A123 20Ah Quebec Group buy(Canada) cells ARRIVED 24.57$/cell

[Doctorbass]

So at what point is it reasonable (as in what testing/use is required to be done) to say that these sells live up to the hype and are a long lasting bargain?

Try finding better... :wink:

 

[ohzee]

At this Price they are a bargin.

I Have a friend with an off grid setup using A123's His expecting 10 years of use with the way he has set his system up.
I certainly think its possible

I was wondering if that would be possible with these cells.. it sure seems like a good way to do it.

You have any details on his setup he do a blog or anything ?

 

[nechaus]

Yeah i can get some, they are a123 18650 cells, his doing 40 % dod at the most on a long non sunny week, the a123 setup is in conjunction with solar, and up to .5c discharge with the huge capacity, apparently its possible to reach the 10,000 cycle mark with these cells with an amazing bms. Its such a long time

 

[Wheazel]

So at what point is it reasonable (as in what testing/use is required to be done) to say that these sells live up to the hype and are a long lasting bargain?

Try finding better... :wink:

That will probably not be possible at this time, and my question was not a trollattempt.
I am merely interested to know from you with extensive battery experience.
Is there a risk that cells can start to die suddenly even if treated right,
or is it more or less certain that all of them will last a long time after initial tensiontests and loadtests turn out well?

 

[Doctorbass]

So at what point is it reasonable (as in what testing/use is required to be done) to say that these sells live up to the hype and are a long lasting bargain?

Try finding better... :wink:

That will probably not be possible at this time, and my question was not a trollattempt.
I am merely interested to know from you with extensive battery experience.
Is there a risk that cells can start to die suddenly even if treated right,
or is it more or less certain that all of them will last a long time after initial tensiontests and loadtests turn out well?

Ok i'm sorry for the too short answer :lol:

Here is what i think:
These cells was tested and tested and tested.. They are probably one of the most tested LifePo4 cells by independent tester, RC user and company … the Chevy Volt builder also have choosed them. Well.. the LiFePo4 nano chemistry that A123 developed is the lifepo4 best chemistry ever made.

I strongly believe that these cells will last 10 years no prob. Now about these lower price grey market cells I can’t say but I would be really surprised if they would not.

There is 3 important factors about the cell health: the IR, The capacity and the current leakage ( the self discharge)
From now I have NOT seen any negative fact about these 3 parameters on the cells I got.

So I would believe they are like the new one except that their nominal capacity migh be a bit lower due to the manufacturing tolerances probably.

For long life use, every lithium cells have some preferences. They don’t like heat so keep them between 10 and 25 celsius to prolong their life. They don’t like being too much time at full SOC and being depleted so keep them in a range between 80-20% SOC.


Doc

 

[Fishmasterdan]

I would love to see your BMS and case set up when and if you build one!!!

 

[Mike B]

Doc, I have always been curious about real life longevity testing on A123's LiFePO. We agree, this chemistry is superb when compared to the competition. Have you seen any data out past 1000 cycles? And thanks for that video, awesome power. --Mike

 

[Spacey]

2P is enough and will be ok at 60mph too.

60mph is around 10kW so in 20s it's like 130A current so each cells will see 65A continuous wich is way below their stress point!

1p would do the job too.

Remember these can take 300A continuous!

Nice project! wich motor do you plan to use?

Doc

That's good to know as I don't think I could afford 60 of the cells...40 might be my limit.

I was thinking of buying either the Golden Motor 20KW BLDC motor or the Agni 95R motor

I know the Agni would probably be a better motor but the brushes in them put me off as they are not cheap....but then I don't know how long they would last?

 

[mistercrash]

Doc the data you provide for us is super cool, thanks again for this. But one thing I'm not thankfull for is you are giving me a reason to start thinking of spending money I don't have. :lol:

Can a 24S2P battery made of A123 20Ah pouches be run safely for a long time without a BMS if the pack is balance charged every time? I think it can but I just need to make sure. Since I got a quote on 48 cells at less than $25 per cell shipped, I'm thinking I should build a pack for my scooter and then sell the 14S16P pack I just built with konion cells.

 

[Doctorbass]

Doc one thing I'm not thankfull for is you are giving me a reason to start thinking of spending money I don't have. :lol:

I'm sorry, I know i've been responsible for probably hundreds thousand $$$ expenses since i posted everything i'm doing about ebike 8)

Can a 24S2P battery made of A123 20Ah pouches be run safely for a long time without a BMS if the pack is balance charged every time?

NO they do require BMS.

Unlike the konion, any lifepo4 will not last long time without balancing feature

Doc

 

[mistercrash]

Can a 24S2P battery made of A123 20Ah pouches be run safely for a long time without a BMS if the pack is balance charged every time?

NO they do require BMS.

