Battery Problem ?any ideas?

[vindiboy]

I have three leisure batteries 80 amp hr Gel connected together, 80 watt Solar Panel via Fox Control, currently reading 14 .4 volts, and obviously charger on hook up and engine charging, The third battery in the line is reading 11.5 volts on the tester, I would have thought that all the Batteries should give the same reading as they are coupled together as I said and the first one is at 14-4v on the tester, Is something wrong, the system has been in use for 7 years with no changes or problems, fuses are good .Any help appreciated.

[flicka]

Hi Malc,

Not absolutely sure, but I suspect the Battery showing 14.4V may have a Cell going down & drawing the current from the others.

What is the middle Battery voltage ?

 

Hopefully Brambles or Clive will be along shortly, for a more definative answer.

[vindiboy]

flicka - 2011-04-15 9:13 PM

 

Hi Malc,

Not absolutely sure, but I suspect the Battery showing 14.4V may have a Cell going down & drawing the current from the others.

What is the middle Battery voltage ?

 

Hopefully Brambles or Clive will be along shortly, for a more definative answer.

Hi Flika, it's 12.5 volts.thanks.

[Keithl]

Malc,

 

If you disconnect the negative of each battery in turn what is the voltage of that battery then? This may answer the question of whether a battery is failing.

 

Keith.

 

Edit, How can the voltages be different when they are all coupled in parallel? (unless there is a large resistance in the connecting wires).

[Guest Tracker]

As Keith says, if all three are properly conected with clean and tight connections they MUST all show the same voltage near enough?

 

Which suggests dirty or loose connections or an internal break in the connecting cables?

 

The only way that I know to test batteries is to fully charge each one individually and check the voltages and/or specific gravity afterwards and after a 24 hours resting period and before they are all reconnected.

 

My first suspicions would fall on the connecting cables being dirty or damaged?

[Brambles]

As Flicka as mentioned me, I shall respond. Yep! I go along with the comments on bad connections.

 

Assumming you have direct cables linking the batteries together then they should all read the same in effect.

If they are different then you have high resistance somewhere so measure the volts beween respective positives, and then respective negatives. Should be in effect zero volts between positives, and ditto for negatives so may highlight the problem connections.

 

However I suspect, just slightly, that your batteries may be connected serperatly to the controller to individual battery connections. If so then I would suggest the batteries may be failing.

 

However going back the the connecting cables, the most likely problem will be any crimped terminals.

It is also possible because the 2nd and 3rd batteries are reading low volts then they will have sulphated over time and no longer have much Ah capacity.

Jon.

 

 

 

[vindiboy]

Hi Guys, well today I removed both front seats from the Hymer so I could get to Battery 1 and 2 properly and as expected there were bad and loose connections so that is what the problem was, I have remade the connections and tightened the nuts on the fuse carriers,quite loose they were, so now all appears to be well, a reading of 14-1 volts across the terminals of two of the batteries and 14v on the third, but there is a longer cable run to that one so that is to be expected.So many thanks for your responses and help. I have my Ferry booked now,out on Wednesday 20th back 27th July, Sea France via CCC £118 .best I could find, more expensive Dover Dunkerque Norfolk line, so any way I am happy with that.so Norway here we come,thanks again Malc. :-) :-) :-) :-) :-) :-)