Bongo Fury

Well I won myself a nearly new Numax 110Ah on ebay - not a lot cheaper than new but hey! And so now I've got to get to grips with how to install the split charge relay and rewire interior lights, etc. Despite reading as much as I can on previous threads, I'm still not confident on what I need to buy. It was Barnet Al I think who chose not to actually cut wires from the fusebox but to use small spade connectors to divert wiring to a new fuse box. I like that idea. And I've picked up on the fact that the Towsure relay may not be poky enough to survive an episode of charging a flat leisure battery. So I think I need to get:

For the split relay charging:

1.5m length red cable - 70Amp rating for alternator-starter battery-leisure battery run
short length of black cable - 70Amp rating for earthing the leisure battery
2 x 50amp fuse (one near each battery connection)
2 x 50amp fuse holders (mountable)
1 x 70amp relay (4 connector)
1 x Towsure type relay (to control the 70amp relay)
Some low amperage wire to make a connection to the alternator charging light circuit (unless the Towsure comes with wiring)

For the rerouting of the cars wiring:

1 x fusebox (8 gang should be plenty?)
Small spade connectors that will go onto the existing fusebox lugs
Plenty of low amperage wiring (how low? not sure) for the wiring runs between fuseboxes etc.

I've copied stuff from the website catalogue of Vehicle Wiring Products nad put it in a MS Word doc at http://charlotte.homecall.co.uk/LB01.DOC

One thing I cant seem to find is the low amperage split charge relay referred to as TF1170-2 Smart Combi Relay and which seems to be liked (is this an alternative to the Towsure one, which gets mixed reviews?)

I'd be really grateful for any steer BF experts could give as to whether I'm getting this right (I'll PM Barnet Al too in case he is not reading BF threads).

One final thing. I'll have to put connectors on the ends of the 70Amp cable. Is soldering them the best option (I think I have enough solder somewhere if I cna find a suitable heat source for the job (probably a blowtorch carefully used, as my soldering iron or my new propane gas soldering iron wont have nearly enough oomf).

Thanks dudes

Mike

Too late tonight to comment - watch this space!

Thanks Pippin - great to have the attention of a BF heavyweight. This is not a 'tomorrow' job for me - happy not to rush into it!! Making tents out of tarpaulins is more my line

Mike

Good luck Tarquin.... Make sure you keep notes how you get along. We will also get a leisure battery in the next couple of years, so may be knocking on your door for help
Out of interest how much did you pay for the battery? and have you got the tray etc to seat it?

Have seen a company offering to do everything for £1750.00?

Hi Mike

I've just done mine last weekend. Not actually got round to wiring up any loads yet though.

I procastinated and procastinated about using a heavy duty relay but in the end I went for the 30 A relay that Dandy used. I figured the worst case when the battery is too flat to charge via the van circuit would be a blown fuse and having to recharge the battery from a main charger.

Got mine off ebay from discout towing supplies. They've got one on the go at the moment 190047041645

If you cable yours up the way I did it's dead simply I took photos of every step and plan to do a howto. Got rellys staying this weekend so won't get round to it this week.

Here's a few photos to be going on with

Thats excellent corblimey & looks like a really neat job too (dont want wires lying about all over the place). I'd be v interested in your notes and idiots guide to what parts to buy and where. Does your setup work fine so that the charge light on the dash doesnt remain on dimly. What was it decided you in the end not to go for 70Amp relay etc. (mind you in general if its good enough for Dandy it is probably good enough for us all - I'm sure he'll take that as a compliment). Have you rewired the Bongo yet so cig. sockets, lights, radio etc. are coming off the leisure battery? I dont want to cut wires really so need to source the small spade connectors that Barnet Al mentions he used.

