joost wrote:
Hi,

In an attempt to restore a pair of sulphatated Trojan T105 batteries I
ordered a desulphator kit, soldered it together and hooked it up to
the batteries. After it had been pulsing for a week and a half, the
batteries needed to be recharged (the pulser is powered by the
batteries). I connected my nice CTEK 15 A charger WITH THE PULSER
STILL ATTACHED to the batteries. I'm afraid this was a mistake. In my
understanding, the batteries should absorb the peaks produced by the
pulser and not damage the charger. However, now it seems that my
charger is only outputting 17.0 volts (always) and heavily
overcharging any battery that I connect it to. The peaks from the
pulser might have been higher than I thought.

I opened the casing of the charger, but couldn't any component that
looked fried. Can anyone tell me where to start looking for the
defective component? It is quite a complicated microcontroller
controlled charger, but I still have some hope that there is a single
component that needs replacement for it to start functioning properly
again.

Test for shorted power semiconductors or anything attached to a heatsink.

It's probably a Murphy's law type thing, but most power supplies fail with
no output, but battery charges like to magically fail at full voltage
output, just to destroy your batteries at the same time.