Bit of a guide here, for anyone looking to re-enforce their power system, by adding a second battery in the boot
Firstly, what you'll need:-
4AWG Cabling - Enough to run from the front battery, to the boot (Minimum- larger, 0AWG for example, will carry the voltage, and keep it higher)
Smaller guage cabling, to carry switching current
2X Fuseholders, and fuses
Split Charging Relay - Not available from Maplins anymore, but available from CAD/Autoleads etc.
Second Battery, ideally suited to Deep-Cycle applications, larger capacity is preferable
Battery Terminals, to connect large cabling to Rear Battery
Assorted Connectors, for connection to relay/ground-point/front battery
Instruction:-
1. Fuse this cabling, within 18" of the front battery, before it enters the cars firewall, and before the split charge relay
2. Use suitable connectors to attatch the 4AWG cabling to either of the Large connections on the split charge relay
3. Use a smaller size cabling, and run a length to an ignition-live source within the vehicle. This may be your fuel pump, or more commonly, the +ve connection of your altenator. This results in the relay being actuated, when the vehicles engine is running
4. This ignition live source should be connected to the input of the split charge relay
5. Using the same smaller cable as the input connection, connect the output connection of the Relay, to a suitable ground source
6. Secure the relay in a safe, but accessable position, under the dashboard, or engine bay will be suitable
7. Next step is to connect to the rear battery, use a length of 4AWG, from the non-used large connector of the split charge relay, to the +ve terminal of rear battery
8. Be sure to fuse this cable a few inches before it reaches the +ve terminal of the rear battery
9. Run another length of 4AWG from the -ve terminal of the rear battery, to a suitable grounding point in the boot
10. Power on the engine, checking the voltage at the relay, to be sure it is being powered on as required, and the batterys are being joined together by ther relay while the engine is running. You should hear a click from the relay, as it actuates
11. A circuit breaker, along the cable joining both batteries is optional, but will give you an extra bit of control, allowing you to disconnect front and rear batteries as required
In addition to these steps, it is also reccomended that you uprate the "Big 3" connections in your engine bay. That is:-
-ve battery to chassis
+ve altenator to +ve battery
-ve engine to chassis
Overall, this should give a tremendous improvement- Voltage levels to amps will be improved, allowing them to produce higher power levels, voltage drop from large cable lengths should be reduced, and the risk of flattening your front battery through playing for long periods while stationary should be removed aswell
Hope that helps
