Battery Charging from Engine

[bob1651]

Hi everyone,

My 2006 T5 California is not putting anywhere near enough amps into the leisure batteries all of a sudden. I have just replaced the two original ones (11 years old) thinking that they were well past their best. But the new batteries are having the same problem. On hook-up they are being fully charged (upto 15 Amps) on the VW display. But never more than 1 Amp with engine running even when at 30% capacity. Have tested the alternator and its pumping out 14.1volts at 2000rpm and seems to keep the cranking battery at 100%. Had the van from new and always had enough battery for a weekend and if longer a short run with the engine would boost batteries to 80% very quickly. Any ideas?

 

[MattBW]

There is a large fuse between the two batteries, if that goes it can cause some issues with charging, is that still ok?.

 

[Loz]

...and the split charge relay could be borfed..

 

[calikev]

There is also a 80 amp fuse under the passenger seat that is for the split charging

 

[bob1651]

Thanks, will double check the fuses tonight. If the fuse has blown surely I get no power to the batteries?

 

[MattBW]

The batteries are in parallel so I suspect if the fuse between them has gone then only one of the batteries may get charged which will confuse the system.

 

[WelshGas]

Don't forget, besides the 80 amp fuse under the passenger seat which is related to the Alternator/split charging system there is also a 50 or 75 amp Cube fuse on the Rear Leisure battery +tve connection.
If the 80 amp fuse goes then there will be no charging of the Leisure batteries but if the 50 amp cube fuse goes then only 1 Leisure battery will be charged.

 

[Iron Van]

Is there a way to tell the condition of each battery? Or does the control panel just give an overall reading? For instance, if say a cable came off one of the batteries, other than a rapid consumption rate ( and because its new, I wouldn't know what would be normal ) would I get an indication anywhere?

 

[Loz]

Is there a way to tell the condition of each battery? Or does the control panel just give an overall reading? For instance, if say a cable came off one of the batteries, other than a rapid consumption rate ( and because its new, I wouldn't know what would be normal ) would I get an indication anywhere?

They are wired in parallel so a single reading. The only other thing you could do is add a small meter to the rear one.

 

[Iron Van]

Brilliant, thanks Loz

 

[bob1651]

Thanks for the advice yesterday. I ran out of time and light yesterday evening to check the fuses. However I did put my multi-meter on the batteries after removing the hook-up and the cranking battery mains charger.

The new engine battery reads 12.57 Volts
The new passenger seat battery reads 13.39 volts
The new under wardrobe battery reads 13.07 volts
The VW display reads 13.4 volts & 100%

Bear in mind none of these battery were rested as they have just been removed from main charger and hook-up before I took the readings.

Have left everything off the Van including the VW control panel and will take the readings again tonight (24 hours later) for comparison.

It does seem clear at this stage mains electric charging is fully working and I have confirmed I'm getting 14.1volts from the alternator to the cranking battery. And that from the alternator to the leisure side I'm only getting 1 Amp when engine is running.

I have seen the fuse on the under wardrobe battery, but is the passenger seat fuse as easy to find?

Thanks

 

[calikev]

Yes it is massive and desperate from the little fuse board

 

[bob1651]

Hi Guys, you lot are awesome! Found the fuse (80amp) and it had blown. Replaced and now sorted!!!! Loads of head scratching, replacement batteries, unable to open roof at 2am in morning after blast through France was low point with 2 Adults and 2 Kids! As soon as I put fuse in and started engine I got 24 amps of charging!

Thanks again!

 

[Hotel California]

Great , but now the Q is : What caused that (rather big) fuse to blow...?
Could be bad luck and onetimer , do keep an eye on things i suggest.

 

[bob1651]

Great , but now the Q is : What caused that (rather big) fuse to blow...?
Could be bad luck and onetimer , do keep an eye on things i suggest.

Had the batteries checked before trip (as they were 11 years old). That may have caused it? Bought a pack of two fuses just in case! Hopefully its a one off!

 

[WelshGas]

Had the batteries checked before trip (as they were 11 years old). That may have caused it? Bought a pack of two fuses just in case! Hopefully its a one off!

11 yrs is a long time for Leisure Batteries. The Checks you had may not have told the full story. If a battery is failing, or a cell, a larger current may be required to charge it and that may have been the cause of the fuse failing.
I see in your original post you now have new batteries so that should have sorted everything out.