Zippy/ Flightmax / Turnigy/ Blue lipo testing (pt 2)
- Thread starter johnrobholmes
- Start date
I was just thinking about that...and I do think I know
All together I had 3 packs with cells below 2v, 2 of them I charged super slowly at like 50mah (it took days) and are cycling and testing 100%. The 3rd one I was getting cocky about recovering the others so I just threw it on the charger and hit it with 1c -2c charging right away.
Not enough data points for a solid conclusion. But it kind of makes sense that gas production would be avoidable at very low rates but not at higher rates in the chemical reaction that is a (over-discharged) lipo cell
All together I had 3 packs with cells below 2v, 2 of them I charged super slowly at like 50mah (it took days) and are cycling and testing 100%. The 3rd one I was getting cocky about recovering the others so I just threw it on the charger and hit it with 1c -2c charging right away.
Not enough data points for a solid conclusion. But it kind of makes sense that gas production would be avoidable at very low rates but not at higher rates in the chemical reaction that is a (over-discharged) lipo cell
mwkeefer
1 MW
Someone here (I won't name names) actually lances their puffy packs to release the built up gasses at the edge folds.
I've done it and not caused a fire, but those cells are very much lower capacity about 1/5th lost.
These things will drop like stones (seems to be a common thread amongst everyone's experience) from 3.5 into oblivion if allowed.
What sort of useable capacity were you seeing on the 5800 size packs in use?
I've got packs here with hundreds of cycles on them and still no puffing, then I've got some which went off the cliff at some point (below 2.9-2.5 depending) due to either an old beeper (BM6) or somthing else I screwed up and miscalculated... those packs are all puffy!
-Mike
I've done it and not caused a fire, but those cells are very much lower capacity about 1/5th lost.
These things will drop like stones (seems to be a common thread amongst everyone's experience) from 3.5 into oblivion if allowed.
What sort of useable capacity were you seeing on the 5800 size packs in use?
I've got packs here with hundreds of cycles on them and still no puffing, then I've got some which went off the cliff at some point (below 2.9-2.5 depending) due to either an old beeper (BM6) or somthing else I screwed up and miscalculated... those packs are all puffy!
-Mike
Hyena
10 GW
Ampeater could you add or substitute one of the tests for a charge to 4.15v and discharge to 3v ? That's how many of us are using ours, although most of us rarely take them to the 3v LVC - maybe 3.3 would be more realistic?
You could probably do away with with the 4.3 or 4.0v, I don't think any of us routinely over or under charge them that much.
4C seems like a good load too, for most of us running 10ah packs that's a 40 amp load, which would be a good average of cruising at maybe 20-30 amps and short bursts of acceleration at several times that.
Your tests sound cool, I look forward to the results
You could probably do away with with the 4.3 or 4.0v, I don't think any of us routinely over or under charge them that much.
4C seems like a good load too, for most of us running 10ah packs that's a 40 amp load, which would be a good average of cruising at maybe 20-30 amps and short bursts of acceleration at several times that.
Your tests sound cool, I look forward to the results
Hyena said:Ampeater could you add or substitute one of the tests for a charge to 4.15v and discharge to 3v ? That's how many of us are using ours, although most of us rarely take them to the 3v LVC - maybe 3.3 would be more realistic?
You could probably do away with with the 4.3 or 4.0v, I don't think any of us routinely over or under charge them that much.
4C seems like a good load too, for most of us running 10ah packs that's a 40 amp load, which would be a good average of cruising at maybe 20-30 amps and short bursts of acceleration at several times that.
Your tests sound cool, I look forward to the results
I'm torn between real world tests and theoretical tests with nice linear variation with my parameters that you could easily graph to show trends (changing cycle live vs voltage)....you could extrapolate 4.15 from a graph
I know 4.3v isn't very realistic, but aren't you a little curious to see you many cycles you could REALLY get? If you didn't mind smoking your cells? This is an unusual opportunity to get data that would otherwise be very expensive. Who knows what I'll find
I'm also having second thoughts on the 4c charging rate...I wanted to be able to fit 2x full cycles per hour, 48 per day, to be able to fit 500 into a reasonable time (and really, I'd like to see 1000+ on at least one of these tests). But 1c charging is more realistic for mine, and most peoples ebike applications. Maybe 2c will be a happy medium?
