Boston-Power Swing 5300 Li-ion cell test

Just for the info. Boston Swing5300 mAh cell, made in China, after two years of resting in paperbox under the table in the office.

Nominal capacity test made on $$$..$$ professional battery tester (0.7C charge, 0.2C discharge at 100% DoD 4.2V-2.75V): 5345 mAh / 19.56 Wh / 10s DCIR test at 50% DoD: 26.6 mOhm.

"Realistic" capacity test (0.5C charge, 1C discharge at 80% DoD 4.1V-3.2V): 4380 mAh / 15.5 Wh
 
Pajda said:
Just for the info. Boston Swing5300 mAh cell, made in China, after two years of resting in paperbox under the table in the office.

Nominal capacity test made on $$$..$$ professional battery tester (0.7C charge, 0.2C discharge at 100% DoD 4.2V-2.75V): 5345 mAh / 19.56 Wh / 10s DCIR test at 50% DoD: 26.6 mOhm.

"Realistic" capacity test (0.5C charge, 1C discharge at 80% DoD 4.1V-3.2V): 4380 mAh / 15.5 Wh
Click to expand...

"$$$..$$ professional battery tester"
More information please. That doesn't mean anything. Model number and manufacturer at least would be great.

Thank you for posting that info! Slightly better than what I said previously, but still only a sociopathic battery user would charge and discharge to those voltages. On both ending voltages, the cells are well into the non-linear regions of the charge. Practical day to day use and expecting a long battery life span, you would never charge to 4.2v or discharge to 2.75v

I'll test at these rates/voltages for 2 full cycles on my next round of tests...we'll see soon enough if I match your results! I can absolutely do all of this. And for a couple of charge/discharge cycles no real degradation of life will be noticed.
 
First off I want to say that I own an iCharger 4010 Duo. They are not some cheap $40 charger! Go look around, they typically cost $350 AND you still need to buy a beefy PSU that can deliver the current this beast can devour. These things are well worth the money considering that it can charge and discharge 2 sets of 10S at crazy current rates. If you are not into testing cells, don't ever spend $350 on a charger! I bought it for the purpose of being able to test cells...like I present here. I've used my Klein tools $140 clamp on amp meter and a Chinese made amp meter that I trust to confirm that the ICharger is reading current correctly. They all agree...so I'm pretty sure that if the iCharger says 5.5 amps, that I'm really doing 5.5 amps...or whatever is the amperage.

My iCharger over the past year has charged and discharged something like 2000-3000 LION, LIFE and LIPO cells of various types and ages. I have a pretty good "feel" for what I should get from a cell.


This is my battery holder set up on the iCharger for all test results shown below. IE: 4S4P

BP%20cells%20in%204S%20holder.jpg


My settings on the iCharger for all the below results are discharge to 3v and charge to 4.1v at 3.4 amps.
My expectations are for 4P to see 20,000 to 20,400mah.

I've noticed the 25 BP cells I have don't ever charge to 4.1v. They charge to 4.06v. This will effect the capacities I'm seeing! The 600 brand new Panasonic cells I just bought, with no change on the charger at all, charge to 4.08 to 4.1 volts.

4P or 1/4th the Ir of a single cell, The iCharger reads 12.5 mOhms or 49 mOhms per cell at 3v per cell. I have an ISDT D2 and a couple of battery testers that test Ir. I'll confirm with them later. I'll check again at 4.06v per cell. As a cell charges or discharges, it's Ir will also change. The extremes of charge are the best indicator for Ir variance.

First discharge to 3v. 18,947 mah or 4736 mah per cell...a little low IMHO. I really want another 1000mah.

BP%201%201st%20full%20discharge.jpg


First charge from 3v to 4.1v. 19,047mah or 4761 mah per cell is better, but still feels 1000mah low to me.

BP%204%202nd%20full%20charge.jpg


Second discharge to 3v. 18,991mah or 4747mah per cell...pretty close to the first discharge. I call that a pattern.

BP%203%202nd%20full%20discharge.jpg


final charge at 3.4 amps...19,178mah or 4794 mah per cell.

BP%20charge%209amps.jpg
 
Good info Electricgod

My test with Zktech ac-20 today is in line with what Pajda stated. The "real word test" of 4.1V to 3V at 5A discharge gave me 4460mAh. Another test at a 3.4A discharge of 4.1V to 3V gave me 4539mAh.

Now I feel we should not overlook one other thing when comparing the Panasonic 3400 mAh to BP Swing 5300. That is the continuous discharge rating. The BP Swing 5300's have a continuous discharge rate of 13A. The discharge rate for the Panasonics NCR18650B that I have found is 4.9A. So if you compare two of the Panasonics in parallel to the BP's you get 9.8A continuous discharge. Lower discharge rating usually does mean higher mAh which of course happens with two of the Panasonics in parallel compared to one BP Swing 5300. And there is also the cost issue of what two of the Panasonics will cost you compared to the BP Swing 5300's.

