Sargent E160 power unit problem

[Adam H]

Got this power unit, it’s been fine and everything seems to be working in the back, but noticed yesterday when switching over to vehicle battery that no voltage is showing, it did before. Although I've also noticed that the liesure battery doesnt seem to take charge as good ( unless im dreaming it ), previously when driving the liesure battery would charge but it doesnt seem to be doing that.

I’ve checked the fuses in the sargent unit but beyond that I have no idea what to look for or where to check, I've also included pics of the fuses in the front of the van and the liesure battery incase it matters lol. Complete notice under the bonnet.

Any ideas ?

Many thanks

 

[Adam H]

Never mind, I was told that there was a fuse under the bonnet next to the battery, although none of them had blown, simply removing them and putting them back in seems to have made it come back to life crisis averted

 

[Adam H]

Ok, So it seemed to work for a few days, now today its gone again. I've tried to look for bad connections etc. The two yellow fuses in the pic are new and put in today, I "think" those are what im suppose to be looking at, one comes from somewhere under the van ( i assume the sargent unit/liesure battery ) into the fuse, then into the 30A auto switcher. The other one then goes from the auto switcher to the fuse, then off to the main battery. Black on is found and attached to a bolt on the van.

Any ideas what I can look for next, could the Auto switcher be playing up ?

 

[Nigel W]

Firstly let me say that I am not an auto electrician so I am unable to offer any technical advice but after checking all the fuses and connections I would suspect the split relay.
Assuming you don’t have a volt meter or a mate with one then If you google the name, Brocott, you will see they only cost about £12.00 so if it was me I would just buy one, swop it over and keep my fingers crossed.

 

[Adam H]

Thats exactly what I've done found one on Amazon so should be here tomorrow. If its not that, then I have no idea what else to look at

 

[Nigel W]

Thats exactly what I've done found one on Amazon so should be here tomorrow. If its not that, then I have no idea what else to look at

I’d also get a cheap voltmeter just so you can test some obvious circuits and the battery voltages

 

[Adam H]

I’d also get a cheap voltmeter just so you can test some obvious circuits and the battery voltages

I think I've got a few already ( brought an electrical tool box off a car boot one time lol ) but I honestly wouldnt know how to use it anyway

 

[Adam H]

Ok quick self tutorial on how to use a volt metre on youtube, Just tested the black and red wires attached to the switch relay and the one coming from the liesure battery is 13v and the one coming from the van battery is 12v, which I assume is a good thing. But not so much if I need to find the problem lol

 

[Nigel W]

if your leisure battery is at 13v then it’s fully charged.
The vehicle battery is low at 40% charge
Take readings direct from the battery’s with the engine running and that will tell you if they are charging.
Your only issue could be that the display just isn’t showing the vehicle voltage which may be a fault on the Sargent unit and that’s easy to get over.

 

[bytejunkie]

Take readings direct from the battery’s with the engine running and that will tell you if they are charging.

if he does that, at the starter battery, won't he see the health of the alternator, as the alternator effectively bring the poles at the battery up to 14v ish?
i know the two are akin, but if you're looking for battery health, then disconect after charging and monitor how well it stores its charge?

not questioning you, just looking to learn a bit more, as the electrics side of my camper is next.

 

[Nigel W]

if he does that, at the starter battery, won't he see the health of the alternator, as the alternator effectively bring the poles at the battery up to 14v ish?
i know the two are akin, but if you're looking for battery health, then disconect after charging and monitor how well it stores its charge?

not questioning you, just looking to learn a bit more, as the electrics side of my camper is next.

Your spot on but he has taken readings with engine off (I think at 13 and 12v) now we are trying to establish if they are charging with engine running and if the split relay is working.
mind you I’m not an expert so I only know the basics and a little knowledge can be dangerous so input always appreciated and welcome.

 

[Adam H]

Ok so, I've now replaced the auto switching relay, the display for the vehicle battery is still not showing when the van is off. But if I start the van, both liesure and vehicle battery voltages show.

However i dont think its charging the battery, as im sure when the van was running, the liesure battery voltage would normally show as 13.8, but currently it doesnt seem to be showing above 12.2. If i then flick the switch over to vehicle battery while the van is running, it shows it being about 11.8 which i believe is also low ?

So does that mean potentially the alternator isnt doing what its suppose to be ?

 

[Adam H]

Just been outside again, put a voltmetre to the battery ( van battery ). Engine off 12.7 volts, Engine on 14.8, Engine on with lights, radio etc so putting it under load, 14.4.

So i think im right in assuming the alternator is working as it should. So I should start looking more at the sargent unit and/or the liesure battery ?

 

[DXX]

No idea what your set up is but batteries degrade over time.
A trip to a battery specialist would be wise, they can load test both batteries. It’s not just a case of measuring voltages.

 

[BCH]

Did you sort this out Adam as mine is the same not showing vehicle battery voltage? I have changed the fuse next to the battery and all good. This has only happened since I had a flat battery and jumped started it

 

[Adam H]

Yes mate, It was an earth problem, as soon as it was earthed properly everything started to work as it should again. Random as it worked perfectly fine for months, then suddenly stopped working.