Re: [SilverStreak] Newbie battery question

["waymark1@xxxxxxxx" <waymark1@xxxxxxxx>]

Sorry, I didn't come up with this idea on my own. I originally got it from my basic 
electricity and basic electronics teacher at Maplewood High school in Nashville, Tn. 
He was a retired radio and electric power engineer (not a lifetime schoolteacher). 
I'd provide his name but that was over 40 years ago and I don't recall it; he was rather 
elderly then. I do remember that he drove a Jag XKE.

It is true that there are specialized lubricants for moving electrical contacts.

The heat conductive grease used on CPU and other semiconductor to heat sink mating 
surfaces is not applied a lubricant but as a contact improvement and corrosion protectant. 
If aluminum powder is used, it is certainly not intended as a lubricant - when aluminum 
powder oxidizes it becomes corundum, the same stuff as is used on Alox (aluminum oxide) 
abrasive sheets and grinding wheels. The aluminum provides most of the heat conduction 
and the grease provides sealing against oxygen to prevent corrosion of the (usually) 
aluminum heat sinks, semiconductor cases, and the aluminum powder in the grease.
Other thermal greases or pastes are nonconductive of electrical current while highly 
conductive of heat. Zinc oxide is one ingredient that conducts heat but not electricity.

That (most) greases are hydrocarbons does not mean they are conductive. The plastic 
insulation used on most wiring is composed of hydrocarbon and it is decidedly nonconductive. 
Pure carbon and graphite (carbon allotrope) are fair conductors and are commonly used as 
dynamic contacts. Many motor and generator brushes, distributor rotor contacts, etc., are 
made of carbon-graphite mixed with other materials.

The heavily loaded contact between the trailer coupler and the hitch ball would seem to 
provide an excellent ground connection; however, experience is that it is a poor and 
intermittent connection. Why? The grease or oil that is on the surfaces of the coupler and 
ball is an insulator (dielectric). Failure to have a wire ground between the trailer and tow 
vehicle causes "fluting" - pitting of the surfaces from arcing as the contact makes and breaks. 
Going without grease or oil causes galling - microscopic pressure welding or seizing - of the 
surfaces. Rust also appears rapidly. Rust is an excellent fine abrasive. Special grades are 
called "jeweler's rouge." So a lubricant is necessary to reduce mechanical wear, but will 
cause electrically induced wear due to arcing through the insulative grease film between the 
parts. And, of course, flickering markers and taillights.

Common bearing and chassis grease is not designed to be used for electrical contact protection. 
Special greases are used by automotive and equipment contacts to improve contact by preventing 
corrosion. An example is the grease you find when unplugging automotive computer and electronic 
equipment connectors. Commonly instructions will be found to the effect that you are warned not 
to wipe the grease off the contacts (unless, of course, you have a tube or can of the special 
contact grease to provide a replacement coating). The grease that comes in the bulb sockets 
should not be wiped off or out either, particularly not to be regreased with common bearing and 
chassis grease. There is usually enough grease in the sockets (since manufacturers began greasing 
the sockets) for bulb replacements for the life of the vehicle.
One specialized paste is sold for spark plug terminals, distributor rotor contacts and tips, 
distributor cap posts and tips, distributor cap towers, etc.

"Dielectric" means "insulating."

Battery terminals and clamps are a particular problem area for grease between the mating surfaces 
because they have a relatively large contact area and low contact pressure per area. Chassis 
grounds do not present such a potential of high resistance from grease contamination as they 
usually are provided with toothed washers that will bite through any grease and dig into the chassis 
metal for a good contact.

I have personally experienced smoking battery clamps caused by ordinary lubricating grease raising 
the resistance of the connection. Thoroughly removing all grease, wirebrushing the post and clamp 
inner surface, and reconnecting fixed the problem. A coating of grease over the connection, worked 
into the recesses and then the excess wiped off, protects from future corrosion.

Aluminum wire, used on some RVs years ago (I hope no longer), is a special case. The oxide of aluminum 
is a total insulator, unlike the oxide of copper, which is a fiar conductor. Aluminum wire connections 
require a special corrosion inhibitor paste. The device connection screw clamps bite into the wire so 
that no paste is in between the wire and the clamp screw. (Certain devices specify that no paste be 
used on their connections.)

Acid corrosion of battery posts and clamps is due to damaged seals around the bases of the posts 
(like from beating on the posts, picking the battery up by the posts) or overcharging of the battery. 
Ideally, no acid ever exits the battery. Protective coating of the terminals is in recognition that 
in vehicular applications "ideal" does not happen, not for long. Also, corrosive mists blow all over 
the vehicle from road spray, ocean salt air, air pollution, etc. This is bad enough over the entire 
vehicle. Add electricity and it is worse.

