Load Testing the Leisure Batteries- Question (1 Viewer)

[Emmit]

Hi All,

Now that I've got the battery charger working in the 'van I'd like to test the batteries on the Habitation side. (Please be gentle with me)

From what I've read, all??? I have to do is make sure that the batteries are fully charged, (I'm going to test them individually),
give them an hour to settle and then put a load of 5amps on them for a specific amount of time equated to their capacity. They are supposed to be 110Ah.

In order to put that load on them I thought about plugging in the Inverter and switching on a 60watt household bulb. I could then work out the capacity remaining in each battery (measured separately.)

Have I got it right that the bulb would impart a load of 5 amps or do I have to allow for the inefficiency of the inverter.

I can't use the light sources of the 'van because we're LED'ed to within an inch of it's 'Light'.

Any assistance in helping this numpty gratefully received.

 

[andy63]

Your 60w bulb should equate to around a 5 amp load on your 12 v system .. maybe a bit more ... check it with a meter ...
Have you reason to suspect your batteries are not holding a resonable charge or just curious. ..
You wouldn't want to be running the battery down to more than say 50ah on each battery max and wouldn't expect it to recover to 12.7 volts with that sort of discharge.. more like 12.3v ... I suppose it would give a comparison with the other battery..
Andy..

 

[Emmit]

Thanks for your swift reply Andy.

I know that the two batteries are of different ages (I know that this isn't ideal) and I am just curious as to 'Where they are' right now.
For two months of our latest tour in Spain/Portugal I know that they relied on the Solar alone to keep up with input and, in November /December that is not the best time of the year.
I take on board what you say about not putting them through the wringer and I'll ensure that they don't go down to 50% during the test.

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[andy63]

It's all entertaining stuff and a constant source of debate on here..
It's also difficult to comment sometimes as everybody's use varies so much and their charging systems and regimes also..
I just change them when the capacity isn't there any more..ie when the voltage drops off too quickly under the use I give them..
You could record your tests ie load time applied and voltages at given intervals and the recovery voltage after load removed... and post the results..
See what folk have to say..
Andy.

 

[iceclimber]

Hi, unless you've got something like a Victron BMV700 monitoring the batteries, I would suggest that doing load / voltage tests etc... could be a bit of a 'finger in the air' exercise. Better to do the tests & know precisely whats going 'in'' & 'out' of the batteries. Repeat the exact tests again 1 month, 3 months, 6 months time & compare results.
After having a BMV700 installed for 2 years now, you get to sort of 'just know' by looking at the readings if something is a bit amiss ?