Odd reading on Hymer control panel when solar not active.

[Henry Walpole]

Hi, I hope someone might be able to shed some light on a strange problem.

The Hymer control panel in my BMC-I-690 can be used to show the voltage levels in the vehicle starter battery. This works fine during daylight hours but after dark the reading appears to suggest the starter battery is flat (although it is not). The reading for the leisure batteries is accurate day or night.

I can only assume it is something to do with the solar panels which I know from measuring voltages provide charge to both starter and leisure batteries. This issue has existed from new (a few months ago). The solar panels were fitted as an extra by the dealer but as he's in Germany I thought it might be easier to ask here first.

Attached is a picture of what I see after dark when looking at the starter battery level on the panel. Any ideas? Thanks.

 

[Rapides]

Missing/blown 50A fuse at the starter battery? Daytime panel shows what should be going to the starter battery, nighttime shows what’s coming from the battery. If fuse is dead the battery is not visible to the panel.
Had exactly this issue when I took delivery of my vehicle a couple of years ago, albeit I only have EHU, no solar.

 

[Steve and Denise]

When our 50 amp fuse blew the panel showed all sorts of strange readings replaced the fuse all good again.

 

[63720]

I had the same so did as recommended above.

 

[Rapides]

If the 50A fuse has gone I guess there’ll be no charge getting to the cab battery via the EBL from solar/EHU.

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[Henry Walpole]

If the 50A fuse has gone I guess there’ll be no charge getting to the cab battery via the EBL from solar/EHU.

That's interesting because charge is getting to the cab battery via solar/EHU.

 

[Detnor]

I had a similar problem on my MLI. I eventually spoke to Schaudt, they were insistent I change tbe 20A fuse at the battery. Meter indicated fuse was ok, changed it anyway and the display went back to normal.

 

[Rapides]

Re my first reply, thinking back to it my vehicle was missing both the 50A and 20A fuses at handover. Couldn’t say for sure which of them was causing the panel not to see the cab battery when off EHU.

 

[autorouter]

Is there a 2A fuse near the 50A and 20A fuses by the starter battery? There is usually a 'voltage sense' wire from each battery, that is used for measuring the exact battery voltage, avoiding voltage drop errors along the main current-carrying wires. The voltage sense wire is protected by a small fuse, usually 2A.

 

[Henry Walpole]

Thanks for all the responses. I presume by 'fuse at the starter battery' this means a fuse located physically next to the starter battery? I haven't accessed the starter battery yet, it looks like it's underfloor in the cab but motorhome is in store so need to get up there and take a look.

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[Detnor]

My MLI is 2017 and knowing Hymer, it will be different. The fuse I was instructed to change was the 20A (yellow). If it is a Schaudt electroblok, you could check with them, Udo Lang is really helpful if you give him all of the details.. Udo.Lang@schaudt.gmbh

 

[Henry Walpole]

My MLI is 2017 and knowing Hymer, it will be different. The fuse I was instructed to change was the 20A (yellow). If it is a Schaudt electroblok, you could check with them, Udo Lang is really helpful if you give him all of the details.. Udo.Lang@schaudt.gmbh

Thanks Detnor, much appreciated.

 

[Henry Walpole]

I finally managed to get up to the van today and took at look at the starter battery (which is located under the floor between passenger and driver on my Merc). I could only see two fuses next to the battery, a 2A and a 25A. Both looked ok on visual inspection but I replaced them both anyway.

Although I'm not at the van to test it after dark, I can interrogate via iNet and much to my delight I'm now getting a correct reading from the starter battery so it looks like the issue is fixed!

Many thanks for all the great replies