by Foretravel
The load rating on the D-34 and the Group 31 series batteries has changed. You will find a revised load testing table below. This provides a uniform procedure for load testing Gel Cell and AGM (Absorbed
Glass Matt) batteries on Foretravel motorhome.
1) Batteries must be brought to a full state of charge before any load testing is performed. Remember that the batteries that have just come off a charge, or out of service, will read slightly higher than the actual voltage due to “surface charge.” This surface charge must be removed before testing. Batteries below 12.0 OCV (open circuit voltage) could take from 10 to 24 hours to reach a full state of charge.
2) Batteries must be load tested individually. They must be disconnected from any other battery that is wired in on that particular bank.
3) If the load tester is variable (adjustable) set the load at half the CCA (cold cranking amps) or three times the 20- hour rating. Apply this load for 15 seconds and monitor the battery voltage. The battery should stabilize above 9.60 volts while on load. If the voltage falls below 9.60 volts recharge the battery and repeat the test. If the voltage is below 9.60 volts on the second test condemn the battery.
4) When testing very large batteries (Group 4D or8D), and your tester isn’t able to supply a sufficient load, and then apply a load equal to (2X) the 20-hour rating. An M-K 8D 20 hour rating is 225 (example: 225 x 2 = 450 amp load). Apply this load for 5 seconds while monitoring the battery voltage.
The battery should maintain a voltage of 10.50 volts or higher while on load. If the voltage falls below 10.50 on the first test let the battery voltage recover to 12.65 and retest at 450 amps for 5 seconds. If the voltage falls below 10.50 on the second test condemn the battery.
Below is a table for batteries that Foretravel has used in the most recent years, and are currently using:
