dimitrib90
100 W
- Joined
- Oct 8, 2008
- Messages
- 142
Where can I find some BMI cells? Do they really last more than 5000 cycles? Do BMI cells need a BMS? Sorry for all the questions 
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BMI cells
- Thread starter dimitrib90
- Start date
dimitrib90
100 W
- Joined
- Oct 8, 2008
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- 142
Oh and are Lifebatt batteries just as good?
dimitrib90
100 W
- Joined
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I didnt know that they were all the same cell! Thanks.
Ben
100 W
There's also a couple of versions of the cells. I think (but I'm not sure) that the grey cells are the latest/best ones.
michaelplogue
10 kW
My understanding is that the Lifebatt and BMI cells are the same. The PSI's supposedly have half the charge cycles and half the discharge rate. But the PSI cells are also a lot cheaper as well.
dimitrib90
100 W
- Joined
- Oct 8, 2008
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For my setup I would need 24s6p which would be more than $7000. I need something under $3000 for a 4kw/h battery.
Link
1 MW
Hmm, that comes out to $0.75/Wh. Only cells I know of that are that cheap are Ping's. :?
Ben
100 W
You might be able to do it with Headway cells, but then you're stuck with Headway cells.
dimitrib90
100 W
- Joined
- Oct 8, 2008
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- 142
What could I get for $4000? I really really really need a 70.4V 60ah battery for no more than $4000. I was thinking lifepo4 on ebay.
Ben
100 W
Well it really depends on what you want it for.
For $4000, BMI cells are out of the question. Most cheaper Chinese cells should be able to do 3C maximum discharge (180A max), but just be careful with your decision, because $4000 is a lot of money to send overseas.
For $4000, BMI cells are out of the question. Most cheaper Chinese cells should be able to do 3C maximum discharge (180A max), but just be careful with your decision, because $4000 is a lot of money to send overseas.
Ok.. hold on here..
PSI is the factory that makes the cells..
Lifebat, BMI, and others get their own color shrink wrap but are not the factory.. they get their cells from PSI ( Phoenix Silicon International , in Taiwan)
If you only want a single pack for personal use.. contact Lifebatt in the USA, if you are in Australia contact BMI, in the UK lifebatt has a distributor there as well..
If you know what you are doing, have experience working with building packs, want to buy a whole pile of cells ( 48 cells per case conveniently goes by air without being overweight, a container load starts at something like 5000 cells up to 20,000 cells), contact Raymond King and if you qualify as " Qualified " you can buy direct from PSI.
If you find some older stock, with white ends vs the red and black ends on green shrink, those were previous runs that i suggest you avoid as they are a few years old already.
5000 cycles ?.. come on.. lets be real here.. true cycles on an ebike.. like 50 + DOD from a full charge, expect many years of service ( i am expecting 5 years + myself.. remains to be proven ) but 5000 cycles is a pipedream, how many cycles can you use in a year ?
edit to add: These cells pump out 10C, the real deal.. i use them at 5C on my BMX with an X5304 and a modded controller ( 50 to 55 amps on the CA meter ) and they stay cool to the touch after a 12 km run of wheelies and stop/go wrapped in a blanket inside my backpack !!
And thems the facts Jack..
PSI is the factory that makes the cells..
Lifebat, BMI, and others get their own color shrink wrap but are not the factory.. they get their cells from PSI ( Phoenix Silicon International , in Taiwan)
If you only want a single pack for personal use.. contact Lifebatt in the USA, if you are in Australia contact BMI, in the UK lifebatt has a distributor there as well..
If you know what you are doing, have experience working with building packs, want to buy a whole pile of cells ( 48 cells per case conveniently goes by air without being overweight, a container load starts at something like 5000 cells up to 20,000 cells), contact Raymond King and if you qualify as " Qualified " you can buy direct from PSI.
If you find some older stock, with white ends vs the red and black ends on green shrink, those were previous runs that i suggest you avoid as they are a few years old already.
5000 cycles ?.. come on.. lets be real here.. true cycles on an ebike.. like 50 + DOD from a full charge, expect many years of service ( i am expecting 5 years + myself.. remains to be proven ) but 5000 cycles is a pipedream, how many cycles can you use in a year ?
edit to add: These cells pump out 10C, the real deal.. i use them at 5C on my BMX with an X5304 and a modded controller ( 50 to 55 amps on the CA meter ) and they stay cool to the touch after a 12 km run of wheelies and stop/go wrapped in a blanket inside my backpack !!
And thems the facts Jack..
voicecoils
1 MW
Ypedal said:
All this positive talk will jack up the price ypedal !!!
