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Time for new batteries?


jenevers

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My 5 year old Trojans look like they're on their last legs. 11.9volts this morning!  I fired up the genny and the battery charger "Charge failure" light lit up and it took 4 minutes before it kicked in. It went into bulk charge (surprise, surprise!) at 80amps, but within 30 minutes, had dropped down to 12.7amps. But when I'm running the engine, the Leece Neville alternator is constantly banging in over 100amps. 

I thought the batteries determined how much charge they want, so how come the battery charger is dropping down so quickly?

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1 hour ago, jenevers said:

My 5 year old Trojans look like they're on their last legs. 11.9volts this morning!  I fired up the genny and the battery charger "Charge failure" light lit up and it took 4 minutes before it kicked in. It went into bulk charge (surprise, surprise!) at 80amps, but within 30 minutes, had dropped down to 12.7amps. But when I'm running the engine, the Leece Neville alternator is constantly banging in over 100amps. 

I thought the batteries determined how much charge they want, so how come the battery charger is dropping down so quickly?

 

The charger had probably dropped into float voltage because the batteries are so sulphated, the remaining capacity was charging up (voltage rising) so fast. This indicants that you have probably been rarely fully charging them and have no facility to do an equalisation charge. If your charge has an  equalisation setting use it and it may buy you some time.

 

How do you decide when to stop  charging and what battery monitoring equipment do you have/use.

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2 minutes ago, Tony Brooks said:

 

The charger had probably dropped into float voltage because the batteries are so sulphated, the remaining capacity was charging up (voltage rising) so fast. This indicants that you have probably been rarely fully charging them and have no facility to do an equalisation charge. If your charge has an  equalisation setting use it and it may buy you some time.

 

How do you decide when to stop  charging and what battery monitoring equipment do you have/use.

They've been on constant solar power over winter via Episolar MPPT controller with no power being used.

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Just now, jenevers said:

They've been on constant solar power over winter via Episolar MPPT controller with no power being used.

 

Yes but I bet that uses adaptive charging as well as your charger so may well have spent many days on float voltage.

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Use a hydrometer to take each cell's specific gravity and then compare the state of charge that shows with the state of charge inferred from rested voltage. The greater the difference each test gives, the more sulphated the batteries are.

 

Look at the case ends. If they bow out the battery is badly sulphated.

 

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11 minutes ago, jenevers said:

They are bowed. But how could that happen with solar/MPPT over winter?

 

Because it switches over to float far too early.

Solar is not the "plug in and walk away" that some seem to think it is.

 

Maybe you can programme the controller to increase voltage before it goes into float ? (depends on your system).

On mine it does a 15+ volt equalisation charge every couple of weeks to reduce the sulphation which helps keep the batteries healthy.

 

If your batteries are bowed at the ends, get them out QUICKLY, this is an early sign of very heavy sulphation which can lead to internal shorts and battery explosions.

Are they getting quite warm when charging ?

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  • 22 minutes ago, jenevers said:

    They are bowed. But how could that happen with solar/MPPT over winter?

     

    The same can apply to a mains charger.Both use a computer to determine the charging voltage as the charge progresses, and most if not all seem to use something called adaptive charging. As I understand it they run at maximum output (bulk) with the batteries pulling down the voltage and the regulation starts to take place. The computer measures the rate of voltage rise in bulk and uses that to guess when the absorption charge (regulated voltage) should be complete and when that time is up drops to float charge. All too often both solar controller and charger gets this wrong and drops to float too early so the batteries are not fully charged and start to sulphate. This is why I will often advise turning the charger off and on again  a few times.

 

When you are living aboard the regular voltage dips help force the charger back into the sequence again, but not when you are aboard. I am not clear how this applies to solar controllers, but they also seem to drop to float too soon.

 

I suspect you may not have been fully charging them since new, hence me asking how you monitored your batteries and if you could do an equalisation charge that Trojans seem to demand/enjoy. The higher equalisation voltage will convert more sulphate than the normal charging voltages will.

 

 

Edited by Tony Brooks
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10 hours ago, jenevers said:

I understood that the Episolar controller was supposed to automaticallyngo into equalisation once a month.

Maybe I would have been better off fully charging then disconnecting thd batteries.

They don't get warm btw.

