NimH AAA to 5V, suggestions?
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From: Jan Panteltje on 8 Aug 2010 17:32 On a sunny day (Sun, 8 Aug 2010 14:13:41 -0700 (PDT)) it happened dagmargoodboat(a)yahoo.com wrote in <c584879b-1976-4d86-ada7-e4cdb40f354d(a)f6g2000yqa.googlegroups.com>: >On Aug 8, 1:18�pm, Jan Panteltje <pNaonStpealm...(a)yahoo.com> wrote: >> dagmargoodb...(a)yahoo.com wrote in > > >> >Wondering what other designers do, I started picking up AA cells >> >people toss on the road. �They're usually 1.3v, only 20% used for an >> >alkaline cell.(*) �That's a sin. �If we're going to condone toss-awa= >ys >> >we ought to at least use them fully, don't you agree? �Keeps them off >> >the road, out of the waste stream, and the user enjoys the longer run >> >time too. �Win-win. >> >> Do not alkaline sort of go back up after you remove the load? >> Zi effect? >> May read 1.3 but could well read 1 V in a camera for example with a lot o= >f current charging the flash >> capacitor. > >Roadside batteries come mostly from joggers and MP3 addicts. >Apparently joggers run on AA cells. They wont get far that way :-)
From: Jan Panteltje on 8 Aug 2010 17:43 On a sunny day (Mon, 09 Aug 2010 07:15:58 +1000) it happened Grant <omg(a)grrr.id.au> wrote in <4r6u56prg8d53gmcva02n2kcfvifb0o8u4(a)4ax.com>: >>If the thing does not work right on an almost empty battery then 1000 is the best choice :-) > >It varies so much, my canon A580 camera reports Alkaline cell low too >early, and doesn't like any but the best NiMH cells. So one can go on >to take a few dozen shots sans flash (in warm weather) on alkaline >before the cam packs it in and tells one to replace the battery. > >On NiMH it's only a few shots before death, battery is measured on >load too. > >Some stuff on canon A590, now sadly expired, too expensive to fix. > > http://bugsplatter.id.au/chdk/ > http://bugsplatter.id.au/chdk/a590-power.html > http://bugsplatter.id.au/chdk/a590-power-2.html > >Written up just over a year ago, examines power behaviour of A590 2 AA >cell camera, probably roughly applies to other Canon models designed >for 2 cell operation. > >Grant. I have a canon A470. Same story, but my NiMH holds out a bit longer. I have never used it with non-rechargeables. It sometimes reports empty, and that message then goes away after taking a lot of pics, beats me. If you do not frequently take pictures, the low capacity NiMH last longer and have a lower self-discharge. That means you wont face an empty battery when you need the camera. My Duracell 2500 mAh are empty if left for a week or so, in this camera. The Duracell 1700 mAh just lasts for several weeks, so I only use those. There also exist 'Eneloop' batteries, those are NiMH that keep 85% charge for almost a year, have slightly less capacity too, ideal if you only take pictures every now and then. What it all boils down to, is that I always have some NiMH in the chargers, with 2 chargers running 24/7. Then I have the Li-ion batteries for other camers too.. Then the laptop is charging. Also have a huge sealed lead-acid on backup charge. :-)
From: JosephKK on 8 Aug 2010 19:20 On Mon, 02 Aug 2010 15:38:53 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >I was looking for some 9V rechargeable blocks to power my sign_led display, > http://panteltje.com/panteltje/pic/sign_pic/ >to make it portable (put it in the car side window for example). >Those are expensive, I had one but cannot find it. >So I decided to build a small converter 1.2 to 5 V DC, >singe AA cell about 2.2Ah should give about 10 hours.. > ______________|\|_________ +5 > | |/| | > ---------------------------|-- Schottky | > | | | 5.6_______ || ( | 5t | > | | [ ] | 2t )|| (___| | > | | |--- ---- || ( 2t __ __ | > | | | | || | | | | | | >1.2 V - === | | | --- ----- === >AA --- --- | | c NPN Si --- >NiMH | |22u | ------ b |150u > | | | e BC547 | > | | === | | > | | --- | | > | | |1u | | > ------------------------------------------------------- > Orignal Hand drawn ASCII >That works OK, does not get hot, but maybe it can be done better. >Input current is about 220mA, output about 30mA >Waveform at the collector is a nice assymetrical square wave, but it is a bit a 'soft' >output, loading it lowers the voltage a lot, high Zi. >Also for the ferrite core I grabbed some old small filter core. >no idea what stuff it is made of. >I do use the battery voltage in series to improve efficiency, > >I know there are little chips for 1.2 to 5V or 3.3V, >what is a good jellybean one? >Preferably one I can see with the naked eye and can buy in Europe :-) Hate to be picky but that efficiency is really poor, 240 mW in and 150 mW out. Maybe try a more standard boost configuration.
