(Not) Charging caravan battery while towing.

mir60899 · 19-10-2021, 18:02

Hello to everyone out there,
Just came across a bit of an oddity on our 2006 Elddis Knightsbridge (Avante clone) which we purchased earlier this year.
We have used it quite a bit over the time we have had it but never realised until yesterday that the on board battery is not recharged whilst towing. The thing that gave the game away was using the motor mover to put the van on the hitch at our last site.
Now on our previous van, also an Elddis but a 1998 Jetstream, we would arrive home from the same site and on taking the battery home find it was almost fully charged, needing less than one hour to bring it up to fully charged. This time the battery tok some four hours to fully charge.
An inspection of the owners handbook showed no connection to the split charge circuit on the car, although the 12 volt fridge feed was present.
Not believing the book I took the covers off the 12 volt system and using a multimeter proved that this was indeed the case.
So now I have had to design and build a suitable circuit to get round the problem.
Does anyone else have a similar experience? Because if we had been going to a non hook up site we would have arrived with only a partially charged battery.
Very strange!

solarman216 · 19-10-2021, 22:36

In my experience most split charge systems are pants, also even though the 13 pin connector is common, there are still variations, if you have made your own then stick with it, Rick

micktheshed · 11-11-2022, 18:11

Quote:

Originally Posted by mir60899

Hello to everyone out there,
Just came across a bit of an oddity on our 2006 Elddis Knightsbridge (Avante clone) which we purchased earlier this year.
We have used it quite a bit over the time we have had it but never realised until yesterday that the on board battery is not recharged whilst towing. The thing that gave the game away was using the motor mover to put the van on the hitch at our last site.
Now on our previous van, also an Elddis but a 1998 Jetstream, we would arrive home from the same site and on taking the battery home find it was almost fully charged, needing less than one hour to bring it up to fully charged. This time the battery tok some four hours to fully charge.
An inspection of the owners handbook showed no connection to the split charge circuit on the car, although the 12 volt fridge feed was present.
Not believing the book I took the covers off the 12 volt system and using a multimeter proved that this was indeed the case.
So now I have had to design and build a suitable circuit to get round the problem.
Does anyone else have a similar experience? Because if we had been going to a non hook up site we would have arrived with only a partially charged battery.
Very strange!

Was you're first 'van using 7 pin sockets rather than 13pin as per you're new 'van? 13 pin systems are notorious for voltage drop caused by their small pins and far too small cables, added to the under-sized cable used in modern 'vans I'm surprised anything works.
The only answer is to beef-up the feed to the battery/fridge supply by fitting extra (min. 4mm2 section) feed & earth cables direct from the car battery (via 25A fuse) via a designated 7 pin system spliced into the existing 'van loom.
By doing this I managed to increase the voltage at the fridge by over 2v, from a useless 11.5v to an outstanding 13.7v! Needless to say the fridge actually works on 12v now.
Charging my battery was not a problem (roof-mounted solar panel)but this mod. can only have improved it.

solarman216 · 11-11-2022, 23:43

You have hit on an old thread there mate but nice to know you are still looking in, Rick

19-10-2021, 18:02	#1
mir60899 Member Join Date: Dec 2008 Location: midlands Vehicle: Two Terrano2 tdi's. Posts: 38	(Not) Charging caravan battery while towing. Hello to everyone out there, Just came across a bit of an oddity on our 2006 Elddis Knightsbridge (Avante clone) which we purchased earlier this year. We have used it quite a bit over the time we have had it but never realised until yesterday that the on board battery is not recharged whilst towing. The thing that gave the game away was using the motor mover to put the van on the hitch at our last site. Now on our previous van, also an Elddis but a 1998 Jetstream, we would arrive home from the same site and on taking the battery home find it was almost fully charged, needing less than one hour to bring it up to fully charged. This time the battery tok some four hours to fully charge. An inspection of the owners handbook showed no connection to the split charge circuit on the car, although the 12 volt fridge feed was present. Not believing the book I took the covers off the 12 volt system and using a multimeter proved that this was indeed the case. So now I have had to design and build a suitable circuit to get round the problem. Does anyone else have a similar experience? Because if we had been going to a non hook up site we would have arrived with only a partially charged battery. Very strange!

19-10-2021, 22:36	#2
solarman216 Off road maniac Join Date: Dec 2009 Location: Bexhill on Sea Vehicle: Y60 Patrol Me, 3 ltr Mrs Posts: 17,427	In my experience most split charge systems are pants, also even though the 13 pin connector is common, there are still variations, if you have made your own then stick with it, Rick __________________ Ex banger racer now off road maniac Lokka on the front with manual hubs Diff lock on rear 3 inch SS straight through exhaust Manly winch bumper with 13000 lb winch 10 spike ground anchor, with multiple straps and blocks Super strong body cills capped with scaffold pole 20% stronger springs all round aggressive off road tyres on wheels so just swap. Aim to get stuck and be completely self sufficient in extraction, love getting muddy, 2ft deep is good but rare.

11-11-2022, 23:43	#4
solarman216 Off road maniac Join Date: Dec 2009 Location: Bexhill on Sea Vehicle: Y60 Patrol Me, 3 ltr Mrs Posts: 17,427	You have hit on an old thread there mate but nice to know you are still looking in, Rick __________________ Ex banger racer now off road maniac Lokka on the front with manual hubs Diff lock on rear 3 inch SS straight through exhaust Manly winch bumper with 13000 lb winch 10 spike ground anchor, with multiple straps and blocks Super strong body cills capped with scaffold pole 20% stronger springs all round aggressive off road tyres on wheels so just swap. Aim to get stuck and be completely self sufficient in extraction, love getting muddy, 2ft deep is good but rare.