You have to sand the terminals and immediately apply NoAlOx, just like
Mark says. A thin layer is best as a thick layer will slowly ooze out
and the terminal will become loose.
Re torquing is needed, but probably not every 10k miles. Likely just the
first 5k to 10k and then maybe at 30k or 40k.
Bellville washers help.
http://en.wikipedia.org/wiki/Belleville_washer
Bill D.
On 1/6/2014 7:22 AM, Michael Ross wrote:
I recently took apart a nice little OEM battery pack and every terminal on
it was barely hand tight. I reassembled with SS socket head screws instead
of the Phillips screws, and torqued the 5mm bolts to spec. All you need to
do is torque them right and they will not loosen. Do not use lock washers
as they compromise the clamping force. If you look at bolted joints on high
quality equipment you will find properly designed joints with no
lubrication or thread-locker - they just torque the right. I worked for
Caterpillar and can vouch for their practices - needed to survive the worst
vibration environments imaginable. My Toyota cars over the last 30 years
are all produced this way. I don't use conductive grease, I just go with
clean and tight.
For reference:
1 N m = 8.8in lb = 0.74bft lb
I tightened the 5's to 35 in lb (4 Nm).
Unfortunately, there are a lot of units for measuring torque. Inch pounds
are best for the small wrenches we have in the US.
My joints were the terminals of 32120 cells, SS M5 screws, with nickel
plated copper straps, and stainless steel flat washers (lock washers thrown
away). I am not sure what the terminal with the tapped threads is made
from. It is s tamped and formed part, maybe SS, but could be a plated
brass or copper...
On Mon, Jan 6, 2014 at 7:26 AM, Mark Hanson <[email protected]>wrote:
Hi Folk's,
last night a overvoltage battery balancer #22 shut down the charger at
4.0V. At first I thought it was a bad OV balancer detector but after
replacing the circuit it still did it so I put a scope across the battery
cell and noticed the charging pulsed waveform going from 3.3V to 4.0V 60 hz
when adjacent cells were fairly solid (signifying a high impedance
condition). I thought I had a bad cell but after sanding under the copper
strap & adding 3M dielectric grease & torquing back down, it charged
perfectly with no faults, back to low impedance. I found a few other
battery terminal bolts not tight after 20k miles (even with sealing paint
on terminal bolts CALB 130). So it's best to tighten terminal bolts on
lithiums every 10k miles it seams. I used to tighten terminal bolts on old
lead GC batteries every 500 miles but didn't think it was necessary with
lithiums but apparently they need it as well just less often.
Best Regards,mark
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