Starter and Leisure Batteries dead after weekend hooked up at campsite

[dayman1]

for the sake of £100 change the starter battery it sounds like it just not holding the charge

a replacement for this battery is closer to 200 and I really would like to be sure it's the battery before I buy a new one, in case there is a fault that ends up buggering the new battery as well. Although I agree I'd much rather just replace the battery!

 

[ChrisL]

The 12.6v your seeing is surface voltage but the voltage will drop as soon as you put a load on it, here is some photos of a battery I tested earlier this year, you can see in the first picture that before the test the battery voltage is 12.87v and I've set the load at 2 amps, in the second picture you can see with the test running the voltage has dropped to 8.84v.

 

[dayman1]

The 12.6v your seeing is surface voltage but the voltage will drop as soon as you put a load on it, here is some photos of a battery I tested earlier this year, you can see in the first picture that before the test the battery voltage is 12.87v and I've set the load at 2 amps, in the second picture you can see with the test running the voltage has dropped to 8.84v.

View attachment 941948View attachment 941949

thanks that is exactly what I need to do, I'll be buying a battery tester this weekend for sure. If the battery was goosed would you expect it to start the van at all though even after being charged?

 

[ChrisL]

thanks that is exactly what I need to do, I'll be buying a battery tester this weekend for sure. If the battery was goosed would you expect it to start the van at all though even after being charged?

It would depend on how goosed it was but you can think of it like this, when the battery was new you had the whole surface area of the plates performing a chemical reaction to accept charge and discharge, as the battery gets older the plates can sulphate or become damaged either through under or over charging so now you have a battery with a much reduced capacity which will continue to work until it can no longer provide enough amps to power the load it is connected too then it will fail completely. It is in effect becoming a smaller battery.

 

[GeoffnDee]

is there an easy way to do this?

If there is a 12v power socket fitted on the dash have you anything you could plug into it that would use power ? to check if there is a rapid drop in voltage.

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[headlight]

dayman1 my starter battery was showing 12.7v at rest, tested with a multimeter on the battery terminals.
With the engine running, jump started, it showed 14.4v so was being charged fine by the alternator.
However try to start the van and with a multimeter on the battery terminals as soon as you turned the key voltage dropped to nothing and nothing happened, no lights on the dash and engine didn't turn over.
This was on a 13 month old battery.
Unlike back in the day when starting would become sluggish and you knew your battery was on its way out modern batteries often die with no prior warning.
Answer was fit a new starter battery.

 

[dayman1]

Hello all,

So I checked the current on the engine battery after fully charging it, and when the engine is off it's drawing 50 mAmp, is this normal?

the voltage doesn't drop significantly when I turn the key once before starting, it drops from 12.6 to 11.7, and then once I start it jumps up to over 14v.

I have now also disconnected what I believe to be the charging relay for the batteries as I wondered if that was still somehow sucking power from the starter battery.

Unfortunately when I came out to the van after the weekend though, the leisure battery is now also dead, and reading a voltage of 10.3v.

What is interesting is the voltage from the solar panel is coming in at about 18/19v, but on the output of the control unit it is only reading 4v to the leisure battery.

So I'm thinking there is still a problem that is not the battery.

 

[autorouter]

Unfortunately when I came out to the van after the weekend though, the leisure battery is now also dead, and reading a voltage of 10.3v.

What is interesting is the voltage from the solar panel is coming in at about 18/19v, but on the output of the control unit it is only reading 4v to the leisure battery.

So I'm thinking there is still a problem that is not the battery.

I think you're right about that. If the leisure battery is at 10.3V, then the solar controller output should be reading exactly the same. If it's reading 4V then there is a bad connection/blown fuse somewhere on that wire. There should be a fuse very near the leisure battery, worth checking that with a meter or swapping it for a known good fuse.

 

[dayman1]

The engine battery seems to be holding charge fine now with the leisure system dusconnected fully which is good news.

I haven't gotten to figuring out the issue in the leisure system just yet though, as yesterday I found a fluid leak in the engine, I think it's gearbox fluid so I'm now trying to solve that problem

Thanks everyone for the help so far!