# Compression clamping for LiFePo4 pack?



## BeeMike (Aug 3, 2011)

I was looking at a commercially made swap-in replacement pack for a Ranger EV, and the builder is using heavy duty clamping to apply pressure to hold the pack. This set up is steel end pieces joined by 1/2" or 5/8" all-thread rod along the sides of the pack; pressure is applied by tightening nuts on the ends of the all thread. I was told it was beneficial for the batteries.
Anybody got any photos of similar arrangements, or experience about how and why you do this on your pack?
Thanks!
Michael B


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## EVfun (Mar 14, 2010)

I think you are considering extreme overkill. I was going to point you to pictures of how Thunder Sky (now Winston) Lithium cells are shipped but couldn't find a picture. So I attached a picture of a 4 cell block of GBS Lithium cells from Elite Power Solutions. 

The Thunder Sky system looks almost identical. My TS cells came banded in groups of 4 and groups of 6 cells. I rebanded them into groups of 8 cells, reusing the end plates and making the straps out of stainless steel banding (used to attach signs to poles.) I used 1/2 inch by 0.025 inch thick stainless, which was easy to bend and punch screw holes. I drilled and tapped additional holes in the middle of the plates between the top and bottom banding screws. This provided an easy way to hold the cells down in the car. 

I think you could use 1/8 inch to 1/4 inch thick aluminum to make the end plates from, depending on cell size. I don't think you would need more than 3 straps per side with solid side plates. If you wanted to use all-thread (threaded rod) I would recommend using 10-32.


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## dtbaker (Jan 5, 2008)

personally, I doubt you need banding at all other than to hold things together during install and prevent shifting around as long as they are top-clamped in place in case of accident. I think the tighter you clamp the ends, the more likely to force a top-vent rather than a little flex in case of over-charge or extended over-C discharge causing heat softening of case.

I bought a plastic strapping kit for about $100, and it works great for strapping blocks for 3,4,5 together pre-install....


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## BeeMike (Aug 3, 2011)

Thank you EVfun and Dan for your replies and information. 
Dan-where did you get your strapping kit and which one did you buy?
MIchael B


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## dtbaker (Jan 5, 2008)

in action:
http://www.envirokarma.org/ev/gallery/110228_rearpack.htm



Seller: s.s.g.strapping [email protected] Shipping details: Standard Delivery ----------------------------------- Purchase Details ----------------------------------- Description: 1/2" x .021 Strapping Kit 3M ft strap 300 seals+tools , Item# 120428753762 Qty: 1 Unit Price: $79.99 USD Total: $79.99 USD Shipping and handling: $18.99 USD Insurance - not offered : ---- Total: $98.98 USD


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## BeeMike (Aug 3, 2011)

Thank you, Dan for posting this photo--I realized today that the link to your web
page shows how you used the strapping. This is REALLY helpful to me!
Michael B


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