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Oct 14, 2021, 12:28 PM
Registered User

Durability data?


Great report, thank you. Do you also have any durability data, i.e. the number of charges and discharges (say at 30-35C) before 1+ cells go bad or before the performance degrades so much the battery is unusable?

I fly helicopters with 6S and 12S batteries. I typically make 1,500+ flights a year (all logged). I also fly speed prop airplanes that pulled 100+A on 6S batteries. From experience, not many 6S 5kAh batteries reach 200 flights (2C charges, 30-50C discharges). So far, I made 250 flights with a TP Rampage 80C before a cell gave up, no more than 225 flights with all my Yowoo 100C batteries (graphene batteries by HRB if I am not mistaken), and 375 to 425 flights with all my RoaringTop 75C batteries. Everything else never went beyond 100-120 flights, often not even 50 (Venom, etc...). I killed 2 Yowoo batteries when pulling 250A on them. Thanks again. -Olivier
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Oct 14, 2021, 02:47 PM
aka JetMan Joe
MCSGUY's Avatar
Thread OP
Cycle count is usually not the issue with Lipo's. Outside of infant mortality, random chance and factory specific QC practices associated with a brand the issue is the level of voltage a pack will maintain under a given load profile. A crap pack only able to support a thousand watt discharge before tripping the LVC may actually last longer then a light weight super star able to deliver 3 times the power. It's a matter of preference and understanding.

By design lipo batteries give up some small quantity of lithium every time they're discharged, it's the "fuel" used in the process. Temperature is the primary factor regulating the rate of decay, or fuel expenditure. The voltage bottom, either resulting from discharge or "bouncing" below the low voltage threshold by intermittent loads not adequately supported by the battery is the primary cause of temperature rise, not the actual Amps per se. The SEI layer separating the anode and cathode "thickens" with use accelerated by high temperature. As it does it restricts the ion flow (increases IR) which perpetuates the viscous cycle of reduced performance and temperature increase.

The point is the life cycle of a pack is governed by a host of factors and if one considers "C" in terms of amps rather the performance voltage levels they can generally be "milked" for a long time.

Joe
Oct 14, 2021, 05:27 PM
Flying Hazard
SU-4ever's Avatar
Quote:
Originally Posted by LeFrog
I fly helicopters with 6S and 12S batteries. I typically make 1,500+ flights a year (all logged).
Holy... I also log my flights and after almost 20 years I have made like 3100 flights. 1500 a year is a HELL LOT!
Oct 14, 2021, 07:41 PM
Registered User
"I typically make 1,500+ flights a year (all logged)........."

Wow!!!!! That's averaging 4 flights every single day of the year!!!!!
i'm impressed!!!

"So far, I made 250 flights with a TP Rampage 80C before a cell gave up,"
That might even be more impressive if you are pushing the TP batteries.
Oct 14, 2021, 10:22 PM
Lee Liddle
Knife Liddle's Avatar
One post? Of course if he spent that much time charging, flying , repairing and logging, I guess there's not much time for other activities.

LeFrog, it seems to me that you are the one with all of the "Durability Data". It's time to start writing....
Oct 15, 2021, 05:05 PM
ITTD you're Clear for Takeoff!
IntheTubeDeep's Avatar
Yeah thats a lot of flying!! Since 2010 I reckon I'm up to ~2500 flights probably 2400 on the
beach in harsh environment! Very poor tides for this month been flying the Beaver and Tundra,
my new GT arrived few days ago that will be my goto once I make my 3d design Print Floats with
built in retracts and rudders- will fly GT only on 6s, the SMC or Liperior will be ideal for the huge GT,
and weight not an issue!

Ian from HK sent me a bunch of Graphene 3s 2200s and an A-SPEC 6s 5000 for GT years ago before he
left- which I've had good flying with- heavier than other 2200s but so far no failures! I hadn't used a
3s 2200 for a LONG time- so they were all sitting collecting dust but all 4 seem excellent

Few years back I did an informal test on how long the GT could fly on an A-Spec 6s 5000!

