Batteries permanently connected to charger

[Psycloud]

Just recently I've left the 3 stage charger permanently connected to the battery bank since we're not running the engine much at the moment. Our 12v system runs the ceiling lights, oven fan and cold water pump as well as the bilge (weekly) and shower (never at the moment) pumps so moderate use. Just checking it's OK for the batteries to be permanently hooked up like this - for the most part the charger reads FLOAT.

 

Thanks

 

David

[Chris Pink]

Although in theory it is fine, I am beginning to feel that the reports of battery explosions mean it is not necessarily such a good idea.

 

It's fine while your (complicated electro-chemical system) battery reacts the way the charge expects but if a cell goes down (for instance) the charge has no way of differentiating this fault condition from a battery that needs charging except the temperature sensor which is usually fixed to one battery.

 

Under these conditions it will continue to put a high current into the bank and the result can be disastrous.

[Serenity Malc]

Yello Psydude,

 

You might want to bilge a little more frequently (just to be safe with your new boat) ... and you might want to shower now and again !

 

But your charger should be able to float charge your batteries for a significant time without damage. After all, your batteries like to be kept charged. If you're on the boat every other week this should still be fine, assuming your batteries are OK.

 

Malc.

 

I bow my head to Mr Pink's superior pessimism and technological accumen !

Edited January 14, 2013 by Serenity Malc

[Tonka]

Why bilge, water should be outside of boat. If there is an R in the month then it is too cold to shower

[Psycloud]

Although in theory it is fine, I am beginning to feel that the reports of battery explosions mean it is not necessarily such a good idea.

 

It's fine while your (complicated electro-chemical system) battery reacts the way the charge expects but if a cell goes down (for instance) the charge has no way of differentiating this fault condition from a battery that needs charging except the temperature sensor which is usually fixed to one battery.

 

Under these conditions it will continue to put a high current into the bank and the result can be disastrous.

 

Hmmm - OK I understand this but if I ran the batteries to 50% then recharged them would I not still be under the same risk of explosion if a cell was dead?

 

Yello Psydude,

 

You might want to bilge a little more frequently (just to be safe with your new boat) ... and you might want to shower now and again !

 

But your charger should be able to float charge your batteries for a significant time without damage. After all, your batteries like to be kept charged. If you're on the boat every other week this should still be fine, assuming your batteries are OK.

 

Malc.

 

I bow my head to Mr Pink's superior pessimism and technological accumen !

 

We live on it Malc so the batteries are in constant use. We don't shower on the boat because we use the ones at the boat yard

 

Why bilge, water should be outside of boat. If there is an R in the month then it is too cold to shower

 

I'm not sure it's possible to keep all the water on the outside of the boat - especially when we have a cruiser stern

[mrsmelly]

Although in theory it is fine, I am beginning to feel that the reports of battery explosions mean it is not necessarily such a good idea.

 

It's fine while your (complicated electro-chemical system) battery reacts the way the charge expects but if a cell goes down (for instance) the charge has no way of differentiating this fault condition from a battery that needs charging except the temperature sensor which is usually fixed to one battery.

 

Under these conditions it will continue to put a high current into the bank and the result can be disastrous.

 

This post is very accurate and could be quite a worry to some people. As a liveaboard at present plugged in my charger is indeed always on and all seems ok, however at work we also have batts on charge from landline whenever we are tied up and when cruising and we did quite recently have one battery explode whilst on landline charging which we put down to a battery cell problem and over charging.

 

Tim

[bottle]

Here goes

 

If the charger is left permanently connected, turned on and working, any power you use up to the maximum the charger can deliver will be covered by the charger and the batteries will only supply 'power' when that maximum is reached.

 

So, as long as you do not exceed the maximum, that the charger can deliver your batteries will sit there fully charged and rested.

[Serenity Malc]

Yello,

 

Engage charger ... hit the deck !!

 

But dudes like yourself who've had motor cycles on a maintenance charge throughout the winter have not as I recall had too many explosive events ?

 

Obviously each 100 ah rated battery could potentially make a bigger pop if it was to unfortunately suffer a cell collapse ...... but hey ...... you could get knocked over walking across the road to your boat ?

 

Malc.

[mrsmelly]

Yello,

 

Engage charger ... hit the deck !!

 

But dudes like yourself who've had motor cycles on a maintenance charge throughout the winter have not as I recall had too many explosive events ?

 

Obviously each 100 ah rated battery could potentially make a bigger pop if it was to unfortunately suffer a cell collapse ...... but hey ...... you could get knocked over walking across the road to your boat ?

 

Malc.

 

Also very true which is why many of us still risk being plugged in at all times. If one of my batteries did explode it would probably not be a big deal, the one that exploded on the boat was confined in a very heavy steel box BUT just supposing it had exploded as we were doing our monthly check of it? it did completely explode blowing the casing into some pieces and must have been a hell of a force and it doesnt bear thinking what would have happened to the tester !!

 

Tim

[ditchcrawler]

I have experiential wet cell batteries on charge for years and years and have yet to see one go bang because of it. Our emergency lighting was 110 volt DC and was on constant float, the only time it came off was to prove to the Lloyd's inspector that the lights would stay on if we had a power cut for a day.

[Serenity Malc]

Yello,

 

Maybe the forum addage of buying 'cheap' batteries because of their life expectancy against cost could take on another meaning ?

 

Maybe the dude who buys the stronger cased battery (not necessarily the cheapest), may stand a greater chance of surviving the occasional explosion ?

 

Malc.

