Question about RTE tach board calibration

[am3rican]

I bought an RTE tach board with the built in calibrator. It is all soldered in but now I'm ready to calibrate it. Instructions say I need a 12V power source. Does anyone know if this needs to be a 12V constant source? I have a battery tender that puts out 12V+ but not exactly 12V. Can I use this or does it have to be 12V even?

 

[Photon440]

Since your car battery is (should be) more than 12V, shouldn't be a problem.

 

[am3rican]

Since your car battery is (should be) more than 12V, shouldn't be a problem.

So battery is okay but battery tender is not??

 

[Photon440]

Put a volt meter or multi-meter on the battery tender and check to see if it has constant voltage. Some of them cycle. If it's a steady 12 ~ 14 volts, I'd use it.