Yes i have the same problem with my V-class MP from 2017. I've searched for fuse en relais but it's not clearly to me where i've got to look.
Leisure Battery Not Always Charging
- Thread starter Seadawn
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- leisure battery
Richard DL
Member
Hi Gerbert and PaulE
As you will see from other contributions I’ve made we had an original problem with the additional battery not charger when hooked up - which was subsequently fixed by replacing the relay under the UK side passenger seat I believe. That sorted we are now having the same problem as you’ve described where the additional battery charges fine when hooked up but doesn’t seem to charge when driving along. I have it booked in to Mercedes dealer next week to try and get it sorted as I’m trying to say that the additional battery charging issue has been a problem since we had the car in Dec 2017. If you have any updates on a fix please advise so that I can report to my dealer as I don’t expect them to have too much experience in this area. Thanks.
As you will see from other contributions I’ve made we had an original problem with the additional battery not charger when hooked up - which was subsequently fixed by replacing the relay under the UK side passenger seat I believe. That sorted we are now having the same problem as you’ve described where the additional battery charges fine when hooked up but doesn’t seem to charge when driving along. I have it booked in to Mercedes dealer next week to try and get it sorted as I’m trying to say that the additional battery charging issue has been a problem since we had the car in Dec 2017. If you have any updates on a fix please advise so that I can report to my dealer as I don’t expect them to have too much experience in this area. Thanks.
I’d send a e-mail to the dealer where i’ve bought my MP. They specialized in selling MP’s in the Netherlands, which they import from Germany.
I got respons already; the relay which should connect the leisure battery to the starter-battery with running engine should be besides the leisure battery.
That means i should pull this one from under the driver seat (left hand in my case).
I’m going to check it this weekend.
Oh forgot to reply my results... In my case it was the relay itself. I didn't replace it myself. It's pretty hard to measure something, because you have to take out the battery first to get close to the relay. The garage where i bought my MP exchanged the relay for me and the difference was clear .
With the engine running within a minute i saw the voltage raising on the display till over 14 Volts.
With the engine running within a minute i saw the voltage raising on the display till over 14 Volts.
Richard DL
Member
Thanks Gerbert. - perfect replaced the relay which was burnt out - possibly due to poodle fitting terminals according to garage. - everything is good now so we’re off to France and Spain in the MP running on full batteries all round - whoop whoop!!!
Steve B
Top Poster
Made me smile, I was imagining a poodle installing electrics in your MP
Richard DL
Member
STEVE B - Poor obv !! No poodle just poor unfortunately. Reminds me of - it’s been raining cats and dogs here - I know as I nearly stepped in a poodle !! Bum bum.Made me smile, I was imagining a poodle installing electrics in your MP
Seadawn
Active Member
Back to this thread after starting it some time ago - yep, more battery issues!
We were hooked up with the fridge running and after a couple of days the fridge was shutdown along with other items and voltage below 12. Had to take the van on a long drive, batteries charged back up so survived.
Went into our new dealship and they say that it is an issue on the 7.5 ring and this time it’s the rear cupboard light (last time it was the gas ignition). More than 8 weeks later still no part and have escalated to MB. Dealer now says it was an IT issue and they have now actually ordered the part. Regardless they have left us with a vehicle that only powers the 240v socket when plugged in and the 7.5 fuse is in a blown state. So when we go anywhere we need to drive around as much as possible to get the battery charged to keep things like the fridge running. Gas ignition, lights, etc., not working.
When hooked up it says it is charging, the console shows the charge bars moving up, but it does nothing.
Bar getting this new part anyone got any other ideas, I read above about the relay, fuses, etc., but not sure which to try or to hit the incapable dealer with?
We were hooked up with the fridge running and after a couple of days the fridge was shutdown along with other items and voltage below 12. Had to take the van on a long drive, batteries charged back up so survived.
Went into our new dealship and they say that it is an issue on the 7.5 ring and this time it’s the rear cupboard light (last time it was the gas ignition). More than 8 weeks later still no part and have escalated to MB. Dealer now says it was an IT issue and they have now actually ordered the part. Regardless they have left us with a vehicle that only powers the 240v socket when plugged in and the 7.5 fuse is in a blown state. So when we go anywhere we need to drive around as much as possible to get the battery charged to keep things like the fridge running. Gas ignition, lights, etc., not working.
When hooked up it says it is charging, the console shows the charge bars moving up, but it does nothing.
Bar getting this new part anyone got any other ideas, I read above about the relay, fuses, etc., but not sure which to try or to hit the incapable dealer with?
funkyegg
Top Poster
Hi Richard DL, hope your battery issue is fully resolved now. I'm having the same issue as you and others on this thread. The leisure battery is only charging while hooked up but does nothing when driving around. My battery was replaced by my local dealer back in January because I left it uncharged for too long and I noticed the new battery stopped charging when driving. How did your dealer identify the fault and replace the relay? My dealer seems to know little about this issue. Thanks
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Brian Drought
Top Poster
240v socket only ever works when it's plugged in by the way.
Seadawn
Active Member
Yep, and that's all being plugged in currently does, powers the 240v socket, doesn't charge the batteries or power anything else which when plugged in I believe it should from reading the manual.
Brian Drought
Top Poster
Sorry! I read your post wrong.
I read it the same Brian.
So it is essentially the 12v circuit that is inoperative
Brian Drought
Top Poster
Looking at it the 7.5A is purely lighting (and maybe hob ignition as you've said) and shouldn't have any effect on the charging of the battery. I suspect that's a red herring.
It's pretty easy to see if the charger is doing anything with a multimeter. It's underneath the fridge. They can also check if there's connectivity to the battery from that point.
It's pretty easy to see if the charger is doing anything with a multimeter. It's underneath the fridge. They can also check if there's connectivity to the battery from that point.
Hi All - I have a similar, but not necessarily the same issue.
After being hooked up for 3 days, the fridge has switched itself off.
The roof up/down still operates, but the control console indicates a problem with the battery.
Unsure why, if hooked up, the battery problem would still impact the fridge.
Does the battery have to be fully charged for the fridge to operate? I’d have thought hookup would have sufficed independent of battery status?
TIA for any suggestions
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After being hooked up for 3 days, the fridge has switched itself off.
The roof up/down still operates, but the control console indicates a problem with the battery.
Unsure why, if hooked up, the battery problem would still impact the fridge.
Does the battery have to be fully charged for the fridge to operate? I’d have thought hookup would have sufficed independent of battery status?
TIA for any suggestions
Sent from my iPhone using Tapatalk
Steven rhodes
Top Poster
Check the fuse on drivers seat panel I think thats the charger fuse if its gone a battery symbol will appear
