Can I safely connect leisure battery to main battery which is discharged?

[alekbe]

My main battery is discharged (can't start engine) but both leisure batteries are full (I have solar panels with MPPT charger).
1) Can I safely connect leisure battery under the driver seat to main battery (with cables) to try to start the engine?
2) Should I disable solar charging (I can do that through Victron bloototh app) when doing this?
3) Can I just leave main battery connected to leisure battery to get it charged by solars? The problem is that as far as I remember leisure batteries are little bit different and for sure their efficiency is different from main battery. So I guess it's generally not recommended but will it break anything if I will do that just one time?

California T5 2012 Comfort Edition.

 

[Wildcamper]

I would suggest getting yourself a Smart Battery Charger and charging the starter battery. They are not expensive. This assumes you can get power to a charger. Also, if you have fully discharged the battery it may be beyond recovery.

 

[alekbe]

Yeah I am trying to get the charger but I am in countryside and it's ~20km to town / shop / gas station so it's kind of emergency situation .
I checked battery types and main battery is 80Ah "classic acid" (Bosch S4 S4010 12V 80 Ah / 740 A EN) and leisure batteries are AGM acid (VARTA 7PO 915 105 A; 12V 75Ah 420A DIN 800A EN/SAE/GS).

 

[Ch1pbutty]

Carry a small battery pack / jump starter similar to the below:

 

[WelshGas]

My main battery is discharged (can't start engine) but both leisure batteries are full (I have solar panels with MPPT charger).
1) Can I safely connect leisure battery under the driver seat to main battery (with cables) to try to start the engine?
2) Should I disable solar charging (I can do that through Victron bloototh app) when doing this?
3) Can I just leave main battery connected to leisure battery to get it charged by solars? The problem is that as far as I remember leisure batteries are little bit different and for sure their efficiency is different from main battery. So I guess it's generally not recommended but will it break anything if I will do that just one time?

California T5 2012 Comfort Edition.

Yes you can, with the following provisos.
+tve to +tve BUT Leisure -tve to Chassis earth or Earth point near engine battery, NOT the Engine battery -tve pole.
Connect up and leave for 10-20 minutes, for charge to equilibrate between all 3 batteries.
Disconnect and then Start engine.
You then need to go for a good drive to get some charge into the Engine Battery.

No need to disconnect Solar but you can do if you wish.

 

[Hotel California]

I think the lesure batteries are not made start the engine , but in emergency and no other options you might try ?
Maybe best to make sure everything else is disconnected from the circuit to prevent more damage .
Just while typing @WelshGas posted you can so i think you have a chance to get home before dark !

@WelshGas , so not starting while connected but just leaving them connected a while the lesure batteries top up the starter battery enough to re-start?

 

[Ch1pbutty]

My main battery is discharged (can't start engine) but both leisure batteries are full (I have solar panels with MPPT charger).
1) Can I safely connect leisure battery under the driver seat to main battery (with cables) to try to start the engine?
2) Should I disable solar charging (I can do that through Victron bloototh app) when doing this?
3) Can I just leave main battery connected to leisure battery to get it charged by solars? The problem is that as far as I remember leisure batteries are little bit different and for sure their efficiency is different from main battery. So I guess it's generally not recommended but will it break anything if I will do that just one time?

California T5 2012 Comfort Edition.

I would first disconnect any wires already connected to the donor leisure battery terminal(s) then attach the jump cables from leisure terminals to your main battery (+ direct, - to earth point/chassis).

 

[alekbe]

@WelshGas Thanks, I will try that!
@Ch1pbutty I will definitely get one, thanks

 

[Loz]

Remember, if you disconnect one of the leisure batteries to use as a jump start, the live cable will still be live! so make sure you put a glove over it.

 

[alekbe]

Okay so I finally got cables, but of course too short to connect to leisure battery under driver seat. Moreover I couldn't unmount any of the leisure batteries - to unmount the one below driver seat it seems you have to remove driver seat first? And I couldn't access the one in the back because since there is no electricity I can't open tail gate (I can just open driver doors manually) .
So I took out main battery, put it inside the car and connected to leisure battery under the seat with cables. Then after two hours I put it back and it almost worked - all electronics was working and I could almost start engine - but after few "spins" it didn't want to spin any more (though electronics was still working).

Today I was charging after dark so main battery was charged only from leisure batteries and not from solar panels. The plan is that tomorrow when sun will come out I will charge it again for 4 hours and will try to start the engine.

please keep finger crossed

 

[Loz]

Okay so I finally got cables, but of course too short to connect to leisure battery under driver seat. Moreover I couldn't unmount any of the leisure batteries - to unmount the one below driver seat it seems you have to remove driver seat first? And I couldn't access the one in the back because since there is no electricity I can't open tail gate (I can just open driver doors manually) .
So I took out main battery, put it inside the car and connected to leisure battery under the seat with cables. Then after two hours I put it back and it almost worked - all electronics was working and I could almost start engine - but after few "spins" it didn't want to spin any more (though electronics was still working).

Today I was charging after dark so main battery was charged only from leisure batteries and not from solar panels. The plan is that tomorrow when sun will come out I will charge it again for 4 hours and will try to start the engine.

please keep finger crossed

Remember to first open the tailgate.

