Can anyone help me understand my split charge setup please!

[sotal]

I like to know what is going on with the electrics etc so I can plan how to use it in the best way. Hence why I'm asking so many questions!


I'll post what I know - can anyone fill in the gaps? I can go and look for more details if anyone can tell me what to look for!


I have quite a large starter battery.
I have what I think is an 85Ah Leisure battery on the opposite side under the bonnet. (battery link)
I have a mains hookup system which has a little fuse box and a double mains outlet. It also powers a battery charger.
The charger is a Supercharge 151 (charger link)

With the ignition off the only things that work are the lights and the 12v socket in the kitchen unit (which powers the coolbox)

I am presuming that the lights are running off the SB though?

The LB doesn't appear to have much wired up to it at all. Physically it has one medium thickness wire going from the neg terminal to a grounding bolt just behind the battery. It then has a pair of wires with one going to each terminal (pretty sure this is the mains powered charger).

Other than that it just has 2 more red wires going from the pos terminal. They go a short distance to a fuse holder (one yellow fuse and one green fuse). From the fuse holder - they go off as a pair of wires under the air intake thing and I guess over towards the SB.

The SB itself has a black wire coming from the pos terminal with an inline fuse shortly after (I think this is the coolant alarm?) It has a black fuse box just behind the battery. I can also see a clear looking box with relays or fuses in behind this tucked in on the inner wing.

Other than that I found a relay which doesn't look too original which is mounted to the left of the air intake. It says NAGARES RLP/4-12 12V-40A.

So what else do I need to find to work out what is going on with the split charge system?

[g8dhe]

Try this diagram for starters;



The first 4 circuits in the fuse holder above are the ones that are swapped over from the old fuse box and would normally look like this once converted (only two wires shown, the other two are for the blinds as arrowed);



With the circuits arranged as above, the internal lights, central locking and backup supplies to radio and ECU all come from the LB. The two blinds may also be connected. Finally the 12 volt sockets and radio power and other ancillary supplies all come from the LB. The ignition switch no longer affects the ancillary circuits including the radio which will need to be switched off local to the radio!

[sotal]

Excellent diagram,

Can you tell from my description what type of split charge system I have? Is it likely to be very basic?


I would like to move the interior lights over and possibly the radio. Looking at the fuse box I have no wires coming out of it like your picture.

Are you inserting power into the fuse box with those wires from the LB. In effect replacing the connection between the in and out side of the fusebox with a supply from the LB instead?

If that is the case I take it that you have a wire from the LB to a fuse (what size?) which then goes to a new fusebox? Where did you mount this? This new fusebox then supplies those leads which go into the old fusebox - is that correct?


On another note is it possible to give the radio 2 power supplies? What I'm thinking is to have a rocker switch on one of the switch blanks - normally it would be in the off position. The radio would then just use the ACC feed and turn on and off by itself. However when camping we could then flick the rocker switch and the radio would then be powered from the LB instead and wouldn't need the key on. Is this possible either through a switch which would physically switch from one circuit to the other? Or using a diode to prevent the SB charging the LB through that wiring if the switch was left on?

[g8dhe]

Can you tell from my description what type of split charge system I have? Is it likely to be very basic?

It is most probably one triggered from the ignition circuit, rather than a Voltage Sensing type as the relay on its own is not a voltage sensing type (there could be a board with electronics on it some where but unlikely!). I prefer that type myself.

I would like to move the interior lights over and possibly the radio. Looking at the fuse box I have no wires coming out of it like your picture.

Are you inserting power into the fuse box with those wires from the LB. In effect replacing the connection between the in and out side of the fusebox with a supply from the LB instead?

If that is the case I take it that you have a wire from the LB to a fuse (what size?) which then goes to a new fusebox? Where did you mount this? This new fusebox then supplies those leads which go into the old fusebox - is that correct?

Yes that's right, in the circuit diagram above the new fuse block is top right, with the first 4 leads going to the old fuse box, you normally pull the old fuses out, move them to the new box, and insert the lead from the new block into the lower half of the old fuse position to pickup the circuit, the upper half of the old fuse goes to the starter battery. I mounted the fuse block and relays etc. all on an arm out of the LB +ve terminal connector. see below;

On another note is it possible to give the radio 2 power supplies? What I'm thinking is to have a rocker switch on one of the switch blanks - normally it would be in the off position. The radio would then just use the ACC feed and turn on and off by itself. However when camping we could then flick the rocker switch and the radio would then be powered from the LB instead and wouldn't need the key on. Is this possible either through a switch which would physically switch from one circuit to the other? Or using a diode to prevent the SB charging the LB through that wiring if the switch was left on?

