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Jul 17, 2019, 12:25 AM
Sagitta Fanboy
It's worth noting that pretty much no packs out there can do more than 30-35C sustained without damage, and the ones that can tend to be large/heavy (to have the thermal mass to support the high draw).

We're pretty brutal on our small packs, and they simply are not going to last for a long number of cycles with high draw usage, even if it is only for 20-30s.
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Jul 17, 2019, 01:58 AM
MQ-5B Driver
Doug Cronkhite's Avatar
I run Tattu or Pulse batteries in almost everything.
Jul 17, 2019, 01:49 PM
Sagitta Fanboy
Tattu and Pulse are the same company, so they should be fairly close in performance.
Jul 17, 2019, 02:06 PM
Registered User
Thread OP
Quote:
Originally Posted by mawz
Tattu and Pulse are the same company, so they should be fairly close in performance.
Interesting, I suppose it makes sense. There can't be very many lipo battery manufacturers world wide. That being said I have experienced a wide spread of quality variation in brands. When I first got back into F3A the popular power source had changed from glow power to electric power. Typical system is 10S running between 2,500-2,800 watts. I tried a couple of the less expensive brands and typically would only get a few months of service before the packs would start piuffing. The chargers were of the lower cost options as well. It wasn't until I went with higher cost batteries ( 185.00 per set as opposed to 120.00 per set ) and ISDT chargers that I started getting what I would call reasonable longevity out of those batteries. Keep in mind that I only charge at 1C, always storage charge after a flying session, never discharge below 30% capacity. The batteries after a 7 minute flight may get up to 110 degrees, 115 if I'm flying in windy conditions. IMO there has to be some variation in the cells that are being purchased, assembled and have whatever brand sticker applied.
Jul 17, 2019, 03:10 PM
Registered User
Pulse is owned by Helidirect. That does not mean every battery they make will be produced by Gensace/Tattu or that the cells in one Pulse battery of similar spec to a Tattu has the same cells.
Jul 17, 2019, 03:48 PM
Registered User
Thread OP
Just seems to me there should be some sort of grading system or at least cell matching like the car guys used to do back in the Nicad days.
Jul 18, 2019, 03:08 AM
Registered User
Do not measure IR when pack is discharged, you will read huge non-sense values.
IR should be measured at least at storage level, i.e. 45%, and better closer to 80% charged.
The value per se is not relevant, if not related with the current.
Any IR that led to voltage drop bigger than 0.2V (per cell) is too big, imo.
So for an amp draw in the 40A ballpark, anything bigger than 5mO is too much.
Jul 22, 2019, 10:14 PM
Registered User
Thread OP
A couple Pulse batteries cam in the mail today. I need to change connectors and I can start making some comparisons. In the meantime I spent Thursday through Saturday getting some practice in on my F3A airplane that uses a Pulse 850ma 2s pack for the RX and servos. While charging for a practice session on Sunday I decided to check the IR on that pack just for giggles. Imagine my horror to find these numbers. Obviously the airplane is grounded until the pack is replaced.


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