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Cold weather lipo use...

Cold weather lipo use...

Old 01-12-2016, 08:47 AM
  #16  
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Wow, Mike, that's a ton of current! Have you started pre-heating your packs when running boats on colder days? This is terribly interesting to me.

Yeah, I'm not so worried about mild puffing, now, either; but for certain the IR. Have you settled on any certain load/temp/state-of-charge value to use for your testing?

Thanks,
Gene
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Old 01-12-2016, 10:52 AM
  #17  
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Yes I now keep all my packs warm before running now. Another interesting thing I noticed while testing was that If I started the packs at ambient temps 60's-70's the packs would get to 135-140 during runs, and as the heat increased I would see an increase in speed because of the drop in IR. But if I started the packs heated to 110 they would only get up to 120-125, and the speed would be consistent throughout the run. The fact that the packs werent getting as hot would give me longer cycle life.

A lot of my early testing was done with older 25-30C batteries where we were careful and charged at only 1C. I would test with 2 boats a 4 cell V hull and a 10 cell catamaran. I used to have a lot of this stuff on the computer with my data logging speed controllers so i knew specific amp draws and such. I now have memorized and dialed in my setuos where I don't need to have that info handy, but I would record everything, motor, speedo, battery temps, constant amp draws, amp spikes, etc etc... I have it somewhere but not sure what computer it's on or if i even have it anymore??? I routinely now charge at 2-3C and sometimes even much higher if necessary.

I don't know if you know this but when boat racers do speed runs (we call them saws) we routinely preheat our packs to 140. These are for record trials where we are vying for national speed records and ABUSE (and often destroy) our equipment to obtain these records!!!

I can tell you this about Lipos is that the C rate is a bunch of BS, take your 100C 7000mah lipo, according to the C rate that pack should be able to handle a continuous 700 amp load!!!! yeah just try doing that, and you'll have a BIG fire on your hands, trust me I have boats that draw 250-280 amps over a run and spike at over 400 amps in the corners and this is serious abuse of these batteries. anything more and they would be toast.
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Old 01-12-2016, 01:42 PM
  #18  
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Excellent information! I may have to buy a 12v heating pad

I especially appreciate your statements on that inversely varying initial-temp vs. final-temp phenomenon.

Good sharing,
Gene
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Old 01-13-2016, 09:48 AM
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when we race boats we typically pit out of our cars or trucks, on warm sunny days leaving the batts on the dashboard is sufficient, on colder days I keep the truck running with the heat on and keep the batteries on the floor under the heater.
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Old 11-11-2020, 01:26 PM
  #20  
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Thanks for the info!
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Old 11-11-2020, 01:27 PM
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These are old comments, but I was interested in reading them. Thank you for sharing.
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