i2 Battery screws

[Lx007]

I bought a torque screwdriver, but the lowest setting is 1.2 N-m. Is the proper torque for the i2 factory Li-Ion battery screws 1.0 N-m? I know the Reference Manual states 1.0 N-m, but the "Battery Replacement Instructions" on Segway's Support site state 1.6 N-m.

Do you use a torque screwdriver or wrench for your battery screws, or just use a regular bit and guess? Is 1.2 N-m going to cause me problems if I put the screws in with the torque driver I have?

[GlideGuy]

Originally Posted by Lx007

I bought a torque screwdriver, but the lowest setting is 1.2 N-m. Is the proper torque for the i2 factory Li-Ion battery screws 1.0 N-m? I know the Reference Manual states 1.0 N-m, but the "Battery Replacement Instructions" on Segway's Support site state 1.6 N-m.

Do you use a torque screwdriver or wrench for your battery screws, or just use a regular bit and guess? Is 1.2 N-m going to cause me problems if I put the screws in with the torque driver I have?

I use a torque screwdriver set to 1.0 N-m (9 in-lbf) for the Li-Ion batteries on my i2's. If I'm not mistaken, the NMh batteries on the Gen 1 machines are spec'd at 1.6 N-m.

It is surprisingly light torque. I'm betting that anyone "guessing" at the proper torque without a torque screwdriver is WAY over tightening the screws...and have a large variance in torque from one to the next. This is probably the cause of water leaks at the battery seal.

Also, remember to torque the two screws closest to the connector first, then the outside two screws. This assures the battery connector seal is properly seated and sealed.

Although there is a 60% difference in the two torque settings that you referenced, I believe the most important thing is to use a torque screwdriver for even tightening, in the proper sequence. It would be better to tighten to the lower spec for the Li-Ion batteries, but I'm betting that is not a big deal.

[GlideGuy]

OK...Segway has lots of conflicting info!

My i167 guide says to tighten the screws to 0.5 N-m
My i2 guide says to tighten the screws to 1.0 N-m

So...at face value, those would be the manufacturer's recommended torques for the two battery types. It makes sense that the Li-Ion batteries would require higher torque since the screws are longer and will "twist" more in the torquing process (vs actually tightening)...not to mention the batteries are heavier.

However, according to Segway's battery replacement guide, the proper torques would be 1.0 N-m for the NiMH (gen 1) batteries (vs 0.5 N-m in the manual) and 1.6 N-m for the Li-Ion batteries (vs 1.0 N-m in the manual).

Again, I believe the most important thing is to use a torque screwdriver in order to assure EVEN tightening of all screws...more so than 1.0 vs 1.6 N-m.

[KSagal]

A consideration on this spec is that the screws have a rubber washer as a compression ring on them. This is for seal, but will clearly impact how much torque you should use, as you are not just dealing with the screw, base and hard plastic of the battery, but also a softer medium.

I do not have that much to offer to the minute detail asked for. I just hand tighten my screws with a hand driver, and not use torque drivers for this. I do not believe they are that accurate at these light torques anyway.

[Lx007]

I agree, 1 N-m is surprisingly very little torque. The bits I'm using are 7" long, so I would like to test and see how much torque is lost in the twist of them as well as the screws and sealant on them.