Camping Interior Westfalia leisure battery charging
Hacksawbob For searchability: Westy Charging leisure battery relay
== I wanted to get my head around this so I did a bit of digging in the fuse box head scratching in Bentley and the Westfalia diagrams and with a lot of help off the forum (thanks Bigherb especially) this is my understanding how the charging system works on a Westy.
Note the leisure relay 'earth' is cancelled out by the positive feed from the ignition this means the relay is fed 2 positive feeds to the switched side during engine cranking so the relay doesn't engage and the leisure battery and starting battery aren't connected until the engine has started. There are two benefits from this firstly the leisure doesn't sap current during engine starting, also there would be considerable current being pulled through the white red wire between the batteries from the starter motor. (Note: the main positive feed from the starting battery to the starter motor isn't shown on this diagram)
California Dreamin I do question the accuracy of the above diagram ^^^^ the pinouts do not match up with my own experiences and the relay implies that it has two joined terminal 87's where as in my experience the relay fitted is a 'b' type which has an 87 & 87b which are NOT joined.
Alternative UPGRADED relay' to replace the weak original Westfalia relay mounted at the side of the leisure battery:
The correct relay is a single pole double contact SPDC, not to be confused with a Single pole double throw SPDT. Also known as Double make & break. NORMALLY OPEN (closes with engine running) The only 5 pin relay to have an 87b....notice that 87 & 87b are NOT joined *************this is very important.
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Having said all of this.....I now challenge you to find one! they are as rare as hens teeth.. Besides, now is your opportunity to upgrade to something more substantial, you will need to replace two terminal ends on the heavy wires going to terminal 30 & 87 on the relay, from 6.3mm (standard females) to larger 9.5mm ones but this new dedicated split charge relay is a 60 amp replacement, so ultimately will be more reliable.
http://www.autoelectricsupplies.co.uk/p ... tegory/149
Comparing the old to new relay pin out numbers:
The terminal that was going to 85 (trigger from alternator) now goes to W1 (6.3mm will fit to the smaller 4.8mm terminals on the new relay with slight crimping) The terminal that was going to 86 (earth wire) now goes to W2 (6.3mm will fit to the smaller 4.8mm terminals on the new relay with slight crimping) The terminal that was going to 30 (starter battery) now goes to C1 (this 6.3mm female needs changing for a larger 9.5mm kind) The terminal that was going to 87 (leisure battery) now goes to C2 (this 6.3mm female needs changing for a larger 9.5mm kind) The terminal that was going to 87b (Fridge feed) now goes to C3
Notice***that C2 & C3 on this new relay are also NOT joined...just like the original :ok If they were connected, it would mean that the fridges 12 volt side, could be powered from the leisure battery even with the engine turned off.
