[ausev] PET battery strapping

[Erik Bigelow]

Hi Tom,

Interesting idea I must say. The strapping would be more than strong
enough to handle the load. Have you seen anything claiming acid
resistance of the strapping? Of course that's not an issue if you're
using sealed batteries. 

Have you looked at Ebay? Might cut the initial investment down a lot.

One potential problem might be crushing the corners of the batteries on
the edge. When large cartons are banded they have cardboard corner
pieces to diffuse the crushing force.

Any of the more experienced folk have ideas?

Erik

-----Original Message-----
From: ausev-bounces at austinev.org [mailto:ausev-bounces at austinev.org] On
Behalf Of tomsmail
Sent: Tuesday, August 22, 2006 1:32 PM
To: AustinEV News Announcements and General Discussion
Subject: [ausev] (no subject)

Austin EV group,

I'd like to make a proposal for a group purchase (since the
group appears to be ammenable to these in general) for some
tools and material.

Has anyone considered using industrial strapping, the kind
used for skids and boxes, to secure batteries to the EV?

I've looked into Signode Polyester (PET) straps and the
specs are impressive.  I think an installation done with PET
straps would look sharp as well as save space and weight.

There are two kinds of plastic straps used in industry: The
Polypropylene (PP) which are the more rigid straps you find
on cartons and large boxes of consumer goods, and Polyester
which is softer but has more strength (Its made of woven
fibers encased in plastic).

The "Tenax" 2225 PET straps from Signode have a breaking
tension of 2500 lbs.  The strap is 19mm wide.  They have
excellent stretch reforming and tear resistance.  You apply
them with a hand tensioner tool and a sealer tool.  The
seals are small metal clips that get crimped on.  According
to a Signode spokesman, the seal joints will not fail under
tension before the straps themselves fail.

Tenax comes in 2,400 ft rolls, which is probably a lifetime
supply for a small group such as this one.  In practice, you
would install several strap loops around a battery pack. 
Putting a loop in each dimension allows you to use the
strapping as a "unitizing" secure.  In practice, you would
re-strap the battery pack each time the batteries were
removed for mantainance - not an obstacle given the amount
of strapping per roll.

If you've ever used all-thread before, then you'll know what
I mean by space savings.

http://www.signode.com/na/northamerica.htm
http://www.strappingtoolsandparts.com
http://www.acme-packaging.com/index2.html
http://www.strapex.com/en/home.html

Startup Costs are:
$139    2225 3/4" PET Strap Roll of 2400 ft.
$132    34DY metal clips, box of 1000
$399    D34 Side action Sealer hand tool
$120    WPCT Tensioner hand tool
----------------------------------
$790	Total

I am proposing that the cost be shared first among the most
interested, needful, end users and second by the
organization's general fund so that newcomers can benefit
too.  If you're interested please respond.

I'll volunteer the first ammount.  Also, (ulterior motive)
it would be nice, if this is going to go all the way, that
it were decided upon soon so that I (or others) can use this
stuff in preparation for the September Renewable Energy Fair
in Fredricksburg

Thanks,
Tom
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