Talk:DEWBOT XII Havoc
Battery Testing
In spite of the fact that we test all batteries with a Battery Beak (Manufactured by Cross the Road Electronics - marketed by AndyMark) before competition, we experienced two battery failure in competition: one at Westtown (battery AD) and a more complete one at MAR Championship (battery AF) where we just managed to crawl to the batter at the start of the match.
As a result, we tested all competition-rated batteries 18-20 April using the CBA (Computerized Battery Analyzer) III (manufactured by Optim Engineering - marketed and sold by West Mountain Radio). The CBA measures the voltage of a battery over time under a fixed current load until a set terminal voltage is reached. For this testing, the load is set to 7.5 amps; terminal voltage to 10.5 volts. The CBA reports Amp Hrs.
And the CBA III performance charts (below):
Three batteries were removed from service as a result of the testing: AD, AE & AF. Note that AC had previously been removed from service. The batteries AC-AF all entered service in 2014 and came from two consecutive orders of two batteries each. With the exception of these four batteries, the only other gap in our in-service batteries is "V" from 2013. "U" is the oldest battery in service (also from 2013), so "V" almost certainly died of old age. This makes the AC-AF group appear as if it may be associated with a manufacturing QC lapse.
Read the full CBA III Report.
Our last full battery test with the CBA III was conducted in March 2014. These test are labor and time intensive. Since then, we have relied on the Battery Beak to assess battery health.
Key findings of this test are:
- The Battery Beak does not identify all failed batteries. As a result, reliance on the Battery Beak alone exposes the team to battery failures in competition (as at Westtown & MAR Championships).
- The CBA III does appear to correctly identify failed batteries (as identified by competition failures) which the Battery Beak misses.
- The CBA III appears to also identify failing batteries (such as "AE"), allowing these to be removed from competition service prior to obvious failure.
- It is clear that the team should reinstitute a regular CBA testing regime.
The CBA III is no longer manufactured. The team has ordered a CBA IV from West Mountain Radio. This augments rather than replaces the old CBA III (with is compatible with Windows 10). The team has also ordered two replacement batteries to be delivered to our pit at FRC Championship.
