Attaching extra wires to a side-terminal battery

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Dick Grady

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Feb 13, 2001, 3:56:11 PM2/13/01
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I own a 1999 Chevy Tahoe (truck-based station wagon). The battery has terminals
on the side, with bolts holding the cables to the battery. There are no
terminal posts. I want to connect some other wires (to power amateur radio
gear) directly to the battery terminals, but I'm having difficulty.

I tried an adapter about 3/16 inch thick, which fits over the bolts and has
screw terminals for other wires. But then the bolts were too short. The bolts
of the original equipment cables are captive (at least I could remove then from
the battery cables), so I could not use longer bolts. And in any case, the
positive terminal already has 2 wires, and the addition of the adapter would
require a bolt longer that those stocked by my local auto-parts stores.

I tried a thin metal plate with 1/4-inch lugs for slide-on terminals (bought it
at Radio Shack). Now I could bolt the cables to the battery. I attached the
radio wires with slide-on terminals, and on a test drive one of the slide-on
terminals came off; this was on paved streets and gravel roads; and I want to
use this arrangement on rough terrain off-road.

What I need is an adapter which screws into the battery, and which has a
threaded hole to accept the original equipment bolts. Any idea where I can get
a couple of these?

Or does anyone have any other suggestions?

Buying another battery with both side and post terminals has already been
suggested, but this battery is only 1.5 years old, and I don't want to throw
away a perfectly good battery.


Dean Dardwin

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Feb 13, 2001, 5:53:01 PM2/13/01
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Dick,

The bolts are not captive, it just seems that way. Pound them out with a hammer. The
bolts are standard hardware items; any hardware store can fix you up. Be very
careful that the new bolts do not bottom out in the battery case. If they do, you'll
ruin the battery. Measure carefully.

Dean

Mike Romain

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Feb 13, 2001, 6:37:33 PM2/13/01
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I wire up hundreds of mobile data communication systems to GM's and I
use the battery power tap like GM recommends.

If you follow the second red wire off the battery, it goes to the tap on
the firewall right behind the battery. It is an 11 mm nut. Some have a
dust cover on them, some are open.

The direct ground is just in front of the battery on the fender and has
a wire direct to the neg terminal. 1/2" nut.

Putting something under the side posts is bad news. You will get
electrolysis between the different types of metals and the connection
will corrode fairly quickly.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail
88 Cherokee 235 AT's
Build and Canadian Off Road Trips Photos:
(Updated 01/13/01 with 'Fall and Winter '00' and 'Disco Follies')
http://albums.photopoint.com/j/AlbumList?u=1161190

Bruce Linley

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Feb 13, 2001, 10:36:09 PM2/13/01
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>Dick Grady wrote:
>>
>> I own a 1999 Chevy Tahoe (truck-based station wagon). The battery has terminals
>> on the side, with bolts holding the cables to the battery. There are no
>> terminal posts. I want to connect some other wires (to power amateur radio
>> gear) directly to the battery terminals, but I'm having difficulty.
>>
>> I tried an adapter about 3/16 inch thick, which fits over the bolts and has

When you get a new battery, look for one that has BOTH the screw on
terminals on the front AND the posts on the top. Some battery makers
do this to avoid having to make two battery models. The bonus is easy
hook up of additional leads!


--
Bruce James Robert Linley | +---+---+--_ | "Ocha tte nigai demo... hito no chi
linley at megami dot org | | |NV | UT | wa atatakakute tottemo amai no"
Programmer, Fortunet Inc. | \ CA \ |___ | "Tea is always bitter... but blood
Las Vegas, Nevada, USA ---------> \*| AZ | is warm and sweet" - Miyu

Don

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Feb 13, 2001, 10:04:58 PM2/13/01
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I agree with Mike, you use the power terminal on fire wall. We wire up
electric brakes for trailer with that.

Don

DPH

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Feb 13, 2001, 11:21:31 PM2/13/01
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None of the vehicle wiring is particularly good for powering radios. 2-way
radio wiring should be directly to the battery. Vehicle wiring is small,
it has other things drawing current from it, and often there are motors
involved, like windshield wiper motors. And there is always the
alternator. The motors and the alternator can all contribute a whine on
the transmitted signal when you pick up your power off the small vehicle
wiring.

The vehicle battery acts like a big filter. Whine from the alternator and
motors is usually fairly effectively killed by the battery when you connect
directly to the battery. In fact, when you connect directly to the battery
and then at some point start hearing an alternator whine that you never
heard before, it generally means that battery is on the way out, or the
alternator has popped a diode.

