Group Purchase? Lithium Batteries

Do It Yourself (DIY)
41

I got a responce from TS very quickly, good news?

Heres the Email:

Dear Leif Dyrsten,

Thank you for your questions and I hope the following reply may be helpful to
you:

1.We offer one year guarantee for our products on the condition that they are
used in the normal way. Namely, they are protected with BMS and the overcharge
or overdischarg is not allowed.

2.It can stand instant big current,say 10C. If you use 2C rating it can be
discharged for successive 25 minutes.

3.On the condition that we use 0.3CA rating for the battery which is the optimum
charging/discharging current

4.Normally it is within one month but if your order quantity is large the lead
time will be longer.

Any other question pls contact me.

Best regards
Jane
Marketing & Sales Department
Thunderysky Battery Ltd. Co.
Tel: 86 0755 2768 0266, FAXļ¼š86-755-86026678
Email:winstona@thunder-sky.com
Adr: LISHONGLANG NO.3 INDUSTRYIAL ZONEļ¼Œ
GONGMING TOWNļ¼ŒBAOAN Dist., Shenzhen, P.R.C

雷天ē”µęŗęŠ€ęœÆęœ‰é™å…¬åø萄销éƒØ
ē”µčƝļ¼š86-755-27680266, FAXļ¼š86-755-86026678
Email:winstona@thunder-sky.com

Dear Thunder-sky,

I am very interested in making an investment in a great deal of LFP Cells and I have a few questions.

What warranty or guarantee do you offer? Will it cover cells that fail on their own?
In the rating for the cells, the Impulse rating of 10C, how long is an impulse
stated as? How many seconds can an impulse safely discharge the cell?
What is the cycle life rating derived from? Is it from standard discharge,
constant discharge, or impulse discharge?
How long, after an order is placed, can I expect to receive my cells if I live
in South Western U.S.?

Thank you in advance!

-Leif Dyrsten

I replied to this email asking about the mix up with 2C instead of 3C, i also asked if they had data for 3c discharge cycle life. I will keep you updated!

42

You can get 36.5kwh for less than $19,000 with BMS. If you donā€™t get enough for group buy, I think this would be the way to go. You get a 3 yr warranty also if you use the pcm/bms they include. Seems a counter-intuitive idea to go so out of your way to buy a bunch of unproven loose cells from China. Loose cells that have no documented successful use in an EV or otherwise. Iā€™ve searched and can find only bad reviews, unsure fealings and a video of one discusted fellow who showed a shelf full of defective cells. Have you taken the cost and complexity of BMS into account? Iā€™ve spent thousands$ on various lithium packs for small and large scale RC planes and helicopters and there are a few constants among all brands. They must be balanced. They must not be over discharged. And, they must not be over charged. I think materials and components to build your own bms and shipping for the batteries and the latter will end up costing bout $20k, if not more.
Just my 2cents.

43

not sure if this thread is still activeā€¦ but if you can get 1,000,000ah, i might be interested in 45 of the 400Ah batteries

44

[QUOTE=eRubicon;1527]You can get 36.5kwh for less than $19,000 with BMS. If you donā€™t get enough for group buy, I think this would be the way to go. You get a 3 yr warranty also if you use the pcm/bms they include. Seems a counter-intuitive idea to go so out of your way to buy a bunch of unproven loose cells from China. Loose cells that have no documented successful use in an EV or otherwise. Iā€™ve searched and can find only bad reviews, unsure fealings and a video of one discusted fellow who showed a shelf full of defective cells. Have you taken the cost and complexity of BMS into account? Iā€™ve spent thousands$ on various lithium packs for small and large scale RC planes and helicopters and there are a few constants among all brands. They must be balanced. They must not be over discharged. And, they must not be over charged. I think materials and components to build your own bms and shipping for the batteries and the latter will end up costing bout $20k, if not more.
Just my 2cents.[/QUOTE]

There web-site doesnā€™t have enough information and their price is too good to believe. How come there is no discussion about their ev?

45

The thread is active. If you will read the whole thread, it goes into detail about the BMS that we will be using. IT is a great system that has been proven. The cells have been used in many EVā€™s and have been succesful. The cells that the one guy with the video bought were the bad kind, We will be buying the high quailty LFP batteries. Take some time to do your research before talking about them. Any pictures or references you see to the white batteries is not the ones we are getting. WE are getting cells that are yellow in color.

46

I read somewhere that you only need a BMS if you have batteries in parrallel, is this true? It would save me a few bucks since Iā€™ll have a series only battery pack

47

Iā€™m pretty sure, that itā€™s the opposite that is true (regretably).

48

[QUOTE=Houseoffubar;1627]Iā€™m pretty sure, that itā€™s the opposite that is true (regretably).[/QUOTE]

Correct. But no one would every use batteries in parallel for an EV

49

and why not?

how do you think they make large cells? Theyā€™re essentially small batteries in parallel to get the Ah you require.

