PARTS IS PARTS:
Lipo Puff meter
Lithium polymer batteries are increasingly popular in robots.
In combat bots, they are often
abused to the point of failure with
expensive and dangerous results.
Before a pack fails or burns, it often
‘puffs’ to larger than its normal size.
This is a sign that the pack is either
losing capacity or is likely to burn
under a normal current drain.
Puffing is not always obvious and to
check my Lipo packs, I invented the
Puffometer.
How to Make It
The Puffometer is very easy and
cheap to make. You will need a drill,
jigsaw, and some scrap plastic. The
material can be almost any sort of
plastic sheet as long as it is fairly
rigid; in Photo 1, the Puffometer is
made from an off-cut of Garolite.
Measure the height and width of
your pack, then cut a square about
one inch larger all around. Draw a
rectangle with the dimensions of
your pack in the center of the plastic
and then use a drill and jigsaw to cut
out the rectangle. I
found that most of my
packs had larger
dimensions at the wiring
end; you should check
dimensions at the middle
of the pack for a good
fit in the Puffometer.
Check the battery fits
through the cut-out,
clean up the edges, and
you’re done. If you use
more than one type of
pack, simply use a longer
piece of plastic with
multiple holes; just
remember to label each
hole!
PHOTO 1. One size fits all. Get all
your packs tested with one tool.
How to Use It
To use the
Puffometer, wait until
your Lipo pack is at
room temperature. Slide
the pack at least halfway
through the correct hole — it’s that
simple! If the pack does not fit as
PHOTO 2. The Puffometer in action.
and needs to be treated carefully. If
the pack does not fit at all, you need
to discard the pack immediately. SV
EVENTS
Completed and Upcoming Events
Completed Events: Dec
8, 2009 to Jan 9, 2010
The ComBots Cup IV was present- ed by ComBots on December
19th and 20th in San Mateo, CA.
Gulf Coast Robot Sports- 4 was presented by Gulf Coast Robot
Sports in Bradenton, FL on January 2nd.
Upcoming Events for
March - April
Central Illinois Bot Brawl 2010 will be presented by Central Illinois
Robotics Club in Peoria, IL on March
6th. Go to http://circ.mtco.com
for more information.
2010 Robot Rumble will be presented by Carolina Combat
SERVO 03.2010 31
