Are my Aux Batts too tired?

But were the 2007 Calis fitted with AGM batteries? I suspect not. In which case wouldn’t these Varta batteries do just as well?
They will be OK, but as explained here, AGM are considered more cost effective over their longer life expectancy.

 
”In the long-run we are all dead” and that also applies to all types of leisure battery. ;)
 
But were the 2007 Calis fitted with AGM batteries? I suspect not. In which case wouldn’t these Varta batteries do just as well?
I think it’s amazing that the originals have lasted for such a long time.
What ever their make or type is I would be tempted to try and stick with the same if available. They obviously suit the on board electrics.
 
Still running our original 15 year old batteries in 2008 SE. 6 hours after 2 hour drive, showing 12.3v with fridge on.

Attempting 5 nights unplugged in a couple of days. Should just about survive with just the fridge on.

But when they’ve gone, they’ve gone. Mine are getting there.
 
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Still running our original 15 year old batteries in 2008 SE. 6 hours after 2 hour drive, showing 12.3v with fridge on.

Attempting 5 nights unplugged in a couple of days. Should just about survive with just the fridge on.

But when they’ve gone, they’ve gone. Mine are getting there.
still running same batteries mine shows 12.5 when charged, still get 4 days of grid.
 
Is it a bad idea to let your batteries get really flat, or not an issue?
 
Is it a bad idea to let your batteries get really flat, or not an issue?
Yes is the short answer. They shouldn't go below 50% capacity for any prolonged length of time as that will reduce their lifespan.
The fridge or Parking Heater will cut out at 11.5v to protect them but lights or use of 12v sockets have no such function and can drop the voltage much lower. Do not depend on the % shown on the Control Panel, but the voltage shown is accurate.SoC-AGM.jpg
 
Yes is the short answer. They shouldn't go below 50% capacity for any prolonged length of time as that will reduce their lifespan.
The fridge or Parking Heater will cut out at 11.5v to protect them but lights or use of 12v sockets have no such function and can drop the voltage much lower. Do not depend on the % shown on the Control Panel, but the voltage shown is accurate.View attachment 112627
Thanks for this. Most useful.
 
VW fit Varta LA80 .
Replacement batteries have to have the same physical dimensions, but there are not many quality makes that have those dimensions and are AGM and at least 75/80 amp capacity.
Prices vary but Tayna Batteries are a competitive supplier.
I have now got a pair of LA80s and want to fit them. Testing with a multi-metre I have got 12.7V charge on both. Once they are fitted do you know a good way of testing to see if they are both working and holding their charge. I am new to the game of leisure batteries, so forgive my ignorance please.
 
I have now got a pair of LA80s and want to fit them. Testing with a multi-metre I have got 12.7V charge on both. Once they are fitted do you know a good way of testing to see if they are both working and holding their charge. I am new to the game of leisure batteries, so forgive my ignorance please.
Voltage. Voltage will reveal everything you need to know especially if you can reduce the load to close to zero.

Strategies to measure voltage:

  • Bm2 is popular. It's a Bluetooth voltmeter.
  • Victron mppt (bt)
  • Epever mppt with display.
  • Plug in cigarette lighter thing. (Not useful for wardrobe battery)
  • Multimeter (cumbersome to test. If you choose this strategy install an accessible test point)
  • Control panel (not useful for wardrobe battery)


Experience tells us that you need to keep a good eye on the wardrobe battery. For this a Bluetooth monitor or direct display of some description is a good idea.