No one would ever do it, UNLESS there is battery balancing. You would need balancing for each battery, but thereā€™s nothing wrong with putting batteries in parallel for an EV. Most people DONā€™T do it, because they donā€™t want to spend money on battery balancing equipment to make sure the parallel batteries are matched.

50

[QUOTE=Craig;1626]I read somewhere that you only need a BMS if you have batteries in parrallel, is this true? It would save me a few bucks since Iā€™ll have a series only battery pack[/QUOTE]

Whether you are in series or parallel, you should always balance your batteriesā€¦ the thing is, its not widely commercially available. Iā€™m going to be testing some stuff soon with lead acid, and then weā€™re working on LiFePo balancers. Basically, however you discharge or charge, you want to make sure that you donā€™t over charge or over discharge each battery in the system. If one tanks in a series pack, the rest go down with it. If you balance while discharging, you can help eliminate that problem, or at least sense it before its a problem.

www.evfr.net

I should be posting some pictures of the controller and BMS that a local company is working on. Iā€™m their testbench.

Just get a monitoring system at least, and monitor each battery voltage. If one tanks, get somewhere you can recharge.

51

I am interested in the group purchase, I will not be able to afford it for a month or two though. I also have a few questions:

First, you quoted $180 for the 90ah battery, on the the thundersky website they say $220 for the 90 ah battery. $180/battery is the discount price for 100,000ah. Maybe their website is out of date?

Second, shipping will probably be quite expensive. Will it be divided proportionally to how many batteries one buys?

Third, when payment time comes how are we going to make sure that someone isnā€™t going to take all the money and disappear, assuming that it has to be paid in full by one person? I doubt thundersky will allow x different people to pay for one order. I donā€™t mean to be inflammatory or passing judgment on anyone here, itā€™s just that we are all looking to spend at least a few thousand to a few tens of thousands of dollars.

I personally would be interested in 26 of the 90ah batteries for a motorcycle project.

Also, as for the BMS the one on metric mind is 100% clear to me. Do you just need the voltage clampers by themselves or do you need software to control them?

52

[QUOTE=russen;1671]I am interested in the group purchase, I will not be able to afford it for a month or two though. I also have a few questions:

First, you quoted $180 for the 90ah battery, on the the thundersky website they say $220 for the 90 ah battery. $180/battery is the discount price for 100,000ah. Maybe their website is out of date?

Second, shipping will probably be quite expensive. Will it be divided proportionally to how many batteries one buys?

Third, when payment time comes how are we going to make sure that someone isnā€™t going to take all the money and disappear, assuming that it has to be paid in full by one person? I doubt thundersky will allow x different people to pay for one order. I donā€™t mean to be inflammatory or passing judgment on anyone here, itā€™s just that we are all looking to spend at least a few thousand to a few tens of thousands of dollars.

I personally would be interested in 26 of the 90ah batteries for a motorcycle project.

Also, as for the BMS the one on metric mind is 100% clear to me. Do you just need the voltage clampers by themselves or do you need software to control them?[/QUOTE]

Sorry that I have not been on in a while.

I have found out that we can buy directly from the manufacturer (cheaper) IF we get the 100,000AH it is calculated $1 per AH. So 1x 90 ah cell is $90.

Shipping will deffinantly be divided to how much you purchased, any other way would be unfair. Unless you wanted a rediculously low quantity, like 3 batteriesā€¦

I was planning on using one of those financial institutions that makes a ā€œcontractā€ that must be fullfilled a certain way. So that whoever buys the batteries (prob me) is legally binded to distribute them to their respective buyers. To have the cells shipped to indv. people would defeat the purpose of group rate.

YOu need the clampers and then the main module that they all connect to as well as the display.

-Leif

53

Wow if I could get it for the 100,000 Ah discount Iā€™d take 45x 200 Ah!

54

I am now thinking we should wait it out a couple months incase the (on the slim chance)Eestor comes to market. SO in a month we will meet back on this thread and post what batteries we want for our evā€™s.

55

Do you have a link to, or any info on size, weight, voltage, and AH, on the EEStor.
Itā€™s hard to find info on them.

thank you,
Jason

56

[QUOTE=camillo;1879]
Itā€™s hard to find info on them.
[/QUOTE]

Thats itā€¦ They have not come out yet, and they are being very secretive about it all. There is a thread started in this forum in the batteries section.

57

What i did find out about the EEStor sounds great. Keep us informed on anything you can find out about them. I might be ready in a few months to join in on the buy.:smiley:

Thank you
Jason

58

Yes, EESTOR is VERY secretive, and they donā€™t even have a web site. If you click on www.eestor.com, you get a message saying that the domain name is for sale. In 2 years of highly touted claims by EESTOR, I have yet to see anything to convince me that their battery will ever be released. I hope Iā€™m wrong.

59

From what Iā€™ve read they say they are on track for meeting their goals (interview in January 2008 I believe) and they have just sent some systems to Zenn motorcars. I remember they said something about production starting this year.

60

just imagine how much more affordable an EV will become. $2100 for a 52kwh pack!! that weighs 300 lbs! Damn. I sure this comes out quicker. I will be getting two (: