[Mobile-Portable] Wire Size

[K0DAN]

>    In the cab, I split these power sources to feed three other radios: An
> FT-8800, a TM-331 (220), and a Cobra CB rig (my Jeep Club uses Channel 20
> during off-road runs).  All of these power feeds are separately fused.
>
>    This arrangement works just fine and nothing has given me any trouble.
>
>    I plan to replace the FT-90 with an FT-857D.  Because this rig runs
> much
> higher power, I plan to replace the cable runs from the engine
> compartment.
>
>    My question is: How much bigger should I go?  I am thinking about
> 8-gauge.  Will this be adequate?  (The length is approximately 15-feet.)

If you'll run all 3 rigs at the same time, I'd bring in #8, then do the
power splits. Keep the #8 right to the high current rig. Fuse everything.

#10 is probably OK for just one rig at a time, but going a little heavier is
always wiser. Even with #10 you're gonna lose current capability. Bigger
is better.

> r question: What is considered state of the art, now, for an
> in-line fuse holder?  I might as well upgrade to the best style of fuse,
> while I am doing the upgrade.

Lots of different opinions here, but many people seem to be going to the
Anderson Power Poles. Lots of flexibility as to wiring, adding accessories,
portable metering, tapping off extra lines, adding fuse strips, etc., etc.
Do a GOOGLE on "Anderson Power Pole" and you will find the major suppliers,
and will find all kinds of nifty tips, photos, etc.

BTW the larger guage wires are a bit more tricky to connect to the Andersons
Power Poles, but they CAN be done.
>
>    Additional question: What is a good source for small quantities of this
> heavier wire?  My local hardware store does not carry anything larger than
> 10-gauge.

Might be just as easy to buy the bulk wire online, or even prefab cables for
rig(s). See above paragraph (PowerWerx, WestMountainRadio, etc.).

If you want to find stuff locally, try Rat Shack (their in-stock is
always a gamble), plus any of the shops that do mobile stereo installs,
truck repair, marine (boat) maintenance, trailer wiring, etc., will probably
have what you're looking for. Maybe not cheapest, but convenient & local.
>
>    Final question: Does anybody have any experience with these new (to me)
> DC power supplies.  They are said to maintain a reliable 13.6-Volt output
> regardless of the input voltage (within reason).  In principle, they seem
> like a good idea, especially when running the HF rig for prolonged periods
> with the engine turned off.

Caveat emptor. Remember every time you go thru a power conversion, you are
giving up some energy to operate the hardware, and the output efficiency
is a variable. Also an unknown is the amount of RF noise these devices put
out. And finally, you have one more potential point of failure...you want to
minimize these! Some power supplies are probably good products, some most
likely junk. (For example I have a cheapie "400W Inverter" I got at WalMart,
and there's NO way this thing can pass 400 watts, peak or otherwise. It's
suitable, MAYBE, for 100 watts. It was cheap, so I'm not complaining, just
don't believe the marketing claims.)

I am from the old school and believe in power supplies which have
transformers, big capacitors, and filter chokes. And high current ratings.
They are simple, reliable, HEAVY, and easily serviced. And...not very
suitable for the mobile environment. Switching supplies and inverters are
great, but do have some trade-offs.

In general, there's no easy ways around an install....inverters, etc., are
great for emergencies, but you'll be happier & more reliable in the long run
if you do it right, which means extra time, labor, and expense.

Good luck!

And 73,

Dan
K0DAN

>
>           <<<<<     Bil Seymour  --  WA6MOD    >>>>
>
>                   "Everyone Follows the Bass Player"

PS But the lead guitar gets the girls....