Only showing one leisure battery connected

[TheWanderer]

Hello, I wonder if anyone can help with a battery/ control panel display issue.

About a week ago my control panel started to show only 50% leisure battery capacity which I deem as registering only one leisure battery (showing approx 24hr remaining and only the half battery level display.

I had a similar thing happen a few weeks after I picked it up last summer and diagnosed it as a blown cube fuse on the rear leisure battery which I replaced and it sorted it out. (Back up to 60hrs on the display and full battery indicator) It’s not the cube fuse this time and I’m not sure what else to check.

Appreciate any advice.

Notes:

It’s an Ocean, 6.1. Got it new last summer.

I have a 100w solar kit from Roger which is trickle charging the two leisure batteries and engine battery and I’ve not had any issues with that to date.

Used the van as a daily drive in recent months and not used the leisure batteries on their own for any trips.

Both leisure batteries are at 13V so I believe they are both fully charged and continue to hold charge/ be topped up by the solar panel. Engine battery is 12.2 V. I’ve disconnected and reconnected the batteries with no change.

 

[California_Ocean]

How is the solar connected?

If both batteries are showing good voltages and you believe them to be full then it could be that there is a charge current going to the batteries that has bypassed the VW shunts, preventing them measuring the current in/out of the batteries accurately.

If the negative of the solar is connected to an earth point in the van, then this will not be the cause.

If the charger negative is connected directly to a battery pole then the CU will be getting quite confused and may well be displaying false values.

 

[TheWanderer]

Hi, thanks for getting back to me.

I installed the solar kit soon after collecting the vehicle last year and from memory the feed goes from the solar panel to the Dual battery MPPT then to the negative battery pole on the rear leisure battery and another feed from that negative pole up to the passenger seat to connect to (I think) the relay to charge the engine battery also. I may be missing something as I no longer have the instructions and it was a while ago!

If it had bypassed the shunts, could this happen all of a sudden or would that have been the case from the outset?

One thing to note is that I’ve not had this issue all the while I’ve had the solar on and working for almost a year (showing 60hrs on the control panel and full battery etc) which makes me think it might be a fuse or something and my first thought was the rear battery cube fuse which appears ok looking at it today. Are there any other fuses I could check (similar to the cube fuse on the rear leisure battery?) could the van software just suddenly not recognise the charge like you mention?

Thanks

How is the solar connected?

If both batteries are showing good voltages and you believe them to be full then it could be that there is a charge current going to the batteries that has bypassed the VW shunts, preventing them measuring the current in/out of the batteries accurately.

If the negative of the solar is connected to an earth point in the van, then this will not be the cause.

If the charger negative is connected directly to a battery pole then the CU will be getting quite confused and may well be displaying false values.

 

[California_Ocean]

Hi, thanks for getting back to me.

I installed the solar kit soon after collecting the vehicle last year and from memory the feed goes from the solar panel to the Dual battery MPPT then to the negative battery pole on the rear leisure battery and another feed from that negative pole up to the passenger seat to connect to (I think) the relay to charge the engine battery also. I may be missing something as I no longer have the instructions and it was a while ago!

If it had bypassed the shunts, could this happen all of a sudden or would that have been the case from the outset?

One thing to note is that I’ve not had this issue all the while I’ve had the solar on and working for almost a year (showing 60hrs on the control panel and full battery etc) which makes me think it might be a fuse or something and my first thought was the rear battery cube fuse which appears ok looking at it today. Are there any other fuses I could check (similar to the cube fuse on the rear leisure battery?) could the van software just suddenly not recognise the charge like you mention?

Thanks

Depends on your usage pattern. If this has changed recently, then there may well be a latent discrepancy that is only now showing up. Generally speaking, when using shunts to monitor batteries then the shunts should not be bypassed if you want the monitoring to be accurate. It is best to connect the solar charger negative to a convenient earth point rather than the battery poles - then you can be sure that any charge current goes through the shunts and is registered by the CU.

 

[yossarian]

Try disconnect and reconnect the two pin plug on the rear battery ibs sensor. If your battery jumps to 100 percent the sensor is probably underreporting most likely due to the problem @California_Ocean described.

 

[TheWanderer]

Thanks both, @yossarian I'll try disconnecting the IBS sensor on the rear battery negative post today and see if that works. Not a fun task unloading and loading the boot to access the rear battery each time but needs must! Cheers.

 

[yossarian]

Take a photo of that battery and connections in case further diagnosis is required. If it's easier you could try do the same to the under passenger seat battery first but there's a very small chance it's that one.

 

[TheWanderer]

Take a photo of that battery and connections in case further diagnosis is required. If it's easier you could try do the same to the under passenger seat battery first but there's a very small chance it's that one.

Yes good idea, I'll do that and report back. Cheers

 

[Markgray6.1ocean]

Did this sort your issue by disconnecting the ibs sensor? I have the same issue!

 

[yossarian]

Did this sort your issue by disconnecting the ibs sensor? I have the same issue!

Read the whole thread. If you don't have an incorrectly installed solar system resetting the IBS will not improve matters much.

If you are showing low / 50% battery the most likely cause is a cube fuse. Search for that.