Override PMS in order to use LB sockets whilst engine running

C

Chris_t6.1

Member
T6 Pro
Hi,

I noticed that my usb ports normally powered by the leisure battery don’t work when the engine is running. I think this is pretty common as a few other friends who have converted vans have said the same.

Is there an easy way to override this? I know the leisure battery can provide power when the engine is running as the fridge is powered.

Would be useful to charge the kids iPads when on a long journey.
 
So I have struggled to work that out! A google image search suggests it’s this but not 100% sure. Do I need to pop it off and see if I can find a model number on the back?

I think it maybe my power distribution unit blocking it as this link has a section saying when the engine is running the master circuits are automatically disabled except the fridge to comply with regulations.

I guess my only option is to take a feed from my Victron energy load output and run a new usb charger from there.
 
It does look like the systems used in Bailey Motorhomes, having had a dig found a manual for one that has this note in it:
Screenshot_20230826-194721-01.jpeg
I'm not sure why this would be done, maybe with limited alternator power they prioritise the fridge and LB charger?

Some more digging suggests BCA PowerPaet Seattle Control Panel:
justcaravanparts.co.uk

Powerpart SEATTLE Control Panel

SKU: BC18016 PowerPart SEATTLE Control Panel. Digital Control Panel for the 12V system. Controls Master, Lights, Awning Light, Pump as well as providing a Voltmeter, Clock and internal temperature as Standard (Other Options are available but are not plug and play and may require extra tools and...
justcaravanparts.co.uk justcaravanparts.co.uk
 
I have heard of these weird shut off systems before - I don't know what regs they are conforming to, possibly something to do with preventing screens being used in motion? I never found out!
I would just bypass that and install sockets yourself.
 
So you can run all your toys from the vehicle battery whilst driving but not the leisure battery! Another hang over from caravan days by the look of it. It would be ridiculous if you could not run your heaters and water heaters whilst driving for example.
 
Yep just found similar clues on this page with user manuals, finding the installer manual would be the key to see how things are wired.

Resources - BCA Group

Looking for Power Distribution Technical Support for your Caravan or Motorhome? C-Line Products / Sockets & Switches Filename Water-Pressure-Probe-Fitting-guide.pdf Download File Control Panel Filename Montana-Control-Panel-User-Manual.pdf Download File Seattle-Manual.pdf Download File...
bcagroup.co.uk bcagroup.co.uk

I'm struggling to see where an EMC issue may exist given the amount of wiring already in modern vehicles, and in a Transporter the wiring is in a big metal box that would mostly shield any emissions. I guess the coach built motorhomes don't have that. Seems mostly to be backside covering for liability.
 
If you do either put your own feed in or look to move the ones you have keep in mind that USB sockets have a small parasitic draw as they are active electronics. You will ideally need to keep some way of isolating from the battery when not using the van for a while.

Might be worth taking the cover of and seeing what's there if it doesn't disturb things too much, the link to the forum suggested that the Sargent system had a simple link wire that could be removed, yours may be the same.
 
Hmm just a thought but in the blurb there is this list of what the fuses do:

There are 12 separate fuse protected outputs for: Auxiliary, Lights, Hob/Oven, Heater, Pump/toilet, Control Panel Ignition, Control Panel Perm, Fridge, Fridge 3S, Permanent, Leisure Battery, Vehicle Battery.
Click to expand...

The one that catches my eye is "control panel ignition" - if the control panel has all the smarts and the grey box is just the connections and relays there is a chance that it's the control panel commanding the cut off when it sees voltage on the line protected by the "control panel ignition" fuse. Maybe if that was removed the control panel would never know when the engine was running...
 
I’ll take a look when back next week see, but unsure what I would change on the panel to make it work?

If I do hardwire I’ll go from the load output on the Victron then I can set it to auto disconnect if battery drops below a certain voltage.
 
Chris_t6.1 said:
I’ll take a look when back next week see, but unsure what I would change on the panel to make it work?
Click to expand...
I suspect one of your fuses will be labelled something like "ignition" or "fridge ignition" or some variation. I can see there are labels in the photo above but not quite clear enough to read.

There is a chance that if you pull that fuse the whole system will stay in ignition off behaviour. That's a guess based on descriptions as I cannot find a public wiring diagram for these systems.
 
There must be an ignition live feed somewhere to tell the system when the engine is running (ignition is on). It would make sense to find this rather than plumbing in any new circuits.
A simple switch on this line would enable you to override the safety cutout.

I wonder if the cut out exists to save the component manufacturers from having to certify their products for use in a moving vehicle?
 
The Bear78 said:
I wonder if the cut out exists to save the component manufacturers from having to certify their products for use in a moving vehicle?
Click to expand...
Exactly this. Though it's also to do with risk as there seem to be manufacturers that don't do it, seems to be quite UK centric.
 
IMG_4805.jpeg
IMG_4806.jpeg


Tried pulling CP ignition, ign spare and m spare but still not working whilst engine is running. I wonder if it’s in the control panel itself?
 
How about trying it with the vehicle battery fuse removed, possibly in conjunction with the CP IGN fuse? I would try anything like that. It must have a signal of some sort - I am thinking possibly raised voltage from the alternator. Just to see if this works, of course you most probably need it connected for the fridge power.
I am just musing as to what I would do if it were me that had this cock-eyed system.
 
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