Leisure batteries not connected to each other

[BenCar]

Need some knowledge please forum:

I've a solar system connected to the rear leisure battery, works v well and I can monitor on the app.
It seems that the front leisure battery, which is shown on the control panel, is having a hard time. The readings between the 2 are wildly different. It's obvious the solar power isnt getting through to the front leisure battery. ChatGPT tells me that the connections between the batteries is broken. I've replaced the 80amp fuse under the passenger seat but it's not done anything.
Then ChaGPT went crazy and had me looking under the bonnet, which it then admitted was a mistake.

Anyone have further ideas for me to check next please?
Thanks
Ben

 

[WelshGas]

Need some knowledge please forum:

I've a solar system connected to the rear leisure battery, works v well and I can monitor on the app.
It seems that the front leisure battery, which is shown on the control panel, is having a hard time. The readings between the 2 are wildly different. It's obvious the solar power isnt getting through to the front leisure battery. ChatGPT tells me that the connections between the batteries is broken. I've replaced the 80amp fuse under the passenger seat but it's not done anything.
Then ChaGPT went crazy and had me looking under the bonnet, which it then admitted was a mistake.

Anyone have further ideas for me to check next please?
Thanks
Ben

75 amp cube fuse on the +tve terminal of the rear leisure battery.
The 80 amp fuse under the seat , by the front leisure battery, is on the supply from the alternator.
If the cube fuse fails the 2 leisure batteries are separated so solar will charge the rear battery and alternator will charge the front. All leisure power is connected to the front battery.

 

[Sad]

"ChatGPT can make mistakes" I find it can just wildly make stuff up too!!

 

[ArunAlec]

"ChatGPT can make mistakes" I find it can just wildly make stuff up too!!

I think some VW dealers must be using it!

 

[BenCar]

75 amp cube fuse on the +tve terminal of the rear leisure battery.
The 80 amp fuse under the seat , by the front leisure battery, is on the supply from the alternator.
If the cube fuse fails the 2 leisure batteries are separated so solar will charge the rear battery and alternator will charge the front. All leisure power is connected to the front battery.

OK, thanks. I'm pretty sure I changed that recently but I've ordered a new one and will check.
b

 

[andyinluton]

OK, thanks. I'm pretty sure I changed that recently but I've ordered a new one and will check.
b

You need to get both batteries to a similar state of charge before reconnecting- the power surge as current flows from one to the other if they are different can blow the fuse.

 

[Califan61]

Need some knowledge please forum:

I've a solar system connected to the rear leisure battery, works v well and I can monitor on the app.
It seems that the front leisure battery, which is shown on the control panel, is having a hard time. The readings between the 2 are wildly different. It's obvious the solar power isnt getting through to the front leisure battery. ChatGPT tells me that the connections between the batteries is broken. I've replaced the 80amp fuse under the passenger seat but it's not done anything.
Then ChaGPT went crazy and had me looking under the bonnet, which it then admitted was a mistake.

Anyone have further ideas for me to check next please?
Thanks
Ben

Just a thought, is your solar connection directly to positive and negative terminals on rear battery? I understood the negative should be to the chassis to bring both batteries into the same circuit. Others who are more knowledgeable can confirm.

 

[WelshGas]

Just a thought, is your solar connection directly to positive and negative terminals on rear battery? I understood the negative should be to the chassis to bring both batteries into the same circuit. Others who are more knowledgeable can confirm.

On the T5/6 it doesn't matter but on the T6.1 it does as each leisure battery has its own battery monitor module .

 

[BenCar]

Thanks forum,
It was the inline fuse from the rear battery +tive.
Hopefully in the time it took me to notice there was a problem the front battery didn't take too much of a battering. Was v low occasionally.
b

 

[WelshGas]

Thanks forum,
It was the inline fuse from the rear battery +tive.
Hopefully in the time it took me to notice there was a problem the front battery didn't take too much of a battering. Was v low occasionally.
b

Those Cube fuses seem to be very fragile. Originally they were 50 amp then upgraded to 75 amp . I read somewhere that the T6.1 was upto 100amps.

 

[BenCar]

Those Cube fuses seem to be very fragile. Originally they were 50 amp then upgraded to 75 amp . I read somewhere that the T6.1 was upto 100amps.

Turned out it wasn't the cube fuse, but the inline one from the battery further up the cable. I've now got some spare cube fuses just in case though.

 

[Rololux]

Turned out it wasn't the cube fuse, but the inline one from the battery further up the cable. I've now got some spare cube fuses just in case though.

As a matter of interest, where is this fuse located? Is it near the front battery - i.e. under the seat? I had a similar problem a couple of years back, and it was fixed by the dealer under warranty, so I never got to find out details.

Strange thing is that the fuse doesn’t seem to appear on any of the circuit diagrams, at least the ones I have seen (mine is a T6.1).

 

[BenCar]

As a matter of interest, where is this fuse located? Is it near the front battery - i.e. under the seat? I had a similar problem a couple of years back, and it was fixed by the dealer under warranty, so I never got to find out details.

Strange thing is that the fuse doesn’t seem to appear on any of the circuit diagrams, at least the ones I have seen (mine is a T6.1).

Directly connected to the positive of the rear battery in the boot access panel.

 

[WelshGas]

Directly connected to the positive of the rear battery in the boot access panel.
View attachment 140128

That is an Aftermarket addition.
Which wire is it on, the large diameter red wire or another red wire?