Now, as for attaching wires to a side-terminal battery, it couldn't be
simpler. Just go to Sears, get the adapters that replace the bolts in the
cable connectors to the battery with bolts that have big lead lugs that
resemble the battery connectors on the conventional batteries. Then just
get conventional battery connectors and attach your wires to those.
Problem solved. I use this method to power aux. equipment on rental cars.
Very easy hookup. And U get nice, steady, whine-free 12 volts.

DPH

Bruce Chang

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Feb 14, 2001, 12:49:22 PM2/14/01
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There are also battery terminals you can buy that replace your current battery
terminal on the battery cable. You tighten that one in like normal but it has
a stud and nut on the opposing end that you can put a terminal ring over and
attach to a side mount battery too..

it looks like this.

http://pix.crutchfield.com/lifestyle/2000/h21101091.jpeg

Good luck,

-Bruce

Bob May

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Feb 15, 2001, 5:46:02 PM2/15/01
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Lets try it again, shall we? There is a wire off of the battery just
for purposes like this. As another poster said, it's on the firewall
and it's intended to be used for strange things like a mobile rig and
other things. I might note that if that terminal wasn't there, the
best place for 12V is at the starter where there is a stud on the
starter solenoid.
Never ceases to amaze me when people try to make things difficult for
themselves.
--
Bob May
Remember that computers do exactly what you tell them to do, not what
you think that you told them!
Bob May


Bill Kitterman

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Feb 15, 2001, 9:07:59 PM2/15/01
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I don't know Bob... many of these Ham Radio Operators are set in their ways
and opinions from you or me will not change their preconceived notion that a
wire termination six inches from the battery terminal is bound to have
noise.

Bill Kitterman

"Bob May" <bob...@nethere.com> wrote in message
news:t8on32g...@corp.supernews.com...

Dick Grady

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Feb 15, 2001, 9:01:01 PM2/15/01
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On Thu, 15 Feb 2001 21:07:59 -0500, "Bill Kitterman" <bki...@bcn.net> wrote:

>I don't know Bob... many of these Ham Radio Operators are set in their ways
>and opinions from you or me will not change their preconceived notion that a
>wire termination six inches from the battery terminal is bound to have
>noise.
>
>Bill Kitterman

6 inches? I wish it was 6 inches. In my vehicle, it's 6 *feet* of wire! The
aux battery stud is diagonally across the engine compartment from the battery.
The battery is left front. The stud is on the under-hood fuse and relay panel
located in the right rear of engine compartment. 6 feet of wire will pick up a
lot of noise.

DPH

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Feb 16, 2001, 11:15:02 PM2/16/01
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Bob May wrote:

> Lets try it again, shall we? There is a wire off of the battery just
> for purposes like this. As another poster said, it's on the firewall
> and it's intended to be used for strange things like a mobile rig and
> other things.

So how big is it? #12? #10? If you are talking about, say a low band
200 watt rig, it better be...


> I might note that if that terminal wasn't there, the
> best place for 12V is at the starter where there is a stud on the
> starter solenoid.

Where do you get this stuff? If U put it on the starter, then you have
the resistence of the wire from the battery to the starter that allows a
voltage drop _and maybe some induced whine_ when the starter is cranked.
Neither of these can be good for the solid state electronics in the
modern radios. Plus, when making and breaking contacts to the starter,
you may be allowing an inductive field set up the field and armature
coils of the starter to collapse through the radio. Bad juju.
Collapsing magnetic fields can generate very high voltage spikes. And,
of course, the filtering capacity of the battery is on the wrong side of
a length of wire from the battery to the starter.

The _best_ place for a tap for a 2 way radio is _still_ at the battery.

>
> Never ceases to amaze me when people try to make things difficult for
> themselves.

Difficult? The least difficult tap for continuous power in a car is
still at the battery.

DPH

DPH

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Feb 16, 2001, 11:18:39 PM2/16/01
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Dick Grady wrote:

Sure, lets string a wire around the engine compartment with full exposure to the
electric fields generated by the spark plugs. Click click click in your received
audio. No thanks.

DPH

Mike Romain

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Feb 17, 2001, 5:03:06 AM2/17/01
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DPH wrote:
>
> Bob May wrote:
>
> > Lets try it again, shall we? There is a wire off of the battery just
> > for purposes like this. As another poster said, it's on the firewall
> > and it's intended to be used for strange things like a mobile rig and
> > other things.
>
> So how big is it? #12? #10? If you are talking about, say a low band
> 200 watt rig, it better be...
>

The positive tap is fed by a 10 ga and the negative tap is fed by a 12
ga.

