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charging - possible dying battery


Murflynn

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I have a bank of 4 x 110AH leisure batteries connected in parallel that I use for motor power in my wee yogurt pot.  I have a separate bank of 2 batteries used as a reserve if the big bank dies.  On my last trip I found the big bank lasted no longer than the small bank. 

 

I have separated the 4 batteries in the main bank and they all tested about 12.2V. 

 

I charged them separately using a PACO '7 stage' charger.  3 batteries took about 2 hours each on bulk, 2 hours on 'absorption' and then went to 'conditioning' in one case and fully charged in the other cases.  One 'bad' battery went straight to 'absorption' for a short while, then to fully charged.   A few hours later I tested all 4 batteries under no load.  The 3 good ones were at 13.1V, the bad one was at 12.7V.   

 

The question is, is the 'bad one' due for replacement, and is it dragging the others down with it? 

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10 minutes ago, Murflynn said:

I have a bank of 4 x 110AH leisure batteries connected in parallel that I use for motor power in my wee yogurt pot.  I have a separate bank of 2 batteries used as a reserve if the big bank dies.  On my last trip I found the big bank lasted no longer than the small bank. 

 

I have separated the 4 batteries in the main bank and they all tested about 12.2V. 

 

I charged them separately using a PACO '7 stage' charger.  3 batteries took about 2 hours each on bulk, 2 hours on 'absorption' and then went to 'conditioning' in one case and fully charged in the other cases.  One 'bad' battery went straight to 'absorption' for a short while, then to fully charged.   A few hours later I tested all 4 batteries under no load.  The 3 good ones were at 13.1V, the bad one was at 12.7V.   

 

The question is, is the 'bad one' due for replacement, and is it dragging the others down with it? 

Without knowing what the output of the charger is, and without knowing at what 'state' it drops from 'bulk' to 'absorption' to 'conditioning' its going to be guesswork.

 

It doesn't look good for the 'bad' battery, but 12.7 is the normal voltage for a fully charged battery. Really you should try the following tests :

 

Fully charge each battery until the charge has dropped to below 2 amps for at least an hour (1 amp would be better if you can get there).

Put a known load (say 50 watts, or 100 watts) and see how long it takes to drag the battery down to about 12.0 - 12.1 volts.

Switch off the load and the battery should recover to about 12.2 volts.

 

Say it has taken 4 hours to drop to 12.2 volts.

12.2 volts is about 50% SoC

 

Using W=A x V then using a 100 watt load for 4 hours your battery capacity is down to about 65Ah from its original 100Ah

If you used a 50w load and it lasted 4 hours then the battery capacity is now down to about 32 Ah

 

When charging the 'bad' battery look to see if it gets warm, there is any sign of 'bad smell' or the case is bowed at the ends - this would all be signs of an internal short, in which case disconnect it immediately and scrap it.

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19 minutes ago, Murflynn said:

I have a bank of 4 x 110AH leisure batteries connected in parallel that I use for motor power in my wee yogurt pot.  I have a separate bank of 2 batteries used as a reserve if the big bank dies.  On my last trip I found the big bank lasted no longer than the small bank. 

 

I have separated the 4 batteries in the main bank and they all tested about 12.2V. 

 

I charged them separately using a PACO '7 stage' charger.  3 batteries took about 2 hours each on bulk, 2 hours on 'absorption' and then went to 'conditioning' in one case and fully charged in the other cases.  One 'bad' battery went straight to 'absorption' for a short while, then to fully charged.   A few hours later I tested all 4 batteries under no load.  The 3 good ones were at 13.1V, the bad one was at 12.7V.   

 

The question is, is the 'bad one' due for replacement, and is it dragging the others down with it? 

The dodgy battery won't bring the others down unless it has an internal short.  You could put it at the end of the bank with a lug mounted isolator switch to be switched in for a bit of an extra boost in an emergency,

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3 hours ago, Alan de Enfield said:

Without knowing what the output of the charger is, and without knowing at what 'state' it drops from 'bulk' to 'absorption' to 'conditioning' its going to be guesswork.

 

It doesn't look good for the 'bad' battery, but 12.7 is the normal voltage for a fully charged battery. Really you should try the following tests :

 

Fully charge each battery until the charge has dropped to below 2 amps for at least an hour (1 amp would be better if you can get there).

Put a known load (say 50 watts, or 100 watts) and see how long it takes to drag the battery down to about 12.0 - 12.1 volts.

Switch off the load and the battery should recover to about 12.2 volts.

 

Say it has taken 4 hours to drop to 12.2 volts.

12.2 volts is about 50% SoC

 

Using W=A x V then using a 100 watt load for 4 hours your battery capacity is down to about 65Ah from its original 100Ah

If you used a 50w load and it lasted 4 hours then the battery capacity is now down to about 32 Ah

 

When charging the 'bad' battery look to see if it gets warm, there is any sign of 'bad smell' or the case is bowed at the ends - this would all be signs of an internal short, in which case disconnect it immediately and scrap it.

but why does it not go to bulk charging for an hour or two like the others?

 

20A charger.

 

I'll run some load tests, as you suggest.

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Just now, Mike the Boilerman said:

Like I said a few months go, the answer to all battery questions is "they are knackered mate, because you aren't charging them enough."

..... Cos you're smartgauge is lying. 

 

 

(lets go round again......) 

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If you do Alan's tests on each battery, it will tell you the answer but will take a long time. 

If you haven't the time, do it on the bad one first. I'd expect good batteries to hold the surface charge at 13v+ for a few hours so there is defo something wrong with the duff one. My starter battery is on it's final fling and drops to 12.7v after 2 hours rest and 12.5v overnight. I'll be getting a new one before winter.

