Low volts on starter battery

[Jofang]

We recently bought a 2016 Hymer B-SL878. When running on a trip the starter battery volts can be as high as 12.4V but when parked at home for a couple of weeks & connected to 230V supply the starter battery shows 11.6V, although this spins the motor no problem for starting. When we bought the vehicle we also bought a new Varta starter battery, same as the original one, as when I saw the 11.6V on the original battery I thought this battery is 6 years old and maybe not long for this world so I replaced it replaced with new. Habitation batteries show 13.5V all the time, so no problem there. As this is my first Hymer I don't know if the 230V supply charges the starter battery or simply supplies power for the interior fittings. My previous Voyageur charged both habitation and starter batteries when hooked up to 230V. I'd also like to buy/acquire a Hymer manual for this vehicle as the one I've been given is 216 pages in french. At my senior years this is likely going to be our last moho, so I want to be sure I've got the correct, necessary information to scrutinise.

 

[Lenny HB]

The EBL gives a 2 amp trickle charge to the starter battery, it is connected by the same fuse that runs the fridge when driving. By the starter battery positive terminal there is a fuse holder with 2 fuses a 50 amp one for split charging & a 20 amp one for the fridge.

I would be worried with the starter battery down at 12.4v it's getting into the danger area of Airbag ECU failer due to low volts it should be up at 12.7 or above.

 

[Jofang]

Thanks for your reply Lenny, but what is an EBL?

 

[Bart]

Thanks for your reply Lenny, but what is an EBL?

Click on the EBL text that Lenny posted for a description of an EBL

 

[Lenny HB]

Thanks for your reply Lenny, but what is an EBL?

Elektroblock, the charger and distribution unit.

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[Jofang]

Thanks Bart. I think I've found a possible lead to the problem. The old battery that I took off when I replaced it with a new one is still in my garage. This was reading 11.6V on the display in the Hymer, which is why I thought it was on the way out. This battery now reads 12.5V after sitting in my garage for 2 weeks not attached to anything. So, it appears that the culprit is the display in the Hymer, or whatever feeds it, not the battery. I'll check the starter battery tomorrow morning with my meter and I'm expecting it to read at least 12.5V. It's too hot to work outside at present where we are.

 

[Jev88]

Multimeter to disconnected battery is far more reliable. You can also measure voltage going to each battery with engine running to confirm your relays have switched.

 

[Jofang]

Thanks Jev, I'll include this test in my plans for tomorrow morning also.

Does anyone know how to rectify the false reading I'm getting on the Hymer display?

 

[autorouter]

Which EBL model is it? You could check that the starter battery voltage is reaching the EBL. There's a couple of good test points, but they can be different for different EBL models.

The display is driven from the Elektroblock (EBL) by a couple of data cables. It gets the reading from the power wires inside the EBL, so that's why it's necessary to check that the voltage is reaching the inside of the EBL.

 

[Bart]

Thanks Bart. I think I've found a possible lead to the problem. The old battery that I took off when I replaced it with a new one is still in my garage. This was reading 11.6V on the display in the Hymer, which is why I thought it was on the way out. This battery now reads 12.5V after sitting in my garage for 2 weeks not attached to anything. So, it appears that the culprit is the display in the Hymer, or whatever feeds it, not the battery. I'll check the starter battery tomorrow morning with my meter and I'm expecting it to read at least 12.5V. It's too hot to work outside at present where we are.

The battery voltage could of risen to 12.5v due to it if being under a load , even a small one , when it was in the MH , then now that the load is no longer on it the voltage has risen , always check the voltage of a battery using a multimeter and also ensure there is no load on the battery , best to disconnect and leave for 30 mins, then check voltage

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[Jofang]

Thanks Autorouter. Although I'm a retired engineer I'm quite illiterate when it comes to modern vehicle electrics so until someone points a finger at the EBL I'm afraid I wouldn't know it from a bar of soap. I plan to do some Internet trawling to help me identify it.

 

[Richard n Ann]

Thanks Autorouter. Although I'm a retired engineer I'm quite illiterate when it comes to modern vehicle electrics so until someone points a finger at the EBL I'm afraid I wouldn't know it from a bar of soap. I plan to do some Internet trawling to help me identify it.

Maybe this is it?

 

[Jofang]

Thanks Richard & Ann. This is a good starting point for me if I can find it. At least I can check fuses and so on and maybe find the output to the Hymer display panel that's giving the erroneous readings.

 

[autorouter]

This is a good starting point for me if I can find it.

It's sometimes well hidden. In my Hymer there's a cupboard with some sliding panels on top by the driver's seat. If you slide back the panel and remove the false bottom of the cupboard it is there. Best of luck finding yours...

Once you find it, the manual can be downloaded from the Schaudt website. There are various language versions including English. The site is in German, you may find it more easily just using Google. If necessary I can get it and put it in the Resources section of this site.

 

[Jofang]

Thanks again Autorouter. Tomorrow morning I'll go searching.

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