New leisure batteries not holding charge

[AliceRosano]

Hello.

I was wondering if anyone can help. We bought an entire new electrical system in September. New panels, invertor, ecc... including batteries ( 4 batteries X 185 amp each).

Somehow we are constantly running the engine as the voltage goes down from 12.7 to 12.2 in 4 hours (when solar is not on).

Inverter is on 24/6 But only used 2 amp, no TV, LED lights and a 240v fridge with a compressor of 110watt (we turn the fridge off at night). The occasional phone or laptop charging but nothing more... 

 

we have had 2 electritian coming and despite the fact that they agreed and the numbers are just not adding up, everything tests fine and all batteries test like they work correctly. 
 

even if the fridge was on constantly (definitely NOT the case) at 10 amp an hour we should still have about 25 hours between 12.7 to 12.2
 

any ideas? Has anyone had a problem like this? Is there a chance of the batteries simply loosing their charge when is cold (basically like a phone battery)? 

 

THANK YOU

 

[Alan de Enfield]

18 minutes ago, AliceRosano said:

Hello.

I was wondering if anyone can help. We bought an entire new electrical system in September. New panels, invertor, ecc... including batteries ( 4 batteries X 185 amp each).

Somehow we are constantly running the engine as the voltage goes down from 12.7 to 12.2 in 4 hours (when solar is not on).

Inverter is on 24/6 But only used 2 amp, no TV, LED lights and a 240v fridge with a compressor of 110watt (we turn the fridge off at night). The occasional phone or laptop charging but nothing more... 

 

we have had 2 electritian coming and despite the fact that they agreed and the numbers are just not adding up, everything tests fine and all batteries test like they work correctly. 
 

even if the fridge was on constantly (definitely NOT the case) at 10 amp an hour we should still have about 25 hours between 12.7 to 12.2
 

any ideas? Has anyone had a problem like this? Is there a chance of the batteries simply loosing their charge when is cold (basically like a phone battery)? 

 

THANK YOU

 

 

 

If you have only been charging the batteries to 12.7v then you have been seriously undercharging them and will have killed them.

You can destroy batteries within a couple of weeks by not recharging them correctly.

 

How you normally charge you batteries ?

How do you know when to start charging ?
How do you know when to stop charging ?

 

I'd guess that you have sulphated the batteries and now probably have only 400 / 500Ah, Do you know how to do a 'capacity test' ?

Edited March 15, 2021 by Alan de Enfield

[nicknorman]

Has this been getting progressively worse since September? I rather suspect so, and if so it is quite likely that your 6 month old batteries have lost significant capacity due to sulphation. Over the winter, your solar won’t have been doing much, and will need to have been supplemented by engine running.

 

What you don’t talk about is how much you have been charging the batteries. Unless you fully charge the batteries every few days (once a week absolute minimum), which takes many hours, the batteries will sulphated and it is easy to lose 50% or more of capacity in a few months.

 

I also suspect that you would benefit from better battery monitoring, something like a BMV712 will tell you how much charge you are actually taking out of the batteries, which might differ from what you think you are using. Having a measure of current allows you to know when the batteries are fully charged, too.

[Tracy D'arth]

What are you charging with, is there an alternator controller box like a Sterling or Adverc or are you relying on the alternator's regulator?

Your inverter only used 2A when running nothing at all, that is 48 Ah a day before you power anything. Why leave it on when you turn off the fridge at night?

Fridge @110w will draw as least 15A from the batteries every hour it is running assuming reasonable inverter efficiency.

 

Remember for every Ah you take out you have to charge at 1.5 Ah.

 

Are you really always fully charging the batteries.  charging until the current in is down to 2% of the battery capacity?

[AliceRosano]

18 minutes ago, Alan de Enfield said:

 

 

If you have only been charging the batteries to 12.7v then you have been seriously undercharging them and will have killed them.

You can destroy batteries within a couple of weeks by not recharging them correctly.

 

How you normally charge you batteries ?

How do you know when to start charging ?
How do you know when to stop charging ?