You should be saying: "They are acceptable, but just too expensive. Maybe PSI can raise the price next run when the product improves" :wink: :wink: :wink:
All this talk of "they're second only to A123 cells, better suited to ebikes, and competitively priced between A123 and headway" is just not helping! 8) :? 8)
BTW, Once I get my X5 running in my bike with the Infineon 45A controller I should be able to get some idea of pack performance in the 4C-6C discharge rate. Likely around the same time as your headway cells get to your door. At the moment they're not being worked hard, I drained 5.7Ah (214Wh) today at a max momentary discharge of 3C. The pack took me 30km with constant but not flat out peddling. That reminds me, better put them on the charger now!
John in CR
100 TW
Dimitri,
I too am putting together 4kwh of packs. Assuming that this is for a bike not a motorcycle, then I see no reason to go with the far more expensive high power cells. On your 70v60ah pack a 1C drain rate would be 60A putting out 4200 watts. With that in mind there's no reason why you can't put your pack together for under $3000.
John
I too am putting together 4kwh of packs. Assuming that this is for a bike not a motorcycle, then I see no reason to go with the far more expensive high power cells. On your 70v60ah pack a 1C drain rate would be 60A putting out 4200 watts. With that in mind there's no reason why you can't put your pack together for under $3000.
John
mcstar
100 W
A bit of clarification here.
PSI is a factory that makes cells, but BMI is a different company/manufacturer that also makes cells. They package them with 2 different labels (that I know of) one is BMI the other is Lifebatt. I don't know if Lifebatt still get's any cells from PSI, you'll have to ask them. The BMI cells though are definately NOT PSI cells. BMI cells are made from LiFePO4 powder that is purchased from Germany and liscenced. Here are some pics of the BMI factory...
http://www.electric-echo.com/lifepo4/lifepo4_bmi_factory.shtml
The differences I know of are this...
BMI cells can source up to 20C whereas PSI can only do 10C.
BMI cells have been tested to cycle at LEAST 5000 cycles with > 80capacity still left. Other testing has shown them to more than 8000cycles in partial discharge.
BMI cells are a bit more expensive but simply put more power to the ground as long as you motor / controller can handle it.
BMI cells cost more, but you get what you pay for.
This is where I get my cells from. I've ordered hundreds of them from BMI and everyone that's used them loves them. They just deliver and that's really what we want right?
PSI is a factory that makes cells, but BMI is a different company/manufacturer that also makes cells. They package them with 2 different labels (that I know of) one is BMI the other is Lifebatt. I don't know if Lifebatt still get's any cells from PSI, you'll have to ask them. The BMI cells though are definately NOT PSI cells. BMI cells are made from LiFePO4 powder that is purchased from Germany and liscenced. Here are some pics of the BMI factory...
http://www.electric-echo.com/lifepo4/lifepo4_bmi_factory.shtml
The differences I know of are this...
BMI cells can source up to 20C whereas PSI can only do 10C.
BMI cells have been tested to cycle at LEAST 5000 cycles with > 80capacity still left. Other testing has shown them to more than 8000cycles in partial discharge.
BMI cells are a bit more expensive but simply put more power to the ground as long as you motor / controller can handle it.
BMI cells cost more, but you get what you pay for.
This is where I get my cells from. I've ordered hundreds of them from BMI and everyone that's used them loves them. They just deliver and that's really what we want right?
TylerDurden
100 GW
These seem to have the sooperdooper Lifebatt package...
http://mvp090-1.104web.com.tw/cetacean/front/bin/ptlist.phtml?Category=132957
http://mvp090-1.104web.com.tw/cetacean/front/bin/ptlist.phtml?Category=132957
That picture is old.... not with current times for sure..
I do find Mcstar's info interesting tho... funny how we don't see any factory labels or logo on any pictures.. PSI or MBI or otherwise.. I'd love to hear the truth on all this.. :?
I do find Mcstar's info interesting tho... funny how we don't see any factory labels or logo on any pictures.. PSI or MBI or otherwise.. I'd love to hear the truth on all this.. :?
TylerDurden
100 GW
Indeed.Ypedal said:
For certain, BMI/LB was sourcing from PSI, but if they now have their own factory... that must mean that the Sandia Labs have been testing PSI cells and the current Lifebatt offerings are not the same as the Sandia tested cells (even though the name is the same).
mcstar
100 W
You may be correct about that TD. I know that some of the people that used to work for PSI now work for BMI. There must have been a fracture in management at some point that caused some to spin off another company. So far, I haven't seen a Sandia Labs report specifically on the BMI cells, I've only seen the PSI one. They are all using the same powder, and a similar sized cell, but the current capacity and stability of the BMI cells seems to be better. Perhaps the process of creating the cells is superior due to better equipment.
