Hillhater
100 TW
Yes... but only at 0.2C discharge.thunderheart said:
If you look at the data for 2.5C (13A) discharge there is significant capacity (10+%) below 3.0v
..at the cost of cycle life !
Boston-Power Swing 5300 Li-ion cell test
- Thread starter thunderheart
- Start date
If you look at the data for 2.5C (13A) discharge there is significant capacity (10+%) below 3.0v
..at the cost of cycle life !
thunderheart
100 W
Hillhater said:
Exactly. 13.7% at 13A.
ElectricGod
10 MW
thunderheart said:
I guess your charger does logging. My Icharger does it too, but I didn't bother putting an SD card in it. That's nice information!
Essentially anything over 4.1v and anything below 3v is is of very limited value so there is no point in using the cells at above or below those voltages. That's pretty much what I've been saying all along.
ElectricGod
10 MW
I finally got that magical 5300mah these cells are advertised at. Of course, as I've pointed out all along, at this discharge rate and voltage levels, there's no real world application that will get you 5300mah. I charged to 4.2v and discharged to 3.75v at .2C. The voltage you see on the LCD is recovery voltage. 21,368mah at 4S = 5342mah per cell.
Hillhater
100 TW
Im not so sure..ElectricGod said:
You could build a 48v, 10 kWh , home storage backup bank (12s, 20p) which could be quite useful !
0.2C would be 1.0kW output... run freezer, lights , Tv etc
0.5C , (2.5kW) would run most household kit.
5 kW ability easy if needed.
Pajda
10 kW
ElectricGod said:
At least by my opininion you should start with this information/measurement
It confirms that you have cells in good conditions and your tester and fixture is also working well.And after that you should add measurement in your preferred voltage range with lower DoD and identify how many capacity/energy will you sacrifice for longer operational life of cells in your app. All of my points was about that you cannot expect to get rated capacity at lower DoD than 100% from any cell on the market. The 100% DoD (4.2V-2.75V in this particular case) is guaranteed by all manufacturers to be completely safe for long-time operation of the cell, but of course you should expect faster wear of the cell. Thats all. :wink:ElectricGod said:
This has been a very good, healthy discussion on the BP batteries. I think by now their capacity capability has surely been discovered. But if the topic is real world use ....all I can say is that the folks that I know that have used them have been very happy with their performance. That really is the issue in my mind. And with any of the current battery technology it is really what the application is and how you manage and use the batteries for that application that helps with accomplishing that satisfaction goal. I still feel they are an under rated and often overlooked choice. The 18650 format has become so prevalent and common that other alternatives are often not investigated. Thanks to all who have been contributing here ...this is what this forum is all about IMO.
ElectricGod
10 MW
Headrc said:
Doing the exact test BP did, I too got similar results.
I didn't ever think 5300 mah was in question...any more than I thought anybodies cell specs were in question.
It's the method used to get it...not really realistic for the use cases I'm likely to ever use. I think this is fairly common. Most people on ES are building EV's. We need current draw well over .2C. I try to average at 1C-2C. In my inbox today I got a PM from someone wanting my help modding their 300 amp BMS for 500 amps. They are seeing peaks well into 400 amps and the BMS shuts off as a result. LOL! Thank you J_haggerty for making my point for me!
Will the BP cells perform well? That wasn't really in question for me. I was pretty sure they would do fine. LION isn't exactly new tech. it's going to work pretty reliably regardless of manufacturer. I did have a couple of questions about soldering to them, but that's the worst of it.
So all in all...these cells will work out pretty nicely. And yeah...they get dismissed a bit much.
thunderheart
100 W
You know what? I really love this culture of discussion full of respect to each other. It's a pleasure to read you comments, guys! :thumb:
ElectricGod
10 MW
thunderheart said:
I WISH it happened a LOT more often! I have a couple of people that have been trolling me for the past year. All they do is leave disparaging comments and are always looking for something to criticize in anything I say. I have a motor thread that has been trolled so many times by them that I have personally gotten it shut down 4 times! I'd then ask the moderators to edit out everything they would say...it was all pointless bickering and negative jabs anyway. Another thread is no longer even searchable or posted anywhere...same thing. They just would NOT EVER stop. I reported one guy to the moderators over and over again. He's pretty smart, just arrogant and full of his own piss and vinegar. I haven't seen a post from him in a couple months now. I requested that his account get locked out. Seems the mods did me a favor.