From: krw on 8 Aug 2010 20:44 On Sun, 08 Aug 2010 21:32:23 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >On a sunny day (Sun, 8 Aug 2010 14:13:41 -0700 (PDT)) it happened >dagmargoodboat(a)yahoo.com wrote in ><c584879b-1976-4d86-ada7-e4cdb40f354d(a)f6g2000yqa.googlegroups.com>: > >>On Aug 8, 1:18�pm, Jan Panteltje <pNaonStpealm...(a)yahoo.com> wrote: >>> dagmargoodb...(a)yahoo.com wrote in >> >> >>> >Wondering what other designers do, I started picking up AA cells >>> >people toss on the road. �They're usually 1.3v, only 20% used for an >>> >alkaline cell.(*) �That's a sin. �If we're going to condone toss-awa= >>ys >>> >we ought to at least use them fully, don't you agree? �Keeps them off >>> >the road, out of the waste stream, and the user enjoys the longer run >>> >time too. �Win-win. >>> >>> Do not alkaline sort of go back up after you remove the load? >>> Zi effect? >>> May read 1.3 but could well read 1 V in a camera for example with a lot o= >>f current charging the flash >>> capacitor. >> >>Roadside batteries come mostly from joggers and MP3 addicts. >>Apparently joggers run on AA cells. > >They wont get far that way :-) They keep going, and going, and going...
From: David Eather on 8 Aug 2010 21:54
On 9/08/2010 9:20 AM, JosephKK wrote: > On Mon, 02 Aug 2010 15:38:53 GMT, Jan Panteltje > <pNaonStpealmtje(a)yahoo.com> wrote: > >> I was looking for some 9V rechargeable blocks to power my sign_led display, >> http://panteltje.com/panteltje/pic/sign_pic/ >> to make it portable (put it in the car side window for example). >> Those are expensive, I had one but cannot find it. >> So I decided to build a small converter 1.2 to 5 V DC, >> singe AA cell about 2.2Ah should give about 10 hours.. >> ______________|\|_________ +5 >> | |/| | >> ---------------------------|-- Schottky | >> | | | 5.6_______ || ( | 5t | >> | | [ ] | 2t )|| (___| | >> | | |--- ---- || ( 2t __ __ | >> | | | | || | | | | | | >> 1.2 V - === | | | --- ----- === >> AA --- --- | | c NPN Si --- >> NiMH | |22u | ------ b |150u >> | | | e BC547 | >> | | === | | >> | | --- | | >> | | |1u | | >> ------------------------------------------------------- >> Orignal Hand drawn ASCII >> That works OK, does not get hot, but maybe it can be done better. >> Input current is about 220mA, output about 30mA >> Waveform at the collector is a nice assymetrical square wave, but it is a bit a 'soft' >> output, loading it lowers the voltage a lot, high Zi. >> Also for the ferrite core I grabbed some old small filter core. >> no idea what stuff it is made of. >> I do use the battery voltage in series to improve efficiency, >> >> I know there are little chips for 1.2 to 5V or 3.3V, >> what is a good jellybean one? >> Preferably one I can see with the naked eye and can buy in Europe :-) > > Hate to be picky but that efficiency is really poor, 240 mW in and 150 > mW out. Maybe try a more standard boost configuration. I don't see the appeal compared to lt1110 - twice as many parts including a custom transformer plus lower efficiency. Not really a winner in my book. |