Avios Grand Tundra: How Long Can GT Fly on 6s 5000!? (15 min 11 sec)


Having Fun with Chrissy Russo Fox5 Surf Report!

Epic Fox5 Surf Report after ELE Servo Strips! (1 min 24 sec)
Last edited by IntheTubeDeep; Oct 15, 2021 at 05:33 PM.
Oct 15, 2021, 07:15 PM
aka JetMan Joe
MCSGUY's Avatar
Thread OP

PowerPoint Slides


I've been preparing a presentation about testing Lipos for my clubs next meeting. I figured I'd share the finished product with you all. I'll be glad to field any question any of the slides might raise.

Joe
Last edited by MCSGUY; Oct 15, 2021 at 07:33 PM.
Oct 15, 2021, 07:31 PM
They Call him Dead!
YellowJacketsRC's Avatar
Nice. Almost as impressive as the amount of work you have put into this study!

We all owe a debt of gratitude!
Oct 15, 2021, 09:20 PM
Registered User
Great slide presentation .
Oct 16, 2021, 12:02 AM
Lee Liddle
Knife Liddle's Avatar
Very impressive. I wouldn't even know where to start with questions. Wish I could attend your presentation.

Just a thought. Maybe you could record the audio from your presentation and at some point put it on YouTube synchronized with the slides. I'll admit it probably won't make you a YouTube star, but I would definitely watch it.
Oct 16, 2021, 12:34 AM
Registered User
Yak52Driver's Avatar
Quote:
Originally Posted by yellowjacketsrc
nice. Almost as impressive as the amount of work you have put into this study!

We all owe a debt of gratitude!
+ 1
Oct 16, 2021, 12:36 AM
Registered User
scott page's Avatar
Quote:
Originally Posted by MCSGUY
I've been preparing a presentation about testing Lipos for my clubs next meeting. I figured I'd share the finished product with you all. I'll be glad to field any question any of the slides might raise.

Joe
This is a fantastic presentation. It would be an incredible addition to Youtube with your verbal presentation. .... Just planting seeds that I'd like to water.

Edit: I see the youtube idea came up already -- ya -- I'd share he heck out of that link.
Oct 16, 2021, 04:52 AM
Lee Liddle
Knife Liddle's Avatar
Yes, absolutely. I forgot about sharing the future video.

Joe, you've obviously put a lot of thought and effort into the slide show. When you have time, please preserve it. You have a great deal of accumulated, reak world, unbiased data and knowledge. This thread is like your journal. A video would be a great addition to it. Kind of like the Cliff Notes that we all read in high school and college.
Oct 16, 2021, 05:28 AM
Hamburger
hamburger's Avatar
Quote:
Originally Posted by MCSGUY
I've been preparing a presentation about testing Lipos for my clubs next meeting. I figured I'd share the finished product with you all. I'll be glad to field any question any of the slides might raise.
cool stuff.
Maybe insert '#21 common misconceptions/fallacies' with arguments we have heard a thousand times but have proven wrong
  • 'charging at higher C-rates does increase pack's temperature - but that increase comes too late to prevent damage when charging a cold pack (even if ambient temperature is ok) -> back to #20'
  • ...
Oct 16, 2021, 08:31 AM
Registered User
Joe thank you for sharing the preso... as always enlightening and good information. Some feedback::
Is voltage scale on page 10 correct?
For battery charts (pages 14 through 17) is the units for TUL really seconds.. perhaps best to leave the units off since that time nomenclature is well understood.
Given the range of battery capacities your testing has expanded into... perhaps dispense with "C" rate test label and simply go with amps.
On page 19... It would be useful information to explain how much capacity is lost by only charging to 4.10 volts...(typically)

Thank you again for your service to the community.

Mike


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