Petroleum greases soften, crack and can even dissolve "rubber" radiator and heater hoses. Only a 
grease approved for vulcanized latex rubber, such as castor (old fashioned vegetable grease), silicone 
or PAO grease made for internal brake cylinder lubrication, may be used on such parts. Grease sold for 
use INSIDE brake cylinders (on parts that contact brake fluid), NOT "caliper slider" or brake pad 
backing plate grease, is such a grease.

An example of the recognition of the problem of grease insulation of static (nonmoving, like a clamp on 
a battery post) electric contacts:

"ANTI-CORROSIVE BATTERY TERMINAL

"BACKGROUND OF THE INVENTION Technical Field This invention relates, in general, to corrosion 
protective covers for battery posts and, more particularly, to covers utilizing grease as an 
anti-corrosive medium.

"The driving public is well aware of the continuing problems with battery post corrosion and the 
resultant electrical power loss because of wire erosion and poor contact points. Another common problem, 
experienced by operators of large trucks and commercial vehicles, is the lack of post contacts on a 
battery for connection to other batteries, auxiliary equipment, etc.

"One of the earlier efforts at providing a protective cover was the invention of J. A. Johnson, U.S. 
Patent No. 1,686,817, consisting of two complemental parts which were filled with grease and then clamped 
[NOTE -->] together about a battery post. A problem inherent with the Johnson device was the problem of 
obtaining good electrical contact because of the grease in that the grease had to be applied before clamping.

"A device that is still widely used and quite effective is the fibrous washer of F.G. Dewey, U.S. Patent 
No. 1,671,016, which is impregnated with acid resisting grease and which surrounds the base of the battery 
post. The Dewey device fails to protect the entire post.
[These are those red and green washers sold by automotive and marine battery dealers.]

"A later device which does cover the post is that of H. D. Weaver, U.S. [NOTE -->] Patent No. 2,269,296. 
The Weaver device suffers from the same problem as Johnson in that the post receiving socket must be coated 
with grease before placement, with resultant poor contact area. Weaver utilizes a tapered screw to make 
electrical contact after the grease placement.

"Other relevant inventions are those of W. T. Hasting, U.S. Patent No. 1,541,495; J. K. Schaefer , U.S. 
Patent No. 2,119,294; W. M. Osborn, U.S. Patent No. 3,152,854; and A. P. Bailey, U.S. Patent No. 3,795,891.

[NOTE -->] "None of the inventions solve the problem of utilizing a corrosion resistant grease to protect 
the entire surface of the battery post and still provide grease free electrical contacts.

"DISCLOSURE OF THE INVENTION The present invention comprises an anti- corrosive battery terminal including 
a terminal block with battery post [NOTE -->] receiving socket and provided with a grease fitting for 
injection of grease within the socket after the block is clamped to the battery post by screw clamps. It 
is therefore a primary object of the present invention to provide an anti-corrosive battery terminal which 
includes a terminal block with post receiving socket which may be filled with grease after clamping contacts 
are made with the post. More particularly it is an object of the present invention to provide an [NOTE -->] 
anti-corrosive battery terminal which includes a terminal block with socket and with screw clamps for making 
secure "dry" contact with the battery post before the addition of grease to the enveloping socket.

"Even more particularly, it is an object of the present invention to provide an anti-corrosive battery 
terminal which includes a terminal [NOTE -->] block with a grease fitting for injection of grease into a 
post receiving socket after electrical contacts are made to the post.

"Another object of the present invention is to provide an anti- corrosive battery terminal which includes 
a plurality of terminal contact posts.

"It is an additional object of the present invention to provide an anti-corrosive battery terminal having 
contact posts which make direct contact with the battery post.

"Additional objects and advantages will become apparent and a more thorough and comprehensive under- standing 
may be had from the following description taken in conjunction with the accompanying drawings forming a part 
of this specification.

"BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a battery terminal made according to the 
present invention, shown mounted to a battery post; the post and socket being shown in outline.

"FIG. 2 is a sectional view taken along line 2-2 of FIG. 1.

"FIG. 3 is a plan view of the terminal of FIG. 1.

"FIG. 4 is a sectional view of the grease fitting, with check valve, of the present invention.

