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Discussion Starter #1
I'm buying a used EV, and I'm thinking forward to upgrading to M1s out of
DeWalt 36V packs.

If I've done my math right, at 3.3V x 2.3Ah per cell, a single pack
represents 75.9Wh. It would therefore require approximately 13.2 packs to
build a 1kWh pack and 132 packs to build a 10kWh pack. I can purchase brand
new packs all day long for $105 (shipping included) on eBay. At $105/pack x
132, it looks like I'd end up at $13,860 for my 10kWh pack. Is there a
better source/price for A123 batteries at the moment?

An area in which my thinking is very unclear is design, cost, construction,
and integration of a bms. Is there a tried and true open-source design
available (my father is an electrical engineer but he'd balk at designing
something from scratch)? If so, how much should I expect to pay in materials
for a bms for a 10kWh pack? Is there a reasonably sophisticated
off-the-shelf bms available for M1 cells? If so, who sells it?

Lastly, who needs a kidney? I'll need to sell one to pay for all of this...

Lon Hull,
Portland, OR





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Discussion Starter #2
I did hope i'd found the ideal source for these packs.. supplier called pt. besitang beng, based in indonesia. Found through the alibaba international trade website. Claimed to be able to supply me with 100 dewalt packs, including shipping to the uk for $3900. basically 30 dollars each plus shipping... unfortunately during my lengthy negotiation for sample shipments (i wasnt going to get burned) he sent his bank details, which were under a different name. searching for this name showed a few fraud warnings under various company names.. so i told him where to go.

I did think immediately that the price was far too good to be true, but hey, you have to investigate at least. if they were available at that price.... wow.

i wonder how much they actually do cost in indonesia / where the cheapest price might be had..?


________________________________

From: [email protected] on behalf of Loni
Sent: Fri 9/28/2007 08:18
To: Electric Vehicle Discussion List
Subject: [EVDL] Dewalt 36V battery packs



I'm buying a used EV, and I'm thinking forward to upgrading to M1s out of
DeWalt 36V packs.

If I've done my math right, at 3.3V x 2.3Ah per cell, a single pack
represents 75.9Wh. It would therefore require approximately 13.2 packs to
build a 1kWh pack and 132 packs to build a 10kWh pack. I can purchase brand
new packs all day long for $105 (shipping included) on eBay. At $105/pack x
132, it looks like I'd end up at $13,860 for my 10kWh pack. Is there a
better source/price for A123 batteries at the moment?

An area in which my thinking is very unclear is design, cost, construction,
and integration of a bms. Is there a tried and true open-source design
available (my father is an electrical engineer but he'd balk at designing
something from scratch)? If so, how much should I expect to pay in materials
for a bms for a 10kWh pack? Is there a reasonably sophisticated
off-the-shelf bms available for M1 cells? If so, who sells it?

Lastly, who needs a kidney? I'll need to sell one to pay for all of this...

Lon Hull,
Portland, OR





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http://lists.sjsu.edu/mailman/listinfo/ev


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Discussion Starter #3
I once contacted one of the bigger sellers of dewalt packs on ebay and
asked what 100 packs would cost and he came up with 100$ a piece
including shipping worldwide. no need to buy them one at the time.

I wrote it here so you can search the log for his name. I don't have it
because of a computer crash.
look for my name, 100, pack, ebay

Dan

Loni wrote:

>I'm buying a used EV, and I'm thinking forward to upgrading to M1s out of
>DeWalt 36V packs.
>
>If I've done my math right, at 3.3V x 2.3Ah per cell, a single pack
>represents 75.9Wh. It would therefore require approximately 13.2 packs to
>build a 1kWh pack and 132 packs to build a 10kWh pack. I can purchase brand
>new packs all day long for $105 (shipping included) on eBay. At $105/pack x
>132, it looks like I'd end up at $13,860 for my 10kWh pack. Is there a
>better source/price for A123 batteries at the moment?
>
>An area in which my thinking is very unclear is design, cost, construction,
>and integration of a bms. Is there a tried and true open-source design
>available (my father is an electrical engineer but he'd balk at designing
>something from scratch)? If so, how much should I expect to pay in materials
>for a bms for a 10kWh pack? Is there a reasonably sophisticated
>off-the-shelf bms available for M1 cells? If so, who sells it?
>
>Lastly, who needs a kidney? I'll need to sell one to pay for all of this...
>
>Lon Hull,
>Portland, OR
>
>
>
>
>
>_______________________________________________
>For subscription options, see
>http://lists.sjsu.edu/mailman/listinfo/ev
>
>
>

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Discussion Starter #4
btw, contacting A123 might also be a good idea. they may eventually wake
up and at least match the price of dewalt packs.
couldn't hurt to try right..

