On Fri, 9 Aug 2013 21:00:44 +0000 (UTC), Cydrome Leader
wrote:

Jeff Liebermann wrote:
On Mon, 5 Aug 2013 15:05:05 +0000 (UTC), Roger Blake
wrote:

Given the less-than-steller reviews and HF's reputation for electronics,
I should not have bought this thing, a 12 Volt 6 or 2 amp (switch
selectable) charger for car batteries.(...)

Incidentally:
http://802.11junk.com/jeffl/pics/drivel/slides/dead-battery-chargers.html
All of them died float charging standby and backup batteries on
mountain top radio sites. Mostly, the electronics on the PCB's (with
the numbers ground off) were what failed. I managed to fix one or two
by guessing the regulator IC that was used, but they again failed in
short order. The chargers were replaced by various Statpower/Xantrex
chargers, which have been working quite nicely for the last 7 years.

were these hunk-o-junk units plugged into those hardwired site wide surge
surpessors?

Sorta. All the sites were on some form of backup or emergency power,
such as an autostart generator. The switching transitions are
anything but graceful, with no provisions for zero voltage switching.
The resultant glitches, spikes, surges, and over-voltage hiccups could
easily have blown up the chargers. However, all the sites also have
big MOV surge protectors and LC line filters just after the circuit
breakers, which does a fine job of protecting against glitches and
such. There was plenty of other equipment in the buildings, including
commodity networking hardware, scanners, computahs, weather station,
etc all of which are somewhat sensitive to glitches. Nothing failed
except the battery chargers.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558