What’s draining my batteries?

[Foggy51]

Question for those wiser than me.
What’s drawing power here? Nothing is switched on except the control panel. I noticed that when parked recently with just the fridge (it was 35 degrees outside) on the batteries drained over two days despite 2 Roger solar panels (with Dometic charger)on the roof.
I checked both batteries and they are showing 13.26v so they appear to be charging okay. Surely the control panel wouldn’t use that much power???

I’m stuck.Please Help

 

[WelshGas]

Question for those wiser than me.
What’s drawing power here? Nothing is switched on except the control panel. I noticed that when parked recently with just the fridge (it was 35 degrees outside) on the batteries drained over two days despite 2 Roger solar panels (with Dometic charger)on the roof.
I checked both batteries and they are showing 13.26v so they appear to be charging okay. Surely the control panel wouldn’t use that much power???

I’m stuck.Please Help

View attachment 149692

Have you been using the Inverter socket recently?
Any usb plugs in any of the 12v sockets?

 

[sidepod]

Get your multimeter out. Set it to mV. Find the fuses supplying the leisure stuff.
Stab the probes of the meter leads into the small holes on each side of each fuse.
If you see a reading that’s not zero then that’s where the drain is.

 

[Foggy51]

Have you been using the Inverter socket recently?
Any usb plugs in any of the 12v sockets?

Not on this occasion. Just the fridge albeit in extremely hot weather.

 

[Foggy51]

Get your multimeter out. Set it to mV. Find the fuses supplying the leisure stuff.
Stab the probes of the meter leads into the small holes on each side of each fuse.
If you see a reading that’s not zero then that’s where the drain is.

That’s a good idea. Is that the fuses that are under the passenger seat in a T6?

 

[sidepod]

That’s a good idea. Is that the fuses that are under the passenger seat in a T6?

Not 100% sure as I’ve never had a need to look. I think so.

 

[Markgray6.1ocean]

How old are your batteries? A solar panel is not going to supply 4amp permanently 24hours a day which is what your fridge will be more or less needing when it’s hot inside. Disconnect the batteries and see if anything resets. But consider new ones if they are over 3 years old.

 

[Roger Boeken]

how much solar power do you have ? 100W, 200W panels ?
if fridge and other consumers draw more current than solar delivers that moment there is nothing wrong I think.
On the photo you are parked , roof down I assume ? At 15:37h, the sun is already lower in the sky, and the panels will no longer have a maximum output.

 

[Foggy51]

How old are your batteries? A solar panel is not going to supply 4amp permanently 24hours a day which is what your fridge will be more or less needing when it’s hot inside. Disconnect the batteries and see if anything resets. But consider new ones if they are over 3 years old.

Thanks Mark. Batteries and solar were new this year. Looking back at pictures we were parked in some shade so I’m thinking user error

 

[Foggy51]

how much solar power do you have ? 100W, 200W panels ?
if fridge and other consumers draw more current than solar delivers that moment there is nothing wrong I think.
On the photo you are parked , roof down I assume ? At 15:37h, the sun is already lower in the sky, and the panels will no longer have a maximum output.

Hi Roger, I’ve got two 100w panels. In the pic I sent nothing was turned on except the control panel. I have since seen it drop lower than that even with the fridge on so I’m thinking perhaps it needed the engine turning on to reset itself perhaps?
Sitting on my driveway with the fridge on the batteries are staying topped up nicely with the solar now (driveway faces south)

 

[sidepod]

How old are your batteries? A solar panel is not going to supply 4amp permanently 24hours a day which is what your fridge will be more or less needing when it’s hot inside. Disconnect the batteries and see if anything resets. But consider new ones if they are over 3 years old.

How does a fridge require a permanent 4amp supply? Even in high ambient its duty cycle is around 20mins during the day, less at night.

 

[brcas64]

I would look at the starter battery as well. I was getting some weird readings from the leisure batteries and they were draining quite quickly. I changed the starter battery after it died and the leisure batteries are holding fine now.

 

[dspuk]

A draw of -1 I’d not be concerned about, just opening the door, having lights on and just the control panel will show a number in the - range.

Are you getting a + when the batteries are charging from solar? Are you sure the panels are actually charging the batteries.

2 days in hot weather with just a fridge sounds right, so could it be a solar install challenge?

We get closer to 4 on ours with a 150W panel. Our fridge shows a high number, 9ish from memory while getting up to temp, but then just ticks on and off with a low draw.

 

[Foggy51]

I would look at the starter battery as well. I was getting some weird readings from the leisure batteries and they were draining quite quickly. I changed the starter battery after it died and the leisure batteries are holding fine now.

That’s really interesting. My solar charges the starter battery too (once leisure batteries are charged). The starter is potentially the original battery so I’ll keep an eye on that. Thanks

 

[Foggy51]

A draw of -1 I’d not be concerned about, just opening the door, having lights on and just the control panel will show a number in the - range.

