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Today's Topics:

   1. Re: Tesla batteries (maybe good news via Valence batteries)
      (Cor van de Water)
   2. Re: Mavins motor?s bearings ([EMAIL PROTECTED])


Message: 1
Date: Thu, 13 Sep 2007 11:56:24 -0700
From: "Cor van de Water" <[EMAIL PROTECTED]>
Subject: Re: [EVDL] Tesla batteries (maybe good news via Valence
To: "Electric Vehicle Discussion List" <>
Content-Type: text/plain;       charset="iso-8859-1"

I would expect that each DeWalt pack with its own BMS will do its
internal balancing, so I expect that you will get the best results
treating each pack as a black box - you would not even need to open
the original packs, so warranty is not even voided if you can find
a reasonable way to connect to the tabs of the complete pack.

With each pack as a module taking care of its internal balance, you
will only need to care for the total balance, like when having
multiple Lead-acid battery strings, you don't connect individual
cells (because you can't get at them) and even if you form high 
power strings, it is advised to interconnect the strings with 
thinner wires to allow a slight imbalance between strings to 
accommodate differences in temperature and chemical mix and such.
The thinner parallelling wires will eventually balance the modules
without causing undue stresses on a particular module or its BMS.

In your drawing: keep all red wires, remove all blue wires and then
add a blue wire between the middle 3 red wires.

BTW, in order to reduce discharge differences between strings due
to different resistance from for example wire length differences,
you can best use the top left and the bottom right as places to
interconnect your 3 strings, not connect both sides in the middle
because then the middle string will suffer most deep discharges.

Hope this clarifies.

Cor van de Water
Systems Architect
Proxim Wireless Corporation
Email: [EMAIL PROTECTED]    Private:
Skype: cor_van_de_water     IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225    VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675    eFAX: +31-87-784-1130
Second Life:

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Osmo S.
Sent: Thursday, September 13, 2007 8:56 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Tesla batteries (maybe good news via Valence batteries)

  What is the best way to make parallel-series packs out of Dewalt packs? Does 
this very artistic sketch of mine make any sense?

What size the wire making parallel connections should be?
Any ideas how the packs should be physically placed to get as short, safe and 
sensible connections as possible?


P.S. Jeff, it would be easier to follow the threads if you keep the messages 
you are replying to in your mails.  :)

Jeff Shanab kirjoitti 12.9.2007 kello 15.01:

> Dewalt packs are connected in series, not of much use for us. You 
> can't really cut them free and if you rotate them, the cell can be 
> damaged.
> But you could take say 24 such packs as is and interconnect each tab 
> for balancing and connect the + and _ for power to get a [EMAIL PROTECTED] 
> module
> My plan is make 12 cell sub-modules (that can be replaced if
> necessary.)
> 12 of these submodules are in the battery module with bms and can be 
> interconnected either 6x2 or 4x3 for [EMAIL PROTECTED] or [EMAIL PROTECTED] 
> with the 
> same electronics and case. (The case is re-useable, ie not permanently
> sealed.)
> _______________________________________________
> For subscription options, see

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Message: 2
Date: Thu, 13 Sep 2007 11:57:43 -0700
Subject: Re: [EVDL] Mavins motor?s bearings
Content-Type: text/plain;       charset=ISO-8859-1;     DelSp="Yes";

> As far as I can tell, the tranny/differential oil was ment to run   
> freely inside the motor, also around the rotor. Is that possible?   
> What if there is air instead of oil (should the distance between the  
>  rotor and the stator be different etc)?

This is the motor used in my Ranger EVs, which is directly mated to  
the rear axle. They use an aerospace "Tribolube" instead of normal  
gear oil, so I guess this is what you engineers call  
"application-specific". No wonder mavin got them cheap: once Ford  
stopped making the electric Rangers, there was no use for such an  
odd-ball motor - they probably still have enough in stock for repairs  
for the next decade, considering how few of them are on the road. The  
only people who would find this motor cost-effective would already  
have a Ranger EV drive train to begin with.


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End of EV Digest, Vol 2, Issue 37

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