twin charging systems

helen&tony · Post by **helen&tony** » Fri Nov 23, 2007 11:15 am

Hi
Here's a bit of a poser. I had someone in England (a nationwide towbar fitting service) fit an intelligent charging system to the Bongo to power the caravan battery, and 'fridge. I asked them to fit it in the front close to the battery, and run a couple of cables to the rear over the top of the chassis. Now, in my day the customer got what they wanted, but this silly A**E fitted it behind the left hand side rear trim panel, presumably picking up it's power from the rear fag lighter. My original idea was to put a switch under the bonnet, and when we're not towing the caravan, we could switch it to the leisure battery which I have fitted under the bonnet. Now, my question is , can I fit a second intelligent charging relay under the bonnet,and a switch on each system so that I can switch either one on , and the other one off depending on my preference, so I can either go caravanning, or camping , and have 12v. whilst camping. If this is possible, what is the current reccommendation for an intelligent relay for an LB.
Manythanks inanticipation of a little help
Cheers
Helen

Griffin · Post by **Griffin** » Fri Nov 23, 2007 11:44 am

Hi sorry I cant help about the charging units (although it sounds possible) but, if they have picked up the power from the lighter socket in the rear I would be very wary about using it. The problem is the wiring used (at least in my Bongo) is very very thin and a fridge would draw far too much current for it. If it was a National chain I'd take it back.

alphabetter · Post by **alphabetter** » Fri Nov 23, 2007 12:24 pm

Griffin wrote:Hi sorry I cant help about the charging units (although it sounds possible) but, if they have picked up the power from the lighter socket in the rear I would be very wary about using it. The problem is the wiring used (at least in my Bongo) is very very thin and a fridge would draw far too much current for it. If it was a National chain I'd take it back.

Basically the same view. I don't see any reason why you can't fit too charging units. However the wiring to the rear cig lighter isn't good so unless they've run new wiring I doubt you'll get good performance from a unit fitted in the rear.

I would personally move the unit you already have and rewire as needed.

helen&tony · Post by **helen&tony** » Fri Nov 23, 2007 12:47 pm

Hi Griffin & Alphabeta
I had the same thought regarding the fag lighter wire. I only presume that this is the wire they used, as it's the only live behind the trim on that side. Strangely enough, though, and I can't explain why, it worked on our journey all round France, Switzerland , Italy, Greece, and here in Bulgaria, but , like yourselves, I wouldn't have believed it!!! I still would like to know what is the favoured split charge system at the moment, if you could offer advice, as I understand, from what I see on the Forum, that there is a problem with the leisure battery blowing fuses when it is discharged a long way.....Ta
Helen

mikeonb4c · Post by **mikeonb4c** » Fri Nov 23, 2007 2:37 pm

The fuses are there to protect the intelligent charger (voltage sensing relay) as it would blow if the fuses didnt when a deeply discharged LB attempts to 'suck in' charge. This is an issues for those of use who fitted a Towsure VSR and 27amp wiring as per corblimeys excellent sheet, becuase tehre was no other idiots guide at the time (I'm going way back in time to 9 months ago - evolution in Bongo World is a million times quicker than that on planet Earth). The heavier duty VSRs and wiring in kits now available on ebay take 70amps and - in theory - are not at risk of blowing. Then again some have said that - in theory - a deeply discharged LB might attempt to draw more than 70amps. At his point we need Pippin or some other Electric Guru to comment

helen&tony · Post by **helen&tony** » Fri Nov 23, 2007 2:54 pm

Aha, Mike
All is now clear on the fuse bit...I've never had such a problem on my old type2 even with a deeply discharged LB. I've been looking on e-bay to find a suitable voltage sensing relay to no avail. No matter how i phrase the search, I have no luck....probably my stupidity!!!
Cheers
Helen

corblimey · Post by **corblimey** » Fri Nov 23, 2007 3:07 pm

More importantly the fuses are there to stop your van going up in smoke in the event of a problem. That's why they should be placed as close a possible to the battery so they protect as much of the circuit components as possible.