Good stuff folks ...and as always Electricgod extremely documented and detailed. Always great to cut through the "unreal" marketing.
 
Headrc said:
Good info Electricgod

My test with Zktech ac-20 today is in line with what Pajda stated. The "real word test" of 4.1V to 3V at 5A discharge gave me 4460mAh. Another test at a 3.4A discharge of 4.1V to 3V gave me 4539mAh.

Now I feel we should not overlook one other thing when comparing the Panasonic 3400 mAh to BP Swing 5300. That is the continuous discharge rating. The BP Swing 5300's have a continuous discharge rate of 13A. The discharge rate for the Panasonics NCR18650B that I have found is 4.9A. So if you compare two of the Panasonics in parallel to the BP's you get 9.8A continuous discharge. Lower discharge rating usually does mean higher mAh which of course happens with two of the Panasonics in parallel compared to one BP Swing 5300. And there is also the cost issue of what two of the Panasonics will cost you compared to the BP Swing 5300's.

Good stuff folks ...and as always Electricgod extremely documented and detailed. Always great to cut through the "unreal" marketing.
Click to expand...

The BP cell has far higher C rate than the Panasonic cell for sure! The Panasonic cells are 1.4C, not 2.4C like the BP's. For this first test I wanted to compare 1C charge and discharge on the Panasonic cells with 4 BP cells in parallel. The idea was to get a feel for what the BP cells can do against something I just tested 600 of. Later on, I'll test 1P. And yes...ANY cell at well under it's C rating will do better than AT it's C rating.

I'm deliberately ignoring price point ATM. I want to deal with just what the cells are doing. Not everybody will get These cells at .07 cents per mAh.

The iCharger can't discharge at 4P and 2.4C or 9.6 amps. ICharger specs say 40 amps for 1S, but I've tried and max discharge I've ever seen is 7 amps. Marketing hype? So when I do 1C discharge tests on the BP cells, it will be at 1P, not 4P.
 
Totally understood ...and I like the way ya think ... must be that real first name! :) Anyways ...I was just wanting to point out that there are always other things to consider when comparing cells ...unless the specs really are the exact same.
 
Doing a full capacity test is not done frequently enough to "damage" cells, whether following vendor max specs like 2.75-4.2V or a "gentler more normal" 3.2-4.1V is a personal choice.

As long as you are precise & consistent.

Of course in testing for longevity, even gentler 3.7-4.05V would be better, but still destructive testing at say 1000 cycles.

IMO the baseline performance of a battery should be evaluated at low currents first, say 0.2C charging and 0.5C discharging.

Then the peak discharge-rate vs V sag & heat rise can be done separately, longevity is pretty much irrelevant for those use cases.
 
Does anybody understand what problem does ElectricGod have with Boston cells? He measured capacity 4761 mAh in the range 4.1V-3V with 0.85A discharge current per cell. This equals to ca 90% DoD and this result is completelly fine for this cell. If you need rated capacity from each cell on the market you have to use 100% DoD range and 0.2C discharge rate. In this case it is 4.2V-2.75V and 1A and only then you will get rated 5300 mAh.
 
I wanted another 1000mah per cell doing my "standard use" test, but that wasnt a complaint, just an expectation based on a feeling of what I thought I should get.

I'm now doing tests down to 2.75v and at .2C discharge. No one would ever use these cells like this since it's a completely unrealistic use case, but hey if I actually get 5300mah per cell...well OK. I'm not saying BP is any better or worse than anybody else in this regard. ALL LION makers use similar kinds of silly testing to "get" the capacities they advertise for their cells. no one in the real world would EVER use LION cells in this manner. IMHO...advertised capacity ought to be at 1C charge/discharge and at actual real world use case voltages.

I'll post my results...lol...next year. .2C will take a very long time at 4P.
 
A portable powerpak for running an efficient notebook, tablet, charging phones.

Few lights, a couple fans while camping, in
a vehicle or on a boat.

Even a 12V compressor fridge, often only averages 4A or so.

Flashlights, other gadgets.

Really, any use case not involving propulsion.
 
Well that was epic...OK no not really. This is discharge on 4P at .2C. 19,756 mah or or 4939 mah per cell is a bit short of 5300mah. I'll do a charge at .7C and another .2C discharge just to be sure. Still...even if they end up with the capacities I've already demonstrated, I'd buy more of these cells for sure! The voltages displayed are recovery. The cells discharged down to 2.75v each.