 

I'd guess that you have sulphated the batteries and now probably have only 400 / 500Ah, Do you know how to do a 'capacity test' ?

Hey. Thank for the reply. No we charge the batteries when they go down to 12.2 up until we get 13.4

 

23 minutes ago, Alan de Enfield said:

 

 

If you have only been charging the batteries to 12.7v then you have been seriously undercharging them and will have killed them.

You can destroy batteries within a couple of weeks by not recharging them correctly.

 

How you normally charge you batteries ?

How do you know when to start charging ?
How do you know when to stop charging ?

 

I'd guess that you have sulphated the batteries and now probably have only 400 / 500Ah, Do you know how to do a 'capacity test' ?

Thank you. We charge the battery when they are 12.2 and we charge them until the BM2 is on 14.4 then stop the engine and the voltage drops to 12.7 (fully charged). 4 hours later they are 12.2 v again

[ditchcrawler]

1 minute ago, AliceRosano said:

Hey. Thank for the reply. No we charge the batteries when they go down to 12.2 up until we get 13.4

 

 

You need to know what current you are putting in, just hitting the voltage is not good enough

[TheBiscuits]

1 minute ago, AliceRosano said:

We charge the battery when they are 12.2 and we charge them until the BM2 is on 14.4 then stop the engine

 

Yep, you have killed the batteries by undercharging.

 

 

[Alan de Enfield]

When you switch off as soon as you get to 14.4 volts you are reading the surface charge, not the charge in the batteries.

 

You need to charge to 14.4 - 14.6 volts and the current is a maximumn of 2% of battery bank capacity (1% is better)

You need to hold it within these parameters for a minimum of one hour before switching off the charger.

 

You have killed you batteries.

 

How many hours per day do you normally charge the batteries ? (not what you need to do now they are kaput)

Edited March 15, 2021 by Alan de Enfield

[PeterF]

An engine like the Beta 43 in its currently supplied spec has a 175Amp alternator, it could get the batteries up to 14.4V in less than one hour while putting well over 100amps back into the batteries, the batteries are not charged at this point, the alternator will keep the voltage at around 14.6-14.6V for several more hours as the amps slowly reduce from over 100 to in your case 14Amps (ideally 7Amps) at which point the batteries are charged.

[AliceRosano]

44 minutes ago, nicknorman said:

Has this been getting progressively worse since September? I rather suspect so, and if so it is quite likely that your 6 month old batteries have lost significant capacity due to sulphation. Over the winter, your solar won’t have been doing much, and will need to have been supplemented by engine running.

 

What you don’t talk about is how much you have been charging the batteries. Unless you fully charge the batteries every few days (once a week absolute minimum), which takes many hours, the batteries will sulphated and it is easy to lose 50% or more of capacity in a few months.

 

I also suspect that you would benefit from better battery monitoring, something like a BMV712 will tell you how much charge you are actually taking out of the batteries, which might differ from what you think you are using. Having a measure of current allows you to know when the batteries are fully charged, too.

Thank you. Sorry, I forgot to mention this on the description.  We have a BM2 battery monitor. We charge the batteries when they are at 12.2 v and keep the engine running until we reach full capacity 14.4. Turn the engine off, usually the voltage drops to 12.7 (fully charged). 
 

4 hours later they are 12.2v again
 

we are turning the engine on every day, sometimes twice a day because of this reason

 

[AliceRosano]

46 minutes ago, Tracy D'arth said:

What are you charging with, is there an alternator controller box like a Sterling or Adverc or are you relying on the alternator's regulator?

Your inverter only used 2A when running nothing at all, that is 48 Ah a day before you power anything. Why leave it on when you turn off the fridge at night?

Fridge @110w will draw as least 15A from the batteries every hour it is running assuming reasonable inverter efficiency.

 

Remember for every Ah you take out you have to charge at 1.5 Ah.

 

Are you really always fully charging the batteries.  charging until the current in is down to 2% of the battery capacity?

Hi! Thanks for the reply.

we keep the engine running until our battery monitor shows 14.4v. Turn the engine off then, voltage drops to 12.8 or 7... 

