Re: Big 12 volt batteries

[Nawaz Qureshi <nqureshi@usbattery.com>]

Hi Brian:
I believe you are referring to the radial grid design commonly used in the starting
type (SLI) batteries to maximize their cold cranking ability. This design
minimizes the ohmic resistance of the grid so that it can deliver higher current at
the same voltage drop (or higher voltage at the same current). I was deeply
involved in the original design of this grid while at Globe Union, Inc. ( Now
called JCI), in the mid 70's, using the advanced mathematical modeling via
computers. I continued  this work at Exide (then called ESB, Inc.) and was issued
two patents on this design in 1979 and 1982.
Since then,  almost every battery maker  is using similar radial designs for their
SLI products.

To answer your question, radial grid design will not noticeably improve the high
rate capability of the deep cycle batteries, because their resistance is already
low due to higher thickness of the grids.  In addition,  these batteries  use much
higher resistance rubber separators with glass mats for longer life with deep
discharges. This higher  resistance of the separators has the largest effect on
the voltage drops under high discharge currents and overwhelms the already minor
effect of the grid resistance.
What I was trying to tell you,  in my preceding post,  was that the grid thickness,
and the alloy characteristics,  provide the "meat" for corrosion: the thicker it
is, the longer it will take to corrode. A  radial design will not affect the
corrosion life of the grid at all.  USBMC's EV-145 uses rectangular grids, just
like all of the other "jumbo" deep cycle products from all manufacturers  of good
batteries.

On the bench test the USBMC's EV-145 will go from 650 to 1000 BCI cycles.
(Cycle life is not fixed number)

I hope this helps.

If you need further info / help, please feel free to pose questions.



Brian wrote:

> At 11:45 AM 6/25/99 -0700, you wrote:
> >USBMC's EV-145 uses 0.107 inch thick positives and 0.085 inch thick negatives.
> >The same thickness plates are used in our golf car batteries. Moreover, we use
>
> Thanks for the reply with technical details, however you didn't quite
> address my observation of a Trojan battery.  It had very thin collector grid
> wires, even near the terminal indicating higher resistance and more voltage
> drop at EV currents.  Do the US batt EV-145 have grid wires which are
> thicker at the terminal end and taper towards the far side of the plates?
>
> >Our field tests show that the EV-145 lasts just as long as the golf products.
>
> As many cycles as a 6V flooded?  How many BCI cycles?  Sounds interesting.
>
> -Brian
> 23,300+ EV miles since 5/97!  (See web page.)
> http://www.norfolk-county.com/users/ws3f/ws3f.htm