AR54.10-D-1129-06A Notes on Fault Causes During Battery Testing

AR54.10-D-1129-06A Notes On Fault Causes During Battery Testing

Notes on possible faults when checking batteries with Midtronics MCR717
Carrying out the battery test incorrectly may lead to a false statement about the battery condition.

When testing batteries with the Midtronics tester (MCR 717), be sure to observe the following information:
- Technical equipment condition
Deviating from the original condition of the measurement lines and terminals leads to incorrect measurement results. The terminal clamps used here are special "Kelvin clamps". Only the original terminals may be used.
If the terminals are defective the device must not be sent for repair as a matter of urgency. Defective terminals can be replaced separately, although if part of the line in front of or in the terminal is damaged, the whole device must be sent in.

- Always connect the MCR 717 directly to the battery.
It is not necessary to disconnect the poles on the battery for the measurement. The measurement takes place directly at the battery and must not be carried out at other points, such as at the jump start point.

- An incorrect data input on MCR717 distorts the measurement result.
All inputs on MCR717 must be carried out conscientiously.

- Charge and test again
Batteries which have been tested with the measurement result "Charge and retest" must be completely charged before a retest.
A so-called "partial charging" is insufficient for a reliable evaluation of such batteries.

- Batteries must only ever be loaded after charging.
After charging an increased surface voltage is applied to starter batteries. This distorts the measurement result or leads to a fault message. After charging only ever load the batteries for about 2 minutes or allow to stand with no load for several hours. To provide a load for example, switch on low beam and afterwards allow the battery to stand with no load for 5 minutes.

Auxiliary batteries
The Midtronics MCR 717 measuring device (1) is only designed for testing starter batteries. Some additional batteries (traction batteries) are designed for a current draw over longer periods. Cold cranking amps are therefore not specified on these batteries, only the open circuit voltage can be checked.

The measurement of open circuit voltage is a simple and effective method in order to check the condition of the additional battery (traction battery).

As a rule a built-in voltmeter is fitted to campers for the measurement.

Open circuit voltage in V Charge level in %
greater than 12.80 100
approx. 12.55 75
approx. 12.30 50
approx. 12.20 25
less than 12.00 0

The measurement should take place at an ambient temperature of 20 to 25 °C and take place some hours after charging is complete.