On Tue, 27 Jan 2004 12:55:14 -0500, DSK wrote
(with possible editing):

Larry W4CSC wrote:
....The model is VEC1093A.
http://www.battery-rechargeable-char...y-charger.html
WalMart has it discounted to $89 and change from its $110 retail.
Walmart also makes refunds and returns just too easy, any port in the
country.

Sounds like a great leap forward in technology if it really will do the
same job as a "$800 West Marine smart charger." FWIW I bought a
UL-marine rated 40 amp 3 output smart charger for about half that, but
it's still a lot more than this Wal-Mart charger.

The only problems I see
1- you can't put 480 watts through a box much smaller & lighter than the
West Marine kind, something's gotta give.

Not necessarily. I've never seen the West Marine unit (nor the one
that Larry recommends), but the large auto parts store chargers use
large transformers and that is where they get their weight. It sounds
like the VEC unit is built on a switching supply and they are MUCH
lighter, because when they use a transformer, it is simply for
isolation and therefore carries substantially less current. Switching
supplies act sort of like a bucket brigade. They dump a bunch of
charge into a capacitor (bucket) and transfer it over to the battery,
rather than trying to regulate a constant or pulsating voltage. This
dramatically reduces both the weight and cost of the charger. As a
side effect, it also allows substantially better charging
characteristics as it becomes easier to measure battery condition
during short pauses.

I.e., it's different technology. There can be downside, however.
Switching supplies can produce substantial rf interference, but since
this is used to charge batteries and not power an electrical system,
it probably doesn't matter.
--

Larry W1HJF
Email to rapp at lmr dot com