Unlike the konion, any lifepo4 will not last long time without balancing feature

Doc

That's disappointing. I really thought that if I have 24S that's broken down to basically 4 6S that can be balance charged with two Hyperion 1420i chargers, and a LVC on the controller set to something like 65V, I could do it without a BMS. It's a bit like 700 sized RC helis running on 12S. There's no BMS on those things but the LVC is set conservatively and the lipos are balance charged every time and there's no problems there. I don't know, I'll take your word for it, I don't want to end up screwing 48 A123 cells. That would be a very expensive mistake for me. Thanks Doc.

 

[Andje]

mister, your solution will work just fine. Many of us using the more dangerous Lipo chems run without a BMS and bulk charge most of the time. I think you and Doc are confusing "balancing" with "BMS". As you say, if you give yourself a conservative overall LVC that you monitor or use a CA to control, then you won't kill them on discharge. If you use two Hyperions to charge, you can run either Bulk charge or Balancing charge, and if you go all the way to set up the Balancing for every charge cycle you will have a bulletproof solution. If you bulk charge then I would have some way of checking the individual cells every once in a while like the Battery Medics, or even just somewhere accessible you can stick a multimeter. Bulk charging, even on the Hyperion, runs the risk that one cell gets disconnected at some point in the charge/dishcarge and then screws all the others. That is the only scenario a BMS would avoid, and if you build your battery well its almost impossible to mechanically happen; more likely you would screw your pack with an electrically compromised cell, and if you test them properly first, again, almost impossible.
Of course I bow to DocB, but I think that while balancing your cells is important, the method is irrelevant, and the Hyperions are expensive precisely because they balance supremely well.

 

[mistercrash]

Thanks Andje,
I do respect Doc's knowledge and opinion very much. But I think you're right about saying that Doc thought I meant bulk charging which is not what my intention was. My intention would be to balance charge every time I recharge the battery, just like I'm doing for the konion pack I have now. It's working really well, the cells are all equal to each other. It does take a bit more time to recharge fully but that is not a problem for me.
I was disappointed and happy at the same time about Doc's answer, if it wasn't safe to do it that meant I save a thousand bucks But now I am contemplating spending money I don't have again. Heck! I even have a drawing made of how I want to do it :lol:

 

[999zip999]

It's the chance that one or more cells would drift over time with just bulk charging. My old Ping had to run without the bms twice for 2-3 weeks and all cells where will behaved. I just bulk charged to 60.3 with that 2a charger. Even that signalab has to be watched on the balance side it has it problems. Does signalab have hi discharge 12s bms like it's 16s ? Because it would be easyier for me to have 2- 12s batteries in some ways. Must make a cardboard box for battery size ( 's ). Two 36v chargers at 6amp. each. 36v40ah or 72v20ah choice. Need two 40amp. plus bms's. No for a basic 12s signalab. Sratching my head.

 

[cor]

For long life use, every lithium cells have some preferences. They don’t like heat so keep them between 10 and 25 celsius to prolong their life. They don’t like being too much time at full SOC and being depleted so keep them in a range between 80-20% SOC.
Doc

Hi Doc,
Do you know the temp spec of these cells?
Storage and operational limits?
Of course, I like to keep them long, but 25 deg C is not a realistic upper temp in many areas.

 

[MitchJi]

Hi,

That's disappointing. I really thought that if I have 24S that's broken down to basically 4 6S that can be balance charged with two Hyperion 1420i chargers, and a LVC on the controller set to something like 65V, I could do it without a BMS.

If you balance charge the pack with dual hyperion's and monitor the parallel groups with something like Celllogs you can do it safely.

they do seem like a great value but i think the test of time will be whether they swell and puff up and if the tabs end up being too fragile for the high vibrations they get exposed to on the vehicle.

Vibration won't be an issue with the tabs if the pack is properly built (cell bodies, tabs and wiring all vibrate together).

 

[battman]

This may tie in with Doctor Bass's comment about them not liking being at full SOC for much time - be wary charging these in cold temperatures!
I have a 3P24S pack of these in a motorcycle in Arizona.
I noticed a significant irreversible capacity loss (10%+) and increase in IR after fully charging these cells (3.6V) during cold spells (it was < 10 Celcius but not as low as 0C) over the past couple of winters. Cold weather like that is not so common in the low desert here, but might be a more frequent occurrence for other folks.

Note that the cells I have are the Cellman ones, not the more recently available 20AH A123.

For long life use, every lithium cells have some preferences. They don’t like heat so keep them between 10 and 25 celsius to prolong their life. They don’t like being too much time at full SOC and being depleted so keep them in a range between 80-20% SOC.
Doc

Hi Doc,
Do you know the temp spec of these cells?
Storage and operational limits?
Of course, I like to keep them long, but 25 deg C is not a realistic upper temp in many areas.

 

[999zip999]

battman how many charge cycles ?

