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Discussion Starter #1
Re: [EVDL] Battery post melted. But not the weak battery the strong onenext to it.

Hello Lawrence,

A new battery that has only 10 miles on it could melt the post. This is =

normally call shrink back of lead post which melts the surface of the lead =

post.

Back in 76 when I pick up my EV, the battery engineer said when you install =

new batteries and links, torque them to the recommended torque =

specifications listed by the manufacture. In my case it was 95 inch lbs fo=
r =

a stud type post and 75 inch lbs for a zinc plated copper battery clamp on =

lead posts.

This torque value will only last about 5 miles on a lead post. After =

driving 5 miles, it is common to lose 5 inch lbs. Then re-torque again. =

Then drive 10 miles and do it again and you see it only looses about 2 inch =

lbs. Drive 20 miles and check them again. If you are now only losing 1 =

in.lb. or less than you can check them every 100 miles.

Another method I use after the first initial torque, is doing a battery lin=
k =

shunt test which can be done instead of using the torque wrench after the =

initial torque.

The battery link shunt test, involves connecting a multi-meter in parallel =

with the battery link using the milliampere scale. Do not connected to the =

link ends, but connect the leads directly to the lead post or lead pad.

Next, you turn on the charger to 5 amps and record the ampere value of each =

link connections on your battery log sheet. A ampere reading may be about =

0.001 amps for a good connection. Check each link and if you see a ampere =

reading higher than the lowest reading, then tighten the link connection =

until it as close to the lowest reading one.

Using this method, it only takes me about 15 minutes to do the test on 30 =

batteries about once a month.

Note: To do this test, you leave on the charger, so the following safety =

requirements should be done:

When I do this shunt test, I use a standard ratchet wrench that I cover the =

handle with a thick heavy duty glue type heat shrink. I cover the batteries =

that I am not testing with several sheets of neoprene rubber sheeting. I =

work from the center of the pack to the edge slipping the rubber sheeting t=
o =

expose the next battery I am working on. I also lap over the rubber sheetin=
g =

over any metal body parts.

If you are not wearing lineman boots, then it best to stand on a rubber mat.

Roland








----- Original Message ----- =

From: "Lawrence Rhodes" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Thursday, December 09, 2010 10:38 AM
Subject: [EVDL] Battery post melted. But not the weak battery the strong =

onenext to it.


Lets have some fun. It's damp out and about 60=B0F. I just took my daught=
er =

to school and a Mercedes sport coupe is approaching from the rear as we go =

up a hill to my house. I had just pulled into the road ahead of him and I =

wouldn't want to slow him down but he had already changed lanes to pass my =

poor little underpowered(he he) Ford Aspire. I shifted into second and put =

the pedal to the metal expecting to take off like a scalded cat. It was =

great for about one second. Unfortunately I heard a pop and the voltage =

meter went to zero. Rats. I parked the car not able to coast to the crest =

of the hill and go home on gravity drive. Measured all the batteries and =

one was 11.4v and the one next to it was 4.5v. Walk home to get tools and =
a =

jumper. When I got back and took off the cover for the rear batteries I =

found the 4.5v battery had melted its post. I stuck my meter into the hole =

that was left of the post and it measured 12.9vdc. The weak battery
was neg. to the pos of the good but the melted battery post was on the neg =

side(other) of the good battery. It was connected to a sturdy 1/4 inch =

thick buss bar to the next good battery. Why would the post on the opposit=
e =

side of the good battery away from the bad battery take the hit. Shouldn't =

the post on the bad battery go first. I always thought that the lowest =

battery was the one to eat it. All the other batteries measured 12.8 to =

13vdc. I jummpered out the bad battery and drove home. Tail between legs. =

Lawrence Rhodes..

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Registered
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70 Posts
Discussion Starter #2
Re: [EVDL] Battery post melted. But not the weak battery the strong onenext to it.

Lawrence,

I was not surprised to see that you destroyed a post
when I read you use solid bus bar, because that means
that you are trying to keep the batteries in place
by their posts.
I think it has been said numerous times on this list,
to avoid damaging posts from excessive force, use
flexible interconnects as the batteries move *much*
more than you would ever think possible...

Roland can tell you how to re-cast the post.
It is also in the archives.

My impression is that the fact that the broken post
is on a good battery is coincidence.
But now that you know that you have a weak battery,
you can keep an eye on it and charge it some
extra if needed. 11.4V sounds way too low (absolutely
dead or a shorted cell)

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130



-----Original Message-----
From: [email protected] on behalf of Lawrence Rhodes
Sent: Fri 12/10/2010 12:08 AM
To: Electric Vehicle Discussion List
Subject: [EVDL] Battery post melted. But not the weak battery the strong on=
enext to it.
=

Lets have some fun. It's damp out and about 60=B0F. I just took my daught=
er to school and a Mercedes sport coupe is approaching from the rear as we =
go up a hill to my house. I had just pulled into the road ahead of him and=
I wouldn't want to slow him down but he had already changed lanes to pass =
my poor little underpowered(he he) Ford Aspire. I shifted into second and =
put the pedal to the metal expecting to take off like a scalded cat. It wa=
s great for about one second. Unfortunately I heard a pop and the voltage =
meter went to zero. Rats. I parked the car not able to coast to the crest=
of the hill and go home on gravity drive. Measured all the batteries and =
one was 11.4v and the one next to it was 4.5v. Walk home to get tools and =
a jumper. When I got back and took off the cover for the rear batteries I =
found the 4.5v battery had melted its post. I stuck my meter into the hole=
that was left of the post and it measured 12.9vdc. The weak battery
was neg. to the pos of the good but the melted battery post was on the neg=
side(other) of the good battery. It was connected to a sturdy 1/4 inch th=
ick buss bar to the next good battery. Why would the post on the opposite =
side of the good battery away from the bad battery take the hit. Shouldn't=
the post on the bad battery go first. I always thought that the lowest ba=
ttery was the one to eat it. All the other batteries measured 12.8 to 13vd=
c. I jummpered out the bad battery and drove home. Tail between legs. =
Lawrence Rhodes..

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| Multiple-address or CCed messages may be rejected.
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