Bob,
I have come to realize that bonding the negative 12VDC lead to chassis
at the power supply is a very bad idea. The applications note below
explains why.
k9yc.com/PowerSupplyBondingAndAudioDistortion.pdf
The PSU chassis SHOULD, of course, be bonded to every other chassis in
the station.
In response to the original question, I am currently using a Powerwerx
switching supply rated at 20A to float charge a pair of 6V 220 AH golf
cart batteries. Before I bought those batteries, I used one of the
biggest deep cycle batteries that Costco sells. They last at least 3
years in that sort of service. I used a float voltage of 13.8VDC with
them, simply setting the regulator in the PSU to that voltage. The golf
cart batteries want a higher float voltage. All of the 12V gear in my
shack runs off this nominal 12V bus.
The Powerwerx unit is RF quiet. I bought it to take on a DX trip. Before
that, I used a little 10A regulated switcher that I paid about $10 for
at the Milwaukee hamfest 10 years ago. It was VERY noisy, so I had to
add a bunch of ferrite chokes to it, as well as a cap across the AC
line. But it, combined with the Costco battery, was enough to keep up
with my rigs, even during heavy contesting.
I replaced the Costco batteries with the golf cart batteries as part of
a solar rig for the shack. Thanks to the very tall redwoods that hold up
my wire antennas, the solar panels are useless during the winter, but
provide good charging during the summer months when my electrical rates
go sky-high, hence the Powerwerx.
73, Jim K9YC
On 12/8/2013 8:39 AM, Bob McGraw - K4TAX wrote:
I use exclusively the ASTRON SS-30M at my stations and shop.
Actually have 3 of them. I find them to be reliable, acoustically
quiet although I do and can hear the fan switch on and off, and I find
they are electrically quiet.
I did add a true GROUND terminal to the rear panel. Internally I
connected the AC ground/green wire to this point and the 12V DC Neg to
this point. This point becomes "station ground".
I also put a internal tooth lock washers between the outer shell and
the base where the 4 screws attach the outside cover. This assures
the metal parts are electrically bonded and not insulated by a layer
of paint as found in many instances with equipment today.
As far as I'm concerned, the SS-30M it is a very good supply for the
money.
73
Bob, K4TAX
----- Original Message ----- From: "denton sprague"
<denton@oregontrail.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Sunday, December 08, 2013 10:14 AM
Subject: [TenTec] which power supply…station efficiency
I am upgrading a bit here…
got a new full sine wave ups coming with two aux battery packs to
replace my old cyberpower 3000 ups.
Ups has AH rating of 336 and each aux battery pack is 864 AH….
I am also looking at replacing my Astron 35m power supplies with more
efficient switching power supplies or running my TT Eagle or my Omni 7
and various sundries that use 12 vdc with a battery pack, charger and
a battery booster when needed.
So my question is…what switching power supplies are my fellow hams
using and how well do you like them?
I am aiming for efficiency, rf quietness and flexibility.
Other than the station, the ups will be used to fire a smaller flat
screen tv, satellite receiver, iMax and a lamp….nothing total over 500
watts draw…at least to my calculations.
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