A123 AMP20M1HD-A Battery pack kit

[docnjoj]

Way to go, agniusm! This would allow soldering balance leads directly to the blocks. Definitely not as elegant as your connectors and traces but could save on costs of making the board, perhaps?
otherDoc

 

[agniusm]

docnjoj, this is for the end terminals, design remains the same . My concirn was end blocks 10mm. These were heating up while pulling lots of current. Copper copes with that easy.
EDIT: OK, here's what i am proposing:

I was doing some testing with copper today:

One cell in the last pack i build was hitting top limit very fast, while others was still at 3.3V so i decided to swap it. So here is some cell swap porn:

Strange cell out (#2)

and new one in

 

[jimw1960]

I am interested in getting one of your kits, but it has been a long time since I checked where for find a good source for the 20Ah A123 pouch cells. Could some of the users post some reputable sources. I was looking at A123rc.com and they have the cells for $32 each, but someone mentioned that they could buy them for $25. Any help would be appreciated.

 

[agniusm]

I got mine from victpower. People here buying from them. We did purchase some from onspower and they were all good, long tabs. One of my customers is trying to buy some from victpower, short tabs which looks like ok for my kit. Try to get in thouch with him and you might benefit from paying for postage half price. PM arkmundi

 

[docnjoj]

Yes that looks great for the 100 amp set! Thank you for showing how easy it was to change a cell out. That is truly one of the beautiful features of your design, agniusm. Great work!
otherDoc

 

[deVries]

docnjoj, this is for the end terminals, design remains the same . My concirn was end blocks 10mm. These were heating up while pulling lots of current. Copper copes with that easy.

How many amps can the aluminum end terminals pass continuous without much if any heat buildup? Can you attach your temperature probe to end terminals to give us an idea of heat/amps, when applied continuous at 40amps 30amps 20amps and 10amps and give us the terminal temps vs cell surface temps for these lower continuous amp loads too?

Your 75amp test showed a 50c temp under continuous load at end of discharge with a starting temp of about 39c. Also, one of your cells dropped really low from 2.54v vs the other cells under load after end of discharge, so one of your cells appears to have lower "unbalanced" capacity. Wow, the weak cell even dropped to 1.74v under a quick load of 75amps once it was already down to 2.54v, so that was extreme loss of voltage under such high loads.

Obviously, that's a good lesson to limit amp draw when battery gets low and you're on the road.

Thanks for the video and tests... keep'em coming.

Btw, I calculated you should have got at least 12.8 minutes of run time draining capacity using 16Ah at 75A. You only got 9 minutes of use. Had you gone 10-30 seconds more under 75A load the battery would have been destroyed or severely damaged. (One cell dropped to 1.74v under load from 2.54v, which should have been more than 16Ah of capacity used.)

If my calculations are correct, see below, then you're losing at least 30% of capacity to heat loss energy???

Am I correct or ???

75A / 16Ah = 4.6875, so 60 minutes / 4.6875 = 12.8 minutes to use 16Ah @ 75A.

Can you calibrate both temperature probes, or at least make certain one is calibrated correctly??? We need to know one is verified accurate after a real calibration test.

 

[agniusm]

Multimeter probe is more or less acurate. I got more than 9 mins and perhaps close of what you calculated. That was second run as i forgot to set the time as you have asked before hence 39C starting temp. there is no point on doing 10a draw. 40a will be fine. But i bet you will be in to testing parameters you need. For now this is all i got, and have to direct my time towards other tasks.

 

[deVries]

I got more than 9 mins and perhaps close of what you calculated.

If you check your video you did not apply any load until 41 seconds after you started the timer. I'm certain you consumed more than 16Ah, when you had already stopped the loading at just before 8:58. So, 8:17 was your actual run time for loading. Your starting cell voltages were nominal at 3.29v, so you probably didn't run but many seconds before you remembered to start the timer again. Say you forgot for 45 seconds, though you probably caught the mistake within seconds w/video on, then that load time beyond 16Ah was only about 9 minutes total (8:17 + time to catch timer mistake) vs what should have been 12:48.

That's why I'm really curious for you to *please* just do one more test anywhere between 30A-40A. I think that is more the normal range of use for eBikes, and maybe the battery will run more efficiently in this amp range. Please video one more new test in that 30-40 amp range, and remember to start the timer when the load begins with temp probes ready and battery cells at 3.3v nominal.