But yes please...what you said and a lot more often please.
I have frequented a **lot** of listservs and discussion boards over the years, starting long before the web, or even the public internet.
The most successful forums are those where
Be NICE, i.e. respectful and kind
is the #1 rule, and rigorously enforced by mods, no matter how smart, knowledgeable or prolific the poster.
Doesn't mean smarmy touchyfeely all rainbows and kittens.
Just basic polite consideration, try to be gentle, focus on the issues, no insults.
Pretty obvious stuff our parents should have required of us before we went off the kindergarten.
Not that I do it all the time myself, but I don't mind being reminded. . .
The most successful forums are those where
Be NICE, i.e. respectful and kind
is the #1 rule, and rigorously enforced by mods, no matter how smart, knowledgeable or prolific the poster.
Doesn't mean smarmy touchyfeely all rainbows and kittens.
Just basic polite consideration, try to be gentle, focus on the issues, no insults.
Pretty obvious stuff our parents should have required of us before we went off the kindergarten.
Not that I do it all the time myself, but I don't mind being reminded. . .
ElectricGod
10 MW
john61ct said:
Yes...I agree.
Hypothetical situation:
Let's say I was not getting remotely close to 5300mah for these cells. I presented my results and nothing I did got me but 4000mah...even when testing exactly like BP did.
It is not unusual for people to attack the individual, their character or intelligence. "Clearly they are idiots or stupid or just don't have a clue"...etc. Nit pick everything they say and find fault in anything.
I find this sort of approach to be condescending and arrogant on the part of the person with that opinion. It's also 100% counterproductive and only serves to create offense. It is possible that there is an equipment issue or they really are legitimately NOT getting the results that others are getting. It happens. Bad or out of spec parts happen.
I've had this experience some time back with a batch of brand new mosfets I bought from Digikey. I tested every one of them and then double checked my results on other equipment. The numbers I was seeing matched up from both sets of tests. I posted those results on ES and was immediately attacked and called an imbecile. I presented my results, how I tested and again got nothing but attacks. After a while I just stopped bothering to post anything. I knew I didn't make any mistakes and that I had in fact received 40 mosfets that were not close to factory specs. It happens, no manufacturer tests every last part they make. Sometimes bad parts slip through. Nothing I said or presented got me anything other than personal attacks. I was vilified and the manufacturer (AOT) was lauded as perfect...uhhhh...OK....I disagree.
Anyway, I'm glad that didn't happen here. I wanted to test at practical values first and present them before going for the method to get the advertised cell capacity. The closest to that things got was questioning why I was testing at all...which was fine.
I value folks who do "consider the source" of technical specs ....and then spend the time to test those specs in a professional manner. It saves me time! So thank you for that ....and to others like Thunderheart who actually started this whole thread. Too many folks take marketing (like news) as the gospel and do not test the information they are given. It is a valued and under appreciated service when someone puts in the hard work to challenge that information, document how they did the testing and then offer it up for others ....for free! A big round of applause on my part goes out to those that do this.
krlenjuska
10 W
- Joined
- Feb 18, 2019
- Messages
- 94
I just found 4 Sonata 4400mAH in some ASUS battery pack. Big suprise for me
First time for me to see something like this.
First time for me to see something like this.
transposon
100 W
Thanks for all of the testing for these. What is the recommended max discharge rate for these before sag or heat becomes a problem? 1.5C? 2C?
transposon
100 W
Thanks Headrc.
I wish we had some temperature data to go along with this thread.
I wish we had some temperature data to go along with this thread.
