Charging current on EHU

[Lord Deadfish]

Hi, I posted the below in my introduction post a few days ago.

When I first viewed the vehicle the leisure batteries were flat but were charged up when I collected it. I’ve driven it just over 120 miles home but today, (the day after collection) it’s only showing a reading of 12.2V and 40%. The voltage rises to over 14V when I run the engine so it would seem the alternator is charging them OK but they don’t seem to hold their charge. It initially indicates 100% after running the engine but over a period of an hour or so drops to 40%. Quiescent current seems to be around 200-400mA. I’ve done a bit of a search on this topic but am still not clear what should be a “normal” reading but a drop in capacity as quickly as that doesn’t sound too encouraging to me. I thought I would just get a few opinions before getting back in touch with VW. Any suggestions appreciated.

Whilst waiting for VW to respond I did a bit of investigative work myself and discovered the 75A fuse on the + post of the rear leisure battery had blown. I obviously have no way of knowing how long it had been in that state. I would never have thought of looking there if it hadn’t been for the info on this site so its more than paid for its subscription already.
After replacing this and charging up both batteries on a CTEK (keeping the rear disconnected) they both charged up to around 13V. I reconnected the rear and the whole system looks a lot healthier. Took the roof up and down, ran the fridge and heater for a while and it still showed 80-90%.
Today the hook-up lead I ordered arrived so I thought I would try that out. When I plugged it in it was pulling about 8A and it’s still showing over 7A some 8 hours later. Is that “normal”? There’s nothing switched on. Given the leisure batteries were pretty well charged up it seems high. I’ve tried to find an answer to this on various threads but can’t see anything.

Bugger. I’ve just been out to look again and it’s dropped to 2A so maybe all as you’d expect?

Thanks, Ian

 

[WelshGas]

Hi, I posted the below in my introduction post a few days ago.

When I first viewed the vehicle the leisure batteries were flat but were charged up when I collected it. I’ve driven it just over 120 miles home but today, (the day after collection) it’s only showing a reading of 12.2V and 40%. The voltage rises to over 14V when I run the engine so it would seem the alternator is charging them OK but they don’t seem to hold their charge. It initially indicates 100% after running the engine but over a period of an hour or so drops to 40%. Quiescent current seems to be around 200-400mA. I’ve done a bit of a search on this topic but am still not clear what should be a “normal” reading but a drop in capacity as quickly as that doesn’t sound too encouraging to me. I thought I would just get a few opinions before getting back in touch with VW. Any suggestions appreciated.

Whilst waiting for VW to respond I did a bit of investigative work myself and discovered the 75A fuse on the + post of the rear leisure battery had blown. I obviously have no way of knowing how long it had been in that state. I would never have thought of looking there if it hadn’t been for the info on this site so its more than paid for its subscription already.
After replacing this and charging up both batteries on a CTEK (keeping the rear disconnected) they both charged up to around 13V. I reconnected the rear and the whole system looks a lot healthier. Took the roof up and down, ran the fridge and heater for a while and it still showed 80-90%.
Today the hook-up lead I ordered arrived so I thought I would try that out. When I plugged it in it was pulling about 8A and it’s still showing over 7A some 8 hours later. Is that “normal”? There’s nothing switched on. Given the leisure batteries were pretty well charged up it seems high. I’ve tried to find an answer to this on various threads but can’t see anything.

Bugger. I’ve just been out to look again and it’s dropped to 2A so maybe all as you’d expect?

Thanks, Ian

View attachment 130354

You seem to be on top of things, but it might be worthwhile to give the Leisure Batteries a good charge. The built in charger has “ smart “ capabilities so I would leave it plugged into EHU for at least 24hrs after the Float Charge is instigated.
I don’t know how long the batteries were flat but every episode can cause damage and shorten the batteries life if prolonged.
The % reading on the Control Panel is not a very accurate calculation but the voltage is.

 

[dspuk]

No idea what the 7A draw is, if you have nothing running, but not knowing the 6 system as well as I know the 6.1 I’d check the draw without the EHU in.

2A is around about normal - it shows 1A just to light up that screen, so any other lights you have on will easily top that up to 2.

Sounds like it is all fine now to me, I’d leave it plugged in for about 12H and go give it another good run for an hour.

 

[Lord Deadfish]

Thanks both, yes I’m leaving it on overnight. It’s dropped to 1.6 now so looking better. They obviously weren’t as fully charged as I thought they were. That chart is very useful - thanks.