You are our great A123 scientist researcher too. We seriously need your science experiments. You have the perfect test equipment & setup. You're great at video, and you are becoming our famous ES documentary actor.

Maybe you're too busy to do the test today, :lol: but you could do it within a couple of weeks or so...

Thanks. Oh, and what's interesting about your test is the cell-pouch temp peaked at 51c after 9 minutes at 75A, so the cells are increasing in temp more so than your end terminals at end of discharge. I wonder if your copper end terminals will really decrease the IR of the battery? You need to do another load test at 75A to see how much more time you can run the battery with the copper terminal vs aluminum. Since your battery cell-walls are getting so warm, I wonder if the copper terminals will really help lower the IR of the battery?

 

[jimw1960]

If I may add. I am pretty sure the 20Ah ratings are for 1C discharge. When I tested some of these cells a year ago, I was getting something like 19.6Ah at 1C. It does not sound suprising that capacity drops to the 16-17Ah range at nearly 4C discharge. Also, 51 C is really not that hot (123 F for us yanks). It can get that hot on a sunny summer day in Arizona.

 

[agniusm]

I got more than 9 mins and perhaps close of what you calculated.

If you check your video you did not apply any load until 41 seconds after you started the timer. I'm certain you consumed more than 16Ah, when you had already stopped the loading at just before 8:58. So, 8:17 was your actual run time for loading. Your starting cell voltages were nominal at 3.29v, so you probably didn't run but many seconds before you remembered to start the timer again. Say you forgot for 45 seconds, though you probably caught the mistake within seconds w/video on, then that load time beyond 16Ah was only about 9 minutes total (8:17 + time to catch timer mistake) vs what should have been 12:48.

That's why I'm really curious for you to *please* just do one more test anywhere between 30A-40A. I think that is more the normal range of use for eBikes, and maybe the battery will run more efficiently in this amp range. Please video one more new test in that 30-40 amp range, and remember to start the timer when the load begins with temp probes ready and battery cells at 3.3v nominal.

You are our great A123 scientist researcher too. We seriously need your science experiments. You have the perfect test equipment & setup. You're great at video, and you are becoming our famous ES documentary actor.

Maybe you're too busy to do the test today, :lol: but you could do it within a couple of weeks or so...

Thanks. Oh, and what's interesting about your test is the cell-pouch temp peaked at 51c after 9 minutes at 75A, so the cells are increasing in temp more so than your end terminals at end of discharge. I wonder if your copper end terminals will really decrease the IR of the battery? You need to do another load test at 75A to see how much more time you can run the battery with the copper terminal vs aluminum. Since your battery cell-walls are getting so warm, I wonder if the copper terminals will really help lower the IR of the battery?

deVries, i am doing these tests to see how the end terminals behave and how they heat up at certain current. This is done to test the kit only. Other info is completely irrelevant. If cells have 17AH or 15AH capacity i dont care. Whats the point in doing tests at 30, 20, 10 amps anyway? If its good for 40A, which it is, and 75A for say 5 mins, it will certainly be good for 30,20,10 amps. Thats all to it there is. Now tested copper terminals at 150A and they are good for that, thats why i want to introduce them to my kit to make it more versatile at fraction of the cost and maybe get more business?! Cells heated up to 50C, and my concirn is not to damage my cells and is totaly irrelevant to these tests which are intended for the kit. Such info was a bonus.
If you need 30,20... amp tests you could do them your self and have real data at hand. You can do 3,5,10 amp test on balancing connector and other stuff and let other people know. I dont have time and recources to do mad science thingy here and this goes as far as to make the kit do what it supose to do and improve it as much as i can with given time, finances and enthusiasm.

Thanks for input

 

[agniusm]

I got more than 9 mins and perhaps close of what you calculated.

If you check your video you did not apply any load until 41 seconds after you started the timer. I'm certain you consumed more than 16Ah, when you had already stopped the loading at just before 8:58. So, 8:17 was your actual run time for loading. Your starting cell voltages were nominal at 3.29v, so you probably didn't run but many seconds before you remembered to start the timer again. Say you forgot for 45 seconds, though you probably caught the mistake within seconds w/video on, then that load time beyond 16Ah was only about 9 minutes total (8:17 + time to catch timer mistake) vs what should have been 12:48.