If you want to keep your GM vehicle under warranty, these taps must be
used.

If you want the bulletin # I could look it up.

Drew A. Durigan

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Feb 17, 2001, 12:03:26 PM2/17/01
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The best thing to do is get a dual-terminal battery. This gives you the side
terminals you need to match your car, plus top terminals for accessories. Get
a pair of marine battery terminal clamps (about $2 at Wal-Mart) and you now
have dedicated power terminals for your toys, complete with wing nuts to secure
the wires!

I use this setup in my '84 Delta 88 to power my ham radio equipment. Works
perfectly!

Drew in Sunny Central Florida
-Drew in Sunny Central Florida-

MC 10kW Jesus

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Feb 18, 2001, 10:24:50 PM2/18/01
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You can get battery post extenders from Larsen, ONO and others (car
stereo shops) and this will fix you up.

MC

Mark Keith

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Feb 19, 2001, 2:04:07 AM2/19/01
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Dick Grady wrote:
>
> I own a 1999 Chevy Tahoe (truck-based station wagon). The battery has terminals
> on the side, with bolts holding the cables to the battery. There are no
> terminal posts. I want to connect some other wires (to power amateur radio
> gear) directly to the battery terminals, but I'm having difficulty.

> Or does anyone have any other suggestions?


>
> Buying another battery with both side and post terminals has already been
> suggested, but this battery is only 1.5 years old, and I don't want to throw
> away a perfectly good battery.

GM makes adapters for that purpose. Check the dealer. You want to go
straight to the battery with a radio. You'll have less noise and
regulation problems assuming thick wire. After that battery goes flat,
I'd cut those old things off and go top post myself. I don't like side
post batteries. I've had many problems with those over the years due to
the connectors getting loose etc. I run a ic-706 presently in my
car/truck. I always prefer to go straight to the battery with real thick
wire. I use #6. You'll nver hear me "FMing" or chirping due to severe
voltage drops..:) MK
--
http://web.wt.net/~nm5k

Mark Keith

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Feb 19, 2001, 2:14:21 AM2/19/01
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Bob May wrote:
>
> Lets try it again, shall we? There is a wire off of the battery just
> for purposes like this. As another poster said, it's on the firewall
> and it's intended to be used for strange things like a mobile rig and
> other things. I might note that if that terminal wasn't there, the
> best place for 12V is at the starter where there is a stud on the
> starter solenoid.
> Never ceases to amaze me when people try to make things difficult for
> themselves.
> --
> Bob May

Maybe, but there is a good reason for going straight to the batteries
with the high powered radios. Much less noise generally will be received
by the radio, and also many of the power connections in the cars just
don't have the current capabilty to run a radio without a big voltage
drop. This will cause problems with the radio while transmitting and
make it unstable on voice peaks etc. These radios need 20 amps to run,
and the voltage needs to be stable, which means you want real thick wire
straight to the battery. I use #6. Now, I'm sure you will think this is
overkill but trust me, it really helps the stabilty of an SSB/CW
transmitter. Most do 100w output, which is around 200w input. If you run
a linear amp, the direct connection a MUST. The amps generally pull
upwards to 70-80 amps for the average versions. Myself, I'd never ever
run a radio off car power wiring. And believe me, I'm about as lazy as
they come. If there were not a good reason for it, I wouldn't bother. MK
--
http://web.wt.net/~nm5k

Mark Keith

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Feb 19, 2001, 2:22:20 AM2/19/01
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Bill Kitterman wrote:
>
> I don't know Bob... many of these Ham Radio Operators are set in their ways
> and opinions from you or me will not change their preconceived notion that a
> wire termination six inches from the battery terminal is bound to have
> noise.
>
> Bill Kitterman

But will that wiring handle a radio that draws 20 amps current, and
needs a stable voltage? Maybe, but it will be borderline at best. You
need the capability of drawing 20 amps, with a very small voltage drop,
otherwise the radio if SSB will "FM". On cw, it could chirp. MK
--
http://web.wt.net/~nm5k

lynds...@gmail.com

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May 26, 2017, 8:17:34 PM5/26/17
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Hi Dick,
I am trying to attach a battery isolator to the positive battery terminal, but have side terminals, no posts. Our vehicle has the aux battery stud on the opposite side of the engine compartment, on the under-hood fuse panel, as you described yours. Is it safe to connect our positive cable (via ring terminal) to this tap? Should we get post extenders for the battery terminal instead?

Thanks,
Lyndsay

tbj...@gmail.com

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May 5, 2019, 10:20:18 AM5/5/19
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