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Subject: TWL: Universal AC Adapter
From: Arild Jensen (elnav@XXX.XXX)
Date: Tue Dec 18 2001 - 00:54:24 EST
At 07:25 PM 12/17/2001 -0800, Michael Schooley wrote:
>I plan to use an inverter/charger and DC generators/alternators. My shore
>power hook-up will consist of connecting the inverter/charger to shore
>power. Anybody know of a 24 VDC inverter/charger that works on both 60Hz
>110V and 50Hz 230V (preferable not built by Xantrex :-).
REPLY
Mike the frequency part is what makes this complicated.
Such frquency converters do exist but cost a lot and do not come in small
power packages suitable for your size boat.
Typically they begin at around 15 Kw and go up from there.
My recommendation is to use a straight charger from shore power since most
of the switch mode chargers are not frequency sensitive. However, most
are not universally voltage independent. You either have a 120V or a 230
volt.
If your boat is primarily set up for DC use then all you need is a charger
which can deliver the average load used plus something for charging. To
use the 230V power found in Europe will require a simple step down
transformer 230/120 which also serves as an isolation transformer - which
is a good thing.
If your boat is set up to use some 120V AC 60 hz appliances then you
will need an inverter as well.
If any of the appliances are frequency sensitive this inverter has to be
one or the other. You do not get dual frequency inverters in small sizes.
Purely resistive loads are okay but motors. clocks timers and many
microwaves are not cross compatible.
If I was starting from scratch now I would design for a 24V system and
get a 24/12 converter for that equipment which is not available in 24V. (
mostly consumer navigation gear)
I also think I would avoid a large single inverter in favour of several
smaller inverters dedicated to each appliance.
Then if I bought a domestic appliance in Europe which required 230V 50 hz I
would get an inverter to suit just that appliance.
Next to it might be a 120V 60Z unit but who cares since each derives its
power from the same basic 24V DC battery system.
The large 100 Amp or so charger is frequency insensitive and the isolator
stepup/down transformer takes care of the voltage differences.
Ever since I had to reconfiguer a brand new 44 Carver for European service
I have been working out ideas for doing it better.
We got the boat from the factory sans any appliances, then had to specially
order 230V 50 hz appliances here and installe them.
What a lot of trouble. Even the power outlets had to be specially ordered
from Italy.
That exercise convinced me there was a better way. Only a matter of
finding it! < grin>
Cheers
Arild Jensen
The Electronic Navigator
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