# habitation electrics & Sargent 155 PSU



## Roger7webster (Oct 10, 2006)

Has any one tried to modify the subject psu to allow the habitation electrics to operate when the engine is running
I have asked the Sargent tech dept who as expected declined to offer advise quoting the electronic emission regulations. 
It must be possible to run a separate supply from the leisure battery
to the control panel on/off switch but really need a detailed circuit diagram of the psu and control box 
Any one have any drawings please


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## peribro (Sep 6, 2009)

Here's how to do it on the EC325 - don't know if the two units are similar though.

http://www.motorhomefacts.com/ftopict-69333-.html


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## 100127 (Jul 20, 2006)

Roger7webster said:


> Has any one tried to modify the subject psu to allow the habitation electrics to operate when the engine is running
> I have asked the Sargent tech dept who as expected declined to offer advise quoting the electronic emission regulations.
> It must be possible to run a separate supply from the leisure battery
> to the control panel on/off switch but really need a detailed circuit diagram of the psu and control box
> Any one have any drawings please


Of course it is possible, but why would you want it that way?


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## Roger7webster (Oct 10, 2006)

Thanks for the info but the current 155 unit is not similar to the 325.
Blobsta the question should not be why should I want to but why not!! Most if not all continental vans have the habitation electrics available when the engine is running.
Usually they are fitted with same equipment and are not subjected to the same restrictions.
This problem has been posted many times over the years. It had been easy to to disconnect the relay in earlier UK vans. Now the same relay may well be connected to the fridge and step relay.
So still looking for some practical advise and circuit diagram please


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## 100127 (Jul 20, 2006)

Just curious as to why,


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## seanoo (Mar 31, 2007)

hi , i've done it on my 2007 autotrail scout. it has a ec200 sargeant power supply. for me it was a simple case of cutting a wire inside and just taping up the ends . 
everything works in the hab area now whilst driving.
sometimes my other half likes to sit at the dinette and read or use the loo so it works for us. below is a post i put on another forum a couple of years back

there was a red and yellow wire going into a white connector block in the bottom of the case of the sargeant . there were 2 or 3 connector blocks but only one had the yellow/red wire . i have just cut this and now my hab electrics work with the engine running . fridge and step all ok too. 

hope this helps sean


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## Roger7webster (Oct 10, 2006)

Thank you seanoo just the sort of info I was hoping for.
Will take my psu out as its so difficult to work on in the under bed locker space.


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## Roger7webster (Oct 10, 2006)

Follow up post..
I stripped down my psu unit but as its a printed circuit board with electronic breakers I was unable to modify it
I then decided to connect one lighting circuit direct to the hab battery and fit a blocking diode to stop back feeding the other circuits.
Without the diode all services except the main water pump are available when the engine is running but all are fed through the lighting circuit so there is the risk of over load.
I only need lighting and the toilet pump so will fit a 5 amp fuse and an isolating switch.
A more robust arrangement may be to connect the hab battery supply to the 15 amp heater fan terminal.


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