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(2002 - Series 6) DO NOT BUY BATTERIES FOR ROBOT WARS UNTIL YOU HAVE READ THIS! The test method was the same as the tests performed for Series 5/2001 - our UPS inductor in a bucket of water, hooked up to the logging system on a computer. 
 
 
 
Team Tornado Battery Test 2002: Results |
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Battery Rated Capacity Weight Dimensions Measured Capacity Start Resistance End Resistance Time Into Load Efficiency (Ah/kg) Efficiency (%rated) |
Hawker Genesis 16Ah 6.4kg 180Lx75W x167H 8.84Ah 0.010ohm 0.057ohm 5.57mins 1.38 55% |
Hawker Odyssey 16Ah 6.4kg 180Lx75W x167H 9.52Ah 0.011ohm 0.087ohm 6.33mins 1.49 60% |
Hawker Genesis 13Ah 4.9kg 176Lx84W x130H 7.25Ah 0.011ohm 0.073ohm 4.62mins 1.48 56% |
Hawker SBS15 (new style) 14Ah 4.8kg 200Lx77W x137H 5.97Ah 0.014ohm 0.049ohm 3.92mins 1.24 43% |
Hawker SBS15 (old style) 14Ah 4.8kg 200Lx77W x137H 6.56Ah 0.015ohm 0.051ohm 4.35mins 1.37 47% |
Kiel 18Ah 6.1kg 175Lx75W x175H 7.18Ah 0.018ohm 0.081ohm 5.45mins 1.18 40% |
Dryfit A500 16Ah 6.0kg 180Lx76W x167H 6.24Ah 0.021ohm 0.114ohm 4.65mins 1.04 39% |
Portalac 17Ah 6.3kg 182Lx77W x167H 7.89Ah 0.016ohm 0.113ohm 5.40mins 1.25 46% |
Diamec 12Ah 3.9kg 152Lx100W x105H 5.03Ah 0.021ohm 0.122ohm 3.89mins 1.29 42% |
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Battery Rated Capacity Measured Capacity Efficiency (%rated) |
Hawker Genesis 16Ah 11.40Ah 71% |
Hawker Odyssey 16Ah 12.08Ah 76% |
Hawker SBS15 (old style) 14Ah 11.89Ah 85% |
Portalac 17Ah 15.38Ah 90% |
Diamec 12Ah 7.63Ah 64% |
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Team Tornado Battery Test 2002: Conclusions Comparing the heavier (6kg+) batteries first, it can be seen that the cheaper Lead Calcium types (Kiel, Dryfit and Portalac) do not perform spectacularly - they have a high internal resistance and deliver a poor capacity of only around 1.2Ah/kg (the Dryfit is particularly bad given how expensive it is!). Compare these to the Genesis and Odyssey 16Ah Lead Tin batteries - in all cases these have a lower internal resistance, and deliver a better capacity of about 1.4-1.5Ah/kg. The Odyssey in particular is worth noting - it delivers a final capacity of nearly 10Ah, pretty spectacular for a 16Ah SLA! 
Comparing the remaining (lighter) batteries, the old style SBS15s perform pretty well, although these are no longer available and the ones tested here are the six remaining "good" ones from our original nine. The newer SBS15s are dissapointing, with similar efficiency to the cheap and cheerful (and small) lead calcium Diamec - newer type SBS's are not recommended for use in robots therefore. However, the best of the bunch is the Genesis 13Ah - it has similar efficiency and internal resistance to the 16Ah Hawkers, but is a fair bit lighter.
The low current tests show the difference between low current "backup" type batteries and the high current delivery Hawkers - the measured capacity and efficiency of the Portalac (and to some extent the old SBS15s) increases dramatically at low current, while the 16Ah Hawkers do not improve proportionally that much (although in all cases the measured capacity is greater, as would be expected).
It is worth noting that since these tests were performed, Hawker have again rearranged their battery lineup. The SBS15 and Genesis batteries in future will be aimed at low current and backup situations, and although currently they are all the same batteries internally, the internal construction is going to change. Hawker (and Hawker dealers) will only provide warranties on Odyssey batteries for high discharge cyclic applications, so if you are buying new Hawkers, you need to be buying Odysseys! The Odyssey range consists of the following: PC535 (14Ah), PC545 (13Ah), PC680 (16Ah), PC625 (17Ah), PC925 (26Ah), PC1200 (42Ah), and PC1700 (70Ah). The PC925 is probably the largest battery anyone would want to use in a heavyweight robot!
Remember also that the results should be scalable for different batteries within the same ranges as those tested - i.e. a 26Ah Odyssey is still going to be much better than a 26Ah Dryfit!
Team Tornado Battery Test: Recommendations See our Suggested Suppliers list for details of where you can buy the Hawker, Kiel and Steatite batteries.
Team Tornado Battery Test: Postscript
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If cost is important, and you're not likely to draw a lot of current (e.g. you have a 2WD robot with a non-electric weapon), then lead calcium type batteries such as the Kiels, Steatites or Portalac should do the job. You won't have quite the best performance, but you'll save a lot of money. Alternatively, any of the Hawkers in good secondhand condition will be a good buy.