Turning the inverter off a night sounds like a good idea but it still doesn’t explain the situation...

 

Honestly, the fridge is only plugged in for 9/10 hours a day and only actually on for like 15 min an hour sometimes even less so it doesn’t explain the energy consumption 

[Alan de Enfield]

1 minute ago, AliceRosano said:

Thank you. Sorry, I forgot to mention this on the description.  We have a BM2 battery monitor. We charge the batteries when they are at 12.2 v and keep the engine running until we reach full capacity 14.4. Turn the engine off, usually the voltage drops to 12.7 (fully charged). 
 

4 hours later they are 12.2v again
 

we are turning the engine on every day, sometimes twice a day because of this reason

 

 

That is because you have not fully charged the batteries.

 

Think of filling a glass with fizzy pop - you have a load of froth on the top so you stop pouring as the glass is full. The froth dies down and not the glass is only half full.

 

You are charging the batteries and as soon as the surface charge (froth) shows 14.4 volts you switch off, the surface charge dissipates and you now have part filled batteries.

 

You need to run the charger for several hours to actually charge the batteries properly.

 

Just now, AliceRosano said:

Honestly, the fridge is only plugged in for 9/10 hours a day and only actually on for like 15 min an hour sometimes even less so it doesn’t explain the energy consumption 

 

 

But you now effectively have only two batteries having killed (probably) 50% of your battery bank capacity - if you keep charging in the same way, it will only be a matter of a 'week or two' before you have virtually no battery capacity at all.

[TheBiscuits]

10 minutes ago, AliceRosano said:

We charge the batteries when they are at 12.2 v and keep the engine running until we reach full capacity 14.4.

 

That means that as soon as your batteries get properly started on charging you stop the engine.

 

Getting the voltage to 14.4V is when the "real" charging starts not when it has finished.

[nicknorman]

31 minutes ago, AliceRosano said:

Thank you. Sorry, I forgot to mention this on the description.  We have a BM2 battery monitor. We charge the batteries when they are at 12.2 v and keep the engine running until we reach full capacity 14.4. Turn the engine off, usually the voltage drops to 12.7 (fully charged). 
 

4 hours later they are 12.2v again
 

we are turning the engine on every day, sometimes twice a day because of this reason

 

The thing is that reaching 14.4 is nowhere near full capacity. You need to look at the current going in (on the BM2) and only when it drops to about 10A at 14.4v is it fully charged. Do you know what the current typically is when you have been stopping charging?
 

Although 12.7 is nominally a fully charged voltage, lead acid batteries have this thing called “surface charge” so immediately after a partial charge is stopped, they might show 12.7 from the surface charge effect, when in reality they might only be at 75% charged. A fully charged battery will show over 13v after charging, it will eventually settle down at 12.7v but only after many hours of resting.

 

unfortunately I think you batteries are sulphated and that is quite difficult to resolve, even partially. You don’t mention the type of battery but if they are open wet cell batteries they might be partially recoverable by a higher voltage charge at say 15.5v for a few hours. But whether you have the equipment to do that is unlikely.

 

The number one most important thing with lead acid batteries is to properly fully charge them regularly, and that means holding the 14.4v until the current decreases to 1 or 2% of capacity. If you don’t, they lose capacity rapidly.

 

May I suggest you have a good read of the first post in this thread, it tells you everything you need to know:

 

 

Edited March 15, 2021 by nicknorman

[AliceRosano]

11 minutes ago, nicknorman said:

The thing is that reaching 14.4 is nowhere near full capacity. You need to look at the current going in (on the BM2) and only when it drops to about 10A at 14.4v is it fully charged. Do you know what the current typically is when you have been stopping charging?
 

Although 12.7 is nominally a fully charged voltage, lead acid batteries have this thing called “surface charge” so immediately after a partial charge is stopped, they might show 12.7 from the surface charge effect, when in reality they might only be at 75% charged. A fully charged battery will show over 13v after charging, it will eventually settle down at 12.7v but only after many hours of resting.

