battery options

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battery options

jeremy rutman
Having finally gotten an ev into running condition (link) I'd like to get a decent battery pack.
I haven't found any list activity on thundersky lately and it looks like they are now 'winston battery'.

Can anyone weigh in on e.g. getting 100 units of these 40Ah LYP cells?

Would getting a few thousand 18650's make more sense - and has anyone done this?
Sorry if these are well-beaten topics, I didn't find any recent threads .
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Re: battery options

gottdi
Thundersky forum is dead. Been so for some time now. Trolls rousted everyone out. No need to go back. Get some prismatic cells like TS, Winston, Synopoly, and others. If you don't mine thousands of connections I guess the tiny cells would work. There are now some A123 pouch cells on the grey market available for purchase. I am working on a 500 cell purchase right now. They do take some work to assemble into a safe container but not terrible. Gobbs of power. The cells are rated at 20 AH or sold as 20 AH but really have about 19 Ah per cell. I have 8 right now.

Did you figure out your controller issue yet? I noticed in the video it was kinda jerky while the wheel was turning.

Nice to see another EV.

Pete :)

I currently use 100AH Hi-Power Cells
http://onegreenev.blogspot.com/
No need to wait any longer. You can now buy one off the shelf. You can still build one too.
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Re: battery options

jeremy rutman
Thanks - would it be possible to join forces on a larger purchase of the A123 cells?
Ideally I'd like 20KWh of energy which I suppose would be 5.5kAh at 3.6V/cell, so your 500 cell lot for 10kAh would be in my neighborhood too.  

Are you satisfied with the hi-power cells, and has somebody done a recent spreadsheet of battery options and prices?
TIA
Jeremy

ps the jerky wheel seems to smooth out at high power. It think it may be due to the rectified power supply (which will have some cyclical droop at 50 Hz which might moire with the rotation freq. ) or a bad phase - if a phase is wired incorrectly would that cause such jerking?

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Re: battery options

David Nelson-5
Jeremy,

For LiFePO4 cells you need to use 3.2V as nominal voltage for Wh capacity
calculations. 20kWh would then be 6250Ah of cells. If you want that to be
the useable capacity you would need 25kWh and if 20kWh is your minimum then
you want even more if you want your pack to remain useable for a while.

On Friday, April 13, 2012, jeremy rutman wrote:

> Thanks - would it be possible to join forces on a larger purchase of the
> A123
> cells?
> Ideally I'd like 20KWh of energy which I suppose would be 5.5kAh at
> 3.6V/cell, so your 500 cell lot for 10kAh would be in my neighborhood too.
>
> Are you satisfied with the hi-power cells, and has somebody done a recent
> spreadsheet of battery options and prices?
> TIA
> Jeremy
>
> ps the jerky wheel seems to smooth out at high power. It think it may be
> due
> to the rectified power supply (which will have some cyclical droop at 50 Hz
> which might moire with the rotation freq. ) or a bad phase - if a phase is
> wired incorrectly would that cause such jerking?
>
>
>
> --
> View this message in context:
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> Sent from the Electric Vehicle Discussion List mailing list archive at
> Nabble.com.
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David D. Nelson
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http://2003gizmo.blogspot.com
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Re: battery options

EVDL Administrator
In reply to this post by jeremy rutman
On 13 Apr 2012 at 1:26, jeremy rutman wrote:

> if a phase is
> wired incorrectly would that cause such jerking?

The manual for the Brusa AMC inverters says that "If the motor does not run
properly (slow and irregular rotation) when the accelerator pedal is
pressed, adjust the phase position switch to the opposite position ... if
the motor then runs smoothly, but in the wrong direction, swap the positions
of two of the motor cables (e.g. R and S) and, at the same time, readjust
the phase switch to the opposite position."

On the AMC3xx inverters, the phase switch is located on the main connection
panel, next to the large multifunction switch.  From the manual it doesn't
appear that the UMOC has an equivalent (but it may be in the software).

However, this does suggest that swapping two of the three motor connections
might make a difference.  I don't think it can hurt to try.

David Roden - Akron, Ohio, USA
EVDL Administrator

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Re: battery options

Cruisin
This post was updated on .
In reply to this post by jeremy rutman
You asked about assembling the 18650 cells and others to put battery packs together. As the first owner of a Li-ion powered EV conversion in the US I assembled 8000 18650 cells for a whopping 30k of wh. It was fun and very costly. It had some advantages over the current LifeP cells but not the advantages to make it care free. A BMS is mandatory and difficult to install in these homemade packs.The battery packs have been removed to be placed in a Sanyo Museum for powering the first Ev conversion on the street. I would not do it again and would not consider what others are doing as well. After replacing with CALB and Mini BMS with a SOC, all the dependability and worry free is now mine to enjoy. You cannot imagine the greif and potential of big time costly problems unless you have done what I have done. In short, DONT DO IT, buy locally from a dealer with a warranty and dont try to save pennies on everything you do or you will be sorry. Been there and done. Now teach classes on the right way to do it.