# [EVDL] It?s A Brick? ? Tesla Motors?



## EVDL List (Jul 27, 2007)

Hi Dave etc,

yes, I mentioned to them (Tesla motors) at each show I've attended over the last 10 years that 6800 flashlight batteries is way too many points of failure & will have reliability issues, probably high self discharge rate. the salesman gave me the line "think of it as 6800 points of redundancy". Although the cells are fused from the battery supplier and should drop out so the car keeps running having the pack go completely dead in 2 months is unacceptable. You would think the balancing circuitry would drop out below 2.5VPC and not kill the pack.

I've been through this before, the head honcho brings all the engineers and says something like "lets put 6800 flashlight batteriers together for an electric car" and they all nod, "yes sir" without pointing the reliability issues with high parts counts to the big cheese.

Have a low parts count day,
Mark 
www.reevadiy.org 

Date: Thu, 23 Feb 2012 06:00:50 -0500
From: "EVDL Administrator" <[email protected]>
Subject: Re: [EVDL] article: ?It?s A Brick? ? Tesla Motors?
Devastating Design Problem
To: Electric Vehicle Discussion List <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset=US-ASCII



> On 22 Feb 2012 at 17:38, Lee Hart wrote:
> 
> > Toyota used lots of little nimh cells in the Prius because that's all
> > they were allowed to use by the Ovonic patents. ...
> ...


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## EVDL List (Jul 27, 2007)

> On 27 Feb 2012 at 19:10, Kevin Sharpe ZCW wrote:
> 
> > I fully understand the issue of potential reliability with large numbers
> > of cells but I think you have to balance it against the need to deliver
> ...


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## EVDL List (Jul 27, 2007)

> Mark Hanson <[email protected]>wrote:
> 
> >
> > I've been through this before, the head honcho brings all the engineers
> ...


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## EVDL List (Jul 27, 2007)

> On 29 Feb 2012 at 22:57, Evan Tuer wrote:
> 
> > Mark Hanson wrote:
> > 6800 flashlight batteries ... reliability issues ... high parts counts ... >
> ...


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## EVDL List (Jul 27, 2007)

Evan Tuer wrote
> why not complain about the number of transistors
> in your computer's CPU, it's about the same thing 
> 

Do you know what a transistor is? Essentially a tiny on-off switch. Can
one big switch turn two circuits on and off? No. 

Can one larger battery do the work of two in parallel? Yes, yes they can.

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