Series Cables for 2 Volt Cells [RE-wrenches]

David Palumbo, Independent Power & Light ipl at sover.net
Sat Jun 12 11:37:02 PDT 2004


 

-----------------------------------------------------------
Give Your Team Access to Their PCs from Anywhere. Increase 
productivity with a secure remote-access solution from 
GoToMyPC Pro. Stay in touch with your office. FREE TRIAL:
http://click.topica.com/caaciqXbz8Qcsbz9JC9a/ExpertCity
-----------------------------------------------------------






Wrenchers.

I recently received (12) HPF85-25P, 1,200 Amp hour, 170 lbs each, 2v cells
from Power Battery Co.
With the cells the manufacturer sent 24 series cables to be used with the
installation.
I initially dismissed these out of hand because they were #6 AWG. Way
smaller than the usual cables we use.
Because there are two series jumpers from cell to cell (there are two
positive and two negative posts per cell) the #6 are not as undersized as
they would be on a single series connection battery. The engineer at Power
Battery assured me that they were ample for series jumpers.
I recalled that in the mid 80's when I put together my first system Peter
Talmage (very knowledgeable engineer and solar guy from Maine) had me use #4
cables for the series connections in the battery bank of L-16's I was using.

I decided to test the 24v bank of 2v cells with the #6 jumpers here in my
shop.
I loaded it up to 2,200 watts and ran the bank down to 20.0 volts when the
OutBack inverter shut off. That process took 14 hours. Load resistive heat)
was steady between 85 to 88 amps. I measured the temperature of the #6
series jumpers many times during the discharge and subsequent recharge (at
85A)and found that the cables (10" in length) were, at most, 6 degrees F
above the ambient air temp of 72F. The FX inverter/charger got up to 115 F
at most during the test. The 2/0 cables connecting the PS2DC disconnect box
and the FX got 12 degrees F higher than ambient and the 4/0 battery to PS
box got 2 degrees F above ambient.

So the question is are we wasting copper by using oversized cables for
series connections?

Dave

-----------------------------------------------------------
Apply now for a No-Annual-Fee Discover® Platinum Card 
0% Intro APR*, No Annual Fee, Up to 2% Cashback Bonus® 
award* Start Saving Today – APPLY NOW! It's fast, easy and 
secure. 
http://click.topica.com/caaciqQbz8Qcsbz9JC9f/Discover Card
-----------------------------------------------------------

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & etiquette: www.mrsharkey.com/wrenches/etiquete.htm

Check out participant bios: www.mrsharkey.com/wrenches/

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at homepower.com

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------







More information about the RE-wrenches mailing list