If you are reading this in the future the advice is not really relevant to a T6.1
 
I have now got a pair of LA80s and want to fit them. Testing with a multi-metre I have got 12.7V charge on both. Once they are fitted do you know a good way of testing to see if they are both working and holding their charge. I am new to the game of leisure batteries, so forgive my ignorance please.
The 2 batteries are wired in parallel so are treated as 1 big battery of 12v and 150 amp hours.
The vehicle alternator and the EHU mains battery charger are connected to the battery under the passenger seat. The Control Panel will show the voltage of the combined battery and the charging voltage from the alternator when the engine is running or the charging voltage from the EHU mains charger if plugged into EHU mains.
The only problem is that there is a 50/75 or 100amp cube fuse ( depends on vehicle year ) fitted to the +tve pole of the wardrobe battery. If that should fail the wardrobe battery is cut off and so you are only running on 1 battery. The Control Panel will not show anything different but the voltage will drop quicker than usual when running fridge or parking Heater.
The only way round this as @yossarian said is to measure the voltage of the wardrobe battery seperately, but its not really a big problem if you don't. Just remember if the Control Panel volts drop quicker than usual check the Cube Fuse.
 
The 2 batteries are wired in parallel so are treated as 1 big battery of 12v and 150 amp hours.
The vehicle alternator and the EHU mains battery charger are connected to the battery under the passenger seat. The Control Panel will show the voltage of the combined battery and the charging voltage from the alternator when the engine is running or the charging voltage from the EHU mains charger if plugged into EHU mains.
The only problem is that there is a 50/75 or 100amp cube fuse ( depends on vehicle year ) fitted to the +tve pole of the wardrobe battery. If that should fail the wardrobe battery is cut off and so you are only running on 1 battery. The Control Panel will not show anything different but the voltage will drop quicker than usual when running fridge or parking Heater.
The only way round this as @yossarian said is to measure the voltage of the wardrobe battery seperately, but its not really a big problem if you don't. Just remember if the Control Panel volts drop quicker than usual check the Cube Fuse.
Thanks. Very helpful. It is a T5 SE 2.5L TDI. The year is 2007. I think there might be a cube fuse there but not sure.
 
The 2 batteries are wired in parallel so are treated as 1 big battery of 12v and 150 amp hours.
The vehicle alternator and the EHU mains battery charger are connected to the battery under the passenger seat. The Control Panel will show the voltage of the combined battery and the charging voltage from the alternator when the engine is running or the charging voltage from the EHU mains charger if plugged into EHU mains.
The only problem is that there is a 50/75 or 100amp cube fuse ( depends on vehicle year ) fitted to the +tve pole of the wardrobe battery. If that should fail the wardrobe battery is cut off and so you are only running on 1 battery. The Control Panel will not show anything different but the voltage will drop quicker than usual when running fridge or parking Heater.
The only way round this as @yossarian said is to measure the voltage of the wardrobe battery seperately, but its not really a big problem if you don't. Just remember if the Control Panel volts drop quicker than usual check the Cube Fuse.
Just to let you know how I got on with fitting the new pair of Auxiliary batteries. Before changing (on the original batteries, in there since 2008). The Control Panel voltage showed 12.3V 50%. I tested the old batteries with a multi-meter and they both showed 12.2V.
Then testing the new Varta LA80s out of the box, they showed 12.7 each. I fitted both and did not check the box fuse on the rear battery (forgot about that) but did everything else by the book.
With the new batteries fitted the control panel showed 12.7V 90%. Then I charged on the hook-up for 24 hrs and the reading was then 13.2V 100%. After a further 12 hrs on checking the control panel again the reading is 13.0V 100%. If you can think of any further tests I would be interested.
I am tending towards a conclusion that the new auxiliary battery fitting has been successful. As you mention, a fuller test will be to keep an eye on things once the fridge, etc., are being used.
One question that crossed my mind is that there a lot of owners on here who talk about being “off-grid” for days. With just a pair of LA80s as a power source how long can you expect to live off-grid, presuming the batteries are in a healthy condition and fully charged up to begin with?
A second question is, over the winter period, when you may not be using your Cali so much, how often should it be put on hook-up to avoid my expensive new aux batts discharging to the point that they are damaged?
Lastly, is it worth investing in one of these smart battery chargers? They are not cheap and I do have an old school trickle charger already. Is it not more economical to just rely on the hook-up and alternator charger instead? There are better birthday and christmas presents than a smart charger.
 