That's why I'm really curious for you to *please* just do one more test anywhere between 30A-40A. I think that is more the normal range of use for eBikes, and maybe the battery will run more efficiently in this amp range. Please video one more new test in that 30-40 amp range, and remember to start the timer when the load begins with temp probes ready and battery cells at 3.3v nominal.

You are our great A123 scientist researcher too. We seriously need your science experiments. You have the perfect test equipment & setup. You're great at video, and you are becoming our famous ES documentary actor.

Maybe you're too busy to do the test today, :lol: but you could do it within a couple of weeks or so...

Thanks. Oh, and what's interesting about your test is the cell-pouch temp peaked at 51c after 9 minutes at 75A, so the cells are increasing in temp more so than your end terminals at end of discharge. I wonder if your copper end terminals will really decrease the IR of the battery? You need to do another load test at 75A to see how much more time you can run the battery with the copper terminal vs aluminum. Since your battery cell-walls are getting so warm, I wonder if the copper terminals will really help lower the IR of the battery?

deVries, i am doing these tests to see how the end terminals behave and how they heat up at certain current. This is done to test the kit only. Other info is completely irrelevant. If cells have 17AH or 15AH capacity i dont care. Whats the point in doing tests at 30, 20, 10 amps anyway? If its good for 40A, which it is, and 75A for say 5 mins, it will certainly be good for 30,20,10 amps. Thats all to it there is. Now tested copper terminals at 150A and they are good for that, thats why i want to introduce them to my kit to make it more versatile at fraction of the cost and maybe get more business?! Cells heated up to 50C, and my concirn is not to damage my cells and is totaly irrelevant to these tests which are intended for the kit. Such info was a bonus.
If you need 30,20... amp tests you could do them your self and have real data at hand. You can do 3,5,10 amp test on balancing connector and other stuff and let other people know. I dont have time and recources to do mad science thingy here and this goes as far as to make the kit do what it supose to do and improve it as much as i can with given time, finances and enthusiasm.

Thanks for input

 

[999zip999]

Agniusm go see you post the pic's of the taps as the holes being off dosen't matter. I got 17.99 ah at 30amp. out of my 24s pack 3.59v to 3.2v your just testing the cell after that

 

[agniusm]

Agniusm go see you post the pic's of the taps as the holes being off dosen't matter.

Didn't got that one, come again. sorry

 

[999zip999]

Sorry I was triing to say thanks for posting the pic's.

 

[agniusm]

Sorry I was triing to say thanks for posting the pic's.

ah, ok, no problem

 

[deVries]

If you read carefully my previous post, see quote below, I am only asking for just ONE more test anywhere you choose between 30A-40A.

That's why I'm really curious for you to *please* just do one more test anywhere between 30A-40A. I think that is more the normal range of use for eBikes, and maybe the battery will run more efficiently in this amp range. Please video one more new test in that 30-40 amp range, and remember to start the timer when the load begins with temp probes ready and battery cells at 3.3v nominal.

Did you video your 150A test w/copper? What were the temps at end of discharge terminal vs cell-wall pouch?

Thanks.

 

[megacycle]

If I may add. I am pretty sure the 20Ah ratings are for 1C discharge. When I tested some of these cells a year ago, I was getting something like 19.6Ah at 1C. It does not sound suprising that capacity drops to the 16-17Ah range at nearly 4C discharge. Also, 51 C is really not that hot (123 F for us yanks). It can get that hot on a sunny summer day in Arizona.

Be interesting to know the Ah per A specs for the pouches.
There looking good at the high C's.

Geez that's hot where you are, cook an egg on the pavement.
I live in south australia and it gets hot here book never reaches 50 degC in the metro areas.
Ive worked out in the 'bush'on mining jobs and it gets that hot and even hotter than 50 degC.
And it's a unbearable, it's like being in a sauna, when you are outside.

Yeh but 50degC wouldnt be too hot for pouch.

 

[megacycle]

Hey just made me think, aluminium over copper might help for blocks pulling big amps.

