The battery in my bike will only have one function, which is to supply juice enough to drive the ignition coils so that the can in their turn feed enough power to the spark plugs to get them to ignite the fuel/air mixture at a rate of say 70 times per second per cylinder. Derek Jones at Racetech Dev Ltd, who will be supplying the Hall Effect Sensor and Trigger Wheel plus the “Black Ignition Box”, which he calls “ECU or Electronic Control Unit”, says that his equipment requires 1-2 Amperes at 12-14 Volts.
The bike will have no generator to charge the battery, or power the ignition, so the ignition power will be of the “total loss” type, which means that the battery will have to have enough capacity to sustain a race heat on its own. I cannot imagine any race heat to exceed 30 minutes so that means that my battery capacity will have to be 2A x 0,5h = 1 Ah (Ampere our).
At first I thought that I could make a DIY battery pack so I looked around for suitable candidates. The French company SAFT has made high technology aircraft batteries for decades, using electrodes of either Nickel/Cadmium or Silver/Zinc and are now producing small battery cells of the Lithium-Ion variety. Their AA sized cells (Li-SOCI2) produce 3,6V and have a capacity of 2,6 Ah so I figured that I could connect 4 of them in series and that would make one battery pack producing 4 x 3,6 = 14,4 Volts and a capacity of 10+ Ah at a weight of less than 100 grams. This until I found that the maximum continuous drain current is 50 milliamperes whereas I need between 1 and 2 Amperes ( without milli in front ). 50 mA = 0.05 A, which means I would have to connect 20 of my battery packs in order to be able to drain 1 Ampere and now the weight of my battery would be about 2 kg. No way Jose. Have to find another solution.
An evening or two of Googling and up comes a Lithium – Ion battery that seems to be the answer to all my prayers.
13,2 Volts – 5-7 Ah – 2,3 Ampere Discharge Current – weight 450 grams – 85 mm high – 35 mm thick – 115 mm wide, lithium –ion technology – can be mounted flat – recharge time 15 minutes.
This thing has everything I need and more and is the choice.