I can always run more tests....
Hyena
10 GW
That's true, assuming the relationship with charge voltage is somewhat linear - which it may well not be. The discharge curve certainly isn't too linear! I guess if you're doing 4.2 and 4.1v charges we will know that it falls somewhere in between. What will be interesting is just how much extra life you get from lower charge voltages. I can't remember who posted it (I think it was Gary) or the exact details but you supposedly get a much longer life from them wiht a 4.15v charge vs 4.2v.AmpEater said:
1C charging is probably more representative of how most are used (in reality most are probably charging at less) but again for the sake of completeness it'd be interesting to charge at 1C and 2C and see how it affects the life. I for one would be happy to contribute towards the cost of another pack for you to test, over and above the circumstances that you are interested in testing for your specific applications.
Another data point which will be interesting to monitor is how the cells recover after discharge. Are you leaving each cell physically connected in series within the pack and bulk charging with balacing occuring during and at the end ? As the tests continue some of the cells will start to give out early, and likewise when recharging some will probably take a charge quicker and will be subjected to being shunted while the others are catching up. Or are you charging each cell individually ?
liveforphysics
100 TW
There are handful of manufacture graphs for LiCoO2 LiPoly batteries (same as RC lipo) that show a massive improvement of 10x the number of cycles by switching from a 4.25 HVC to a 4.125HVC. I know it's hard to imagine 0.125 difference could matter so much, but I would LOVE to get some real world data.
I would also absolutely love to get some 4.3-4.4v HVC cycle data, because if you're going to do an e-bike race or some capacity/weight critical application, you can cram an extra 1-1.5Ah or more into a 5Ah cell by jumping up the HVC, and when discharging, you get it all back out. But what I've not tested is how fast that decreases the life cycle. If you can still get a hundred cycles charging to 4.4v, then it would be totally worth the extra capacity for race events and things (and charge to 4.1v 99% of the time).
I would also absolutely love to get some 4.3-4.4v HVC cycle data, because if you're going to do an e-bike race or some capacity/weight critical application, you can cram an extra 1-1.5Ah or more into a 5Ah cell by jumping up the HVC, and when discharging, you get it all back out. But what I've not tested is how fast that decreases the life cycle. If you can still get a hundred cycles charging to 4.4v, then it would be totally worth the extra capacity for race events and things (and charge to 4.1v 99% of the time).
Hyena said:
I'd love to have more data points. Even picking those 6 tests was difficult, I can think of 100 to do. It would be great to be able to repeat the same set of tests at 1c, 2c, 4c....as well as 1c charge 2c discharge, .5c charge, etc, etc...But it's probably best with a limited budget to "throw away" to look for big trends
If you think about how many dollars it costs to run a bunch of tests compared to the potential value of that data...its not much. When I just did the math and saw how much I was paying per cycle
I realized I can't afford NOT to know some very specific info about cycle life. I actually cut the circuit board apart with tin snips to preserve enough tab to get a good grip on with my leads. I like having single cells to test...no balance issues....3.3v means the cell is at 3.3v. Plus its not nearly as big a strain on the power supply. I could cycle 8 single cells for the same power load as a single 8s pack.
liveforphysics said:There are handful of manufacture graphs for LiCoO2 LiPoly batteries (same as RC lipo) that show a massive improvement of 10x the number of cycles by switching from a 4.25 HVC to a 4.125HVC. I know it's hard to imagine 0.125 difference could matter so much, but I would LOVE to get some real world data.
I would also absolutely love to get some 4.3-4.4v HVC cycle data, because if you're going to do an e-bike race or some capacity/weight critical application, you can cram an extra 1-1.5Ah or more into a 5Ah cell by jumping up the HVC, and when discharging, you get it all back out. But what I've not tested is how fast that decreases the life cycle. If you can still get a hundred cycles charging to 4.4v, then it would be totally worth the extra capacity for race events and things (and charge to 4.1v 99% of the time).
I'm pretty sold on there being a major life cycle improvement by limiting peak voltage. I remember the very thorough MK battery (lead acid) literature showed a factor of 2 life cycle difference just by charging to 14.3 instead of the recommended 14.2v. And I know that its common practice in consumer electronics to sacrifice battery capacity for an increase in lifetime by staying in the middle SOC range. What remains to be seen is exactly how much in these turnigy cells.
But I wouldn't be too surprised to find that life is nearly as good at the "design voltage" of 4.2v either. Ahh! the suspense...
I'm amazed at the charge eff. of these cells. I see it put 5420 mah in....and you get 5415 mah out! Really unbelievable coming from lead where you overcharge by 10% Ah wise, and charge eff. is around 70% due to the large voltage swing from charge to discharge (high IR I've come to understand..)
mwkeefer said:
I've just recently gotten the cells. I'm new to lipo
But the limited playing around I've done shows around 5300mah if charged from a conservative 4.1v to 3.3v. I want to cycle test all 30 packs before I assemble them together and start depending on themswbluto said:
All three arrived with one cell significantly lower than the others....but I think the first two were partially my fault because I left cell-logs connected for 12 hours or so and that drained already low cells down below 2v. The third, now puffy, did arrive even lower than the others. Around 1.6v IIRC.
adrian_sm
1 MW
liveforphysics said:
Have you got any links ?
vanilla ice
1 MW
For anybody wanting to tweak the HVC on the cheap non-adjustable accucel chargers to 4.05 or 4.15v or whatever.. you can set to LiIo (4.1v) and purposely calibrate them off 0.05v if you wanted.
This is the 6, probably similar can be done for the other accucels. http://www.youtube.com/watch?v=9hvR7dGAkEo
This is the 6, probably similar can be done for the other accucels. http://www.youtube.com/watch?v=9hvR7dGAkEo
dogman dan
1 PW
Wow, sleep a few hours, miss two pages.
Re Hyena's post about soldering to paralell packs, here's a crimp sleeve that can connect a few large wires. http://endless-sphere.com/forums/viewtopic.php?f=14&t=19058
Re Hyena's post about soldering to paralell packs, here's a crimp sleeve that can connect a few large wires. http://endless-sphere.com/forums/viewtopic.php?f=14&t=19058
GCinDC
100 MW
I'm curious about the cliff. I've been dangerously over it a couple times, where my 20s pack was reading 66V, and I felt the nauseating sag with each acceleration...
When I then throttled it, what did the voltage drop to? 60V? Driving in traffic, I can't be watching the CA.
I'd love to see a graph of two lines: resting vs load voltage for each 1Ah used of the pack... Nice to know when approaching the cliff, esp knowing some cells may be closer to the point of no return! Though obviously, by the time I hit 66V, I'm pedaling on the sidewalk... :lol:
As for my 20S2P 20C Turnigy pack, I've got 270 'cycles' on it (usually charged after 5Ah or 1/2 usage), ~1900 miles, and if it's lost any punch from Day 1, I can't tell! The thing is a BULL.
Wakes me up in the morning!
In other news, I got another order of Blue Lipos (ordered Monday, shipped Tues, delivered Fri) - 5 x 3s 2200mah packs. I'm now debating how to wire them for my 7s5p BionX extension/replacement pack.
Should I make a 7s pack and THEN parallel them? Or should I make a 3s5p pack, and 4s5p and THEN serialize it. I'm leaning toward that, since:
- It might be handy to have individual an 4s 11Ah pack and a 3s 11Ah to add to my ride if the bionx thing doesn't pan out
- I can easily pop the 3s or 4s pack onto the icharger to do a nice balance charge.
BTW, Anyone know if I can balance charge 7s pack with two balance taps on the iCharger 1010B+? The JST-XH connection dongle has a lot of connectors, but can it only use 1 row at a time? The console allows 7s programming tho... Sparks on the way?
When I then throttled it, what did the voltage drop to? 60V? Driving in traffic, I can't be watching the CA.
I'd love to see a graph of two lines: resting vs load voltage for each 1Ah used of the pack... Nice to know when approaching the cliff, esp knowing some cells may be closer to the point of no return! Though obviously, by the time I hit 66V, I'm pedaling on the sidewalk... :lol:
As for my 20S2P 20C Turnigy pack, I've got 270 'cycles' on it (usually charged after 5Ah or 1/2 usage), ~1900 miles, and if it's lost any punch from Day 1, I can't tell! The thing is a BULL.
Wakes me up in the morning!In other news, I got another order of Blue Lipos (ordered Monday, shipped Tues, delivered Fri) - 5 x 3s 2200mah packs. I'm now debating how to wire them for my 7s5p BionX extension/replacement pack.
Should I make a 7s pack and THEN parallel them? Or should I make a 3s5p pack, and 4s5p and THEN serialize it. I'm leaning toward that, since:
- It might be handy to have individual an 4s 11Ah pack and a 3s 11Ah to add to my ride if the bionx thing doesn't pan out
- I can easily pop the 3s or 4s pack onto the icharger to do a nice balance charge.
BTW, Anyone know if I can balance charge 7s pack with two balance taps on the iCharger 1010B+? The JST-XH connection dongle has a lot of connectors, but can it only use 1 row at a time? The console allows 7s programming tho... Sparks on the way?
El_Steak
10 kW
vanilla ice said:
Thanks for the info! I was actually avoiding those chargers because I tought they were limited to 4.1 (LiIo) and 4.2 (LiPo) max volts only. Hopefully this trick works with their new 4 in one way charger as well !
I'm becoming more and more interested in the 10C+ cyclic life. Problem is....cycle testing a 5.8ah cell at 10c requires 58A of current, and the most any of the cycle chargers can dish out right now is 30A. So I'm thinking about buying some 2200mah cells and putting them through
Charge 4.1v -> 3.3v at 1c / Discharge 3.3v -> 4.1v at 10c
Charge 4.1v -> 3.3v at 10c / Discharge 3.3v -> 4.1v at 10c
And just working on the assumption that they are essentially the same cells / chemistry.
And, while I'm at it, I think I'm going to pick up 2 1000mah cells for some 30C testing
Charge 4.1v -> 3.3v at 1c / Discharge 3.3v -> 4.1v at 30c
Charge 4.1v -> 3.3v at 10c / Discharge 3.3v -> 4.1v at 30c
Which should be fun because it only costs dollars and only takes hours or at most a day or two
I've also seen an anecdote by a seasoned lipo flyer that achieves over 1000 cycles that swears by a .08c charge rate. I think I'd round it up to .1c to make things easier...which is "overnight", so if it did indeed offer significant life improvement it would be useful to large EVs (like mine). So I'm contemplating buying a "whimpy" little 6 or 10a cycle charger and sticking it in the corner for, oh, months and months, and doing
Charge 4.1v -> 3.3v at .1c / Discharge 3.3v -> 4.1v at 1c
If it actually hit over 1000 cycles it would take over 500 days to complete. At that point the seasonal temperature swings would be a big issue, but I guess it doesn't get any more "real world" than that. But it's got me thinking about the need for a climate controlled, fire proof place to charge, store, and cycle test lithium cells. Obvious choice - shipping container, aka, The BatteryBunker
- Rugged steel structure, steel walls
- Non-flammable insulation, perhaps on the outside (I've got that covered already, side project)
- Climate controlled (window mount ACs/heat pump, cheap and plentiful)
- Fire suppression system (heat activated dump extinguishers exist specifically for electrical fires in enclosed spaces, fairly cheap)
My shop is packed full already. I've got plans underway in the near future for a full size shop made from recycled shipping containers, and I've been considering buying one sooner than that as overflow space. Just thinking out loud again....
Charge 4.1v -> 3.3v at 1c / Discharge 3.3v -> 4.1v at 10c
Charge 4.1v -> 3.3v at 10c / Discharge 3.3v -> 4.1v at 10c
And just working on the assumption that they are essentially the same cells / chemistry.