I know the PSI cells are all green, but the BMI ones are gray. BMI did this to distinguish themselves from PSI.
I'll try to find out more about it.
Hey Mc.. have you personally pulled 200 amps ( 20C ) from one of these ? Or have any test data of such loads ? ( Not poking, just sceptical.. )
mcstar
100 W
Raphael,
For this you need 455cells. That will weigh in close to 500lbs. I can arrange a shipment directly to you for an order like this.
PM me for more details.
mcstar
100 W
Ypedal said:
No problem, I hear ya on that. Frankly, no I haven't done it myself since I don't have anything that can handle that much power (yet). There is a guy here http://www.electric-echo.com/lifepo4/lifepo4_bmi_testing.shtml that's logged peaks of nearly 140 amps in his E-Car. At that output he's putting out about 20hp! Whew! The battery pack that BMI sells is marked with ratings of 20C though, so they think it can do it. I'm going to try starting my truck with a 12V 10AH pack this weekend and see if it holds up. I'm not sure how much current it's draw, but it should be close to 200A. I'll let you guys know if doesn't go up in smoke
michaelplogue
10 kW
If you notice on the Sandina report, they have those cells that they tested listed with a 1,500 life cycle - as opposed to 5,000...... 
miro13car
100 kW
Hi!
Iam the one who bought 36V 10Ah pack from Life Batt.
Ypedal,
on my pack you definitely cannot draw 200A , because there are three 160A fuses inside , interesting 12 cells in series, 3 fuses. Good engineering.
I use pack to power Tidal Force bicycle, Canadan model restricted to theoretical 500W.
But used with low int. resistance batt like Milwaukee Moli One or my recent LiFePo TF controller will allow draws very close to 1700W/read on WattsUp/ .
The most I've drawn from LifeBatt was 1680W and 48A.
Under 48A voltage sags to 35V , so is below 3V/cells.
Voltage sag is real life indication of performance of cell.
Jozzer swears that on his motorcycle /run on LifeBatts/ at 10C voltage per cell doesn`t drop below 3V/cell.
It bothers me a bit that even under 5C in my case voltage/cell would still drop below 3V.
However he uses thicker wire for sure, I am using run of 5 feet of AWG10 from batt to controller.
But still it is 50A versus 100A for 10Ah battery.
Another important thing.For all of you N.Americans living North of Mid USA.
According to Sandia reports on LifeBatt cells it losses 0.8% of capacity for avery 1degree of C of temperature drop.
So if temp drop from 25C to 15C you lose 8% of capacity.
Difference can be dramatic between summer and winter.
I experienced it first hand when I went for my long ride at 5Celsius outside. I went only 29km before voltage indicator on the top of battery dropped to only green LED. I immediately disconnected wire from battery.
Norway for example could not use it in their electric Think.
Chemistry for warm climates??
Iam the one who bought 36V 10Ah pack from Life Batt.
Ypedal,
on my pack you definitely cannot draw 200A , because there are three 160A fuses inside , interesting 12 cells in series, 3 fuses. Good engineering.
I use pack to power Tidal Force bicycle, Canadan model restricted to theoretical 500W.
But used with low int. resistance batt like Milwaukee Moli One or my recent LiFePo TF controller will allow draws very close to 1700W/read on WattsUp/ .
The most I've drawn from LifeBatt was 1680W and 48A.
Under 48A voltage sags to 35V , so is below 3V/cells.
Voltage sag is real life indication of performance of cell.
Jozzer swears that on his motorcycle /run on LifeBatts/ at 10C voltage per cell doesn`t drop below 3V/cell.
It bothers me a bit that even under 5C in my case voltage/cell would still drop below 3V.
However he uses thicker wire for sure, I am using run of 5 feet of AWG10 from batt to controller.
But still it is 50A versus 100A for 10Ah battery.
Another important thing.For all of you N.Americans living North of Mid USA.
According to Sandia reports on LifeBatt cells it losses 0.8% of capacity for avery 1degree of C of temperature drop.
So if temp drop from 25C to 15C you lose 8% of capacity.
Difference can be dramatic between summer and winter.
I experienced it first hand when I went for my long ride at 5Celsius outside. I went only 29km before voltage indicator on the top of battery dropped to only green LED. I immediately disconnected wire from battery.
Norway for example could not use it in their electric Think.
Chemistry for warm climates??
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