Power Supply And Earthing
Powering the DL1
The DL1 units are supplied with a power lead for connection to a standard car cigarette lighter socket, with the centre pin connected to +12v and the outer of the connector connected to vehicle ground. If appropriate (typically on a road car), this can be simply attached to a cigar lighter type connector and the lead plugged into the unit to power it, however in many cases it may be more appropriate to either permanently power the device from the vehicle loom or power the system from a separate battery, details of how to do this are below.
Permanently wiring into the vehicle
If the unit is to be wired directly into the engine wiring loom, rather than using the cigarette lighter socket, a fused supply must be used, with a fuse rating of no more than 1 amp. It is also highly recommended that the unit has it's own external power switch so it can be easily turned off. We also recommend that the units power supply is isolated from the power supply when the car is being cranked over and only turned on when the engine is running. It is possible that leaving the unit turned on during cranking may corrupt the data in the logger.
Also please note that in all cases the GPS receiver is powered on whenever there is power to the main unit - it does not turn on and off with the main unit, so if the DL1/DL90 is left connected to the battery it will flatten it.
Powering from a separate battery supply
The unit can be powered from a battery if required - this is often appropriate for temporary installations where a cigar lighter is not available. The unit requires a minimum of about 10v and draw about 100mA-200mA, so the size of the battery should be chosen to give sufficient run time. For example a 1Ah battery would give about 5 hours operation. Because of the current supply requirements only rechargeable batteries should be used, you cannot use disposable batteries.
If you do require a battery pack, Race Technology keep a wide selection in stock - call us with your requirements.
Important notes for Power Supply and Earthing/Grounding
Absolutely fundamental to the correct operation of in car electronics is a stable, noise free, clean power supply. Even more important is a really good ground connection. All Race Technology products are designed with extensive protection and filtering on the power supply inputs, but if the power supply input has excessive high voltage spikes or low voltage drop outs then it may cause problems with the operation of the electronics and even permanent damage.
A good ground connected to the electronics is even more important as the ground cannot be "filtered" in the same way as the voltage supply - if the grounding is poor then accuracy and reliability will be affected.
There are several points that should be borne in mind when connecting a good power supply and ground:
- Keep all connections as short and tidy as practical, messy wiring is potentially very dangerous.
- Use thick wire, this is particularly important on the ground connections. This is increasingly important with long runs.
- Take power/ground connections back to the battery if possible.
- Never use the same power/ground connections that are used for the engine management system, ignition system, alternator or any other "high power" device on the vehicle.
- Make sure that the power supply is fused at an appropriate level, 1A would be appropriate in most cases.