 

What are the times and values the controller is set to? If by some chance its for sealed batteries or AGMs the voltages are likely to be too low for open cell LAs and it may not do an equalisation.

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On 22/06/2021 at 09:25, Tony Brooks said:

 

What are the times and values the controller is set to? If by some chance its for sealed batteries or AGMs the voltages are likely to be too low for open cell LAs and it may not do an equalisation.

They're set for Flooded Lead Acid. Strangely enough the Trojans seem to be coming back to life after a few runs out in the boat, with the Leece Neville banging in over 100amps?

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A bit of bulging is normal, as long as its not too bad.

Top up the water, do a good charge then an equalisation for a few hours and see how things go. Trojans do recover quite well.

Its also quite possible that only a single cell has failed but even if that is the case at 5 years it would probably make sense to replace the whole lot.

We are full time off grid liveaboards and our Trojans are just over 5 years, still ok  but not sure we will get another winter out of them.

 

...........Dave

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16 minutes ago, jenevers said:

They're set for Flooded Lead Acid. Strangely enough the Trojans seem to be coming back to life after a few runs out in the boat, with the Leece Neville banging in over 100amps?

 

I suspect you have run for longer at the Leece Neville regulated voltage that the other charging sources will allow.

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10 hours ago, dmr said:

A bit of bulging is normal, as long as its not too bad.

Top up the water, do a good charge then an equalisation for a few hours and see how things go. Trojans do recover quite well.

Its also quite possible that only a single cell has failed but even if that is the case at 5 years it would probably make sense to replace the whole lot.

We are full time off grid liveaboards and our Trojans are just over 5 years, still ok  but not sure we will get another winter out of them.

 

...........Dave

They are only slightly bulged. They seem to be coming back to life, so should get me through this summer.

10 hours ago, Tony Brooks said:

 

I suspect you have run for longer at the Leece Neville regulated voltage that the other charging sources will allow.

Well running the engine/alternator has certainly made a big difference?

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1 hour ago, jenevers said:

They are only slightly bulged. They seem to be coming back to life, so should get me through this summer.

 

Good luck with that.

 

Ours were 'slightly bulged' shortly before one decided to overheat, fizzing and coming close to bursting. Id ignored previous bulging as it had been described as 'normal' by someone on here.

 

If it bursts it creates an unholy mess or could even explode.

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28 minutes ago, The Happy Nomad said:

Ours were 'slightly bulged' shortly before one decided to overheat, fizzing and coming close to bursting. Id ignored previous bulging as it had been described as 'normal' by someone on here.

 

 

Agreed, to say "a bit of bulging is normal" is telling porkies and underestimating / understating the the dangers.

 

If a bit of bulging was 'normal' it would be 'normally seen' - it isn't.

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5 minutes ago, Alan de Enfield said:

 

 

Agreed, to say "a bit of bulging is normal" is telling porkies and underestimating / understating the the dangers.

 

If a bit of bulging was 'normal' it would be 'normally seen' - it isn't.

 

We were really lucky as the one of five that decided to go belly up was the very one that had the 'over heat' sensor fixed to it. As a result the Mastervolt Combi wouldnt go into charge mode when we were leaving the boat.

 

So if it had been one of the others I would have been able to merrily leave the whole bank on charge and the overheating one would likely have burst/exploded.

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29 minutes ago, The Happy Nomad said:

overheating one would likely have burst/exploded.

 

I reckon we were seconds from an expolosion.

 

Middle if the night and the CO alarm went off. Woke up in shock and tried to work out what we had that would generate CO and came up wth nothing, Opened the windows and wafted some towels about until the alarm stopped.

Back to sleep and about an hour later alarm goes off again - open windows and waft the 'gas' out.

Then got to think something serious is going on so started to have a good look around.

 

Our engine room is under the saloon floor with the door into it from the aft cabin, opened the door and crawled in, started to choke and eyes stream and throat burn. Crawled forwards to the battery bank and the heat was phenominal, Identiified that one battery was so hot it was untouchable, the other five were as normal.

 

Got some spanners and disconnected the terminals.

 

Next morning tried to extract the battery but it was still too hot to touch, later in the day managed to get into it properly to see it was shaped like a rugby ball.

 

I really do think we were very close to a battery explosion and having bits of battery and acid shot all over the engine room.

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