"Chuck Gould" wrote in message
ps.com...


Got any tips based on observation or experience for maintaining or
troubleshooting a battery charger?


Mike wrote:

All I can do is echo Wayne's remarks about proper wire sizing, but that's
mainly for a fast charge, or starting amps. For a trickle charge it isn't as
important.

--Mike

Ideally, connect the charger *directly* to the battery terminals but at
least make sure there is no risk of a loose connection IN THE BOAT'S
wiring between the charger connection point and the battery. If there
was a loose connection you might over-voltage all your on-board
electronics. *Expensive*. Some chargers are protected against this and
are labelled as suitable for running 12V equipment even without a
battery connected, Otherers are not, so take care.

Make sure the charger is suitable and safe for use on a boat. A quality
marine charger has a fully isolated output. Many car chargers have the
-ve output terminal grounded. Your 12V system and your on-board mains
should only have the 0V and the protective ground joined at a SINGLE
point and the battery charger is *NOT* an appropriate or safe place to
do so. Depending on the design, the RFI filter at the input to a
switched mode charger may *by design* leak enough current from Live to
ground to swamp your galvanic isolator and render it ineffective at
protecting your propeller etc. from rampant electrolysis.

(This problem is not exclusive to battery chargers, any 3 wire mains
applience with a switched mode PSU can contribute to the problem as can
2 wire (no ground) appliences where some connection is made to the 12V
ground (laptop computers connected to the instruments, entertainment
centres with the aerial braid grounded where the aerial is mounted etc.
The only *certain* cure is an isolation transformer on the incoming
mains feed, but on boats with simpler equipment, carefull choice of
appliences and unplugging anything 'fancy' {i.e. with push-button
controls} when its not in use, can minimise the problem.

Gotta go, I have to fit a battery charger . . .


--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:
'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
All varnished hot moulded wooden racing dinghy.