2 new leisure batteries, but volts still dropping quickly

[daveinbracknell]

Hi,

Rookie query.

My recently purchased 2013 T5 SE came with new leisure batteries. Seat and wardrobe.

I have had the van on EHU for longer than two days. Display shows 100%. Also, they are being charged from the engine.

But they are not holding volts. When either the fridge or parking heater are turned on, the volts very quickly (minutes) drops to 10v then shuts down either appliance.

If I didn't know any better I'd say that new batteries are needed. Buy they are dated 2023 and clearly new.

Any ideas on what to test?

 

[WelshGas]

Hi,

Rookie query.

My recently purchased 2013 T5 SE came with new leisure batteries. Seat and wardrobe.

I have had the van on EHU for longer than two days. Display shows 100%. Also, they are being charged from the engine.

But they are not holding volts. When either the fridge or parking heater are turned on, the volts very quickly (minutes) drops to 10v then shuts down either appliance.

If I didn't know any better I'd say that new batteries are needed. Buy they are dated 2023 and clearly new.

Any ideas on what to test?

Ignore the % Display. That is a very iffy calculation. Voltage is accurate. What is the voltage after charging and 12/24hrs later with nothing switched On. Also what is the current drawn?

 

[WelshGas]

Also check the 75amp cube fuse on the +tve pole of the rear/wardrobe leisure battery.

 

[daveinbracknell]

Ignore the % Display. That is a very iffy calculation. Voltage is accurate. What is the voltage after charging and 12/24hrs later with nothing switched On. Also what is the current drawn?

Where is the best place to measure the current? I'm assuming the wardrobe battery as this is easily accessible.

 

[daveinbracknell]

Also check the 75amp cube fuse on the +tve pole of the rear/wardrobe leisure battery.

I'll check this this weekend.

I'm fitting two solar panels so everything will be out for this. Thanks for your support.

 

[WelshGas]

Where is the best place to measure the current? I'm assuming the wardrobe battery as this is easily accessible.

The Control Panel will show the current drawn at rest. Should be 1 amp or less.

 

[Roger Boeken]

I find small clamp meter like :
https://www.owon.com.hk/products_cm2100_series_smart_ac|dc__clamp_meter
very usefull. CM2100B with Bluetooth allows reading and logging on your smartphone.
Contactless measurement on minus cable either battery will give you some insight about charging/discharging leisure batteries under different load/charge conditions.

example : closing and opening electric sliding door .

30 sec to close, 30 sec to open. Short peak value of 14A. In this example I assume both batteries deliver same current . I will measure with 2 clamp meters later .

 

[daveinbracknell]

I find small clamp meter like :
https://www.owon.com.hk/products_cm2100_series_smart_ac|dc__clamp_meter
very usefull. CM2100B with Bluetooth allows reading and logging on your smartphone.
Contactless measurement on minus cable either battery will give you some insight about charging/discharging leisure batteries under different load/charge conditions.

example : closing and opening electric sliding door .
View attachment 122695
30 sec to close, 30 sec to open. Short peak value of 14A. In this example I assume both batteries deliver same current . I will measure with 2 clamp meters later .

Clamp meter. Brilliant idea . Something is clearly loading the batteries excessively. Time to do some digging.

 

[yossarian]

While a DC clamp meter is a useful device don't overlook post 4 which solves your problem for free.

 

[daveinbracknell]

I'll check this this weekend.

I'm fitting two solar panels so everything will be out for this. Thanks for your support.

Yep, 75amp fuse blown

 

[daveinbracknell]

Two 100w panels from Solar Camper Solutions now fitted and working. Very simple installation.

 

[WelshGas]

Two 100w panels from Solar Camper Solutions now fitted and working. Very simple installation.

On the Leisure system all the circuits are connected to the underseat battery. The rear battery is just wired in parallel with the front battery. If the Solar +tve is wired BELOW the cube fuse on the rear battery then the Control Panel voltage will mimic the Solar output voltage as long as the cube fuse is OK. If the cube fuse blows, and they seem to be fragile, then the 2 voltage readings, Solar and Control panel, no longer mimic each other and you get an early warning.

 

[daveinbracknell]

So far, all is working well. Fridge and heater both reliably running as needed. Thanks for your help.