DIY budget split charge system

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ronsealdeath

Sagging Member
Posts
1,851
Location
Swansea, Wales
Hi there, after getting hold of a couple of Optima batteries (a red and a blue top) I decided to put together a split charge setup based on madhatmans thread in the 'common faults and questions' section. I figured it was so easy to put together and pretty cheap (and satisfying) I'd post up some pics and a shopping list.
I went for it being pretty over the top in terms of capacity so you could scale that down quite a bit;
1 x 200amp relay £7.99
1 x bag of terminal connectors with heat shrink £2.99
3m of 16mm2 copper cable £9
2 x midi fuse holders with 4 100amp fuses and connectors £7
1 x pack of 1N4001 diodes £0.99
You will also need a small fuse holder and some thin wire with end terminals. I had all this lying around in my electricals box.
So about £28 all in. Cheaper than that T-maxx jobbie but without the fancy flashing panel to show off in the cab with!

You need some pliers, a knife, a soldering iron and some solder. That's about it.

Put it all together and you end up with this



Relay


Fuse holder


You can just see the diode in-between 85 and 86




Basically the red thin wire goes to the alternator B+ and the thin black wire to earth. There is a diode in-between these terminals to quench any back current. The big terminals of the relay have thicker cable running to each + on the house and starter batteries. They have a fuse at the end closest to each battery with the fuse being the wekaest link; wire takes 120A, relay 200A and fuses 100A. See MHM's thread for the details.
I'll take some photo's when it's hooked up. I used a similar system on my RRC and it worked a treat.
The final stage to this setup is to use a 25mm2 wire from each + on the two batteries with a cut-off witch in the middle of it. This is used for jump starting and yes I used it on my RRC to great effect!

:crutch:
 
well done :)

fyi, you can also buy a voltage sensing relay for 12quid delivered and hook it to a 200a relay. saves the alt bit.
 
I like this! :D May have to do the same.

Depending on whether or not I go down the twin alternator route. Haven't decided yet.

This does look much easier though. :)

It is really simple Rob. Ill post some pics of the setup under the bonnet when I put it in. As trax says you can use another relay to detect voltage and avoid fiddling with the alternator, to power the big relay.
 
It is really simple Rob. Ill post some pics of the setup under the bonnet when I put it in. As trax says you can use another relay to detect voltage and avoid fiddling with the alternator, to power the big relay.

Cool. I will give it a go then I reckon. Might have to use the voltage sensing relay just to save messing about. :)
 
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