DIY Electric Car Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
70 Posts
Discussion Starter #1
I see that ~ 24.5 inches of 4/0 wire is 0.1 milli Ohm. What do you think of
using this method as a shunt?

Thank you,

Dave Delman
1981 Electric DeLorean Project
electricdelorean.com



************************************** See what's new at http://www.aol.com
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
 

·
Registered
Joined
·
70 Posts
Discussion Starter #3
[email protected] wrote:
> I see that ~ 24.5 inches of 4/0 wire is 0.1 milli Ohm. What do you
> think of using this method as a shunt?

Yes, ordinary copper wire can be used as a shunt resistor. It's
certainly cheap and easy! Plus, the wire is already there anyway. You
can connect a sensitive milliammeter to two points X inches apart that
just happen to give you the right resistance, and have a high current
ammeter.

There are couple problems: The resistance per foot of wire is only
approximate, so your ammeter will need to be calibrated with a good
known accurate ammeter. Copper has a positive temperature coefficient,
so the hotter the wire, the higher the apparent current will be.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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

·
Registered
Joined
·
70 Posts
Discussion Starter #4
Hi Dave,

Yeah, you can do this. But current shunts are made of
an alloy which doesn't change resistance with heat,
within its ratings. Copper wire will change. The
other source of error is the connections. On shunts,
the sense lead terminals are independent of the power
terminals. This will be difficult to do with copper
cable and lug ends. If you're going to the trouble of
instrumenting with an ammeter, I'd recommend you use a
shunt. I've gotten several off eBay for as little as
$5. New ones, maybe $50 or 60, guessing.

Jeff M





--- [email protected] wrote:

> I see that ~ 24.5 inches of 4/0 wire is 0.1 milli
> Ohm. What do you think of
> using this method as a shunt?
>
> Thank you,
>
> Dave Delman
> 1981 Electric DeLorean Project
> electricdelorean.com
>
>
>
> ************************************** See what's
> new at http://www.aol.com
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>



____________________________________________________________________________________
Check out the hottest 2008 models today at Yahoo! Autos.
http://autos.yahoo.com/new_cars.html

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

·
Registered
Joined
·
70 Posts
Discussion Starter #5
http://www.allelectronics.com/cgi-bin/category.cgi?item=SNT-600

$18 for 600 amp shunt, just bought one. it didn't come with the bolts
as shown in the picture just fyi.

Jack

Jeff Major wrote:
> Hi Dave,
>
> Yeah, you can do this. But current shunts are made of
> an alloy which doesn't change resistance with heat,
> within its ratings. Copper wire will change. The
> other source of error is the connections. On shunts,
> the sense lead terminals are independent of the power
> terminals. This will be difficult to do with copper
> cable and lug ends. If you're going to the trouble of
> instrumenting with an ammeter, I'd recommend you use a
> shunt. I've gotten several off eBay for as little as
> $5. New ones, maybe $50 or 60, guessing.
>
> Jeff M
>
>
>
>
>
> --- [email protected] wrote:
>
>
>>I see that ~ 24.5 inches of 4/0 wire is 0.1 milli
>>Ohm. What do you think of
>>using this method as a shunt?
>>
>>Thank you,
>>
>>Dave Delman
>>1981 Electric DeLorean Project
>>electricdelorean.com
>>
>>
>>
>>************************************** See what's
>>new at http://www.aol.com
>>_______________________________________________
>>For subscription options, see
>>http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
>
>
>
> ____________________________________________________________________________________
> Check out the hottest 2008 models today at Yahoo! Autos.
> http://autos.yahoo.com/new_cars.html
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
 
1 - 5 of 5 Posts
Top