Cell Selection, Lithium Ion Battery Pack
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- čas přidán 4. 06. 2023
- Internal Resistance, Cell temperatures, Discharge Testing, Sag measurement Model3-NCR21700 4800mAh 13.8A continuous
BTW INR 21700-40EC 4000mAh 12A continuous
BTW INR 21700-40PC 4000mAh 20A continuous
Lishen LS LR2170SA 4000mAh 12A continuous
SAMSUNG INR21700-50E 5000mAh 9.8A continuous
SAMSUNG INR21700-40T 4000mAh 45A continuous
MOLICEL INR-21700-P42A 4200mAh 45A continuous
@BATTERY BUILDER
Amazing information !!! Thank for your testing !!
I just did a 12a discharge test on my fake Molicel P42A so i can compare to your test cells. Seems its behavior is very similar to the LiShen LR2170SA.
My temperature results will be a little higher because i insulated the cell and temperature probe to get more real world in pack temperatures.
I want to see samsung 50s
My jbd bms is not giving full output i reconnected the jumper wires 2-3 times still its not working
What equipment do i need to determine CDA on batteries that have no markings on the label? I would be using these batteries for 18v tools ie drill, saw etc. I'm guessing that a 20a discharge battery would work without overheating
ATORCH DL24 discharge tester is $30 on AliExpress. The one I purchased worked well for verifying cell capacity at different current flows up to 20A. Take note - the cell temp sensor they provided was not accurate.
@8:04 I’m getting ready to build a 13-16s 5p 21700 for my ebike which I’m designing to run at up to 60a continuous, with peak discharge of 170a.
So 12a/cell is my continuous target, which is seems the 50E is staying under 60 degrees C and delivering super mah. But I think my bursts of 170a are way over what these can take.
Of course in an ebike, it would be 10 seconds at 170, then down to 60a max cruise speed, with realistic cruise being more like 25a (for 20-25ah battery).
So the question is how much damage it does during short bursts. Is it so fast that it messes with the intercalation of the ions, the electrolyte, the anode or cathode doping?
So even though ill take a hit in range and cost, im shook for something that will stay under 60c at 20a/cell and allow bursts of 35-40a per cell.
I just ordered a tester that will allow up to 20a discharge test. I wish I had your system but its too expensive lol.
My main test will to see if the cell I got was a rewraped cheap cell , which hopefully a 20a full discharge test will reveal.
Current draw is proportional to motor speed. If your peak current draw is 170A, it will immediately come down with increasing motor RPM. I asked my cell supplier if 140A/5p = 28A/cell (a few seconds) was ok for a 12a continuous cell. They were not concerned and I have had no issues. I believe acceleration time is important. In my application 0 to max RPM takes 10 seconds or less. Samsung 50E has rated discharge capacity at specified current draw. To determine if your cells are legitimate, I would check the capacity at the rated charge/discharge rates.
@@HOTPAXX, yes, I will set it so it comes down but if I let it go deep into flux weakening the 170a will flow until the magic smoke comes out of the motor. Lol.
My plan is to set phase current to the maximum until my motor sounds like a transformer getting ready to blow during acceleration. Then my controller allows me to set several RPM-power limits, so the first limit I would determine maximum continuous cruise speed (based on motor temperature), and then set the controller to limit to that current at that RPM and higher. And then if I decide to use flux weakening, I would set more limits such that going uphill or into the wind, it wouldn’t allow flux weakening but downhill/with the wind it would allow it. But at less than maximum continuous current.
But I will also have 3 speeds so i can set it:
Speed 1: acceleration and top speed of original POS ebike
Speed 2: Double original acceleration and up to 50 kph (maximum legal here)
Speed 3: 170a acceleration, 60a cruise speed (should be 70 kph),
I will get the controller next and the battery last since the controller with my present battery will probably be able to define what specs I need on the battery. 170a on my present battery would probably send it into LVP by time it reached 100a. Lol