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Adding a 2nd Leisure Battery to a Beach

gareth230380

gareth230380

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35
Location
Maidstone, Kent
Vehicle
T5 Beach
I'm looking to put a 2nd leisure battery in my Beach under the drivers seat. My current battery is 7 years old and so am going to purchase 2 batteries at the same time so they are matched.

The question I have is relating to the load and earth when fixing in parallel.

I've looked at the wiring diagrams for the 2014 Beach/SE and it shows the load and earth all comes from the Primary battery under the Seat with the Secondary battery in the back having direct links to and from it (with a fuse on the +).

This is really easy to do and I was going to copy until I read more. My understanding is this will create a voltage drop between the two with the primary battery working harder but also the secondary battery would not then charge fully.

The way to create a balanced system is to connect them the same but to take the load from battery A and the earth from battery B. This would mean removing the earth on my passenger seat battery and adding the earth to the new battery under the drivers seat.

Am I getting overly worried and not need to do this as surely VW would have done it this way if it was so crucial?

Does anyone have a monitor on each of their batteries and see an imbalance?
 
WelshGas

WelshGas

Retired after 42 yrs and enjoying Life.
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T5 SE 180 4Motion
I'm looking to put a 2nd leisure battery in my Beach under the drivers seat. My current battery is 7 years old and so am going to purchase 2 batteries at the same time so they are matched.

The question I have is relating to the load and earth when fixing in parallel.

I've looked at the wiring diagrams for the 2014 Beach/SE and it shows the load and earth all comes from the Primary battery under the Seat with the Secondary battery in the back having direct links to and from it (with a fuse on the +).

This is really easy to do and I was going to copy until I read more. My understanding is this will create a voltage drop between the two with the primary battery working harder but also the secondary battery would not then charge fully.

The way to create a balanced system is to connect them the same but to take the load from battery A and the earth from battery B. This would mean removing the earth on my passenger seat battery and adding the earth to the new battery under the drivers seat.

Am I getting overly worried and not need to do this as surely VW would have done it this way if it was so crucial?

Does anyone have a monitor on each of their batteries and see an imbalance?
This is how VW wire the 2 Leisure Batteries on the SE/Ocean.
There is also a 50 amp, upgraded on the T6 to 75 amp I believe, Cube fuse on the +tve pole of the 2nd battery.

EEAC37D9-0A53-4EEE-A956-3CFFAAD08061.jpeg
 
Last edited:
Tarquers

Tarquers

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Messages
250
Location
Wrocław
Vehicle
T6.1 Beach camper 150
So when on hook up your 240 socket inside runs off the invertor? Seems a bit of a waste, or is it VW being economical with the drawing? The positive terminals are at the same voltage as they are connected to the same supply point. The earth is also common as both negative terminals are connected together. You may get a bit of a drop down the cable between the batteries under the seats, but probably not enough to measure.

Used to use a series/parallel setup on tanks with 24v, with 10 batteries in, we used to rotate the batteries around to maintain even charge and discharge but never really worked out the physics of it. As in theory it is all one big battery. Same here? Call an expert in at this point!
 
gareth230380

gareth230380

VIP Member
Messages
35
Location
Maidstone, Kent
Vehicle
T5 Beach
This is the wiring diagram showing earth and loads going from a single battery and different to the one you’ve posted? Really confused now. May get an auto electrician to sort.

5705E775-88A2-42DF-9E67-F51C5AC4CC68.jpeg
 
Tarquers

Tarquers

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Messages
250
Location
Wrocław
Vehicle
T6.1 Beach camper 150
if you leave the earth where it is, you can take the supply side across to the new (third battery) like this:
Connecting Two Batteries in Parallel
 
WelshGas

WelshGas

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T5 SE 180 4Motion
So when on hook up your 240 socket inside runs off the invertor? Seems a bit of a waste, or is it VW being economical with the drawing? The positive terminals are at the same voltage as they are connected to the same supply point. The earth is also common as both negative terminals are connected together. You may get a bit of a drop down the cable between the batteries under the seats, but probably not enough to measure.

Used to use a series/parallel setup on tanks with 24v, with 10 batteries in, we used to rotate the batteries around to maintain even charge and discharge but never really worked out the physics of it. As in theory it is all one big battery. Same here? Call an expert in at this point!
Incorrect.
there is a Mains 230v socket on the mains circuit.
There is a 150 w, now 300 w On the T6.1, Inverter that runs off the Leisure Batteries.

The 230v EHU mains circuit isn’t shown on that circuit diagram.
 
WelshGas

WelshGas

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gareth230380

gareth230380

VIP Member
Messages
35
Location
Maidstone, Kent
Vehicle
T5 Beach
the 2008 wiring diagram (see attached) does as per your document, guessing they changed it in the T5.1

DCC3C602-4F3D-4698-95F9-126967E1073F.jpeg
 
Tarquers

Tarquers

Lifetime VIP Member
Messages
250
Location
Wrocław
Vehicle
T6.1 Beach camper 150
Incorrect.
there is a Mains 230v socket on the mains circuit.
There is a 150 w, now 300 w On the T6.1, Inverter that runs off the Leisure Batteries.

The 230v EHU mains circuit isn’t shown on that circuit diagram.
My comment based on your diagram, garbage in, garbage out. Regardless of source of diagram, if it’s wrong it doesn’t help when offered as a source.
 
WelshGas

WelshGas

Retired after 42 yrs and enjoying Life.
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My comment based on your diagram, garbage in, garbage out. Regardless of source of diagram, if it’s wrong it doesn’t help when offered as a source.
That is the 12v Leisure Circuit with the 12v Inverter Nothing to do with the 230 v EHU circuit.
If you want further explanation to understand it I would refer to the VW document in Post 7.
Unlike some, I am prepared to offer some information . If you Disagree with VW then that’s your prerogative and I suggest you take it up with VW oh mighty one.
 

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