 

unfortunately I think you batteries are sulphated and that is quite difficult to resolve, even partially. You don’t mention the type of battery but if they are open wet cell batteries they might be partially recoverable by a higher voltage charge at say 15.5v for a few hours. But whether you have the equipment to do that is unlikely.

 

The number one most important thing with lead acid batteries is to properly fully charge them regularly, and that means holding the 14.4v until the current decreases to 1 or 2% of capacity. If you don’t, they lose capacity rapidly.

 

May I suggest you have a good read of the first post in this thread, it tells you everything you need to know:

 

 

Thank you. Yes, for sure, I’ll read through that. 
The batteries didn’t actually get any worst or better in time. When the system was installed there was so much solar going in we didn’t notice any problems. With solar working from when we were waking up to 8 pm... 

As soon as the light changed we realise that unless there is constant charge going in they weren’t holding much. It didn’t  metter if we were cruising for an entire day or only having the engine on for a couple of hours in the evening they still only lasted, and still only last to this day, about 4 hours ?. Literally nothing changed since we got them installed. 

 

also, if the batteries were damaged Would that show up in the test run by the electrician? Each battery was tested separately and they all come up as working perfectly fine.
 

So confusing...

 

[Alan de Enfield]

5 minutes ago, AliceRosano said:

Thank you. Yes, for sure, I’ll read through that. 
The batteries didn’t actually get any worst or better in time. When the system was installed there was so much solar going in we didn’t notice any problems. With solar working from when we were waking up to 8 pm... 

As soon as the light changed we realise that unless there is constant charge going in they weren’t holding much. It didn’t  metter if we were cruising for an entire day or only having the engine on for a couple of hours in the evening they still only lasted, and still only last to this day, about 4 hours ?. Literally nothing changed since we got them installed. 

 

also, if the batteries were damaged Would that show up in the test run by the electrician? Each battery was tested separately and they all come up as working perfectly fine.
 

So confusing...

 

 

How were ther batteries tested ?

 

The common method used by 'electricians' is to use a tester as used in garages to test car starter batteries, this entails a short circuit for a few seconds and does not work on a battery bank of leisure batteries.

 

Anyone who has an understanding of 12v electrics and batteries (and how they work) will do a controlled discharge test.

 

This is why I asked you earlier if you understood, or could do, a discharge/capacity test.

You are most likely wasting your time with 'electricians', you need someone with detailed 12v boat electrics knowledge.

Edited March 15, 2021 by Alan de Enfield

[Tracy D'arth]

58 minutes ago, AliceRosano said:

Hi! Thanks for the reply.

we keep the engine running until our battery monitor shows 14.4v. Turn the engine off then, voltage drops to 12.8 or 7... 

Turning the inverter off a night sounds like a good idea but it still doesn’t explain the situation...

 

Honestly, the fridge is only plugged in for 9/10 hours a day and only actually on for like 15 min an hour sometimes even less so it doesn’t explain the energy consumption 

You have ruined your batteries by not fully charging. The voltage is not the yard stick, its the final charging current that you need to monitor. You keep charging till the current falls to around 2% or less of the battery bank capacity.

[nicknorman]

16 minutes ago, AliceRosano said:

Thank you. Yes, for sure, I’ll read through that. 
The batteries didn’t actually get any worst or better in time. When the system was installed there was so much solar going in we didn’t notice any problems. With solar working from when we were waking up to 8 pm... 

As soon as the light changed we realise that unless there is constant charge going in they weren’t holding much. It didn’t  metter if we were cruising for an entire day or only having the engine on for a couple of hours in the evening they still only lasted, and still only last to this day, about 4 hours ?. Literally nothing changed since we got them installed. 

 

also, if the batteries were damaged Would that show up in the test run by the electrician? Each battery was tested separately and they all come up as working perfectly fine.

So confusing...

It’s not possible to test a leisure battery in a few minutes. The electrician is perhaps using a car type load tester which indicates whether a battery is OK as a starter battery - starter battery has to supply a very high current but only for a few seconds, with a total discharge of perhaps 1Ah.