 

[Doctorbass]

This may tie in with Doctor Bass's comment about them not liking being at full SOC for much time - be wary charging these in cold temperatures!
I have a 3P24S pack of these in a motorcycle in Arizona.
I noticed a significant irreversible capacity loss (10%+) and increase in IR after fully charging these cells (3.6V) during cold spells (it was < 10 Celcius but not as low as 0C) over the past couple of winters. Cold weather like that is not so common in the low desert here, but might be a more frequent occurrence for other folks.

Note that the cells I have are the Cellman ones, not the more recently available 20AH A123.

For long life use, every lithium cells have some preferences. They don’t like heat so keep them between 10 and 25 celsius to prolong their life. They don’t like being too much time at full SOC and being depleted so keep them in a range between 80-20% SOC.
Doc

Hi Doc,
Do you know the temp spec of these cells?
Storage and operational limits?
Of course, I like to keep them long, but 25 deg C is not a realistic upper temp in many areas.

ANY lithium cells DONT like to be charged in cold temp So it's not a matter of brand new grade A cells or rejected cells... it's a matter of physical and electrochemical conditions with lithium cells

If yuo read correctly the A123 documentations you will see that the recomanded temp during charging process is near the ambiant temp.

There is two things that happen in cold temp.. the IR of the cells is really high ( stressing the cell if charging at normal current) and the electro chemical interaction process during charging is les efficient from what i understod after reading the battery univercity documentations.

That's why every commercial EV have a battery warmer and an algorithm that manage the cell temp prior to begining the charging process.

About the 100% SOC stress, that's why they recommand to STOP the charging current once the cell reach C/20. as Otherwise it will make some corrosion on the anode, degrade it and increase their IR

Doc

 

[999zip999]

Should batteries sit a bit befor charghing for temp to even out or to rest s.o.c. ?

 

[Doctorbass]

Should batteries sit a bit befor charghing for temp to even out or to rest s.o.c. ?

Yes, the cell must reach a given temp before to be cahrged like any other lithium cells that are used in cold temp.

Doc

 

[nechaus]

I am ordering 150 of these babies..

god they are so cheap. cheaper than headways 15 ah cells. and that's shipped!!!!!


What bms are you ppl using for 24s?

 

[pgt400]

I am ordering 150 of these babies..

god they are so cheap. cheaper than headways 15 ah cells. and that's shipped!!!!!


What bms are you ppl using for 24s?

Better than headways too....check out mini bms.

 

[battman]

ANY lithium cells DONT like to be charged in cold temp So it's not a matter of brand new grade A cells or rejected cells... it's a matter of physical and electrochemical conditions with lithium cells

If yuo read correctly the A123 documentations you will see that the recomanded temp during charging process is near the ambiant temp.

Thanks, I understand the concept of reading documentation correctly. The only documentation available to me was the attached spec sheet which does not mention charging conditions. If you can post a link to the additional documentation you have that describes the recommended charging temperature then I promise I will read that correctly too.

View attachment A123 Systems AMP20 Data Sheet.pdf

battman how many charge cycles?"

I don't know how many charge cycles. I have drawn 5630AH from a 60A pack, which would be about 93 cycles if I fully depleted the pack between each charge, but I rarely even deplete the pack to 50% before charging.

 

[Doctorbass]

ANY lithium cells DONT like to be charged in cold temp So it's not a matter of brand new grade A cells or rejected cells... it's a matter of physical and electrochemical conditions with lithium cells

If yuo read correctly the A123 documentations you will see that the recomanded temp during charging process is near the ambiant temp.

Thanks, I understand the concept of reading documentation correctly. The only documentation available to me was the attached spec sheet which does not mention charging conditions. If you can post a link to the additional documentation you have that describes the recommended charging temperature then I promise I will read that correctly too.

battman how many charge cycles?"

I don't know how many charge cycles. I have drawn 5630AH from a 60A pack, which would be about 93 cycles if I fully depleted the pack between each charge, but I rarely even deplete the pack to 50% before charging.

All from Battery Univercity:

Many battery users are unaware that consumer-grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the pack appears to be charging normally, plating of metallic lithium can occur on the anode during a subfreezing charge. The plating is permanent and cannot be removed with cycling. Batteries with lithium plating are known to be more vulnerable to failure if exposed to vibration or other stressful conditions. Advanced chargers, such as those made by Cadex, prevent charging Li-ion below freezing.

Fast charging of most batteries is limited to a temperature of 5 to 45°C (41 to 113°F); for best results consider narrowing the temperature bandwidth to between 10°C and 30°C (50°F and 86°F). Nickel-based batteries are most forgiving in accepting charge at low temperatures, however, when charging below 5°C (41°F), the ability to recombine oxygen and hydrogen diminishes. If NiCd and NiMH are charged too rapidly, pressure builds up in the cell that will lead to venting. Not only do escaping gases deplete the electrolyte, the hydrogen released is highly flammable. The charge current of all nickel-based batteries should be reduced to 0.1C below freezing.

http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures


Doc