Difference between revisions of "Camping Interior Fitting a split charger"
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== Split charge == | == Split charge == | ||
[http://www.keithandsylvia.co.uk/tech%20pages/splitcharge.htm | Also see] | |||
Wiring a split charge relay is pretty simple, the theory is that as soon as the alternator starts charging the relay links the leisure battery into the charging circuit so that it is charged in parallel with the main battery. When the engine is not running or is cranking the engine (important) then the two batteries are separated. This allows the leisure battery to be discharged while leaving the vehicle battery to start the engine. I have been asked why not just connect the relay to an ignition switched live (one which comes on with the key) and indeed I have done so in a Ford recovery van to charge a second battery for jump starting. The trouble is the T25 (T3) does not have an accessories position on it's key, the Ford did and this was disconnected when the engine was being cranked. If the leisure battery is not disconnected during cranking then a large load will be placed on the linking wires and the fuses (you will use fuses won't you?) will blow. | Wiring a split charge relay is pretty simple, the theory is that as soon as the alternator starts charging the relay links the leisure battery into the charging circuit so that it is charged in parallel with the main battery. When the engine is not running or is cranking the engine (important) then the two batteries are separated. This allows the leisure battery to be discharged while leaving the vehicle battery to start the engine. I have been asked why not just connect the relay to an ignition switched live (one which comes on with the key) and indeed I have done so in a Ford recovery van to charge a second battery for jump starting. The trouble is the T25 (T3) does not have an accessories position on it's key, the Ford did and this was disconnected when the engine was being cranked. If the leisure battery is not disconnected during cranking then a large load will be placed on the linking wires and the fuses (you will use fuses won't you?) will blow. | ||
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The numbers on the relay are standard and any accessory relay of the type sold for spotlights etc will do, the fuse sizes should work fine (a bigger fuse will be OK but make sure the fuse is rated less than the wire), The 'thin wire to no charge light' on the T25 (T3) is blue and runs from the alternator, behind the fuse box to pin 11 on the multi-pin connector behind the dash. You can connect into it almost anywhere but I would recommend behind the fuse box if going for the front of the van as the multi-pin connector and the thick-film circuit it plugs into are quite delicate and best not disturbed if working OK. If you have a 12v fridge then it probably already has a relay wired like the one above and, if you can locate it, you can simply join to the wire feeding terminal 86 on that relay. | The numbers on the relay are standard and any accessory relay of the type sold for spotlights etc will do, the fuse sizes should work fine (a bigger fuse will be OK but make sure the fuse is rated less than the wire), The 'thin wire to no charge light' on the T25 (T3) is blue and runs from the alternator, behind the fuse box to pin 11 on the multi-pin connector behind the dash. You can connect into it almost anywhere but I would recommend behind the fuse box if going for the front of the van as the multi-pin connector and the thick-film circuit it plugs into are quite delicate and best not disturbed if working OK. If you have a 12v fridge then it probably already has a relay wired like the one above and, if you can locate it, you can simply join to the wire feeding terminal 86 on that relay. | ||
== Fridge. == | == Fridge. == | ||
Revision as of 14:56, 8 February 2006
Split charge
Wiring a split charge relay is pretty simple, the theory is that as soon as the alternator starts charging the relay links the leisure battery into the charging circuit so that it is charged in parallel with the main battery. When the engine is not running or is cranking the engine (important) then the two batteries are separated. This allows the leisure battery to be discharged while leaving the vehicle battery to start the engine. I have been asked why not just connect the relay to an ignition switched live (one which comes on with the key) and indeed I have done so in a Ford recovery van to charge a second battery for jump starting. The trouble is the T25 (T3) does not have an accessories position on it's key, the Ford did and this was disconnected when the engine was being cranked. If the leisure battery is not disconnected during cranking then a large load will be placed on the linking wires and the fuses (you will use fuses won't you?) will blow.
Enough theory, the wiring ....
The numbers on the relay are standard and any accessory relay of the type sold for spotlights etc will do, the fuse sizes should work fine (a bigger fuse will be OK but make sure the fuse is rated less than the wire), The 'thin wire to no charge light' on the T25 (T3) is blue and runs from the alternator, behind the fuse box to pin 11 on the multi-pin connector behind the dash. You can connect into it almost anywhere but I would recommend behind the fuse box if going for the front of the van as the multi-pin connector and the thick-film circuit it plugs into are quite delicate and best not disturbed if working OK. If you have a 12v fridge then it probably already has a relay wired like the one above and, if you can locate it, you can simply join to the wire feeding terminal 86 on that relay.
Fridge.
To wire a 12volt fridge use exactly the same circuit but replace the leisure battery with the fridge in the diagram above and check the current drawn by the fridge for wire sizes and fuse ratings. The same 'sense' wire (the blue one) can operate both relays comfortably (mine has been like that for two years at time of writing).
Finally at all costs be safe, although 12v wont give you a shock the current produced by a battery will easily set fire to the wiring if allowed to 'short', make sure all connections are insulated, mount the relay on something solid and make all connections securly, in order of preferance solder, terminal strip or crimp, don't use scotchloks and always fit the fuses.