 

The only way to test a leisure battery is to fully charge it, then discharge it whilst measuring the Ah taken out, until the battery reaches a low voltage of say 12.2v (which is about 1/2 the capacity, so the actual capacity is this times 2). That takes many hours per battery.

[ditchcrawler]

If your batteries are at 12.2 volts to fully recharge them would need the engine running for about 8 to 10 hours at well over tickover to get near to fully charged.

 

How much solar do you have, I know its doing nothing now but could give us a clue as to whats been happening

[AliceRosano]

1 minute ago, ditchcrawler said:

If your batteries are at 12.2 volts to fully recharge them would need the engine running for about 8 to 10 hours at well over tickover to get near to fully charged.

 

How much solar do you have, I know its doing nothing now but could give us a clue as to whats been happening

Thank you. We have 4 panels 320watt each.. we also have a sterling Alternator to battery charger which should speed up the charging process from the engine 

[Tony Brooks]

Although expensive please don't feel too bad about this. Your experience is exceptionally common with new boaters who have not yet got to grips with battery charging.

 

Running the engine at whatever speed gives the highest charging amps for many hours, probably over 12 hours, will hopefully restore at least some of the lost capacity but it won't restore it all. You can reduce the revs as the charging current drops but keep it at the speed that's delivering the highest charge it can.

 

Please ignore any battery monitor reading that purport to tell you how well charged the batteries are, it's probably a lie. Stick with the tail current at 14.4V + as described above.

 

NO, the Sterling will not make a significant difference to charging time to fully charged. It will get to a part charged level sooner that without it but from then on it may well make things worse because I think it drops to float and such devices usually drop to float too early so you can no longer get 14.4V +

 

If t drops the charging voltage to below 14.4 before the tail current is 1% to 2% of battery capacity then its making things worse. If that happens it may pay you to  learn how to bridge the input and output once a week when you fully charge the batteries

 

You may also find the solar drops to float before the batteries are fully charged.

[Tony Brooks]

14 minutes ago, nicknorman said:

It’s not possible to test a leisure battery in a few minutes. The electrician is perhaps using a car type load tester which indicates whether a battery is OK as a starter battery - starter battery has to supply a very high current but only for a few seconds, with a total discharge of perhaps 1Ah.

 

The only way to test a leisure battery is to fully charge it, then discharge it whilst measuring the Ah taken out, until the battery reaches a low voltage of say 12.2v (which is about 1/2 the capacity, so the actual capacity is this times 2). That takes many hours per battery.

 

It is possible to do a test of leisure batteries in a fairly short time providing they are properly topped up open cell batteries. Once the batteries have been off charger for more than an hour or so AND a load has been drawn from them you can infer the state of charge from the voltage. If you then do a hydrometer test to measure the acid density that will also give you the state of charge. Both should be more or less the same and the greater the difference the more sulphated the batteries will be.

[nicknorman]

8 minutes ago, Tony Brooks said:

 

It is possible to do a test of leisure batteries in a fairly short time providing they are properly topped up open cell batteries. Once the batteries have been off charger for more than an hour or so AND a load has been drawn from them you can infer the state of charge from the voltage. If you then do a hydrometer test to measure the acid density that will also give you the state of charge. Both should be more or less the same and the greater the difference the more sulphated the batteries will be.

Well without wishing to confuse the OP too much, I’d disagree to some extent. One reason for loss of capacity is excessive material shed from the plates, which can occur without sulphation. Your strategy only identifies capacity lost to sulphation.

[Tony Brooks]

I agree but suspect if significant shedding had taken place a cell would have shorted. At least it would be more accurate than a discharge tester.

[nicknorman]

28 minutes ago, AliceRosano said:

Thank you. We have 4 panels 320watt each.. we also have a sterling Alternator to battery charger which should speed up the charging process from the engine 

The Sterling A2B does speed up mid-charge charging quite a bit, overall charge time to a modest extent. But it also means the voltage reaches 14.4v at a lower state of charge than it would have done without the A2B.

 

Unfortunately lead acid batteries are obstinate things and you simply can’t force charge into them quicker than they will accept it, which in the latter stages of charging is quite slow.