True test? Nah, I’m just a battery geek who reads a lot and has his own preferences. 
I like to think those preferences are based on sound science though.
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If you told me right now batteries were water resistant, I’d probably believe you 
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I’ve having a tough time making a decision about going with the p42a vs the 40t. I’m looking at a 12s9p build and my calculations show on the 40t if I set the cell continuous discharge to 25amps my system demand shows a battery pack peak discharge of 225 amps and the potential for my motors to pull 178 amps, so about 50 amps of headroom.
On the p42a cell in the same 12s9p configuration with the settings set at 35 amps cell continuous discharge my pack can then do 315 amps continuous and again my motors can potentially pull 178 amps. Thats a considerable amount more headroom… but Mooch, you also just said perhaps a better safe continuous output for the p42a is around 25 amps. Would that also mean the 40t’s safe continuous output should be lower than 25 amps? Any suggestions on which way I should go. I’m satisfied with the predicted performance of both cells, the p42a offers a bit more range and headroom but I would be happy with either cell. What I’m trying to understand is would one cell or the other have a particular advantage when talking about longevity and cycle life? Current prices show I gotta spend about $755 Canadian for the required p42a cells vs $587 for the required 40t cells. Are the p42a worth the extra 170 bucks under my circumstances? For context its for a hybrid street light off road build, I’ve got a few 40% grade hills I climb but mostly its pretty flat and range is a priority for me.
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Umm…actually…round cells are completely waterproof (hermetically sealed) and can easily be used underwater. Not at all recommended but possible.
At the low voltage for each cell you get only microamps flowing through clean water. Even a salt-saturated solution only slowly discharged a li-ion cell in my testing. The cell self-destructed from electrolysis though when in salt so definitely not recommended.
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The P42A beat out the 40T a little bit for most situations. When just looking at performance the P42A is the slightly better choice IMO. Staying under 25A or so improves performance, increases cycle life, and reduces risk versus running at higher levels.
They perform about the same though and a lot of people wouldn’t notice The difference.
I haven’t tested the cycle life for them so I can’t comment on the better choice for that.
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Cool, thanks Mooch. Sounds like i have to weight the dollars vs slight performance gain. Appreciate your feedback
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That’s easy…run the hell out of at least four of each cell and compare performance every hundred cycles. 
They just need to be wrapped like a pack would (to trap the heat) and charged and discharged hard enough to bring the temps up.
They don’t need to be pulsed or to simulate the different current draws when used in a board. Any discharge over a few milliseconds long is just more of the same for a cell. Continuous discharge testing will come within a couple percent of what would happen if pulse discharged. The best cells identified using continuous discharges would be the best cells identified using a simulation of “typical” board use.
Only if the cells were performing to within a couple percent of each other could the results change for continuous vs pulse/variable discharge testing. But if they are performing that close then it’s very hard for anyone to notice the performance difference anyway.
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Hold up, is this Mr Battery Mooch from the YouTubes?
Welcome, thanks for visiting and commenting in detail 
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damn that soda looks good.
edit:
I just stole some of my roommates fanta that shit looked so good.
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Most people build packs with at least 4 cells in parallel and I may be wrong but we (except for Dr @Arzamenable) rarely draw more than 80a. Am I wrong to think that i wouldn’t know the difference between the P42a and the 40T?
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I don’t recall the last time I went for a ride and drew less than 80A 
. At least max amps
Avg be nice and low tho 
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I am not gonna add the names of all the 4WD speed demons in that post…
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I don’t even know you need to be a speed demon (although it’s way more fun). But just AWD will really test that batt…
Pro tip, make sure it’s built well
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yep
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No, you are not wrong. That’s what I was saying in my post.
You probably wouldn’t notice. IMO, any perceived difference in performance from ride to ride would be due to a large number of variables other than small differences in cell performance alone.
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So is it safe to say 25A would be the recommended battery amp settings for P42A? For esk8s context of course.
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It depends on how hot they get in your pack, how they’re charged, the cycle life you want, etc.
25A-30A is about a far as I would recommend taking them for okay cycle life as long as they are not stressed otherwise.
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Uummm so I’m totally abusing cells VTC5A 3P I regally do 3seconds burst of 80-90A in a followed by a minit of 15A pulses. I always thought that 3 second burst had time to recover