when I get home after work this evening and have a look the batteries too.

 

Thanks

 

Mike

[smileypete]

+1 to what Chris says.

 

If they're unsealed check the topping up levels and the SGs.

 

If you have an ammeter, check the current draw when they're on float too.

 

cheers, Pete.

~smpt~

[canals are us?]

Interesting thread.

 

I took a good look at my batteries as the charger hasn't switched off yet for 3 days and it would seem 2 of the batteries are dead as the viewing window in the top is not green but black. The other two are showing a green light. So I presume I need 2 more. The 2 bad ones are sealed. If I need to replace it's going to be unsealed.

 

Would duff bateries stop the charger going into float mode?

 

I have switched the charger off as one battery is slightly warm.

 

James .

[Richard10002]

Those black/green indicators mean nothing. Don't replace your batteries because you can't see the little green floaty thing!

[WotEver]

What Richard said

 

Do you have a multimeter? Can you disconnect the batteries one by one and take voltage readings off each?

 

Tony

Edited June 7, 2013 by WotEver

[canals are us?]

Thanks for the replies Richard and Whotever

 

I do have a multimeter although only used it once. What voltage am I looking for once the batteries are disconnected?

 

Thanks.

 

James

[blackrose]

+1 to what Chris says.

 

If they're unsealed check the topping up levels and the SGs.

 

If you have an ammeter, check the current draw when they're on float too.

 

cheers, Pete.

~smpt~

 

I won't manage to look at the batteries until tomorrow. There is no current draw with them on float, there's an 0.4amp charge which seems slightly higer than usual.

 

I topped them up last weekend. They weren't down that much.

Those black/green indicators mean nothing. Don't replace your batteries because you can't see the little green floaty thing!

 

What little green floaty thing?

What Richard said

 

Do you have a multimeter? Can you disconnect the batteries one by one and take voltage readings off each?

 

Tony

 

I'll also do that tomorrow.

Edited June 7, 2013 by blackrose

[mrsmelly]

Thanks for the replies Richard and Whotever

 

I do have a multimeter although only used it once. What voltage am I looking for once the batteries are disconnected?

 

Thanks.

 

James

Hi James

 

Its pointless checking them if only just disconected. Leave them for 48 hours or longer if possible then check them and remember to make sure they are all seperated to ensure a true reading. 12.7 would be good though its not totaly reliable when they are not under load they can pretend to be ok. If they are down below about 12.5 within a couple of days trust me they will be knackered whatever the experts tell you. We have four batteries at work charged and ready for use and they are not new but we check them fortnightly and they sit at 12.7 for a long time without charging if they are in good order.Also keeping your batteries on a charger tends to make them last quite some time, we have approx 20 batteries on the go on the two boats at work and some are several years old. Maintainance is key.

 

Tim

Edited June 7, 2013 by mrsmelly

[canals are us?]

Hi James

 

Its pointless checking them if only just disconected. Leave them for 48 hours or longer if possible then check them and remember to make sure they are all seperated to ensure a true reading. 12.7 would be good though its not totaly reliable when they are not under load they can pretend to be ok. If they are down below about 12.5 within a couple of days trust me they will be knackered whatever the experts tell you. We have four batteries at work charged and ready for use and they are not new but we check them fortnightly and they sit at 12.7 for a long time without charging if they are in good order.Also keeping your batteries on a charger tends to make them last quite some time, we have approx 20 batteries on the go on the two boats at work and some are several years old. Maintainance is key.

 

Tim

 

Hi Tim,

 

I will disconnect them and check them minimum of 2 days after and check the voltage is at least 12.7v. Great to know what voltage I'm looking for.

Blackrose, sorry to hijack your post!

 

Thanks. James

[blackrose]

 

 

Its pointless checking them if only just disconected. Leave them for 48 hours or longer if possible then check them and remember to make sure they are all seperated to ensure a true reading. 12.7 would be good though its not totaly reliable when they are not under load they can pretend to be ok. If they are down below about 12.5 within a couple of days trust me they will be knackered whatever the experts tell you. We have four batteries at work charged and ready for use and they are not new but we check them fortnightly and they sit at 12.7 for a long time without charging if they are in good order.Also keeping your batteries on a charger tends to make them last quite some time, we have approx 20 batteries on the go on the two boats at work and some are several years old. Maintainance is key.

 

Tim

 

That would be a pain - I live aboard and can't easily do that without batteries.

 

Surely the batteries should be left after the charger has been swictched off? Couldn't I just do that for a couple of days and then disconnect and check them individually?

Edited June 7, 2013 by blackrose

[canals are us?]

 

That would be a pain - I live aboard and can't easily do that without batteries.

 

Surely the batteries should be left after the charger has been swictched off? Couldn't I just do that for a couple of days and then disconnect and check them individually?

It's a pain for me as I'm a liveaboard too but plan to remove the two batteries and tempoarily rewire the existing negative feeds from the batteries I need to remove/test and just run waterpump, loo flush on the 2 other batteries so as not to draw any current from the batteries being tested.

 

James

Edited June 7, 2013 by canals are us?

[Richard10002]

It's a pain for me as I'm a liveaboard too but plan to remove the two batteries and tempoarily rewire the existing negative feeds from the batteries I need to remove/test and just run waterpump, loo flush on the 2 other batteries so as not to draw any current from the batteries being tested.

 

James:cheers:

The green floaty thing is what you are calling a green light, or a black light. As far as I know, these indicators are little balls that float in a tube.... I don't really know how they are supposed to work, but I do know you shouldn't make decisions based on them - whether lights or balls

[bottle]

Confushus he says, two 'problems' (Blackrose and Canals are us) in one thread, much confusion.

[blackrose]

The green floaty thing is what you are calling a green light, or a black light. As far as I know, these indicators are little balls that float in a tube.... I don't really know how they are supposed to work, but I do know you shouldn't make decisions based on them - whether lights or balls

 

I don't think my batteries have them - or at least if they do I've never bothered with them.

Confushus he says, two 'problems' (Blackrose and Canals are us) in one thread, much confusion.

 

I thought we were being given the same advice?

[trackman]

Green indicators are meant to show whether the batteries are charged or not. They work on the specific gravity of the acid. When the SG is high they float high, are visible and give a green indication. This implies a charged battery.

It is all very crude. For a start, the SG indication is very inaccurate. Then, the indication applies only to the one cell, the others may not be the same.

Finally, it can give a false black indication if the acid level is low due to the need for a top up with distilled water.

Still has some use as a quick measure of when charging may be needed though.

[bottle]

 

I don't think my batteries have them - or at least if they do I've never bothered with them.

 

I thought we were being given the same advice?

 

You are but the mention of green indicators by 'canal are us' (post #8) added a little confusion, I think for you. (post #12)

[smileypete]

 

That would be a pain - I live aboard and can't easily do that without batteries.

 

Surely the batteries should be left after the charger has been swictched off? Couldn't I just do that for a couple of days and then disconnect and check them individually?

 

If they're not sealed then I'd just check the SGs after a full charge and rest period. Might be useful to run them halfway down and check the SGs again.

 

If the finishing charge or float current is relatively high, or they're quite thirsty, it could be a sign they're getting on and need a closer eye kept on them.

 

cheers, Pete.

~smpt~

[blackrose]

Yes, they are getting on - they're 8 years old, but they were doing fine during the month I was away from shore power recently.

 

I think they are probably knackered even though they deliver enough for my frugal 12v needs, although they seem to power the 1.25kw vacuum cleaner from the inverter ok.