 

[California4x4]

Okay so I finally got cables, but of course too short to connect to leisure battery under driver seat. Moreover I couldn't unmount any of the leisure batteries - to unmount the one below driver seat it seems you have to remove driver seat first? And I couldn't access the one in the back because since there is no electricity I can't open tail gate (I can just open driver doors manually) .
So I took out main battery, put it inside the car and connected to leisure battery under the seat with cables. Then after two hours I put it back and it almost worked - all electronics was working and I could almost start engine - but after few "spins" it didn't want to spin any more (though electronics was still working).

Today I was charging after dark so main battery was charged only from leisure batteries and not from solar panels. The plan is that tomorrow when sun will come out I will charge it again for 4 hours and will try to start the engine.

please keep finger crossed

This sounds like quite the adventure. Good luck!

 

[WelshGas]

Okay so I finally got cables, but of course too short to connect to leisure battery under driver seat. Moreover I couldn't unmount any of the leisure batteries - to unmount the one below driver seat it seems you have to remove driver seat first? And I couldn't access the one in the back because since there is no electricity I can't open tail gate (I can just open driver doors manually) .
So I took out main battery, put it inside the car and connected to leisure battery under the seat with cables. Then after two hours I put it back and it almost worked - all electronics was working and I could almost start engine - but after few "spins" it didn't want to spin any more (though electronics was still working).

Today I was charging after dark so main battery was charged only from leisure batteries and not from solar panels. The plan is that tomorrow when sun will come out I will charge it again for 4 hours and will try to start the engine.

please keep finger crossed

Open the Tailgate. Remove the rear leisure battery, making sure you isolate the +tve connection which will still be live.
Connect to installed engine battery correctly and start vehicle.
VW fit AGM batteries as Leisure and Engine. They are the same physical size with the same capabilities. In fact Varta sell the F21 as an engine battery and the LA 80 as a leisure battery. If you look on their website both are identical in every way except the Leisure LA80 has a longer warranty period. The F21 is also a little cheaper. One Forum member fitted 2 x F21 batteries as replacement leisure batteries.

 

[alekbe]

It worked! After ~4h of charging main battery from leisure batteries (+solar panels) engine started without any problems . I was driving around ~1.5h to get it fully charged (I hope), tomorrow I hope engine will start again. Thanks everyone for help!

Now however I have some other problems :

1) VW radio panel wants me to enter some PIN code, which of course I don't have (can't find it in the papers; I am not first owner of this car). From what I read I can get it from VW Service (they should have it in their database?) or get some kind of physical "keys" that I put into the control panel to reset it?

2) On California panel under the roof both popup-roof icon and aux. heating icon are blinking which normally means malfunction AFAIK. I hope this is normal that it happens after main battery is disconnected. I tried opening and closing roof and it works, but icon is still blinking. However I can't start aux. heating - it says "error. no programme". Do you guys know if I can reset control panel somehow?

 

[Loz]

You will probably have to reset the one touch windows as well.
turn the control panel off by pressing the off button twice, then back on again.

 

[westfalia]

@WelshGas has got the control panel reset
on the tip of his fingers
that should sort it.

 

[WelshGas]

It worked! After ~4h of charging main battery from leisure batteries (+solar panels) engine started without any problems . I was driving around ~1.5h to get it fully charged (I hope), tomorrow I hope engine will start again. Thanks everyone for help!

Now however I have some other problems :

1) VW radio panel wants me to enter some PIN code, which of course I don't have (can't find it in the papers; I am not first owner of this car). From what I read I can get it from VW Service (they should have it in their database?) or get some kind of physical "keys" that I put into the control panel to reset it?

2) On California panel under the roof both popup-roof icon and aux. heating icon are blinking which normally means malfunction AFAIK. I hope this is normal that it happens after main battery is disconnected. I tried opening and closing roof and it works, but icon is still blinking. However I can't start aux. heating - it says "error. no programme". Do you guys know if I can reset control panel somehow?

View attachment 71244

As @Loz has said.



Check Control Panel Diagnostics.
Control Panel Off and wait 30 secs
Control Panel On
Press and Hold R lower button and then press Control Knob for 5 secs.
New Hidden Menu . Scroll to VW Diagnostics.
If there are any codes shown, take note and then Reset/Clear.
Return to Main Menu.
Switch Off Control Panel using L lower button. Wait 30 secs and Switch On.

Try Roof/Heater or Fridge

 

[alekbe]

After switching off Control panel and switching on controls stopped blinking and AUX heating works again! Thanks and Happy New Year to every one!

 

[Grumposaur68]

Yeah I am trying to get the charger but I am in countryside and it's ~20km to town / shop / gas station so it's kind of emergency situation .
I checked battery types and main battery is 80Ah "classic acid" (Bosch S4 S4010 12V 80 Ah / 740 A EN) and leisure batteries are AGM acid (VARTA 7PO 915 105 A; 12V 75Ah 420A DIN 800A EN/SAE/GS).

Do you have breakdown cover that could come out to you?

 

[Siarhei]

You can replace your main "classic" battery with AGM with no problem at all. It does the same job. As for vice-versa - I would not suggest, but there's nothing criminal in here as well.