Battery CCA

[rob and jen]

Hi,

I have recently been having problems with my caravan mover and was informed to test the battery cca reading.

I have took the battery into a car dealer shop and they have told me it can't be tested because leisure batteries are different to car batteries - as we know!

However, has anyone had their batteries tested before in the Manchester area?

 

[rob_jax]

Hi Rob,

I doubt if anyone (Kwikfit or whoever) would be equipped to perform a CCA test (cold cranking amps - measured at -20

 

[AlanJ]

Hi Rob

I recently had cause to suspect the new battery in my Bailey. I took the battery to my dealer who did a "drop test" on it - no it was not dropping it from a great height - but some sort of test meter that they put on for a minute or so and then proclaimed the battery ok. This has proved to be the case it is ook.

Might be worth asking your dealer to test it first?

 

[rob_jax]

Hi Alan,

A drop-test (cranking amps) on a leisure battery isn't a great idea - like the cold cranking amps test it simulates the load a car starter motor will draw - and will typically draw 200+ Amps from the battery.

This isn't a good idea on a leisure battery...

It's better (but takes a lot longer) to measure the battery under the same conditions (but at the maximum level) as it was designed to be used. In the case of a leisure battery this means measuring the available time whilst supplying 20 Amps...

Robert

 

[rob and jen]

Thanks to you both for your advice.

After talking to Truma they tell me that RC of the leisure battery is not important in terms of the mover use. They say that it is the initial burst of energy from the battery that is required to get the mover going. After experimentation last night I have found that my 'red' battery low light on my mover control box comes on pretty quickly when I operate the mover - even when the mover is not engaged to the wheels. So I tend to think that the RC of the battery is at fault, i.e. not holding it's charge for long. When the mover is engaged the light comes on straight away.

Rob, I will try you method tonight and guess I could achieve the same result by using lights in the van, when the battery is hooked up, to get 20amp drain (using coorect number of lights of course) and still measure with the meter?

 

[rob_jax]

Hi Rob,

Yes you coulduse the lights in the caravan - a 10 watt bulb will draw approximately 1 amp - so you are going to need 20 lamps in the caravan - and I doubt if you've got that many...

Hence the reason for suggesting old headlamp bulbs - usually there are a couple kicking around the garage, left over from a previous car, and won't fit the current car - so can be sacrificed for this test.

But from your description of how the battery reacts - it sounds stuffed - in particular it sounds as if the cell plates are suffering from Sulfation - the battery has been stored in a partly discharged (below 50%) state for months at a time - and an irreversible deposit of Sulfate on the plates has robbed the battery of it's ability to hold charge.

Irreversible? Not if you have a CTEK or similar charger that will recover a battery in this condition...

Robert

 

[rob and jen]

Robert,

Fair shout. That said when I thought of it:-

2 downlights at back of van, 2 on kitchen area, 2 at front and 2 in Bathroom + 3 down the center of the van - 11amp ish.

Omnivent on full will pull 4amps

Blower fan on heater will give me 1amp

Radio about another 1, so around 17amps in total. See how it gets on. Thanks!

 

[rob and jen]

Robert,

Test complete. Had 17amp going on in the van and measured battery. After 20min the voltage dropped to 10v and after 35min it was down to 7.5v. So looks like battery is at fault. But do I but a new one or go for the charger you mention? Feels like a new battery os saftest bet.

 

[rob_jax]

Rob

The battery should have supplied that current for several hours - so I'd suggest a new battery.

And then keep it fully charged when not touring - maybe once a month (or more often) with a good quality charger...

Robert