[RE-wrenches] Small Wh and large LRA

[Mick Abraham]

Mark, you may wish to contact the engineers at Maxwell to see about adding
some ultracapacitors to a small battery bank. The caps would "charge up"
during idle times and be there to provide the kick when the item starts up.
Here's a link: http://www.maxwell.com/ultracapacitors/

The capacitors cannot replace the battery bank but would add a lot of surge
ability. Be sure to report back on the List so we can see your results and
learn together.

Thinking lower tech...if the high surge item is a pump perhaps the same mfr.
offers a soft start package. OR: there are some aftermarket soft start
controllers in the well industry that may help.

Mick Abraham, Proprietor
www.abrahamsolar.com

Voice: 970-731-4675


On Thu, Mar 18, 2010 at 4:41 AM, Warren Lauzon <windsun at wind-sun.com> wrote:

>  The kicker is the large startup, so you may need to use batteries with
> low internal resistance, such as the Concorde AGM's. You will also have to
> make sure your cables are good for the max current to avoid any voltage drop
> which would cause a low voltage shutdown.
>
> Aside from that, just go with around 200-250 AH of battery storage
> (assuming 12 volts). A pair of golf car size batteries would probably work
> if they are something like Crown or Trojan.
>
>
> ..................................................................................................
> Northern Arizona Wind & Sun - Electricity From The Sun Since 1979
> Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
>
> ..................................................................................................
>
>   ----- Original Message -----
> *From:* Mark Dickson <Mark at OasisMontana.com>
> *To:* 'RE-wrenches' <re-wrenches at lists.re-wrenches.org>
> *Sent:* Wednesday, March 17, 2010 2:56 PM
> *Subject:* [RE-wrenches] Small Wh and large LRA
>
>  Hello Wrenches,
>
> I’ve been asked to design a battery based PV system for a load that has a
> high start up surge of about 62A @ 115V.  The thing is, once it is running
> it will only run for ~10 minutes per day at 11A.  So the daily loads are
> very low.  How do I size a battery bank large enough to handle the large
> start-up surge, yet reasonable enough to cover the modest daily load?  Is
> there a rule-of-thumb for this?
>
>
>
> Best regards,
>
>
>
> Mark Dickson,
>
> NABCEP Certified Solar PV Installer ™
>
> Oasis Montana Inc.
>
> ------------------------------
>
> _______________________________________________
> 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
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20100318/8ec683cb/attachment-0004.html>