Optima battery problem

[fjweaver]

I needed to replace my 2nd battery & bought a 4-5 year old used one (Optima) from my brother-in-law. This is to be used both for starting & leasure.

When I went to the boat at the weekend it was completely flat (having been fully charged a couple of weeks ago) and so I charged it overnight. After that it showed 11.4v.

When I tried to test it for starting and was as if it was flat, the starter just clicked. I was worried that there was a problem on the circuit for the 2nd battery so I swapped over with my starter battery (also Optima yellow top ) and got the same result - so there's something wrong with the 'new' one. It seemed to power the lights, GPS etc ok and is now reading 11.2v

I know that it had never been used as a starter before as my brother in law's boat only had an outboard & he used it purely for lights, nav etc taking it home to re-charge.

It's been kept charged but not used for the last year or so and kept in his garage

Any ideas what the problem could be?

 

[KenMcCulloch]

A fully charged battery should show something like 12.6 -12.7 volts so i think the answer, sadly, is that your brother-in-law has sold you a battery that has reached the end of its useful life.

 

[Chris_Robb]

Do check the battery wiring. I recently bought a new battery thinking I had a duffer. Turned our to be the battery clamps. If you have the type that have screw clamps holding the cable, then suspect them - and get them replaced anyway with crimped terminals.

 

[fjweaver]

I don't think it's the connections since I swapped the 2 batteries around. My existing battery worked in both positions/connections and the other failed in both

 

[KenMcCulloch]

[ QUOTE ]
I don't think it's the connections since I swapped the 2 batteries around. My existing battery worked in both positions/connections and the other failed in both

[/ QUOTE ]
That does suggest that the battery is probably knackered. Even an expensive battery like Optima has a finite life and if it's 4or5 years old it would probably be time to think about replacing it anyway. It may also be that the way it has been used (low current draw and then recharging with a very basic charger [I am guessing]) may not have been the best thing. Cut your losses (or see if b-i-l is willing to take the loss), and buy a new one. No need to spend lots, if the boat is in regular use a new 'leisure' battery from Powermax or similar every 4 or 5 years or so will do you fine and not cost the earth.

 

[andy_wilson]

I agree with Ken. A 4-5 year old battery that has been stood for a year?

Knackered!

 

[fjweaver]

he did charge it regularly with one of the decent maintenance chargers - surely that would be ok for the battery?

 

[VicS]

[ QUOTE ]
I charged it overnight. After that it showed 11.4v.

[/ QUOTE ] Thats still flat.

A fully charged battery should read, as already said, around 12.7 after resting for 12hours. 12.8 even when still newish. The volts will fall fairly quickly at first if monitored daily but progressively more slowly taking several weeks before the volts fall to 12.5 ish

Anything below 11.7 is effectively flat. The relationship between state of charge and volts is virtually linear so 12.2 is half charged.

With only an outboard for charging it probably spent a lot of its early life not fully recharged unless it was always taken home for recharging.

It is said that a battery should not be left standing on a concrete floor!!!! Don't know why not!

 

[pvb]

Old wives\' tale...

[ QUOTE ]
It is said that a battery should not be left standing on a concrete floor!!!! Don't know why not!

[/ QUOTE ]No truth in this at all! Doesn't matter what the surface is.

 

[VicS]

Re: Old wives\' tale...

[ QUOTE ]
Doesn't matter what the surface is

[/ QUOTE ] That would have been my thoughts.. don't leave a battery standing on any floor then!

 

[michael_w]

Re: Old wives\' tale...

[ QUOTE ]
[ QUOTE ]
Doesn't matter what the surface is

[/ QUOTE ] That would have been my thoughts.. don't leave a battery standing on any floor then!

[/ QUOTE ]

Err...Why not?

 

[VicS]

Re: Old wives\' tale...

[ QUOTE ]
Err...Why not?

[/ QUOTE ] The truth is that it is a cold surface that a battery should not be left standing on..hence the advice not to leave it standing on a concrete floor.

If the bottom of the battery is cold compared with the top because electode potentials are temperature dependent a small emf develops between the top and bottom of the plates which results in a small current circulating, not between the plates and an outside circuit as in normal use but between the tops and bottoms of the individual plates. This results in the deposition of lead sulphate on the plates which builds up slowly over time and as it is almost impossible to remove by normal charging simply adds to the rate at which a battery deteriorates.

 

[pvb]

Don\'t think so...

[ QUOTE ]
The truth is that it is a cold surface that a battery should not be left standing on..hence the advice not to leave it standing on a concrete floor.

[/ QUOTE ]I think the real truth is that in olden days batteries had hard rubber cases which had a fairly high carbon content. If they were stored on a concrete floor, inevitable condensation could cause stray currents leading to premature discharge.

As far as cold surfaces are concerned, a lower battery temperature will lessen the rate of self-discharge.

 

[VicS]

Re: Don\'t think so...

[ QUOTE ]
As far as cold surfaces are concerned, a lower battery temperature will lessen the rate of self-discharge

[/ QUOTE ] Overall at a lower temperature by storing in a cool place but not where a temperature gradient will be created between the top and bottom.

Stray currents across a damp surface could cause a slow discharge but that could be overcome by periodic recharging, as can self discharge. Sulphation is what causes the permanent deterioration.