[RE-wrenches] unique battery bank design question

[Darryl Thayer]

I would guess that it depends upon the use cycle, you always put more electrons back in than you take out, If you are assuming a 90% recharge efficiency recharging once every three days, a few percent of the recharge excess energy could be used.  BUT I strongly agree I have seen too many problems with taped battery banks so avoid is the first rule.  
 
This would make an interesting measurement.     

From: mac Lewis <maclewis1 at gmail.com>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Thursday, September 1, 2011 3:59 PM
Subject: Re: [RE-wrenches] unique battery bank design question


Glad I asked!  Do these converters have a decent expected lifetime?  If anyone has any good DC-DC converters to peddle, please contact me off list. 

Thanks for the help. 


On Thu, Sep 1, 2011 at 2:48 PM, Jason Szumlanski <Jason at fafcosolar.com> wrote:

1a x 12V x 24hrs = 288 watt-hours on a 48,000 watt-hour battery. My math
>shows 0.6% of the nominal capacity. And that assumes there is no
>charging source present.
>
>That being said, I would agree that avoiding it altogether is the wise
>decision, but there has to be a level at which the tapped load is
>inconsequential. I'm just curious what that level is!
>
>Jason Szumlanski
>Fafco Solar
>
>
>
>-----Original Message-----
>From: re-wrenches-bounces at lists.re-wrenches.org
>[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Hugh
>Sent: Thursday, September 01, 2011 4:21 PM
>To: RE-wrenches
>Subject: Re: [RE-wrenches] unique battery bank design question
>
>
>At 15:57 -0400 1/9/11, Jason Szumlanski wrote:
>
>>  A 1A @ 12V fan on a 1000aH @48V battery bank can't make any real
>>difference. Correct me if I am wrong!
>>
>
>Yes that is wrong, because after 4 days you have removed 10% of the
>nominal capacity or about 20% of the usable capacity.
>
>Tapping off batteries is bad practice as universally agreed.  One way
>to mitigate it could be to use separate shunt regulators (diversion
>load controllers) for each 12-volt portion.  This would probably be a
>healthy feature for 'balancing' any 48 volt battery and would
>possibly rescue a tapped battery, given enough surplus energy
>availability (which is usually the key thing for battery health).
>
>Just a thought.
>
>The snag is the cost.  ho hum.
>--
>Hugh Piggott
>
>Scoraig
>http://www.scoraigwind.co.uk
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & 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 participant bios:
>www.members.re-wrenches.org
>
>_______________________________________________
>List sponsored by Home Power magazine
>
>List Address: RE-wrenches at lists.re-wrenches.org
>
>Options & 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 participant bios:
>www.members.re-wrenches.org
>
>


-- 



Mac Lewis

"Yo solo sé que no sé nada." -Sócrates

_______________________________________________
List sponsored by Home Power magazine

List Address: RE-wrenches at lists.re-wrenches.org

Options & 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 participant bios:
www.members.re-wrenches.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20110901/5c0bc9ab/attachment-0004.html>