"Chuck Cox" wrote in message
...
Yes, this is an old thread coming back to life...

Back in December I wrote:
As part of a non-boating-related product, my company is
designing what amounts to an automatic 500w DC self-starting
gasoline battery charger. The charger is designed to be
portable, unobtrusive and easy to maintain. If the battery has
sufficient charge, it can self-start, but it can also be
hand-started easily when necessary. It is designed to
automatically start and stop as necessary to keep a battery
charged.

I've used petrol gennys for charging (not auto) and like the idea,
and also agree the preference for diesel. Nice if it's portable -
but that means air cooling - usually noisier.

One factor you haven't mentioned is the desirability of charging
at the maximum feasible rate (minimum running time). Perhaps
you've already got that idea in mind.

Just in case you haven't, I achieved best results charging by
taking my (European) 240v through an intelligent charger, one that
sensed battery voltage direct, and delivered up to 14.4v (variable
depending on battery type) stepping to 13.6v once the main charge
had been delivered (there was also a 16v option for de-sulphating
the batteries. Add water afterwards!).

A shortcoming of most petrol gennys on the market which supply 12v
nominal is that they're usually regulated to 13.4v or so maximum,
which gives a very slow re-charge once you reach 75% or so of
battery capacity. Especially if you're pumping it down a long line
.. . .

JimB

News f2s wrote:
I've used petrol gennys for charging (not auto) and like the idea,
and also agree the preference for diesel. Nice if it's portable -
but that means air cooling - usually noisier.

On the other hand, since we will be operating at only one speed, we can
optimize our noise reduction, so it will be quieter than a
variable-speed motor.

One factor you haven't mentioned is the desirability of charging
at the maximum feasible rate (minimum running time). Perhaps
you've already got that idea in mind.

Yes, the system is designed to operate at an optimal output power. It
should only start when the batteries are low enough to take a full
charge and shutdown when the load drops. It isn't designed to do
trickle or variable charging.

Just in case you haven't, I achieved best results charging by
taking my (European) 240v through an intelligent charger, one that
sensed battery voltage direct, and delivered up to 14.4v (variable
depending on battery type) stepping to 13.6v once the main charge
had been delivered (there was also a 16v option for de-sulphating
the batteries. Add water afterwards!).

This brings up another question; should we incorporate an intelligent
charger or should we interface with an existing external charger? If
your batteries are already connected to a charging system, it will only
confuse things if we try to operate two independent changing systems
simultaneously. My assumption is that most potential users of this
charger already have a charging system onboard. Is this a valid
assumption? I have no experience with off-the-shelf marine chargers,
can they even be interfaced with an external power source?


A shortcoming of most petrol gennys on the market which supply 12v
nominal is that they're usually regulated to 13.4v or so maximum,
which gives a very slow re-charge once you reach 75% or so of
battery capacity. Especially if you're pumping it down a long line
. . .

Because of the binary nature of our system, we don't intend on taking
the batteries to full charge, just to the point where they can no longer
take full charging current. This is the most efficient way to operate
our system since it is optimized to deliver a specific output power and
will lose efficiency at lower output levels.

--
Chuck Cox - SynchroSystems - Synchro.com
,
my email is politician-proof, just remove the PORK

On Fri, 24 Feb 2006 12:51:30 -0500, Chuck Cox
wrote:


This brings up another question; should we incorporate an intelligent
charger or should we interface with an existing external charger? If
your batteries are already connected to a charging system, it will only
confuse things if we try to operate two independent changing systems
simultaneously. My assumption is that most potential users of this
charger already have a charging system onboard. Is this a valid
assumption? I have no experience with off-the-shelf marine chargers,
can they even be interfaced with an external power source?

I think you may find that if you design a basic "core" model, you can
successfully market add-ons geared to end-user needs. I would
personally favour smart-charging because it "covers my bets" for a
multitude of scenarios: the failure of a smart/regulated alternator on
the main diesel, the failure of a charger, and the failure of the wind
to blow and the sun to shine, which would be my primary methods of
charging in order to avoid the wasteful and noisy running of the main
engine for 2 hrs/day to provide a charge.

So if you can make this design "modular", you have the options that
people want: a luggable power supply, a miniature diesel "day charger"
for battery banks, keeping one less fuel type on board, and the
options to tap into tank fuel or to use integral fuel.

It's a great option for small-boat owners, too, who frequently stay on
the hook longer, anyway, and who tend to do more yard work at a
distance from "municipal power".

I am currently on a dock, but would be happier on a mooring (and would
save $1,500/year) if I could have this sort of thing to charge me up.

R.