HPRA AMB Elite timing system, replace amb elite cyclip transponder battery, new elite cyclip battery
HPRA AMB Timing System
Or... How to replace the batteries in your AMB Elite Transponders.
An article by Warren Beauchamp
Prior to 2003, the Human Powered Race America organization relied mostly on manual timing for it's lap races. This involved getting the racers and other volunteers to count the laps and record who finished in what order. Often racers lost track of the laps due to socialization and oxygen depravation. Occasionally we were able to use the IHPVA timing system, but it was notoriously flaky.  In 2000, Warren Beauchamp and Bill Murphy built about 30 blown nose fairings sold sold them to enthusiasts around the country to raise money for a new timing system. Warren also solicited donations from the all mid-west area race directors. Generous donations were received and in 2003 an AMB Elite timing system and 30 transponders were purchased for about $7500. 

The AMB Elite System
This system, in conjunction with it's Orbitz software, allows the HPRA to accurately time up to 40 racers on lap races. Each rider must attach a small "transponder to their vehicle, and  the system relies on a loop wire to sense the transponder each time the rider passes the start/finish line. The signal is picked up by the AMB system and displayed in the Orbitz software. This allow us to see at any given time during the race, who is in the lead, what everyone's lap speed is, what lap they are on, etc. After the race is over, the results can be printed out immediately.

The entire system including box of transponders, decoder, computer, printer, wires, and assorted detritus, fits into a box for easy transport.

The black box next to the grey transport box contains the transponders, It fits into the transport box as well.

Fast forward to 2008.
After 5 years of use, the batteries in the transponders are failing. AMB's stance is that the transponders must be replaced when the batteries die for $100 each. In addition, AMB is now manufacturing a new version of the timing system, and is no longer manufacturing the old style Elite Cyclip transponders.  Unfortunately, without the massive sponsorship awarded to more mainstream sports, the affiliated race directors of the HPRA cannot afford a new timing system, especially when the old one works fine.  After multiple unanswered enquiries to AMB requesting replacement battery information, drastic measures were required.

In the winter of 2007/2008, Warren investigated the possibility of replacing the batteries in the Cyclip transponders. The transponders are potted in blue epoxy, which is poured into the bottom of the plastic Cyclip shell. Warren cut the sides of the shell, then popped out the chuck of epoxy. After chipping away at the large side of the aero shape, an antenna was uncovered. Wrong side! After chipping away at the other side, it was discovered that the battery could not be removed nicely from the system. Fortunately, the transponder circuit board  nicely bisects the block of epoxy, and the whole side of the aero lump of epoxy including the battery was removed from the back side of the circuit board. The battery attachment points were identified. Battery voltage was about 4.5 volts. All attempts to find out the battery make and model were fruitless, as the label was stuck to the epoxy. Further experimentation showed that the 2.4cm x 0.8cm can style battery was filled with a caustic pressurized liquid. Yikes!

How do we know what battery to replace to with? Testing! I attached some wires to what was left of the transponder, and brought it, along with a variable power supply to the 2008 Manchester HPRA races. Experimentation showed that the transponder worked well at 6 - 7.5 volts. Also it was determined that fortunately the transponder code was hard coded, rather than programmed in some type of static RAM, so even after the transponder had been without a battery for over 6 months, it still knew it was transponder 16.
After some research, the only available battery that I could find that is close to what we need is the 4LR44. This is a 6V, 13 x 25mm Alkaline battery. Also there is a Lithium model of this battery with a 10 year shelf life which would be a better choice, model PX28L.

I now need to buy one of these batteries and see if it fits in the AMB Elite Cyclip case (it should barely!). Also I need to figure out how to fasten the battery to the wires. The old battery had welded tabs, but the new one will not.

I stopped by RadioShack and picked up a 4LR44 battery. As you can see, it fits, but just barely. It's much wider than the original battery.

The idea is to attach the battery to the wires with a clip or something, then fill the whole thing with silicone glue to ensure it will withstand the rigors of bicycle racing (and make it easier to replace the battery a second time if necessary). Another option is to build a battery tab welder. Any volunteers?

It turns out that the battery terminals were easy to solder to, so I just soldered on the wires. I am going to let it sit like this over the winter and then measure how much the voltage drops before sealing it up. If the battery drop is too high, it may make sense to include a small switch to disable the battery during the winter.

This solution looks like a viable alternative to purchasing expensive used AMB Elite Cyclip transponders with questionable remaining life.

Transponder #3 gave up the ghost at the Hawkeye Downs races, but we caught it at the transponder check. This weekend I removed it from the shell and it had a different battery, and this time I could read what it was!

It was an Inorganic Lithium 1/2 AA sized 3.6 V battery. Now we know exactly what to replace them with. Here the exact battery: http://www.battery-force.co.uk/detail_SNSL35001A.html

Here is a replacement, with tabs!

10 pack:

With leads, perfect.


I think I'm going to order 10, and do the surgery...



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