[RE-wrenches] Best Battery

Jeff Clearwater jeffc at villagepowerdesign.com
Tue Aug 11 16:35:59 EDT 2020 

Yes Richard is right. When doing these one cycle or lifetime comparisons 
we should derate the rated or useful KWH figures by the round trip 
efficiency:

Round Trip Efficiencies:

FLA - 82-85%
AGM - 88-92%
AGM-Carbon - 90-94%
LFP - 94%-98%

:)

jc

Richard Scott wrote on 8/11/20 10:35 AM:
> Also keep in mind that the battery charge/discharge efficiency is much 
> higher for lithium batteries compared to lead acid.
>
> Richard
>
>
> On Tue, Aug 11, 2020 at 8:17 AM Jay <jay.peltz at gmail.com 
> <mailto:jay.peltz at gmail.com>> wrote:
>
>     Hi William,
>
>     I dont do the math based on up front kwh cost, but on lifetime kWh
>     based on the number of cycles per average DOD that are going to be
>     used. I use this same formula to compare all batteries to each other.
>
>     Jay
>
>     Peltz power.
>
>     For example, a Rolls L16 ex has 3500 cycles at 50% DOD, and it’s a
>     371 amp hr at 6v  or 2.226 kWh
>     Retail is $400
>
>     3500 cycles x 1.1 kWh At 50 DOD=3850 kWh
>     $400 / 3850 kWh = $.10 kWh
>     10 years of 50% cycling daily
>
>     Compared to say a mid grade US battery, 1400 cycles to 50%, 400
>     amp hr. 2.4 kWh
>     $325/1680 kWh = $.19 kWh.
>     3.8 yrs life
>
>     Compare to say BI
>     $1000 kWh roughly.
>     If you get 10,000 cycles, that works out to same cost. $.10 per kWh.
>     27 yrs, but will the chemistry actually last that long?
>     However, you have a massive upfront money cost.
>     And for those of us off grid, you can’t really cycle 100%. And
>     many lithium in the fine print don’t want you to charge to 100%
>     daily. Let’s assume you start the generator at 10% and charge to
>     95%, now your usable amount is actually 85%, not 100%.
>     Cost per kWh goes to $.12.
>
>
>
>
>>     On Aug 11, 2020, at 6:04 AM, William Miller
>>     <william at millersolar.com <mailto:william at millersolar.com>> wrote:
>>
>>     
>>
>>     Friends:
>>
>>     I am hoping y’all can tell me I am doing something wrong with my
>>     arithmetic.  I have registered to purchase Blue Planet batteries
>>     and priced the product.  I come up with math that indicates that
>>     comparing usable amp/hours to usable amp/hours, that the Blue
>>     Planet is 5 times the cost of a flooded L-16 battery array on a
>>     cost per kilowatt/hour.  Can this be true?
>>
>>     I am using these parameters:
>>
>>     1.DOD for flooded L16s: 50%
>>
>>     2.DOD for Blue Planet: 100%
>>
>>     I hope I am wrong.
>>
>>     Also, we often install battery arrays that are upwards of 4,000
>>     AH.  For example, we installed 5,668 of East Penn flooded
>>     batteries on a couple of projects.  To acquire the same capacity
>>     in Blue Planet would require 9 cabinets (again 50% DOD versus
>>     100% DOD).  Is this correct design?  Is it practical to install 9
>>     cabinets?  Does the system detect and compensate for circulating
>>     currents in this many parallel strings?
>>
>>     Thanks in advance.
>>
>>     William Miller
>>
>>     *From:*RE-wrenches
>>     [mailto:re-wrenches-bounces at lists.re-wrenches.org
>>     <mailto:re-wrenches-bounces at lists.re-wrenches.org>] *On Behalf Of
>>     *Jerry Shafer
>>     *Sent:* Sunday, August 9, 2020 12:02 PM
>>     *To:* RE-wrenches
>>     *Subject:* Re: [RE-wrenches] Best Battery
>>
>>     Wrenchel have been very happy with all my Blue Planet battery
>>     systems, best battery you will install.
>>
>>     Jerry
>>
>>     On Sun, Aug 9, 2020, 11:19 AM
>>     <drake.chamberlin at redwoodalliance.org
>>     <mailto:drake.chamberlin at redwoodalliance.org>> wrote:
>>
>>         Hello Wrenches,
>>
>>         What is the best Li-Ion battery to use with an off grid system?
>>
>>         Thanks,
>>
>>         Drake
>>         Athens Electric
>>
>>         -- 
>>         _______________________________________________
>>         List sponsored by Redwood Alliance
>>
>>         List Address: RE-wrenches at lists.re-wrenches.org
>>         <mailto:RE-wrenches at lists.re-wrenches.org>
>>
>>         Change listserver email address & settings:
>>         http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>>         List-Archive:
>>         http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>
>>         List rules & etiquette:
>>         www.re-wrenches.org/etiquette.htm
>>         <http://www.re-wrenches.org/etiquette.htm>
>>
>>         Check out or update participant bios:
>>         www.members.re-wrenches.org <http://www.members.re-wrenches.org>
>>
>>     _______________________________________________
>>     List sponsored by Redwood Alliance
>>
>>     List Address: RE-wrenches at lists.re-wrenches.org
>>     <mailto:RE-wrenches at lists.re-wrenches.org>
>>
>>     Change listserver email address & settings:
>>     http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>>     List-Archive:
>>     http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>
>>     List rules & etiquette:
>>     www.re-wrenches.org/etiquette.htm
>>     <http://www.re-wrenches.org/etiquette.htm>
>>
>>     Check out or update participant bios:
>>     www.members.re-wrenches.org <http://www.members.re-wrenches.org>
>>
>     _______________________________________________
>     List sponsored by Redwood Alliance
>
>     List Address: RE-wrenches at lists.re-wrenches.org
>     <mailto:RE-wrenches at lists.re-wrenches.org>
>
>     Change listserver email address & settings:
>     http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
>     List-Archive:
>     http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
>     List rules & etiquette:
>     www.re-wrenches.org/etiquette.htm
>     <http://www.re-wrenches.org/etiquette.htm>
>
>     Check out or update participant bios:
>     www.members.re-wrenches.org <http://www.members.re-wrenches.org>
>
>
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> List Address:RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> www.members.re-wrenches.org
>


-- 
~~~~~~~~~~~
Jeff Clearwater
Village Power Design
linkedin <https://www.linkedin.com/in/jeff-clearwater-0622a312/>
www.villagepowerdesign.com <http://www.villagepowerdesign.com>
cell - 413-559-9763
~~~~~~~~~~~~~~~~~~~~~~~
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches_lists.re-wrenches.org/attachments/20200811/fa2bd46a/attachment.htm>

More information about the RE-Wrenches mailing list