Why bother the SCR relay is doing this for you, provided you have a switch on the radio to turn on/off. If not, get a new one with a switch and also a remote control so you don't have to keep leaning over to change channels, volume and on/off! Yes it is possible, but a bit of a faff to put together and find decent locations for the switches etc. you could do it with a relay as well triggered from the IG2 circuit to do the change over but its a lot of added complexity for little gain, especially if you don't already have a remote control!

[sotal]

Thanks for that.

I'll see if I can source the bits to make up a little fuse box etc and patch those wires across.


With the radio - I'm hoping to fit an Android Double din shortly which will hopefully give me the normal radio etc but with satnav, dvd, internet etc.

As the Bongo is used as a daily driver I would like the radio to work as you switch on and off (partially to ensure it isn't left on all day!) - but then when we go for weekends away it would be good if we could override it and leave it on.

Got lots of jobs to do now - mini fuse box to make, alarm and RCL to fit, android stereo to buy and fit, LED Cob lights to fit (when they arrive!) and then a reversing camera too if I get chance!

[Titan1995]

I can see an easy way out of this without all this split charging stuff at the front.

I found this out by accident.

I had a powerpack charging from the rear cigarette lighter.

Which in turn powered the circuit once the ign had been turned off.

In fact I have battery isolator terminals to both front batteries [Both starter batteries].

so with both batteries turned off the radio , blinds etc were powered up by the battery pack.

Such a simple piece of kit, no wiring changes just plug it in when you want it and unplug when you don't.

Works for me.

[g8dhe]

Yes that would allow the radio and blinds to work
BUT
it also means that the other circuits around the engine would remain powered whilst actually turning the engine over,
now they go to great lengths in the ignition switch to prevent that happening as the spikes can cause damage to the electronics ...... and not just from spikes across the SB but induced into the wiring harness as the looms run together.

[haydn callow]

You say in your first post above, you think the Coolant alarm is wired to the battery. This should not be the cas, coolant alarm should be connected to a ignition switched live.

[sotal]

Yes - you are probably right - was just guessing.

Something aftermarket looks to be wired up with an inline fuse from the positive terminal on the SB.

[sotal]

I've gathered some bits together and begun to make a patch cable to move the circuits over.

I have the fusebox itself and have made up a positive feed which spits to the four spade terminals on one side of the fusebox. I haven't got enough wire left though to do from the other side of the new fusebox to the bongo fusebox.

When it gets to the point where I actually plug into the fusebox - what did you use on the end of the wire to allow you to plug it into the fusebox? I'm tempted to cut some mini fuses up to steal the legs and solder / heatshrink them on to the end of the wires - is that the best method?

Are they safe just plugged into the front like that?

You can see the start of my patch cable in the following picture - I'm also wondering where to put this fuse box - will it be OK where I have placed it on this picture? There is a mini 2 fuse holder on the side of this bit of the intake - can I put my 4 fuse holder on the top as pictured? Perhaps double sided tape mounting?

[g8dhe]

Use a cut down Spade or fork terminal to insert into the lower half of the fuse socket.
Do make sure your using automotive wiring, the insulation is different from other uses.
Others have screwed the fusebox to the air intake box, so you won't be the first, but having it fixed to the bulkhead is probably preferred.

[sotal]

That is automotive wiring that I have used so far. But I've only got a few scraps left. I need to get some more to do the runs from the fuse holder to the bongo fusebox.

I was going to go for some 15amp twin automotive cable - as I can pick that up from Maplins. Personally I'm not too bothered by the fact that it will be black and red but both will be positive. I've got some thin conduit that it can run in. Unless you can recommend some wire that will be better?

Just reading your BWM site - I notice that fuse 1 controls a lot more than just the lighting - some ignition stuff etc - is that all OK moving over to the LB? I was going to go with the power blinds and the other 2 as per your arrowed photo above. The fridge and tap is already powered by the LB.

[Simon Jones]

These are good for feeding power into the system at the fusebox from LB and it means you can retain the original fuse and just move it over to the piggy back unit. NOTE: you must fit them with the flylead side into the non-live part of the fuse holder on the panel.

[cmm303]

....
Just reading your BWM site - I notice that fuse 1 controls a lot more than just the lighting - some ignition stuff etc - is that all OK moving over to the LB? I was going to go with the power blinds and the other 2 as per your arrowed photo above. The fridge and tap is already powered by the LB.

It is common practice to move the whole fuse 1 circuit to the LB.

[sotal]

These are good for feeding power into the system at the fusebox from LB and it means you can retain the original fuse and just move it over to the piggy back unit. NOTE: you must fit them with the flylead side into the non-live part of the fuse holder on the panel.

So do you just use those 'empty' without any fuses in? They might do the trick - are the bongos just regular mini size fuses?