Are you getting a + when the batteries are charging from solar? Are you sure the panels are actually charging the batteries.

2 days in hot weather with just a fridge sounds right, so could it be a solar install challenge?

We get closer to 4 on ours with a 150W panel. Our fridge shows a high number, 9ish from memory while getting up to temp, but then just ticks on and off with a low draw.

Here’s a screenshot of my solar today (with fridge on and outside temperature of 19 degrees in the shade) at 10:30 with solar in
full sunlight. I think it may have been because it was so hot just outside of Paris and we were in the shade. Night temperatures were still in the high 20’s and it was 36 degrees during the day.

 

[dspuk]

That’s really interesting. My solar charges the starter battery too (once leisure batteries are charged). The starter is potentially the original battery so I’ll keep an eye on that. Thanks

The starter charge will be a trickle and TBH we barely notice ours making a difference and I even changed the MPPT and ran a wire to include it.

 

[dspuk]

Here’s a screenshot of my solar today (with fridge on and outside temperature of 19 degrees in the shade) at 10:30 with solar in
full sunlight. I think it may have been because it was so hot just outside of Paris and we were in the shade. Night temperatures were still in the high 20’s and it was 36 degrees during the day.

View attachment 149848

But are you getting a positive number on the console? Is you Solar earth connected to chassis rather than leisure earth?

 

[thomasamoht]

I was having similar problems. I’m on my way to Norway so I changed all 3 batteries. I’m still getting a draw but the new batteries are night and day with performance even in hot weather and the fridge ice cold it’s barely touching the batteries whereas they were going flat in a day and a half with the fridge on in the heat. If you had new batteries and solar last year maybe the starter if it does go flat again

 

[crookrise]

A lot of misinformation posted, be careful.
Of interest to test my solar panels I wacked the fridge up full and put frozen milk, bread ice cubes in [next to the back panel] 7 days later ice was showing signs of melting.
So no reason why you only lasted 2 days, I lasted 2 days in this weather no solar panels on new van.

Starting point would be to check cube fuses on the batteries.

 

[WelshGas]

A lot of misinformation posted, be careful.
Of interest to test my solar panels I wacked the fridge up full and put frozen milk, bread ice cubes in [next to the back panel] 7 days later ice was showing signs of melting.
So no reason why you only lasted 2 days, I lasted 2 days in this weather no solar panels on new van.

Starting point would be to check cube fuses on the batteries.

A quick way to check the Cube Fuse on rear leisure battery is to connect the Solar Panel output BELOW the cube fuse on the rear battery.

If everything is working correctly then the Solar Panel app will show virtually the same voltage as the vehicle Control Panel BUT if the cube fuse blows then there will be differing voltages on the Solar app and vehicle Control Panel.

 

[Foggy51]

A quick way to check the Cube Fuse on rear leisure battery is to connect the Solar Panel output BELOW the cube fuse on the rear battery.

If everything is working correctly then the Solar Panel app will show virtually the same voltage as the vehicle Control Panel BUT if the cube fuse blows then there will be differing voltages on the Solar app and vehicle Control Panel.

I checked the voltage on both batteries and they were the same. Doesn’t that suggest that the cube fuse is fine? Wouldn’t it only be one battery charging with the cube fuse blown?

 

[WelshGas]

I checked the voltage on both batteries and they were the same. Doesn’t that suggest that the cube fuse is fine? Wouldn’t it only be one battery charging with the cube fuse blown?

Yes, if both batteries have same voltage then cube fuse is fine.
My point was, if the Solar is connected below the cube fuse then you can see at a glance that the solar is working and the cube fuse is OK, without having to physically check the fuse or measure each batteries voltage.

 

[Foggy51]

A quick way to check the Cube Fuse on rear leisure battery is to connect the Solar Panel output BELOW the cube fuse on the rear battery.

If everything is working correctly then the Solar Panel app will show virtually the same voltage as the vehicle Control Panel BUT if the cube fuse blows then there will be differing voltages on the Solar app and vehicle Control Panel.

Two pics showing the solar app and the VW control panel. Voltage almost the same but the app shows 2.2 draw and the controller shows 0.
While this is confusing for me I’m inclined to think all is well.

 

[WelshGas]

Two pics showing the solar app and the VW control panel. Voltage almost the same but the app shows 2.2 draw and the controller shows 0.
While this is confusing for me I’m inclined to think all is well.

View attachment 149902

View attachment 149903

But you have the fridge on. The fridge could be using amps fulfilled by the solar input, so 0amps from the battery.

 

[Foggy51]

But you have the fridge on. The fridge could be using amps fulfilled by the solar input, so 0amps from the battery.

Understood. That makes sense. Thank you