I've avoided using desulfators with any of my intelligent chargers for the
very reason that you've experienced.

BTW, something that seems kinda odd, is that the pdf instructions for the
desulfator kit are dated as modified 25/03/2012, the same date as your post.

The desulfator instructions caution against using sophisticated/intelligent
battery chargers with the desulfator unit.

The desulfators I have are made up of just common components used for
creating the pulsing circuit.

I'm generally very doubtful of "miraculous recovery" products.. dead is dead
(although I do like a good Zombie movie).
Weak, old batteries need to be replaced. Neglect and abuse typically aren't
reversible, IMO.
That said, I do find it believable that a desulfation cycle can be useful as
part of regular service, maintenance and charging routines.
By desulfation cycle, I mean a separate action, not applied while the
charger is connected/active (although marketers claim desulfators can be
connected permanently.. car battery applications, for example).

I'm not familiar with the CTEK charger, but the 17V you're seeing could be
the full upper voltage level of the charger power supply, before it's
regulated down to 13.8V (or the appropriate output voltage), so the
suggestions regarding the likely damaged output devices seem reasonable.

Lead acid batteries are basically the same as they have been for
generations.. the capacity density has been improved and newer production
methods and materials have improved reliability.
Even though chargers now have uP control/monitoring, proper charging
practices are the same. The most practical approach is routine monitoring
and testing.

The most reliable option may be to have CTEK repair and recertify the
charger.

--
Cheers,
WB
..............


"joost" wrote in message
...
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.

Many thanks,
Joost