Ask the Expert: Can the Power Probe be powered by an external battery?

Feb. 27, 2016
Well…yes and no.

Q: Can the Power Probe be powered by an external battery?

A: Well…Yes and no.

Power Probes are normally connected to and powered by the battery installed in the vehicle. This is ultimately the most effective way to use your Power Probe because there are circuit testing advantages that are gained when locked onto the main power and ground sources on the vehicle.

No. 1 – Automatic Voltage Drop Detection. As you check voltages with the probe tip, the tool is always comparing the tip voltage reading to the battery voltage and will alert you if there is too much voltage drop from battery to tip.

No. 2 – The probe is now locked onto the only true ground point on the vehicle. This will not only keep your voltage readings accurate, but you will no longer have to find new ground connection points as you test in different circuits throughout the vehicle. No chance of connecting to a weak ground point that could throw your voltage readings off and affect your testing results.

However, there are situations where connecting the Power Probe to an external battery or power source for testing may be required. Testing trailer wiring and lights is a good example. Since trailers don’t normally have their own batteries, you will need another source of power. Here you have the option to connect the probes battery cable clamps to any portable power source, like a jumper pack. The only thing to remember when using an external battery is you will still need to ground the probe to the vehicle you are testing. Be sure to connect the Power Probe’s Auxiliary Ground Lead to either the vehicle ground lead or the vehicle chassis to complete the ground connection. Once the ground is connected you are ready to use your Power Probe just as you normally would to test and activate the trailer lights.

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