Leisure Battery

[ChrisD]

Hi everyone

 

Could someone please tell me how to test my Leisure battery.

 

I know to take it off the charger and the campervan and measure the voltage an hour later and to compare an hour after that.

 

But the question is, at what voltage would it be considered to be failing?

 

All advice gratefully received.

 

Chris

 

 

[lennyhb]

1) Best way of testing a leisure battery is to fully charge it, let it rest for an hour then & check the voltage:-

2) Place a load on it of say 5 amps (can do this in the van by turning on lights etc.).

3) Leave it with the load for a time that equates to 25% of battery capacity (100A/H battery it would be 5 amps for 5 hours).

4) Turn the load off let the battery settle for ½-1 hour measure the voltage, the battery will now be @ 75% state of charge.

5) Repeat 3, battery will now be @ 50% state of charge.

6) Repeat 3, battery will now be @ 25% state of charge.

[aandncaravan]

The test that Lenny suggests is the usual one advocated and perfectly valid for testing the ability of a battery to deliver power over a short time period.

Generally, very broad brush, it tests the quality of the 'Paste' on the plates, but it doesn't mean the battery will actually perform well in all circumstances as there can be several types of different battery degradation that affects a battery performance. For example it's ability to hold charge over a longer period.

 

Imagine a battery where some material has become dislodged from a Plate so causing a small bridge of the Plates. The battery may still charge up, and discharge in an acceptable manner, so pass the above test.

But if you left it for 2 weeks you might find it self discharges very quickly down to 11.8v.

 

There are other areas of degradation inside a battery, like Corrosion on the Grids, that result in a battery passing the above test, but only by taking a much greater Current than a new battery.

 

For example a battery might require 30% more current to charge up, say a total of 120Ah to give back 80Ah, which might be considered a 'pass' in the above test.

When charging up on the Alternator or Solar Panel that might result in the battery taking one third longer to charge.

 

 

For a Solar Panel powered 'Free Camper' that might be the difference between getting through the evening on a days charge or losing the lights by 21:00?

 

 

In order to try and test a batteries capability across a broader spectrum of internal issues, not just a short tem load test, we would suggest you add a 'pre test' :

 

Before you start the above, charge the batteries fully, for at least 24 hours on a decent Motorhome charger or 48 hours if on the average CTEK Car battery charger.

 

Then wait 2 weeks before initiating the above experiment.

 

If the battery is good it won't have dropped at all, still be over 12.8v.

 

 

When performing the above test we would advise caution in dropping a battery below 50% discharge as many batteries will suffer shortened life.

 

 

One thing you might notice, is that if you perform the above test on a good Varta LFD battery, you will see that the batteries are generally nearer 13.0v at the start of the test than the 12.8v often quoted for Wet Acid batteries.

 

 

[ChrisD]

Hi Guys

 

Lenny really appreciate your reply and the table. This was not dissimilar to the test I had done but your voltage figures and the duration of test were far more accurate than all my tests. According to my tests the battery was okish

 

However: thanks to Alan of A&N caravans for his reply too because that is exactly what had happened.

I suspected that the battery was losing charge so tested it but not as well as Lenny has suggested.

I had returned from a trip feeling the battery could have performed better and left it at 12.7v, then had to go to work and stuff and lo two weeks later 11.2 volts.

 

So then recharged it and have watched it slowly declining hence my post. Bottom line probably a new battery.

 

Can't say thanks enough guys because I am about to embark on a 6 weeks trip to France and like a lot of us would have hoped it was satisfactory for the trip.

 

Long live the forum and our knowledgeable contributors

 

[aandncaravan]

if you go to our recently rewritten battery technology web page, there is information about what we think is the best battery in the up to £140 bracket : http://www.aandncaravanservices.co.uk/battery-technology.php

We don't sell batteries, but you will find one of the cheapest Varta suppliers with a £79 price tag?

 

 

[david lloyd]

ChrisD - 2016-05-29 8:28 PM

 

Hi Guys

 

Lenny really appreciate your reply and the table. This was not dissimilar to the test I had done but your voltage figures and the duration of test were far more accurate than all my tests. According to my tests the battery was okish

 

However: thanks to Alan of A&N caravans for his reply too because that is exactly what had happened.

I suspected that the battery was losing charge so tested it but not as well as Lenny has suggested.

I had returned from a trip feeling the battery could have performed better and left it at 12.7v, then had to go to work and stuff and lo two weeks later 11.2 volts.

 

So then recharged it and have watched it slowly declining hence my post. Bottom line probably a new battery.

 

Can't say thanks enough guys because I am about to embark on a 6 weeks trip to France and like a lot of us would have hoped it was satisfactory for the trip.

 

Long live the forum and our knowledgeable contributors

 

After posting on this forum regarding changing the leisure battery on my Chausson (it was originally fitted with one Banner Energy Bull under the passenger seat) I followed the sound advice of Alan at aandncaravans and fitted two Varta LFD90 batteries purchased from Tayna (excellent service from them too) and have to say that so far they are performing extremely well. The main advantage beyond the improved technology is that they are truly zero maintenance and are, as a result, far safer in the habitation area as they have had to be fitted beneath the cab seats.

 

Given the price, performance and safety of the new batteries I am really pleased.

 

David