[Serenity Malc]

Also very true which is why many of us still risk being plugged in at all times. If one of my batteries did explode it would probably not be a big deal, the one that exploded on the boat was confined in a very heavy steel box BUT just supposing it had exploded as we were doing our monthly check of it? it did completely explode blowing the casing into some pieces and must have been a hell of a force and it doesnt bear thinking what would have happened to the tester !!

 

Tim

 

 

Yello,

 

I don't know whether you're very unlucky ..... or very lucky from your post. I'll go with very lucky ... because it's a positive !

 

Malc.

[smileypete]

Just recently I've left the 3 stage charger permanently connected to the battery bank since we're not running the engine much at the moment. Our 12v system runs the ceiling lights, oven fan and cold water pump as well as the bilge (weekly) and shower (never at the moment) pumps so moderate use. Just checking it's OK for the batteries to be permanently hooked up like this - for the most part the charger reads FLOAT.

Just to add what people have said, seems that unattended batt charging with a high power charger and non sealed batts can be risky, especially in summer temperatures.

 

If it's unavoidable it'd be best to turn the charger absorption voltage down to the minimum where poss, and/or put the charger on a time switch so it can only come on half an hour once in a while. Better still would be a charger with adjustable output current, or use a smaller charger for unattended charging.

 

cheers, Pete.

~smpt~

[Keeping Up]

Wouldn't it be potentially safer to leave it on float long-term, than to use a timer which occasionally switches it on to the (much higher) absorption voltage for even a short time? I don't think the answer is clear-cut.

[by'eck]

Although in theory it is fine, I am beginning to feel that the reports of battery explosions mean it is not necessarily such a good idea.

 

It's fine while your (complicated electro-chemical system) battery reacts the way the charge expects but if a cell goes down (for instance) the charge has no way of differentiating this fault condition from a battery that needs charging except the temperature sensor which is usually fixed to one battery.

 

Under these conditions it will continue to put a high current into the bank and the result can be disastrous.

 

Although its probably of little comfort, I've never had batteries fail with dead cell & resulting overheating etc. whilst they are on float charge over a long period (up to three months).

 

This type of failure has happened to me three or four times over the years but always after a re-charge at absorb voltage say 14.7 volts, following cruising.

[nicknorman]

I have taken to turning the max charge current right down on the Mastevolt Combi when we leave the boat to go home - the thought of 100A going into the bats (well one bat, that being the one with a shorted cell) doesn't bear thinking about, even though its pretty unlikely to happen with newish bats. I've connected a masterview panel which makes changing the settings easy.

[NB Lola]

Had ours connected up for 3 years with the boat only getting holiday/weekend use. So far, no issues.

Edited January 15, 2013 by NB Lola

[Naughty Cal]

We leave our charger permenantly on. Our charger is a "smart" charger that will periodically cycle the batteries to keep them happy.

 

In the over four years we have had the boat it has not caused us a problem or exploded batteries despite at one point having a domestic battery and starter battery with a dead cell in each!

 

We don't worry about leaving ours on as it ensures the batteries are fully charged when we arrive at the boat each Friday, no dead battery concerns here.

 

If we were leaving the boat for longer periods we would still leave it turned on.

[blodger]

We leave our charger permenantly on. Our charger is a "smart" charger that will periodically cycle the batteries to keep them happy.

 

In the over four years we have had the boat it has not caused us a problem or exploded batteries despite at one point having a domestic battery and starter battery with a dead cell in each!

 

We don't worry about leaving ours on as it ensures the batteries are fully charged when we arrive at the boat each Friday, no dead battery concerns here.

 

If we were leaving the boat for longer periods we would still leave it turned on.

Might it not have contributed to the dead cell happening? I find it odd that to prolong battery life we should not use them and keep them at 100% SOC but keeping them on float contributes to rotting of the top plate connections?

[jonathanA]

I'm no expert on batteries and will happily listen to Mr Pink, gibbo etc.....

 

BUT seems to me if you have a smaller charger (20/30 A) then the chance of a faulty cell causing high charge currents to flow leading to explosion MUST be far less, so either turn down the max current on your great big all singing all dancing multi jobbie or buy a smaller charger which is all you need if permenently connected. I bought a 20a multistage as I reasoned when on landline that would be fine to power lights, pumps etc and I wasn't bothered how long it took to charge as it would only be used on landline.

 

I'm pretty sure that high currents plus a faulty cell are need to cause the pyrotechnic batteries.

 

I would also assume a reasonable maintenance regime of checking SG, electrolyte levels and physically looking for bulges, heat and gassing cells would also help avoid the suicide bomber battery.

 

The question for me is a bit simpler is a long period of float charging good for batteries or not ?

[nebulae]

Had a battery explode in my face once.Not something I would recomend.Lucky an eyewash and hose were to hand.Had to pull bits of plastic out of my face.Does everybody understand just how explosive the gas coming from a charging battery is? I disconect the mains supply when leaving the boat and isolate the batterys.Never had a problem with battery charge when coming back to the boat.Better safe than sorry.

[ditchcrawler]

 

 

The question for me is a bit simpler is a long period of float charging good for batteries or not ?

In an earlier post I mentioned having batteries on float for several years, for several read 20+

[smileypete]

'nother option is to run the 12V stuff off a 12V mains supply while moored up, then have a trickle charger for any non sealed batts if they need it.

 

ETA I think some chargers have a 'power pack' mode that might allow this.

 

cheers, Pete.

~smpt~

Edited January 15, 2013 by smileypete