 

[agniusm]

If you read carefully my previous post, see quote below, I am only asking for just ONE more test anywhere you choose between 30A-40A.

That's why I'm really curious for you to *please* just do one more test anywhere between 30A-40A. I think that is more the normal range of use for eBikes, and maybe the battery will run more efficiently in this amp range. Please video one more new test in that 30-40 amp range, and remember to start the timer when the load begins with temp probes ready and battery cells at 3.3v nominal.

Did you video your 150A test w/copper? What were the temps at end of discharge terminal vs cell-wall pouch?

Thanks.

I did it some time ago just did not vid documented it. temps at 40A when ambient 19C got to 23C after 8 minutes of running time. I started these tests to see if i need to change something in my design to allow higher pulls out of the pack, this is why i will be doing copper on end terminals. As mentioned before you will have all the possibilities to do whatever you need when your pack will be assembled.
150A i done just to see, if it looked ok to go ahead with changes. I have a picture of copper diy terminals. Temps were around 30C after same run i did at 75A.

Hey just made me think, aluminium over copper might help for blocks pulling big amps.

Aluminium over copper??? perhaps vice verse? Aluminium is 60% conductivity of copper and that is with certain alloys like 1xxx series some 6xxx series and they are most soft which is no good for threading.

Be interesting to know the Ah per A specs for the pouches.
There looking good at the high C's.

Geez that's hot where you are, cook an egg on the pavement.
I live in south australia and it gets hot here book never reaches 50 degC in the metro areas.
Ive worked out in the 'bush'on mining jobs and it gets that hot and even hotter than 50 degC.
And it's a unbearable, it's like being in a sauna, when you are outside.

Yeh but 50degC wouldnt be too hot for pouch.

Yea, i would like to get hands on A cell to see how they hold.

i have now 2 more 6S packs build and there are cells hitting 3.65 fast. i mean others are still at 3.3. Strange behavior. Left balancing overnight and cell over voltage error on iCharger.

 

[megacycle]

Be interesting to know the Ah per A specs for the pouches.
There looking good at the high C's.

Will carry on looking around see if i can any info on that.

 

[megacycle]

Hey just made me think, aluminium over copper might help for blocks pulling big amps.

Aluminium over copper??? perhaps vice verse? Aluminium is 60% conductivity of copper and that is with certain alloys like 1xxx series some 6xxx series and they are most soft which is no good for threading.

Yeh meant copper onto tab/s, high conductivity, high thermal sink.
Smear of thermal paste and aluminium onto that, not for conducting only for higher heat emmisivity :lol: if that's the right word.
The aluminum is a radiator, the copper is the electrical conductor and heat sink.
Explaining that's like giving birth :x

 

[megacycle]

Good example of ;-

 

[docnjoj]

I am interested in 12S configuration please. Thanks
otherDoc

12S battery pack？where do you use it for ?
maybe we can talk alone by MSN?

I ended up splitting the pack to 2x6S kits from agniusm and it is working fine. I just need to make the hard case for the outside and finish mounting the JST connector that I had to use when I messed up the traces (my fault completely)! The pack will power one of our trikes. No BMS but LVC from kfong and Hyperion balance charge for HVC
otherDoc

 

[docnjoj]

Hey just made me think, aluminium over copper might help for blocks pulling big amps.

Aluminium over copper??? perhaps vice verse? Aluminium is 60% conductivity of copper and that is with certain alloys like 1xxx series some 6xxx series and they are most soft which is no good for threading.

Yeh meant copper onto tab/s, high conductivity, high thermal sink.
Smear of thermal paste and aluminium onto that, not for conducting only for higher heat emmisivity :lol: if that's the right word.
The aluminum is a radiator, the copper is the electrical conductor and heat sink.
Explaining that's like giving birth :x

I didn't realize guys could do that in OZ. Wow!
otherDoc

 

[agniusm]

My uncle told me once he had some aluminum sheets. Today my aunt was coming to visit my mom and i asked her to bring me some. So far good stuff it is. I made some heat sinks for my cells, just need some time to test it out. Same stuff that A123 is using for their modules. Here ya go:

The stuff was used in printing house, paper printing or something like that. Only thing i am not sure about if the coating on one side will not reduce heat dissipation? Perhaps someone knows??!!