Dual Pro RS3 Battery Charger Weirdness

We have 4 RS3 chargers, 2 in the competition tool cart and 2 in the practice battery cart.
The competition cart RS3s are about 5 years old. The other pair is 3 years old.

Are there 2 or more iterations of this charger? The newer pair charges batteries to at least a 0.5V higher finish voltage. I’ve swapped batteries between the chargers and this oddity stays with the chargers.

Below is a snippet of a CBA-V test that alternates between 6A loads for 15 seconds and 16 amp loads for 10 seconds. The top 2 traces are from batteries charged by the newer chargers. The bottom 6 traces are from batteries charged by the older chargers.


Something’s funny.

Has a different amount of time elapsed between when you pulled them off the charger and when you tested them?

1 Like

No more than a few minutes in each case. I should also point out that all of the batteries and chargers were stored and tested at room temperature .

My working theory is that the two newer chargers know AGM batteries when they see them, while the older pair does not.

You may want to contact the manufacturer (not who you bought the chargers from) and ask them about what you are observing.

There may be differences in the design considering the five year difference. However, in looking at the waveforms, I am leaning towards the newer chargers not really sensing AGM batteries. There is every indication that the higher voltage is what a normal lead acid automotive battery charge would be, i.e. 14.5-15 volts. I would wait for an hour or two to test after the battery has been removed from the charger and compare with the curves you show above. There is no indication in the manual that these chargers actually differentiate between battery types. The manual states that the charger goes into “float/maintenance mode” but does not describe what it is doing. Smart chargers often will test and turn on a float charge for a short period of time but will not provide continuous current forever.

This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.