There are some members of electronic forums that suggest coating automotive
battery posts with grease ("any king--axle, lithium, copper") before
attaching cable-end clamps to the posts and swear that it doesn't affect the
Are they nuts? Grease between terminal elements?
What grease--if any--is best, inside or outside the terminal connection?
On 24 Feb 2015 13:55:01 -0500
firstname.lastname@example.org (Scott Dorsey) wrote:
I wish I had known about this spray will have to look for it next
the young men at the parts store said the only grease they knew
about was in the tiny ketchup-pack size
they were busy bragging about how they had ripped off customers
"she didn't need a battery but I sold her a new one anyway, then
sold her old one for $30" and so on.
Not nuts... clamps :-)
The trick here is the fact that the clamps are tightened down
well when you install the battery cables. The tightening pressure is
sufficient to force the surface of the metal clamp into direct contact
with the (soft) lead battery post, squeezing all of the grease
out of this area.
You end up with just about the same amount of direct metal-to-metal
contact between post and cable-clamp that you would if you hadn't
used grease. The grease which remains, fills what would otherwise be
air voids between the post and the clamp. The grease will block
oxygen and moisture (including leaked battery electrolyte) from
penetrating the connection and thus will help preserve the quality of
the metal-to-metal connection.
"In single low-voltage terminals or connections, such as metal-to-metal
joints, grounds, or battery posts, almost any pure grease of light
viscosity will be acceptable. Caution should be used with greases
containing metallic powders to be sure any metal is compatible with
the embedded grease metal. Connection enhancement from embedded metal
powder is very minor, if it exists at all, and there is increased risk
of bad connections if the metal powder has any interaction with the
On 02/24/2015 10:36 AM, Fester Bestertester wrote:
Grease can improve electrical connectivity if designed for that purpose
- check out Dow Corning #4 dialectic grease - we use it on many power
connectors and it not only reduces contact friction, and protects
against oxidation, but the connector actually is often cooler than one
without the grease added!
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
I wouldn't use non-conductive grease on a battery post because the
connection will not always be as tight as it should be.
They sell small envelopes of dielectric grease at the parts counter of
consumer autoparts stores, like Pep Boys, Autozone. The size of
envelopes of ketchup and on a rack next to others with
brake-pad-anti-squeak. spark-plug-anti-sieze, and a couple other things.
It costs between 1 and 2 dollars. Enough for two cars, at least.
They have the envelopes at real autoparts stores too, but not right
there on the counter.
Do some cars still come with spring loaded battery-cable ends.? They
can't be tightened any more than the spring inside makes them tight, and
they eventually get loose, regardless of grease. When they're not
tight enough, they should be cut off and replaced with an add on
cable-end, or if there's not enough slack, a whole new cable. Even on
those with bolts for tightening, I've seen the bolt or nut or the lead
that holds the bolt in place get stripped and require replacement.
If when the car is runnning or you're cranking the engine, the battery
post and the clamp surrounding it are hot to the touch, the connection
there is bad. A good connection will not be discernably hotter than
"room temperature." Backwards from the way it might seem.
With a battery cable at the battery post, after it cools enough that you
won't burn your hand, or with a leather work glove, you can very often
have success by grabbing the cable and rotating it around the post 10 or
30 degrees, and then pushing it back where it was (and pushing down at
the same time, so it might be on a little tighter) It's likely to be
loose enough to do this, because if it weren't loose, you probably
woudn't have the problem in the first place. Also buy a battery
post/terminal brush. Two brushes in one piece, for 4 dollars in
plastic, 6 in metal. You'll need to use this whether you use grease or
not, before you put on the grease. . One brush should last you for the
rest of your life.
I've never used such grease on battery posts, and I've never had a
problem there. But some people might. With a '65 Pontiac, I had
major connection problems between the positive battery cable and
everything else at the starter motor. If I left the headlights on for
two hours or more when the car wasn't running, the starter motor would
barely turn, even if the battery was jumped. I don't think such grease
was easily available in 1969. It certainly wasn't on display at the
parts counter. Maybe it would have solved the problem.
After the new car dealer where my brother bought it replaced the
starter, alternator, and regulator twice each, they said, and then
woudlnt' try fix it anymore (even though they had never fixed it)
because they said the two-year warranty had expired, my brother went to
Viet Nam and gave me the car. and when I took it to Sears for one more
battery, they found the problem for free in less than 5 minutes. What
the dealer couldn't find in 2 years. The Sears man took apart the
connection and scraped or cleaned the parts. When it happened again
(after leaving the headlights on) at first I took it apart too and
scraped the parts with a knife, but eventually I learned to reach under
the car, grab the battery cable and pull it towards me once and push it
back once. I could do this in nice clothes without even getting dirty,
except my hand a little bit. Maybe you can't do this with a compact or
small car. Eventually I came across a buzzer that buzzed when the
lights were left on and that solved the problem .
When I got to my brother's city three years later, the dealer was out of
business. Maybe because they didn't know how to fix a car.
The only purpose of the grease is to keep the elements out of the
connection. Clean terminals and clamps thoroughly. Use baking soda mixed
in water if there is any encrustation and keep the resulting froth out
of the battery cells. Dry with a paper towel then smear everything with
Vaseline and reassemble. Tighten. wipe any excess forced out Vaseline
off. It's worked for thousands of users for the last few eons. A few
posters seem to think 'dielectric grease' means conducting...it doesn't.
In the electrical field there is an anti-oxidant grease called No-Alox
or Penetrox. It's a greasy paste with what may be metallic particles in
it. The only purpose of that is the same as above..it keeps
moisture/oxygen out of the joint to prevent aluminium or copper oxides
from forming. Those are non-conductors, as is the anti-oxidant paste itself.
It is hard enough to remember my opinions, without also remembering my
reasons for them!
I don't go anywhere near my batteries with baking soda. I don't let
mountains of oxide build up, either. Put grease on after assembling
connections. It is to keep air out. Flux brush and petroleum jelly.
On 02/26/2015 12:52 PM, m II wrote:
On Tuesday, February 24, 2015 at 11:37:02 AM UTC-7, Fester Bestertester wrote:
I cranked the engine and measured the same tiny voltage
drop across a clean, tight terminal without grease and
with grease applied before assembly. I know that it's
OK to grease the parts before assembly because GE used
to sell silent wall switches that glowed in the dark.
They were silent because they used mercury, and when I
once took one apart, I found a couple of cylinders
about 1/2" - 1" in diameter and maybe half that thick
that probably contained the mercury, and they rotated
in holes filled with clear grease (silicone?). I
reassembled the switch with those cylinders turned 180
degrees the wrong way, so the switch turned on when
the lever was flipped down.
Use any grease that won't melt at high temperature and
drip, especially into the battery. Axle grease is
probably fine. I use Sta-Lube alumina-based disk brake
grease (named so because it's for wheel bearings that
ride inside disk brake rotors), simply because I have it
and I'm not sure I can mix it with lithium-based grease,
which is a lot more common. I learned as a yout that
you shouldn't mix lithium-based and sodium-based grease
because that forms a grit that wears out ball joints fast.
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