P1040422.jpg
 
ElectricGod said:
.. or 4939 mah per cell is a bit short of 5300mah. The voltages displayed are recovery. The cells discharged down to 2.75v each.
Click to expand...

This value is from 4.1V-2.75V range or full range 4.2V-2.75V?
 
Pajda said:
ElectricGod said:
.. or 4939 mah per cell is a bit short of 5300mah. The voltages displayed are recovery. The cells discharged down to 2.75v each.
Click to expand...

This value is from 4.1V-2.75V range or full range 4.2V-2.75V?
Click to expand...

You do make a good point...I charged to 4.1v...not 4.2v.
So you think that 4.2v would get that missing 360 mah?
 
I dont know if you are familiar with the “Capacity Mapping” of cells that ES member Drk Angel did a few years back, but that test process did show that some cells has considerable mAh capacity between 4.1 and 4.2v.
EG..
https://endless-sphere.com/forums/viewtopic.php?f=14&t=54202&start=25#p1111325
IN|R18650-25 Capacity Bar Graph from .2C discharge graph

Image
 
Yes for capacity testing best to stick to the vendor spec top voltage whatever it is, and even hold a CV/ Absorb stage until accepted mA falls to say .01C if they don't give an endAmps stop-charge spec.

That way the starting "100% Full" is a fixed benchmark and does not vary by charging C-rate.

Yes this is not as high as you want to go, for longevity in normal usage cycling, nor sit there for any length of time.

As the bottom "0%" benchmark, 3V is really as low as I'd go myself, and also not let the cells sit there for any length of time.

I doubt any significant mAh reside between 2.5V and 3V.
 
Swing 5300 Capacity map
Minimal discharge line shows best capacity between 3.50V and 3.60V.
Seems to be no usable capacity below 3.20V.
Optimal static discharged voltage looks to be in the 3.30-3.40V range.

Swing 500.jpg
 
DrkAngel said:
Swing 5300 Capacity map
Minimal discharge line shows best capacity between 3.50V and 3.60V.
Seems to be no usable capacity below 3.20V.
Optimal static discharged voltage looks to be in the 3.30-3.40V range.

Swing 500.jpg
Click to expand...

That chart shows that capacity is pretty linear all the way to 4.2v. Most LION cells are not adding much above 4.1v. It also looks like you drop off fast below 3.2 volts. There's not much use running the pack down below 3.2v per cell.
 
Added scale to measure mAh incrementally.

Swing 500.jpg

4.2 - 4.1V 100mAh
4.1- 4.0V 450mAh
4.0 - 3.9V 450mAh
3.9 - 3.8V 500mAh
3.8 - 3.7V 525mAh
3.7 - 3.6V 700mAh
3.6 - 3.5V 1100mAh
3.5 - 3.4V 650mAh
3.4 - 3.3V 380mAh
3.3 - 3.2V 130mAh
3.2 - 3.1V 80mAh
3.1 = 3.0V 40mAh

Using Paint
Created scale from 1064mAh
Compered 10 to 4 segments
10/4 - shrunk 40%
1000/1064 - shrunk to 94% for accurate scale
copied and pasted to original picture
"copied" and dragged to measure between voltage lines to measure mAh
 
ElectricGod said:
That chart shows that capacity is pretty linear all the way to 4.2v. Most LION cells are not adding much above 4.1v. .
Click to expand...
No. You are not reading the chart correctly..
Between 4.1 and 4.2v. There is only approx 80mAh capacity..
Whilst between 4.0 and 4.1v there is approx 500mAh.
And there is 1000+ mAh available between 3.5 and 3.6v...
..far from linear
But, that is all at 1.06A discharge rate.
If you load them at 10.0A you would have to run them down to 2.8v to use last 600mAh of the capacity below 3.0v
 
A completely different analysis, but to me more useful.

Resting isolated voltage on the Y axis.

Capacity at each voltage - mAh and true usable SoC% - measured by precisely timed CC-load discharge testing,

rather than relying on coulomb-counting.

Should be the same chart & graph, whether measuring on the way up (incrementally interrupted charge cycle) or down (discharge cycle)
 
What a discussion, guys! Love things like that!

So, here is the 0.2C/1.06A discharge map starting at 4.179V (the voltage of the cell charged to 4.20V/100mA cut-off and left 1hr):
4.1V: 98mAh
4.0V: 552mAh
3.9V: 1004mAh
3.8V: 1527mAh
3.7V: 2027mAh
3.6V: 2763mAh
3.5V: 3850mAh
3.4V: 4575mAh
3.3V: 4966mAh
3.2V: 5131mAh
3.1V: 5207mAh
3.0V: 5252mAh

So in 3.0-2.75V range there is only 66mAh or 1.24% of capacity stored.
 
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