Main battery charging when vehicle is not being used

[Old Sid]

Our California has stood idle for a long while. I have used the ‘hook up’ to keep the leisure batteries charged but the main vehicle battery has suffered. I had it replaced yesterday.
I have been told that the hook up will also charge the vehicle battery. This sounds doubtful to me. Does anyone have knowledge of this?
Thanks.
(2016 T6 Ocean).

 

[Hotel California]

It should charge on hook-up , it's been that way in the past so can't see why it should not be on the T6 and T6.1 .
Are you sure nothing is using power in the front ? Have you opend the doors a lot to acces the Cali in that periode?
On my T5 the interieur lights are always OFF just in case

 

[Perfectos]

Our California has stood idle for a long while. I have used the ‘hook up’ to keep the leisure batteries charged but the main vehicle battery has suffered. I had it replaced yesterday.
I have been told that the hook up will also charge the vehicle battery. This sounds doubtful to me. Does anyone have knowledge of this?
Thanks.
(2016 T6 Ocean).

Hi Old Sid,

This is a much debated subject.

The official line from VW is the starter battery is not charged whilst on hook up.
However there is an anomaly of the lesuire charging wiring which allows a minimal amount of charge to the starter battery, I doubt the “trickle” is enough to charge the battery sufficiently.

I had may 18 months old starter battery replaced under warranty as it would not hold a charge after driving extended distance!

I have a Beach and it definitely does not charge the starter battery whilst on hook up , sufficiently to keep the starter battery charged, the Alarm takes about 0.3 amps which depletes the battery faster than the “trickle” received from the EHU

I have raised this subject with the dealer, who confirmed “the starter battery is not charged whilst on EHU” , however a former member of this forum and a VW master Cali Tech, did advise of the anomaly I mention above.
There has been much debate over years, the general consensus is some vans do receive a charge to the starter battery, when on EHU some don’t, go figure that.

If you search for “VWGuru” posts I’m sure you will find his post where he described the anomaly.

All his posts are well worth a read.

I’m sure someone will be along in a minute to say the above is rubbish and they receive a full charge from EHU, but if they do it’s because of the Anomaly, not by design. Safest way is to regularly check you battery with either a plug in monitor ( cigarette type) or amp meter on the battery terminals

As HC says opening / unlocking the Cali, starts all the electrical systems, high pressure fuel pump, computer etc, which will quickly deplete the battery if not driven to top up the battery charge, the electrical system will use the starter battery for approx 20 minutes after unlocking, the vehicle before shutting back down

Was you battery replaced under warranty?

 

[Perfectos]

I use something like this 12v extension / USB adapter, to keep an eye on battery charge , plug in occasionally to the 12v socket in the dash, it can be left in permanently as it has a switch to turn off the device so it will not draw power. Great for the rear 12v sockets also, The voltage meter is surprisingly accurate when compared to a volt meter reading from the battery terminals.

 

[kurienp]

Our California has stood idle for a long while. I have used the ‘hook up’ to keep the leisure batteries charged but the main vehicle battery has suffered. I had it replaced yesterday.
I have been told that the hook up will also charge the vehicle battery. This sounds doubtful to me. Does anyone have knowledge of this?
Thanks.
(2016 T6 Ocean).

If your vehicle is parked on your driveway, garage, get a battery charger/maintainer for your main battery.

 

[Loz]

Our California has stood idle for a long while. I have used the ‘hook up’ to keep the leisure batteries charged but the main vehicle battery has suffered. I had it replaced yesterday.
I have been told that the hook up will also charge the vehicle battery. This sounds doubtful to me. Does anyone have knowledge of this?
Thanks.
(2016 T6 Ocean).

Was your old battery a Moll+ by any chance? There were a number of faulty units that have been replaced.

 

[Perfectos]

Info in thread regarding Mol Battery fitted prior to 2018.

Engine battery dead

Hi you will need to properly trickle charge your engine battery as the output from the alternator is to high to correctly recover a modern battery a quick boost and a drive is no longer sufficient with the tech we have today, you will suffer many more battery issues if that battery is not...

vwcaliforniaclub.com

 

[Perfectos]

Here’s the Thread where VWGuru describes the anomaly

Does the Mains Charger Charge the Engine Battery?

A question often asked. VW categorically say NO, it does not. However there is a body of Forum members that believe it does “ Trickle Charge “ the Engine Battery once the Leisure Batteries are Full. Proof. On site and I plugged in my 2 Voltmeters. Cheap and cheerful but they both under read by...

vwcaliforniaclub.com

 

[Old Sid]

Thank you everyone for such comprehensive replies and for the links to previous threads. It’s also good to see Breeze VW involved in the conversations.
I had periodically used a regulated charger on the main battery. However, it always reported that the battery was fully charged and it switched off immediately. Clearly, a new and different charger is required.
Hopefully, there won’t be another lockdown and this situation won’t arise again. However, this all gives rise to one more question.

What regulated charger would people recommend? I know it needs to be a low current unit to avoid damage to the vehicle ECU. Thanks for the one suggestion so far.

I did consider a solar one that connected via the 12v socket on the dashboard. However, I think this socket is isolated when the engine is not running and I think the sockets in the rear may be connected to the leisure batteries.

All this has made me realise how little I know about some issues. I’m now intending to plug in the EHU whenever the van is idle for more than a few days.
In answer to a query within the replies, I don’t know what battery type the old one was and, at just over 4 years old, it wasn’t replaced under warranty.

 

[Perfectos]

Hi Old Sid

Presuming your replacement starter battery is an AGM type, which it should be, you will need a smart charger with an AGM setting.

The weapon of choice on this Forum seems to be Ctek, I have a Noco genius 10, which does the Job fine.
The Noco is what my local dealer uses in the show room to charge batteries whilst the vehicle is on display not that that’s particularly relevant to which make you choose.

If you google smart charger for car, you’ll get lots of ideas.

 

[Old Sid]

Thank you. I will investigate this.

 

[TripleBee]

Mine does charge.


I only get very strange things happening when on hookup AND on engine battery charging with a separate charger at the same time.
I would charge them separately, and not simultaneously.

 

[WelshGas]

Thank you. I will investigate this.

My 12v socket in the dashboard pull-out draw is live with ignition off. Checked with a voltmeter after 1 hr. So I use a ctek charger plugged into the kitchen mains socket with a ctek 12v plug into that dashboard socket. Then plug the van into mains hookup. Leisure and Engine Batteries then charged simultaneously.