Battery voltage readings.

[canals are us?]

Around sunday I disconnected 2 of my 110amph batteries as they were not indicating green on the viewing window and the 20amp battery charger wasn't going into float, I asked about them on this thread of Blackrose's here:

http://www.canalworld.net/forums/index.php?showtopic=57351

 

I disconnected them and took voltage readings on Sunday after they had been charging for 4 days, then further voltage readings later after resting disconnected.

 

The readings were:

 

Battery 1

 

Sunday 13.02v

Tuesday 12.67v

Today 12.63v

 

Battery 2

 

Sunday 12.98v

Tuesday 12.75v

Today 12.73v

 

Are they OK or need replacing?

 

After 5 hours of these two batteries being disconnected the battery charger went into float, coincidence?

 

Thanks James

Edited June 14, 2013 by canals are us?

[nicknorman]

The voltage readings look fine but that is not the be all and end all of battery health. What may be happening is simply that you have a largish battery bank and a smallish charger, and as the batteries have aged slightly the leakage current has just exceeded the minimum current required for the charger to go into float. Removing some batteries reduces the leakage current proportionally and allows the charger to go into float. It might be better to reconnect all the batteries and have a look in the cells whilst charging. If one cell or battery is bubbling mre than others, that might indicate an ageing battery. That presumes you have open wet cell batteries.

 

Oops just read the other thread and they are sealed. Try checking the charge current of each battery with a clamp meter. If you don't have one, get a DC one from ebay for <£30.

Edited June 14, 2013 by nicknorman

[Grace and Favour]

 

Your batteries may not be perfect - - but I would have thought there's life in them yet (tho' I'm NOT a sparky!)

[canals are us?]

The voltage readings look fine but that is not the be all and end all of battery health. What may be happening is simply that you have a largish battery bank and a smallish charger, and as the batteries have aged slightly the leakage current has just exceeded the minimum current required for the charger to go into float. Removing some batteries reduces the leakage current proportionally and allows the charger to go into float. It might be better to reconnect all the batteries and have a look in the cells whilst charging. If one cell or battery is bubbling mre than others, that might indicate an ageing battery. That presumes you have open wet cell batteries.

 

Oops just read the other thread and they are sealed. Try checking the charge current of each battery with a clamp meter. If you don't have one, get a DC one from ebay for <£30.

 

Thanks, what you say makes perfect sense. What I will do is try reconnecting just one battery and see how it goes while I await a clamp meter. Any you recommend?

 

 

Your batteries may not be perfect - - but I would have thought there's life in them yet (tho' I'm NOT a sparky!)

 

Hi, I'm hoping there is too but if not I'll just run on the 2 working ones for know as I have mains hookup anyway so not totally dependant on them and replace them when essential.

 

Thank you both

 

James.

[nicknorman]

Thanks, what you say makes perfect sense. What I will do is try reconnecting just one battery and see how it goes while I await a clamp meter. Any you recommend?

 

James.

Yes, a UNI-T UT203. You will find them on ebay. If you choose a different model take are that it does DC current as some only do AC current and so are no use to you.

[smileypete]

I'd leave them disconnected for now and recheck voltage every few days, if they're sealed batts but they keep losing charge it's not a good sign.

 

Another thing to try would be put a 5 amp/60 watt load with fuse on them for 6 hours say and recheck the voltage after a rest.

 

Be sure to follow the precautions in The Battery FAQ, they also have tables of voltage vs charge.

 

cheers, Pete.

~smpt~

Edited June 15, 2013 by smileypete

[canals are us?]

Yes, a UNI-T UT203. You will find them on ebay. If you choose a different model take are that it does DC current as some only do AC current and so are no use to you.

Thanks for the info, will check it does DC current

 

I'd leave them disconnected for now and recheck voltage every few days, if they're sealed batts but they keep losing charge it's not a good sign.

 

Another thing to try would be put a 5 amp/60 watt load with fuse on them for 6 hours say and recheck the voltage after a rest.

 

Be sure to follow the precautions in The Battery FAQ, they also have tables of voltage vs charge.

 

cheers, Pete.

~smpt~

Oh dear about loosing current! I have reconnected them and will give it a few days and see what happens, then do a clamp test or just run off the two working batteries for now. Money is tight atm.

 

Thanks James

Edited June 15, 2013 by canals are us?

[smileypete]

I'd rather not leave a suspect batt unattended on a high power charger.

 

If it's a sealed batt that's losing rapidly losing charge then it's very likely to be kaput and not worth spending more time on. It may be a cell is losing charge and that's caused water loss in the other cells too.

 

cheers, Pete.

~smpt~

Edited June 16, 2013 by smileypete