NeilT. £56 for the Numax and he dropped it off to me from Northwich. Not a huge bargain as you can get one new for £71 or so delivered, but the Numax was the one I knew would fit the special tray I had bought from ebay and fitted a while back, and I wanted a big leisure battery. So I set my limit at £57 (funny that!) hoping to get it much lower, but somebody else must have wanted it a lot too as they were the only bidder who stayed in, and they went to £55. The battery is a few months old, unused, kept charged, has receipts and the vendor was a 'proper person' as my wife would say, so I'm happy

Off for a ciggy and bed

Mike

Hi Mike,

The relay's that Dandy and Corblimey have used are voltage sensing, so they don't need to be switched by the alternator charge light at all. Imagine it as sitting on the wire between the positives of the engine and leisure battery, switching the line on when it knows that the engine is running (by the voltage of the engine battery going above a preset limit - say 13 volts)

When the engine stops, the engine battery will settle to below this voltage and the connection will be broken again.

Here you go Mike



As wrster says there is no need to connect the relay to the alternator because we're using a "smart" relay (voltage sensing relay). It make the whole job a 1000x less complicated.

The batteries are simply wired in parallel and the relay sits between the +ve posts of each battery. The relay only needs one other connection to -ve (chassis) so that it can draw power for itself. In my case I actually wired it back to the -ve post of the starter battery but I could have connected it to any good chassis earth.

If you want to try the cheaper relay first and replace it if it doesn't work, you could always install the heavier cabling now and change the relay at a later date. The important thing is you select a fuse that is rated less than the lowest rating of any other component (including cabling) of your circuit. In my case I used a 30 A relay, 27 A cable and 25 A fuses.


I'll put it all into a howto shortly

That sounds yummy corblimey + where you order(ed) the parts from. Then we should give it all to Ozric, send a film crew round to your house (or whatever), do a video for Oz' Bongoogle entry, and we will have produced reassuring guidance on what a lot of us perceive (wrongly it seems) as one of the trickiest DIY Bongo jobs.

I'll look forward to what Pippin has to say too when he chips in. Rewiring the Bongo lights etc. (have you done that?) through the leisure battery is a separate chapter esp. if it can be done without cutting wires in my view (I never could face the snip )

Mike

Only trouble with sending the film crew round is I'd have to rip it all out and start again. I ain't that desperate to get on telly!

I got the relay from ebay 190047041645

All the other bits came from Halfords and my local motor factors apart from the heat shrink that came from CPC

I think I'll order one of thoe corblimey & thanks. Where did you go for your cabling, fuses, fuse holders, cable ends etc.? Have you rewired the Bongo lighting etc. yet?

Whoops know I forgot to answer something; I haven't wired the internals yet. I've got so cold cathode lighting to fit as well.

The fuse holders and fuses came from Halfords the -ve battery lead for the leisure battery came from the motor factors. Asy you can see I already had a box of crimp connectors.

You can get all the bits from Halfords.

Although the glass fuses are a little old hat I prefer the holders because they are not pre-wired like many of the blade fuse holders. You end up with unnecessary extra connections and you don't know the exact current rate of the cable they used if you go with the blade holders.

corblimey wrote:Whoops know I forgot to answer something;

Actually there was another thing you forgot to answer which is wether your installation causes the "battery charge" light to glow. I am guessing that it is only if you connect a relay to the alternator output that you get this problem, but it would be nice to have confirmation.

Also a question from me: does the relay you bought have an override and status indicator you can link to the dashboard if you want? Are the instructions for it online anywhere?

You guess right the charge light doesn't light since there is not interaction with the alternator. That's the beauty of the VSR

The relay doesn't have an override but it does have sensitivity adjustment

If you wanted to have a status indicator you just wire up your choice of indicator drawing power from the switched feed. In fact the relay has a number of outputs so you could use one of those. I don't no if the insructions are available online but I do have a very simple set that were supplied with the relay. If I get time I may scan them for you.

If you want an override you'd be better off going for one of the "proper" VSRs

Oh what a very excellent thread this has turned into. I'm most seriously grateful. For the first time, I think I could actually DO this. Even the battery state indicator light sounds a simple proposition (and can be done at any later stage).

One thing I KNOW I couldnt spot in my Halfords wasa decent length of heavy duty, red insulated cabling for the battery2battery connection. Did you use starter cable corblimey? I've seen comments that solid copper would be better for low resistivity and current rating for a given cable thickness, but is it THAT critical?

I'm going to order the split charge thingamebob right now.

Mike