Anybody got one of these ??

[Rob101]

Hi All,

My split charging system stopped working a wee while back - with the voltage sensing relay clicking on and off incessantly before finally failing..
So I thought I'd begin troubleshooting by purchasing a new VSR from Towsure :




I wired it from my starter battery to the +12VFUSED I/P and 0V EARTH I/P. I was surprised to find this made the O/P connectors all live too with the engine off (at a starter battery voltage of a steady 12.8V). I thought they were meant to be isolated once the voltage fell below a threshold of 13.x volts???? I've turned the VSR adjustment pot to its extremities and this made no difference.. Its not totally broken because if I remove the feed from the battery, I hear the VSR click off..give it power and it clicks on again..

I get 13.6V at the battery with the engine running BTW, so I guess the VSR needs to have a threshold of between 12.8 and 13.6V in my case.

So my questions - 1/ have I bought the correct VSR?? 2/ anybody know the threshold voltage range for switching on these?? 3/ am I making sense / doing it correctly ?!?
and 4/ does anybody have a spare working VSR?!

Mucho thanks for any advice !

[Aethelric]

I got this from my supplier
Pick up voltage is around 13.65-13.75Volts with a drop out of 13.2-13.05 volts.
It seems to work OK but if the the secondary battery has been discharged a little (I've never discharged it a lot) It clicks in and out on start up, for a few seconds as the secondary battery pulls the voltage down.
Its normal for the relay to stay connected for a short time after the engine stops. Try switching on the headlights to drain the excess power off the battery, the relay should open after a few seconds.
Mind you, I would have thought it should have disconnected at 12.8V
Dave

[patnben]

These VSRs are designed for towbar electrics with an "S" type socket for caravans,
hence the fridge output. These are normally only rated at 30 Amps max and should
be fused accordingly. If you are using it for a leisure battery system; then with a
heavily discharged leisure battery you could easily draw 60 Amps from the alternator.
When used like this; they do have the habit of welding the underated contacts together,
you may hear the relay armature clicking even if the contacts are welded.

Normally, any VSR should switch on at around 14 Volts and off at around 13.8 Volts.
With a healthy starter battery - fairly well charged - the alternator output voltage
should be approaching 14.4 Volts without anything else connected. It may be that
discharged batteries are one of your problems; especially if the VSR contacts are
welded together.

[patnben]

Having nothing better to do, I just tested a new unused VSR (Also from Towsure).

Factory setting:
Relay ON: = 13.62 Volts - Relay OFF: 13.13 Volts.

Adjustment:
Maximum ON: = 14.26 Volts.
Minimum ON: = 12.60 Volts.

There is around 0.5 Volts differential over the whole range.

This seems to prove that Aethelric's figures are very close to a general factory setting.

Depending on your charging priorities, you could raise the switch ON voltage towards
14.00 Volts to ensure that the starter battery is fully charged before the secondary
or leisure battery starts to charge. I would certainly not make it any less than the
above factory setting.

[Rob101]

Thanks for the replies guys. crumbs patnben - u've been burning the midnight oil !!! Your test results are very useful, and confirm how I thought the VSR should be working..

I took it out of the van and wired it up to a DC transformer - and stepped up the voltage. nothing at 3V, nothing at 4.5 V then it clicked on at 6V !! (even after turning the adjuster to both extremities).

mm so is the consensus it is either broken, or I've been sent the wrong product - I cant see why a 6V cutoff should exist !

Cheers

Rob

PS/ cheers for the warnings about current too - its only used as a switching relay for a 70Amp relay that handles the load. and its got a 30Amp Fuse across its feeds from the starter battery to protect it..

[patnben]

Having looked at the spec for this VSR on the Towsure site, I see
nothing wrong with using this to drive a heavy duty relay. So the
product is right but it certainly shouldn't be switching at the sort
of voltages you have described. If you have a smooth variable DC
supply then you have proved it yourself that it's way out of spec.
Send it back and get another one.

Being a really old f**t, I have an evening meal and then fall asleep
watching television, wake up at 02:00 and spend the rest of the
night twiddling my thumbs waiting for the sun to appear over the
horizon.

Ben.

[Rob101]

lol - well i'm glad I gave you something to think about in the small hours of the morning Ben !!

I've bought (another) new VSR from a local supplier, and all is working as expected. Looks like Towsure will be getting the duff one back..

Thanks for the advice everybody.. Without it I wouldn't have had the confidence to play + learn as much as I have the past few days..

Cheers

Rob

[dandywarhol]

If the L/B is discharged then the towsure vsr won't cope - better to get a 100 amp one from willington on ebay, or search in here - definitely worth the extra...................