And, while I'm at it, I think I'm going to pick up 2 1000mah cells for some 30C testing
Charge 4.1v -> 3.3v at 1c / Discharge 3.3v -> 4.1v at 30c
Charge 4.1v -> 3.3v at 10c / Discharge 3.3v -> 4.1v at 30c
Which should be fun because it only costs dollars and only takes hours or at most a day or two
I've also seen an anecdote by a seasoned lipo flyer that achieves over 1000 cycles that swears by a .08c charge rate. I think I'd round it up to .1c to make things easier...which is "overnight", so if it did indeed offer significant life improvement it would be useful to large EVs (like mine). So I'm contemplating buying a "whimpy" little 6 or 10a cycle charger and sticking it in the corner for, oh, months and months, and doing
Charge 4.1v -> 3.3v at .1c / Discharge 3.3v -> 4.1v at 1c
If it actually hit over 1000 cycles it would take over 500 days to complete. At that point the seasonal temperature swings would be a big issue, but I guess it doesn't get any more "real world" than that. But it's got me thinking about the need for a climate controlled, fire proof place to charge, store, and cycle test lithium cells. Obvious choice - shipping container, aka, The BatteryBunker
- Rugged steel structure, steel walls
- Non-flammable insulation, perhaps on the outside (I've got that covered already, side project)
- Climate controlled (window mount ACs/heat pump, cheap and plentiful)
- Fire suppression system (heat activated dump extinguishers exist specifically for electrical fires in enclosed spaces, fairly cheap)
My shop is packed full already. I've got plans underway in the near future for a full size shop made from recycled shipping containers, and I've been considering buying one sooner than that as overflow space. Just thinking out loud again....
And you know, the real world relevance of that information would also be pretty much obsolote, since in that 2 years or so, battery tech will again have moved forwards.AmpEater said:
Anything that gives 1000 "full" use cycles with less than 90% drop of capacity pretty much means it will most likely live through the battery technology advances to the point that it's price will probably drop because of more advanced tech being cheaper per kWh with better qualities than the fact that it is 2nd hand and used ... I mean in EV use. Sure there are exceptions (messenger service EV vehicles and such in business use), but for commuters or shopping carts? 1000 _full_ cycles is a LOOOT of use.
ewert said:
Definitely a good point. Who knows if anyone will even care if lipo lasts 1000 cycles 500 days from now. But I'm pretty sure I will.... My plan is to replace gasoline entirely in my life in, oh, say starting 2-3 weeks from now (finally, it's been a long time coming). And since I've already got lipo I'm planning on making them last a few years at least. So any data that I get at an accelerated pace compared to my usage of my cells should be useful to extend their lifetime
And when everyone is going gaga over the latest and greatest maybe I'll be there to snatch their old packs up cheap knowing I've got years of use left in them
mwkeefer
1 MW
Okay... On my oldest pack which hasn't gone off a cliff ever, I just checked my cycle log... Just over a year old, average 2 cycles per day so I'm at 720 cycles and still able to pull 10ah+ from the pack at 3-4c constant peaks. I would guesstimate another 300-700 cycles before hitting the 80% mark - they are 15c/20c turnigy 5ah in 15s2p and are always charged at 2/3C to between 4.15/4.16v
hope that helps, anyone else with similar results?
-Mike
hope that helps, anyone else with similar results?
-Mike
Shipping update: The package that was sent on May 5th, and apparently resent on May 25th, has arrived today, on June 21. I originally chose "Air mail"(Slow-mo method) but it appears the package has the label "EMS Speedpost singapore", so I'm going to guess they routed their packages to Singapore to get through the local EMS blockade. My past hobbyking packages have shipped from Hong Kong.
mwkeefer
1 MW
More recent shipping update:
I ordered an ET Video OSD Pro expander along with a pair of 3S Zippys 5000mah and one 2S on 6/10/2010 via EMS and they arrived this morning via EMS, so total lag time was 10 days (assuming they were shipped the following day from the order) which is fairly acceptible since they have to bounce through singapore now... Just posting to give everyone an idea of lead time for receiving HobbyKing stuff via EMS currently.
-Mike
I ordered an ET Video OSD Pro expander along with a pair of 3S Zippys 5000mah and one 2S on 6/10/2010 via EMS and they arrived this morning via EMS, so total lag time was 10 days (assuming they were shipped the following day from the order) which is fairly acceptible since they have to bounce through singapore now... Just posting to give everyone an idea of lead time for receiving HobbyKing stuff via EMS currently.
-Mike
GGoodrum
1 MW
oooh, more LiPo porn... :lol:
Hyena
10 GW
Move over ladies, there's a new lipo whore in the parlor :lol:
Is that a spark where 2 of the leads on your charger have shorted on the bench leg or just the flash from the camera ?
Is that a spark where 2 of the leads on your charger have shorted on the bench leg or just the flash from the camera ?
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