Take the bad one out of circuit and test the other 3 together (saves you half the time) to see what capacity they have left. 

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9 hours ago, Dr Bob said:

If you do Alan's tests on each battery, it will tell you the answer but will take a long time. 

If you haven't the time, do it on the bad one first. I'd expect good batteries to hold the surface charge at 13v+ for a few hours so there is defo something wrong with the duff one. My starter battery is on it's final fling and drops to 12.7v after 2 hours rest and 12.5v overnight. I'll be getting a new one before winter.

Take the bad one out of circuit and test the other 3 together (saves you half the time) to see what capacity they have left. 

thanks, that makes a lot of sense.  :cheers:

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13 hours ago, rusty69 said:

..... Cos you're smartgauge is lying. 

 

 

(lets go round again......) 

 

Ok :)

 

Are you saying when my Smartgauge gets up to 100% when I'm charging the batteries, it might not be right? That's ridiculous. What is a Smartgauge for if not for telling you when your batteries are charged?

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1 minute ago, Mike the Boilerman said:

 

Ok :)

 

Are you saying when my Smartgauge gets up to 100% when I'm charging the batteries, it might not be right? That's ridiculous. What is a Smartgauge for if not for telling you when your batteries are charged?

I think its meant more as a "fuel gauge"  type instrument that possibly works better showing battery discharge rather than when charging.

 

Obviously it must be correctly calibrated in the first place, in order to achieve a meaningful reading. 

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Just now, rusty69 said:

I think its meant more as a "fuel gauge"  type instrument that possibly works better showing battery discharge rather than when charging.

 

Obviously it must be correctly calibrated in the first place, in order to achieve a meaningful reading. 

 

Would a 'fuel gauge' not say 100% when the tank (battery) is full then?

 

Do some not come correctly calibrated then? Who has to calibrate them? How would a user find out if theirs was not correctly calibrated?

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1 minute ago, system 4-50 said:

For only £200 I will happily calibrate your SmartGuage.  If you have any doubts after this is done I will happily calibrate it again for a further £200 per time.

 

Do you recommend ALL Smartgauge owners have theirs checked and calibrated then?

 

I have three so that will be a LOT of money. But then they are spread far and wide across the country so that's a LOT of traveling you'll have to do....

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3 minutes ago, system 4-50 said:

For only £200 I will happily calibrate your SmartGuage.  If you have any doubts after this is done I will happily calibrate it again for a further £200 per time.

I'll do it for £190 each, or £500 for all 3.if you want to sell...... 

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3 hours ago, Mike the Boilerman said:

 

DEAL!

 

You can have all three for £500. I can buy three more for about £400 including postage.

But can you be sure that the new ones will be correctly calibrated, or will you need to spend another £500 for calibration, just to be on the safe side :) :( 

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11 hours ago, Mike the Boilerman said:

 

Do you recommend ALL Smartgauge owners have theirs checked and calibrated then?

 

I have three so that will be a LOT of money. But then they are spread far and wide across the country so that's a LOT of traveling you'll have to do....

You just post them to me.  Once you can prove to me that you have posted them, then, by a clever form of temporal travel, I can post them, calibrated, back to you before I have received them, saving your valuable time.

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1 hour ago, system 4-50 said:

You just post them to me.  Once you can prove to me that you have posted them, then, by a clever form of temporal travel, I can post them, calibrated, back to you before I have received them, saving your valuable time.

 

Feck moi, for £500 I thought you'd at least come to me!

 

WHAT a rip off!!!

 

(I can post them back to Merlin for recalibration for nothing, remember?)

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1 minute ago, Mike the Boilerman said:

 

Feck moi, for £500 I thought you'd at least come to me!

 

WHAT a rip off!!!

 

(I can post them back to Merlin for recalibration for nothing, remember?)

Post him an empty envelope, Special Delivery.  Tell him there are three Smartguages and a cheque for £500 in the package.

 

Then you'll have six times the fun :D

 

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I should have realised that anything leccy related would bring MtB off his perch and we would enter an :offtopic: pub brawl over the use of Gibbo's algorithms.  Each time I check for any useful contributions I am disappointed :mellow:.   

 

Please Mr Moderator - put this crap in the VP.   :unsure:    

 

:banghead:    

 

......  as for me - I will just go away and buy a new battery.  For £70 it's worth it, to avoid following this unintended thread deterioration.  :P  

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8 minutes ago, Murflynn said:

I should have realised that anything leccy related would bring MtB off his perch and we would enter an :offtopic: pub brawl over the use of Gibbo's algorithms.  Each time I check for any useful contributions I am disappointed :mellow:.   

 

Please Mr Moderator - put this crap in the VP.   :unsure:    

 

:banghead:    

 

......  as for me - I will just go away and buy a new battery.  For £70 it's worth it, to avoid following this unintended thread deterioration.  :P  

To be fair, it was probably my fault. 

 

Oh, the guilt!  I will go away and sit on the naughty step...... 

Edited by rusty69
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36 minutes ago, Murflynn said:

I should have realised that anything leccy related would bring MtB off his perch and we would enter an :offtopic: pub brawl over the use of Gibbo's algorithms.  Each time I check for any useful contributions I am disappointed :mellow:.   

 

Please Mr Moderator - put this crap in the VP.   :unsure:    

 

:banghead:    

 

......  as for me - I will just go away and buy a new battery.  For £70 it's worth it, to avoid following this unintended thread deterioration.  :P  

It is surprising that there weren't more useful posts. The usual suspects must be doing something very important. How did you get on doing Alan's test on the dead battery? I would be interest in the result to get a better handle on the capacity of dying batteries.

 

The banter does keep the thread at the top of the list in case anyone clever does show up...so don't despair too much!

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