Gentle Friends,
After all the chat about the Sony VTC5 and it's potential superiority as a battery for Cera/Luna I broke down and ordered two (minimum order from Orbtronics), which just got here. I built a little processor driven test fixture to load test:
I've modified it a bit since then (improved the holder) but you can see the load resistors (8 total) that are used. They provide a 'pretty average' Cera load of about .1.1 Ohms total. I think it's an accurate analog.
The tester checks the voltage at rest, if it's still over 3.5 Volts it applies the load for 15 seconds (representing a serious EO hit in this test). It samples the loaded voltage at 10 seconds into the cycle. It then rests the battery for 45 seconds before testing again. You can watch the voltages on the little meter or the computer. I can then cut and paste them into a spreadsheet but I'm stalled at how far to go with that and how to post the results.
More runs are needed to confirm, but right now here's what I see looking at the range from 4.1 to 3.5 Volts: The Sony battery has a slight (about 1%) advantage in loaded voltage (say .03 Volts?) at any given point. IMO quite minor and easily overcome by either the NCR1650PD or CGR18650CH with 8 or 10 fewer cycles on it. The NCR went 129 cycles, the VTC went 116 and the CGR 114.
This needs more testing to firm up, but since the VTC is brand new and the other two my kind of beat up 'test batteries' I expect the modest difference to get smaller.
I've no doubt these guys have amazing capacity at very high currents, we just can't take advantage of that and. It would seem the NCR might offer a better compromise for us, giving over 10% more hits per charge?
OF