battery cycle life [RE-wrenches]
Jeff Clearwater
clrwater at earthlink.net
Thu Dec 30 10:11:59 PST 2004
<x-flowed>
Your free subscription is supported by today's sponsor:
-------------------------------------------------------------------
Buy Stocks and Index Funds for just $4 No Account or
Investment Minimums and No Inactivity Fees Automatically
invest weekly or monthly and build your future.
http://click.topica.com/caacVmlbz8Qcsbz9JC9a/Sharebuilder
-------------------------------------------------------------------
Hi William,
I'm not sure your analysis holds true. My experience is that you
cannot convert to equivalent full cycles in a linear fashion. Deep
discharges in an electric vehicle where recharging follows
immediately is one thing - and my experience there (and in the lift
truck industry: RE: Battery Book One by Curtis Instruments) is that
90-95% DOD maximizes battery/energy economics.
But in a home power system where 100% or even 80% DOD ensures that
you are going to spend alot of your time with less than 50% charge in
your batteries due to slow charging from the PV array and cloudy days
and such means that you are going to sulfate the life out of those
batteries in short order.
I design all my off-grid systems and set all my set points so that
the batteries never fall below 45% charge (55% DOD).
Happy Returning of the Light,
Jeff C.
Village Power Design
>Your free subscription is supported by today's sponsor:
>-------------------------------------------------------------------
>Amazing Diet Patch
>The fastest - Easiest way to lose weight! Try it now FREE!
>http://click.topica.com/caacVmibz8Qcsa9hBZia/MyDietPatches
>-------------------------------------------------------------------
>
>Very interesting cycle life curve. If you convert the data to equivalent
>full-cycle values, ie, 10% x 4398 = AH of 439.8 full cycles. And from
>that, it's easy to see the most economical DOD design:
>
>E-Cycles DOD
>440 10%
>464 20%
>484 30%
>506 40%
>518 50%
>530 60%
>542 70%
>558 80%
>570 90%
>600 100%
>
>Based on this data, the economically optimized configuration would
>be designed around the deepest possible DOD. If the data is correct,
>there is clear *penalty* for shallow battery cycling, and a *benefit*
>to deep cycles. When you also consider the time-value of money,
>a smaller pack lets you keep the incremental cost for a larger pack
>in you pocket (or bank, collecting interest) until later when needed.
>The important negative factors are that 1) designing around deep DOD
>leaves less margin for discharge variation/capacity decline, 2) more
>frequent battery pack replacements do come with a cost.
>
>In any case, this does sort of corroborate peoples not-so-great
>results with L16 packs for solar applications (vis a vis cheaper
>golf cart batteries or "real" solar batteries).
>
>/wk
>
>For example, at 50% DOD you get 518
>
>At 07:09 AM 12/29/2004, Todd Cory, Mt. Shasta Energy Services wrote:
>
>>Replying to my own message again... I checked out the
>>spreadsheet... here it is
>>in plain text:
>>
>>L16
>>exp. cycles % DOD
>>4398 10
>>2322 20
>>1614 30
>>1266 40
>>1036 50
>>884 60
>>774 70
>>698 80
>>633 90
>>600 100
>
>--
>[Non-text portions of this message have been removed]
>
>Your free subscription is supported by today's sponsor:
>-------------------------------------------------------------------
>Buy Stocks and Index Funds for just $4 No Account or Investment
>Minimums and No Inactivity Fees Automatically invest weekly or
>monthly and build your future.
>http://click.topica.com/caacVmlbz8Qcsa9hBZif/Sharebuilder
>-------------------------------------------------------------------
>
>- - - -
>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/etiquette.php
>
>Check out participant bios: www.mrsharkey.com/wrenches/
>
>Hosted by Home Power magazine
>
>Moderator: michael.welch at homepower.com
--
~~~~~~~~~~~~~
Jeff Clearwater
Village Power Design Associates
Sustainable Energy & Water Solutions for Home & Village
http://www.villagepower.com
gosolar at villagepower.com
530-470-9166
877-SOLARVillage
877-765-2784
425 Nimrod St.
Nevada City, CA 95959
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`~
==========================================================
Extra! Extra! Read all about it! Get the latest weather,
sports, and lifestyle news you can't afford to miss, all
at a price you can afford to pay! Click now!
http://click.topica.com/caaa9eYbz8Qcsbz9JC9f/TopOffers
==========================================================
- - - -
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/etiquette.php
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
--^----------------------------------------------------------------
</x-flowed>
More information about the RE-wrenches
mailing list