From: John A. <jal...@sp...> - 2007-03-23 15:56:26
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Thanks for the reply. I've been curious about the superCap for some time, but haven't seen an actual implementation. Some of the general references I have seen mention caution and that some kind of protection circuit would be required, as a large value capacitor (in the Farad range) would act like a short circuit for a brief instant and possibly damage things. What size cap are you using, and are you using any kind of protection? Thanks again for the reply, John Alfredo -----Original Message----- From: gum...@li... [mailto:gum...@li...] On Behalf Of tim...@co... Sent: Thursday, March 22, 2007 1:25 PM To: General mailing list for gumstix users. Subject: Re: [Gumstix-users] batteries Hi John, Here are some links: http://www.neonixie.com/store/product_info.php?products_id=261 http://docwiki.gumstix.org/Batteries http://digikey.com search for aerogel Hope this helps Tim -------------- Original message ---------------------- From: "John Alfredo" <jal...@sp...> > Hi Tim, > > What are you using for a supercap? Does it require any additional > circuitry? Do you have a reference you can point me to on this? > > John Alfredo > > -----Original Message----- > From: gum...@li... > [mailto:gum...@li...] On Behalf Of > tim...@co... > Sent: Sunday, March 11, 2007 12:06 PM > To: General mailing list for gumstix users. > Subject: Re: [Gumstix-users] batteries > > Hi Alex, > > > Why do you want to put a supercap in parallel with the pack? > > > Batteries have a constant current and a max current rating. > If you exceed this rating then the battery will have a low > efficiency and you will get a short run time. Adding a super cap > help reduce peak current loads thus extending battery life. > This is a problem mainly when using Ethernet. > > Tim > > -------------- Original message ---------------------- > From: Alex <kb...@gm...> > > You might consider lithium polymer batteries (probably the cheapest way to > > get a lipo and charger is from an auction for a cell phone battery and > > charger on ebay). They have even higher energy density than li-ion > > batteries, and they avoid a lot of their disadvantages. > > > > NiCd batteries are very cheap and can last a long time if cared for > propely > > (they require a full discharge and a peak charge to operate at full > > potential). NiMH batteries have their own set of quirks and > > charging/discharging needs, but they are fairly cheap to replace and don't > > suffer from the memory effect which plagues NiCds. They're a pretty good > > choice. Lithium Polymer batteries are probably the most abuse resistant, > and > > have the highest energy density, but they're also the most expensive (by a > > large margin), and require special charging circuitry (not a problem if > you > > steal it from a cell phone charger, I guess). > > > > Why do you want to put a supercap in parallel with the pack? > > > > On 3/11/07, Daniel O'Shea <da...@oz...> wrote: > > > > > > I've been thinking about power, and comparing different battery > > > chemistries: > > > > > > http://www.powerstream.com/Compare.htm > > > > > > ...if I have enough space to accommodate four AA sized cells, then I > > > can't see any real advantage to using LiIon batteries apart from the > > > possibility of not having to remove them for recharging (and weight I > > > suppose), but if four NiMH (or NiCad) AA rechargeables with a supercap > > > in parallel could provide equivalent power, plus more usable recharge > > > cycles, as well as avoiding all of the disadvantages of LiIon: > > > > > > http://en.wikipedia.org/wiki/Lithium-ion_battery#Disadvantages > > > > > > ...then it seems like the way to go to me? > > > > > > > ------------------------------------------------------------------------- > > > Take Surveys. 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Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ gumstix-users mailing list gum...@li... https://lists.sourceforge.net/lists/listinfo/gumstix-users |