Dan

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Discussion Starter #5
Lon,

I did a low cost real world test to see what unaltered Dewalt 36 v
packs could deliver when the BMS was bypassed. I unhooked my 500 lb 48
volt battery pack in my 1000 lb + GVW sidecar motorcycle and soldered
in leads to ONE 3lb Dewalt pack. I set the max battery amps on the
controller to 150 and min volts to 18VDC. I was able to drive the bike
around the shop. They are pretty amazing. By buying the complete pack
you have already purchased the BMS. I don't think Dewalt is going to
give up their software to allow you to authorize 150 amp output so you
need to figure out a simple way to discharge directly and recharge
through the BMS. A chain of 132 36 volt Dewalt charger guts in a
single fan cooled enclosure might just do the trick. One thing to
watch for. There is a fused link in the pack between 2 of the cells.
You may need to beef this up.

Shawn
-----Original Message-----
From: Loni <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Fri, 28 Sep 2007 3:18 am
Subject: [EVDL] Dewalt 36V battery packs



I'm buying a used EV, and I'm thinking forward to upgrading to M1s out
of
DeWalt 36V packs.

If I've done my math right, at 3.3V x 2.3Ah per cell, a single pack
represents 75.9Wh. It would therefore require approximately 13.2 packs
to
build a 1kWh pack and 132 packs to build a 10kWh pack. I can purchase
brand
new packs all day long for $105 (shipping included) on eBay. At
$105/pack x
132, it looks like I'd end up at $13,860 for my 10kWh pack. Is there a
better source/price for A123 batteries at the moment?

An area in which my thinking is very unclear is design, cost,
construction,
and integration of a bms. Is there a tried and true open-source design
available (my father is an electrical engineer but he'd balk at
designing
something from scratch)? If so, how much should I expect to pay in
materials
for a bms for a 10kWh pack? Is there a reasonably sophisticated
off-the-shelf bms available for M1 cells? If so, who sells it?

Lastly, who needs a kidney? I'll need to sell one to pay for all of
this...

Lon Hull,
Portland, OR





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Discussion Starter #7
Lon,

Michael T Kadie (KD) of this list uses, and I quote here, "96 torn down
dewalt packs with custom balancers that engage on every full charge."
His web site is http://ssi-racing.com where you can see the '65 Shelby
Cobra Daytona Coupe(tm) electric kit car that he built. Maybe he has a
good source for a volume purchase of De Walt battery packs, custom
balancer ideas, etc.....

Alan

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Loni
Sent: Friday, September 28, 2007 12:19 AM
To: Electric Vehicle Discussion List
Subject: [EVDL] Dewalt 36V battery packs

I'm buying a used EV, and I'm thinking forward to upgrading to M1s out
of
DeWalt 36V packs.

If I've done my math right, at 3.3V x 2.3Ah per cell, a single pack
represents 75.9Wh. It would therefore require approximately 13.2 packs
to
build a 1kWh pack and 132 packs to build a 10kWh pack. I can purchase
brand
new packs all day long for $105 (shipping included) on eBay. At
$105/pack x
132, it looks like I'd end up at $13,860 for my 10kWh pack. Is there a
better source/price for A123 batteries at the moment?

An area in which my thinking is very unclear is design, cost,
construction,
and integration of a bms. Is there a tried and true open-source design
available (my father is an electrical engineer but he'd balk at
designing
something from scratch)? If so, how much should I expect to pay in
materials
for a bms for a 10kWh pack? Is there a reasonably sophisticated
off-the-shelf bms available for M1 cells? If so, who sells it?

Lastly, who needs a kidney? I'll need to sell one to pay for all of
this...

Lon Hull,
Portland, OR





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For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

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