[ARC5] [BoatAnchors] ARC-2 power supply

[David Stinson]

----- Original Message ----- 
From: "John Shriver" <john.shriver at gmail.com>
Subject: Re: [BoatAnchors] ARC-2 power supply


> In 1962, in the era of Selenium rectifiers, a 28 volt DC power 
> supply that could run that dynamotor was a "big deal".  It wasn't 
> plug-and-play at all.  I was but a tyke then, but serious silicon 
> rectifiers were at least 5 years away.
>
> On 5/30/2012 11:10 PM, k4pf at juno.com wrote:
>>> Meir WF2U<wf2u at ws19ops.com>  wrote
>>> I wonder what the 73 article did to the ARC-2. Why does it need 
>>> conversion
>> info? Convert it to what? It's plug-and-play, just feed it 28 
>> VDC...

My ARC-2, BC-375 and most other 28-volt dynamotor rigs
are powered by two hefty batteries.
They are kept charged at 27 volts by a recycled, rack-mount
 900 watt computer Uninterruptable Power Supply (UPS)
which used to have 24 volts worth of those small black lead-acid 
cells.
I soldered heavy- duty wire to the old battery leads and ran them
external to the batteries and thence to the load.
The batteries stay charged 24-7.  I have run the ARC-2  over 3 hours
and the batteries never dropped below 25 volts.  A nice "perk":
I also have hours of 115 VAC available if my lights go out.
I have two of these set-ups for 24-volt rigs and one smaller recycled
UPS for the 12-volt SCR-183.  Will need to change the batteries
in about 3 to 4 years, on average.  Also thinking of dropping the 
charge
voltage a little bit.  Very important to use good heavy gauge wire
and good connections to the batteries and to the load.
If you're running a dynamotor at 26 volts at 10 amps and your wiring
has just a half-Ohm of resistance, your rig is only going to get 21 
volts
and your wiring has to dissipate 50 watts of heat.
Better to spring for the good wire ;-)

73 Dave S.