Just to let you know how I got on with fitting the new pair of Auxiliary batteries. Before changing (on the original batteries, in there since 2008). The Control Panel voltage showed 12.3V 50%. I tested the old batteries with a multi-meter and they both showed 12.2V.
Then testing the new Varta LA80s out of the box, they showed 12.7 each. I fitted both and did not check the box fuse on the rear battery (forgot about that) but did everything else by the book.
With the new batteries fitted the control panel showed 12.7V 90%. Then I charged on the hook-up for 24 hrs and the reading was then 13.2V 100%. After a further 12 hrs on checking the control panel again the reading is 13.0V 100%. If you can think of any further tests I would be interested.
I am tending towards a conclusion that the new auxiliary battery fitting has been successful. As you mention, a fuller test will be to keep an eye on things once the fridge, etc., are being used.
One question that crossed my mind is that there a lot of owners on here who talk about being “off-grid” for days. With just a pair of LA80s as a power source how long can you expect to live off-grid, presuming the batteries are in a healthy condition and fully charged up to begin with?
A second question is, over the winter period, when you may not be using your Cali so much, how often should it be put on hook-up to avoid my expensive new aux batts discharging to the point that they are damaged?
Lastly, is it worth investing in one of these smart battery chargers? They are not cheap and I do have an old school trickle charger already. Is it not more economical to just rely on the hook-up and alternator charger instead? There are better birthday and christmas presents than a smart charger.
Well done.
VW recommend plugging into the Mains monthly for 12-24 hrs to fully charge the Leisure batteries.
Fully charged leisure batteries should last for 3-5 days running the fridge, camping lights and charging phones or iPads depending on the weather etc.
 
Voltage. Voltage will reveal everything you need to know especially if you can reduce the load to close to zero.

Strategies to measure voltage:

  • Bm2 is popular. It's a Bluetooth voltmeter.
  • Victron mppt (bt)
  • Epever mppt with display.
  • Plug in cigarette lighter thing. (Not useful for wardrobe battery)
  • Multimeter (cumbersome to test. If you choose this strategy install an accessible test point)
  • Control panel (not useful for wardrobe battery)


Experience tells us that you need to keep a good eye on the wardrobe battery. For this a Bluetooth monitor or direct display of some description is a good idea.

If you are reading this in the future the advice is not really relevant to a T6.1
Had a look at the battery monitoring devices on that well known website beginning with “A”. Apart from the mixed reviews over how well the blue-tooth works and the associated device apps being a bit flakey, a couple of down-sides come to mind and they are important I think. Firstly, these devices appear to use juice from the battery, so are another source of low drain whilst the vehicle stands idle. Secondly, as one of the reviewers mentioned, do you really want to connect the + and negative parts of your battery together with only this small unit and in between? He had added in a 30A in-line fuse on the positive side, to be safe. That’s not a bad work-around if it does not compromise how the thing works. Given the wardrobe auxiliary battery terminals are a bit easier to access than the front ones, I think I might be better off taking my chances with occasional monitoring with my multi-meter.
 
Had a look at the battery monitoring devices on that well known website beginning with “A”. Apart from the mixed reviews over how well the blue-tooth works and the associated device apps being a bit flakey, a couple of down-sides come to mind and they are important I think. Firstly, these devices appear to use juice from the battery, so are another source of low drain whilst the vehicle stands idle. Secondly, as one of the reviewers mentioned, do you really want to connect the + and negative parts of your battery together with only this small unit and in between? He had added in a 30A in-line fuse on the positive side, to be safe. That’s not a bad work-around if it does not compromise how the thing works. Given the wardrobe auxiliary battery terminals are a bit easier to access than the front ones, I think I might be better off taking my chances with occasional monitoring with my multi-meter.

The BM2 is essentially a Texas Instruments CC2541 with a little accompanying circuitry. The magic smoke protection will kick in at some very low amperage, say 1A or so. By all means fuse it, but a realistic fuse size is sub 1A and, as the wires are not long enough to encounter the chassis, it's an exercise in paranoia.

An alternative would be to wire a test point somewhere (fused too) so that you don't need remove the rear battery to check the voltage.

Take away: even a poorly manufactured BM2 is a very minimal safety risk.
 

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