Back to VSRs, I replaced my Towsure relay with one of Martin's (aka Ebayer Willinton). Basically he takes a cheap high current relay pops the lid and fits a voltage comparator circuit in the empty space and sticks all together again. He saw the need for a reasonably priced VSR and plugged a hole in the market. You'll find them on Ebay when he has a batch made up.

If you want one from a proper (whatever that means) manufacturer I found these to be the next best value http://www.quaywestmarine.co.uk/products.asp?recid=568

helen&tony · Post by **helen&tony** » Fri Nov 23, 2007 3:33 pm

Hi Corblimey
Many thanks....bye the bye, I like your cat avatar
Cheers
Helen

corblimey · Post by **corblimey** » Fri Nov 23, 2007 4:09 pm

You should see his catflap

dandywarhol · Post by **dandywarhol** » Fri Nov 23, 2007 6:19 pm

Not sure if "his" and "catflap" should be in the same sentence

The old Type 2 system would have taken a feed straight from the alternator Helen. There can be some problems with dash lights backfeeding with that system on the Bongo.

I would need to go and look at the alternator to find out the max current MIke - maybe someone else might know - it's usually stamped somewhere on the casing. It might belt out around 70 amps but it also shares that with the starter battery and the starter motor will draw up to 500 amps on a cold start for a few seconds so I would doubt the 70A HD relay woud suffer if the leisure battery was totally discharged as the starter battery would take a fair share of that to recouperate.

Out of interest I put an ammeter into my heavily discharged LB circuit (into the fuse holder) for a few seconds and the towsure relay handled over 60 amps

.....I don't think it would take much of that malarky though - I was just experimenting!

timhum · Post by **timhum** » Fri Nov 23, 2007 7:11 pm

Hi Helen and Tony,
It is possible to add another VSR along with your other one. The wiring is simple. Volts from a high current source (like the starter battery) go in, out of the relay and on to the leisure battery. The switch could be in the cable that goes to the chassis to form the ground/negative/earth, whatever they call it.
The advantage of this is that the switch needs only to be a small current switch and could be sited in the cab, not under the bonnet, with thin wire going to it instead of thick stuff.
I am surprised that the wire to your present VSR comes off the back of the fag lighter, the fuse would have popped by now I think. I took my feed for the leisure battery from that fuse box just to the left of the air ducting under the bonnet. There is a nut to the back of it on the right which I fixed a terminal to and fed the relay with. It can supply more current than you need and is close to the leisure battery as well. Use the fattest wire and fuse all the cables as per fact sheet. The work should take no more than half an hour all in, perhaps a bit more if you get fancy with the switch!
I used one of those VSRs from quay west marine but it failed after a year and have used one of willingtons ones which seems fine and might be worth waiting for.
By the way, I PM'd you after our previous posts, it might have not got to you or perhaps you have not noticed it yet. Just a chatty paragraph. John Black was pleased to hear of your news and sends his regards.
All the best,
Tim

madmile · Post by **madmile** » Fri Nov 23, 2007 10:06 pm

I have done the same as Corblimey - I was using the 30amp 'tec3m' relays which I believe are the same as the ones sold by towsure and indespension etc. Out of the last 20 I have bought I have had about 5 or 6 fail, and always protected with 25amp fuse. I have coem to the conclusion that they just dont like daily use to continually top up the leisure battery.
I would recommend those supplied by Martin (willinton) as they should be more than up to the job.

dandywarhol · Post by **dandywarhol** » Sat Nov 24, 2007 1:13 am

Another way of doing it if you still have a Towsure type VSR is to use the VSR to trigger a low curent fed to a cheap 60A relay like THIS.

This should ensure the VSR won't overload.

This doesn't answer Mike's question though.................

helen&tony · Post by **helen&tony** » Sat Nov 24, 2007 7:16 am

Hi Timhum
No P.M. has arrived...maybe try again?
Helen

helen&tony · Post by **helen&tony** » Sat Nov 24, 2007 10:18 am

Hi Folks
Thanks for the input...It seems that I'll have to get one of Mr. Willinton's specialities....How do I contact him?
Cheers
Helen