Hello Al,
You may have gotten shrink back, meaning that you install new battery clamps
on a lead post, that has been pre clean with one of those battery post
cleaners, the battery clamp is setting on the high spots of all these lead
post scratches and when you put on a initial load, these lead surface will
melt back some.
In installing new battery clamps which should be a plated brass type, torque
them to the specifications as call for in the Trojan maintenance WEB site.
I think they are about 75 in.lbs.
Drive the EV only drawing a maximum of 200 to 300 amps for 5 miles and
recheck the torque rating again. You will find it will lose about 5 in.lbs.
the first five miles. Re-torque and then check again in the next 10 miles,
re-torque as needed and re-torque at 20 miles,
You will the battery clamps will stable out by then. Do a check on some of
the connections at a 100 miles, you then can calculated when you should do
the next re-torque of the battery connections.
Its best to get a good torque wrench in the 1/4 inch size, and slip a foam
pipe insulation over the handles after you set and lock it in.
The Trojan WEB site will give you a minimum and a maximum torque rating on
the type of battery connections and posts are use.
One method I use to get more contact are on a battery clamp, is to set the
clamp all the way down pressing against the offset battery base bars.
Therefore the bottom of the battery clamp is increasing the contact area.
If you have post with a top stud, and if the battery clamp is lower than the
top of the post, I installed a short piece of stainless steel tubing that I
cut off a length of 3/4 I.D. tubing. Place it on top of the battery clamp
so it is just about flush with the top of the battery post. Install a
stainless steel washer, lock washer and nut which put additional pressure of
the battery clamp down on to the lead base.
I then tighten the battery clamp to about 40 inch pounds or just hand
tighten it, then tighten the top stud nut to 75 inch pounds which presses
the battery clamp down on the base, then tighten the battery clamp to 75
inch pounds, and finish up with 100 inch pounds with the top stud nut.
There was a battery clamp company back in the 70's that made EV battery
links, that did this type of installation. They were a solid taper brass
connections that had a cable molded into this connection. These type of
battery connection was cover with a fuse on red plastic cover at one end and
a black plastic cover at the other end of the link.
They slip over the taper post with a stud on top which came through the top.
It has a O-ring on the bottom which seals the bottom connection. The nut
was the only fastener use on these types of connections. The taper sides of
this connection put a side force on the battery post which also puts a
internal pressure of the in bedded stud, that can with stand 10 foot pounds.
Not 100 inch pounds.
I try to find these type of battery connections, and do not see them any
where. Back in the 70's these units cost about $20.00 a link, while the
battery cost about $30.00.
I cannot make them in my machine shop for that cost.
I did this type of battery connection back in 2002, did the checks, and now
only check them about once a year. I am still running the same batteries
and battery clamps today.
Roland
----- Original Message -----
From: "Al" <
[email protected]>
To: "Electric Vehicle Discussion List" <
[email protected]>
Sent: Wednesday, September 19, 2007 8:55 PM
Subject: [EVDL] Poor battery connections
> You would think by now that there would be a standardized reliable way to
> get a good high current connection to a lead acid battery.
> When I looked at the standard battery lug for use with Trojan universal
> posts, I notice the actual contact area is pretty small.
> I decided to use the automotive tapered post type connector assuming it
> would have alot more contact area. Apparently they do not..
> I noticed my pack voltage dropping more than usual under load. After a
> short
> trip I checked the connections and sure enough, they ranged
> from warm to downright hot! I pulled one connection and found that even
> though it was tight and clean, it had been arcing in between the post
> and the inside of the connector where it could not be seen. So, what type
> of
> connector are the guys pulling 1000 amps using?
>
> Al
>
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