Advice On Leisure Batteries (1 Viewer)

[Pikeman]

I know there are some very wise one's among you that are hot on this subject, so;

We have a 2001 Benimar, that has twin leisure batteries. We have had the van 4 years now and therefore do not know the age of the batteries. I am trying to establish if the batteries are still viable. We have a battery display that reads the charge percentage and the volts. It has not been on charge or driven for 5 days. The display shows as low as 40%, but volts 12.4 . I have got hold of a Clarke's battery tester and tried it on both batteries - (A) good 12.7 volts, under load 12 volts (B) 13.5 volts, under load 12.7 volts. The batteries also have a condition indicator on the top, which if believed, shows as good condition.

Can I assume that the batteries are good and therefore the display panel is crap?

Is there a more definitive way of testing them?

Cheers,

Keith

 

[funflair]

If they are both standard lead acid testing volts should be 12.7 after resting off charger so 13.5 suggests not rested. How far it drops on load depends partly on the load size but I would say 12 on load is too low and suggests a problem, if they are on together they should read the same, at least one could be duff. If you want to test the available capacity you need to fully charge both and then rest them, then connect a known load of say 5 or 10 amps and monitor the voltage drop, 10 hours at 5 amps is 50ah which is as much as you can safely take from 100ah, the voltage should be around 12 volts when you have finished. Don't let them go below 12.

 

[Landyguy]

Jumping onto this leisure battery thread -
Maybe a silly question but have checked my leisure battery today on a 2013 Autotrail Tribute T715 -
I have been thinking of putting in an extra battery under the front passenger seat but would like to verify the power of my present battery as much smaller than I thought it would be - maybe better to increase the size of present leisure battery as plenty of extra space in its hole -
On the battery it says the following -
model # 685L - Platinum Leisure battery - nothing else apart from a serial number.
Does this mean it is a 68.5 amp hour battery?

 

[Wildbill]

Jumping onto this leisure battery thread -
Maybe a silly question but have checked my leisure battery today on a 2013 Autotrail Tribute T715 -
I have been thinking of putting in an extra battery under the front passenger seat but would like to verify the power of my present battery as much smaller than I thought it would be - maybe better to increase the size of present leisure battery as plenty of extra space in its hole -
On the battery it says the following -
model # 685L - Platinum Leisure battery - nothing else apart from a serial number.
Does this mean it is a 68.5 amp hour battery?

go to a motor factors and get them tested first or some one you know it is always best to pare them up as new
bill

 

[Landyguy]

Just done more googling and it is a 85 Amp Hour battery. Doh!

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[teensvan99]

Hi. landguy
It is always best to use two leisure batteries of the same age and Ah. A 2 year old battery may be 70% as good as when new so putting one new battery onto a 2 year old battery system will drag the new one down to the old ones level most times. Most of us use 100Ah batteries as a norm. Have you thought of a solar panel of around 120Watt. That will give a good boost to any system and should keep you going all summer without hook up where ever you are and keep batteries topped up all winter of hook up.

steve & ann. ------------- teensvan99

 

[Pikeman]

Excuse me folks, can we get back to MY original enquiry on this thread. Thanks for the hijack 'landguy.'

 

[Landyguy]

Thought of a solar panel but probably not enough time to sort out before we go away - maybe easier to put a larger battery in the hole where the present one is and look into extra battery or solar panel later on -
The hole dimensions are L - 260mm, W - 170mm, H - 190mm. with room to spare. - Anyone know what is largest AH at this size? and pricing roughly?
The present battery is lead/acid vented.

 

[Landyguy]

My apologies - sorry about that - oops.

 

[teensvan99]

Hi Pikeman.

4 year old batteries may be well on there way out some are better than others all depending on how they have been looked after. A lot of people only think to look at a battery when it is flat and left for a few weeks. Not good at all. Best for you I would change for new but that is up to you. Around £160>£180 for a pair of good 100Ah. You do need to check batteries every 3 months to see if cables connections are ok and top up if they need it.

steve & ann. ----------------- teensvan99

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[teensvan99]

Sorry for up setting anyone so quickly. Will keep my fingers off the keys.

 

[pappajohn]

(A) good 12.7 volts, under load 12 volts (B) 13.5 volts, under load 12.7 volts.

If both batteries are interconnected in parallel you cannot have two different voltages at two different batteries.

If one reads, unconnected from each other, 12.4v and the other 12.6v the total meter reading when connected together will be 12.5v

 

[Pikeman]

Hi Pappajohn. They are interconnected. Tested them independently and readings were as stated. What do you think that means?

Keith

 

[funflair]

@Pikeman If your readings are correct you need to let them rest off charge and disconnected from each other for a longer period and then tell us what load you put on to take one down to 12 volts.

Martin

 

[pappajohn]

Hi Pappajohn. They are interconnected. Tested them independently and readings were as stated. What do you think that means?

Keith

That means your meter is knackered.

Connected together the independant voltage becomes one combined average voltage.
even connecting a 12v to a 6v will show 9v.
the only way to check a battery while connected to another is with a hydrometer to measure specific gravity.

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[funflair]

I thought when he said tested them independently he had removed them and tested them "independently" doh.

Martin

 

[Pikeman]

Sorry for the vague statements guys. Now you explain, it is bloody obvious to me that the readings should be the same. I have come to the conclusion that something is definitely not right and as I have just found two 100ah units that fit perfectly for £154 delivered. I am going to invest in a new pair.
Thanks for your input.

Keith

 

[PhilandMena]

Just thought I would support Martin's first reply in that a load test is the best way to establish the condition of your batteries. Do not forget to allow the batteries sufficient time to recover after the load has been removed before measy ring state. If you are replacing your leisure batteries you can't go wrong with Banner batteries, recognized as the best available.

 

[pappajohn]

I thought when he said tested them independently he had removed them and tested them "independently" doh.

Martin

That was my first thought....until i read it a little more carefully.