Leisure Battery in need of replacement?

[Blaster T6]

Hi All
I have T6.1 camper conversion professionally fitted from new 4 years ago.

My issue is when parked up overnight the battery doesn't appear to hold enough charge to power my Wallas hob first thing in the morning. The voltage display might show 12.0 but will go down to 11.3 when the hob starts up and it eventually cuts out. I can get around this by running the engine for 5 minutes until the hob is up to temperature. The display will go up to 14v with the engine idling, but this isn't an ideal solution at 7am on a busy campsite.

The hob will work fine in the evening when first parking up, and I try to limit the overnight drain on the battery (fridge on minimum/limited use of lights).

I'm assuming after 4 years the cheap 82ah/90ah leisure battery fitted has come to the end of its life and will need replacing. I don't want to go down the lithium route due to the cost and also I've no idea if my charging system if compatible, so I'm looking for a straight lead/acid replacement. Will going for a larger capacity 120AH AGM battery last longer and give me more resilience for off-grid camping?

 

[CAB]

Yes, it's on it's way out.

12.0 is 50% capacity, and you don't want to be going lower than that or risk damage to the battery.

Voltage sag when the hob starts up will drag it lower, the hob has a voltage sensor, and will cut out if too low, so as not to damage the battery.

Lights won't use much, it's the fridge which is the main power user.

So yes, biggest AGM you can fit in the space.

 

[CAB]

But consider what chargers you have, are they Lithium compatible?

Depending on brand, Lithium is approaching AGM for usable capacity £for£, and no worries about damaging it if you go too low.

 

[t0mb0]

It’s worth considering what kind of usage has killed the existing battery. It might just have had a lot of use and reached the natural end of its life but it’s also possible that some aspect of the use and/or charging could be improved which is worth knowing if you’re installing a new one.

I’m asking as we’re still on the original factory 75Ah AGM leisure battery from 2016. Now it’s very definitely not got the capacity it once had but, at the same time, it’ll happily power our fridge overnight and the fire up the diesel heater in the morning.

 

[DXX]

I have a Wallas XC Duo with 90Ah of AGM leisure battery. I sometimes get the same situation in the morning especially if the solar isn’t really active and the engine hasn’t been run.
The Wallas glow plug doesn’t quite get to ignition temperature before the flame out shutdown activates on the feedback from the thermocouple.
Second start the Wallas fires up straight away as the glow plug is still hot from the first attempt.
A new battery is unlikely to fix it, you may find that the resistance of the glow plug is too low. This glow plug is easy to renew but be aware that it is a widely available diesel engine Beru glow plug that Wallas put a massive price premium on. Have a Search on the Forum with Wallas and you’ll see the part to use.
If you have a multimeter check the old glow plug resistance against the new, my findings is that just 0.1 Ohm too low is enough to prevent first time start up.
If the Wallas start up lasted 3 seconds longer my unit would fire up every time as the thermocouple indicates the flame as lit just as the pump shuts down on flame out.
There maybe a way to tune the PCB to increase the delay but I’m not an electronics expert.

I’m considering removing some material from the glow plug bulb so that there is less mass to heat and it gets hotter in the same start up period, the glow plugs are cheap if not bought from Wallas.
I’ll put some feedback on the Forum when I do this.

No harm in changing your AGM LB as after 4 years and 50 SOC or worse it will have degraded.

 

[Blaster T6]

Thanks for all the feedback- I have noticed the wallas does sometimes fire up on a second attempt, which would tie in with the suggestion that the glow plug needs replacing-I might try this first if it’s an easy fix- I’ll also speak to the installers to see if their set will work with a lithium battery before I replace the LB.

 

[DXX]

I’ve done some testing with my Wallas and I believe I have a fix for the low voltage flame out issue on start up.
I have installed a 10.5v glow plug instead of the standard 12v glow plug, they’re not easy to find so I’m going to get some spares before I reveal the part number.

 

[Linoleum Bonypart]

Lithium with ten year warranty

 

[DXX]

I’ve done some testing with my Wallas and I believe I have a fix for the low voltage flame out issue on start up.
I have installed a 10.5v glow plug instead of the standard 12v glow plug, they’re not easy to find so I’m going to get some spares before I reveal the part number.

NGK 7493, best price is currently Autodoc, I haven’t found another European supplier.
First time start every time, slightly longer than the standard Wallas Beru glow plug but no issues as it clears the housing and the fuel needle.