"BEST MODE FOR CARRYING OUT THE INVENTION Referring now to the drawings, and, more particularly, to FIGS. 1, 
2, and 3, an embodiment to be preferred of an anti-corrosive battery terminal 10, made according to the 
present invention, is disclosed. Battery terminal 10 is in the form of a terminal block 20 defining a battery 
receiving socket 30, a grease fitting 40, and clamp means 50.

"Terminal block 20 may be constructed of any suitable material, either electricity conducting or insulative. 
It is preferred however, that the block be made of conductive material for conduction of electricity to 
terminal contact posts 55, as will hereinafter be explained. Copper and bronze are preferred metals for 
construction of the block and doped plastics, also called conducting polymers, such as polyacetylene doped 
with iodine, may also be highly desirable because of its high electrical conductivity as well as its ability 
to be molded. The block is preferably in the form of of a cube, having outer surfaces including the top 21 
and the four sides, designated generally by the numeral 22, and having an undersurface 23 on the opposing side 
from the top. Formed, by machining or otherwise, on the bottom surface 23 is a battery post receiving socket 
30 which is slightly larger in all dimensions than the battery post 5 of battery 3. Also formed within block 
20 is a threaded con!
 duit 27, extending between socket 30 and the outer surface of the block. In the preferred embodiment conduit 
27 extends between the socket and top surface 21 for the placement of grease fitting 40.

"Grease fitting 40, one type of which is shown in FIG. 4, is provided with threads mateable with the threads 
of conduit 27 so that the fitting may be simply screwed into the conduit. Fitting 40, also known as a grease 
'zerk,' includes a check valve, designated generally by the numeral 45, forming an effective seal, and also 
includes a post 44, rising vertically from block 20, for convenient engagement by a grease gun, not shown. 
While fitting 40 may be located anywhere on the block, for ready access it is mounted through top 21 of the 
block.

"Also mounted on block 20 are a selected number of terminal contact posts 55 for the attachment of electrical 
wires leading to the starter, other batteries, auxiliary units, etc. Contact posts 55 are constructed of any 
suitable material and are preferably in the form of steel machine bolts which are screwed into threaded 
apertures 57 in the block. Where block 20 is constructed of electricity conducting material, electrical contact 
between posts 55 and block 20 may be sufficient, although it is always preferred that posts 55 make contact 
with the battery post 5. Where block 20 is constructed of electricity insulative material, contact between posts 
55 and battery posts 5 must be made. It is obvious that one or more contact posts 55 may also serve as clamp 
means 50 for attachment of block 20 to the battery post.

"For installation of terminal block 20 onto battery post 5, the battery post should be clean and free of oxides 
and other forms of corrosion and the interior surface of socket 30 of block 20 should also be free of grease or 
other contaminants. The block is simply placed over post 5 with socket 30 surrounding the post about the sides 
and top. If desired, though unnecessary, a porous fabric washer 9, well known in the art, may be placed around 
the base of battery post 5. Clamping means 50, in the form of contact post bolts 55, are then screwed into 
threaded apertures 57 until the flattened, blunt end of the bolt securely engages the battery post to obtain 
maximum electrical contact surface. While a single bolt may serve to clamp the block in place to the battery 
post, it is recommended that at least one other bolt 55 make contact with the post, and, as before stated, 
contact is necessary where block 20 is constructed of insulative material. Once bolts 55 are in place, corrosio!
 n preventive grease, or the like, is injected through grease fitting 40 into socket 30 to completely fill the 
socket. Excess grease exiting the base of the socket at the undersurface 23 of block 20 may simply be wiped away. 
If porous washer 9 is in place, air readily flows through the washer to prevent any air bubbles within the socket, 
and the washer soon becomes saturated with grease to form an airtight seal. It is to be particularly noted and 
is an important part of the invention that all contacts between terminal contact posts 55 or clamping means 50 
and battery post 5 are made before the addition of any grease so that the grease, which is electrically 
insulative, can in no way impair the contacts. It is also to be noted that electrical contact can be made over 
a large surface area between the blunt end of bolts 55 and the battery post. Having thus described in detail a 
preferred embodiment of the present invention, it is to be appreciated and will be apparent to those !
 skilled in the art that many physical changes could be made in!
  the app
aratus without altering the inventive concepts and principles embodied therein. The present embodiment is 
therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention 
being indicated by the appended claims rather than by the foregoing description, and all changes which come 
within the meaning and range of equivalency of the claims are therefore to be embraced therein."
[REFERENCE:] http://www.wipo.int/pctdb/en/wo.jsp?IA=US1989001594&DISPLAY=DESC