Forums

Wanted: A 'joule thief' style circuit design...

Started by ~misfit~ September 29, 2019
... that I can use to drain alkaline cells and push the 'charge' into either a lithium-Ion cell 
(for a flashlight), a phone or a powerbank.

I have a combined wireless doorbell - inside/outside thermometer that I quite like. Unfortunately 
it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's the only thing I have that 
doesn't run on rechargeable cells.)

The sender uses AAA cells and the receiver uses AA cells and I buy good quality (expensive) cells 
to get the longest run-time between changes (as it's a PITA to re-pair them and re-set the clock in 
the receiver too often). I though of converting the receiver to run on a single 14500 Li-Ion cell 
(AA size) and a buck regulator or even a wall-wart but that still doesn't solve the issue of the 
sender.

I dislike throwing good quality alkalines away when they still have ~65% of their capacity 
remaining but have had enough leak-disasters to not want to put already semi-discharged cells in 
remote controllers etc. where they then get forgotten about until things stop working. (I've never 
had an Eneloop leak and they run my remotes for about 3 years between charges.)

So I'd like to make a gizmo that takes a single alkaline and pushes out ~5v through a USB cable for 
as long as the cell has juice, preferably at a reasonable current. I have a few different pre-made 
boost modules from the usual suspects but when I tested one the output voltage curve dropped with 
the input so that it wasn't very successful.

If anyone has any ideas for something I can put together with a bit of veroboard or similar I'm all 
ears. I'm tired of having loads of half-used cells sitting around but don't want to just chuck them 
away. I've thought of this before but it's fresh in my mind as I've just bought a 32-pack of each 
size cell and they cost quite a chuck of change.

TIA.
-- 
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy little classification 
in the DSM"
David Melville

This is not an email and hasn't been checked for viruses by any half-arsed self-promoting software.
On Mon, 30 Sep 2019 00:19:07 +1300, ~misfit~
<shaun.at.pukekohe@gmail.com> wrote:

>... that I can use to drain alkaline cells and push the 'charge' into either a lithium-Ion cell >(for a flashlight), a phone or a powerbank. > >I have a combined wireless doorbell - inside/outside thermometer that I quite like. Unfortunately >it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's the only thing I have that >doesn't run on rechargeable cells.) > >The sender uses AAA cells and the receiver uses AA cells and I buy good quality (expensive) cells >to get the longest run-time between changes (as it's a PITA to re-pair them and re-set the clock in >the receiver too often). I though of converting the receiver to run on a single 14500 Li-Ion cell >(AA size) and a buck regulator or even a wall-wart but that still doesn't solve the issue of the >sender. > >I dislike throwing good quality alkalines away when they still have ~65% of their capacity >remaining but have had enough leak-disasters to not want to put already semi-discharged cells in >remote controllers etc. where they then get forgotten about until things stop working. (I've never >had an Eneloop leak and they run my remotes for about 3 years between charges.) > >So I'd like to make a gizmo that takes a single alkaline and pushes out ~5v through a USB cable for >as long as the cell has juice, preferably at a reasonable current. I have a few different pre-made >boost modules from the usual suspects but when I tested one the output voltage curve dropped with >the input so that it wasn't very successful. > >If anyone has any ideas for something I can put together with a bit of veroboard or similar I'm all >ears. I'm tired of having loads of half-used cells sitting around but don't want to just chuck them >away. I've thought of this before but it's fresh in my mind as I've just bought a 32-pack of each >size cell and they cost quite a chuck of change. > >TIA.
https://www.eleccircuit.com/wp-content/uploads/2018/09/step-up-dc-converter-12v-to-5v-fo-micro-computer-min.png https://www.electroschematics.com/portable-5v-power-box/ http://electronics-diy.com/electronic_schematic.php?id=742
On Mon, 30 Sep 2019 00:19:07 +1300, ~misfit~
<shaun.at.pukekohe@gmail.com> wrote:

>... that I can use to drain alkaline cells and push the 'charge' into either a lithium-Ion cell >(for a flashlight), a phone or a powerbank. > >I have a combined wireless doorbell - inside/outside thermometer that I quite like. Unfortunately >it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's the only thing I have that >doesn't run on rechargeable cells.) > >The sender uses AAA cells and the receiver uses AA cells and I buy good quality (expensive) cells >to get the longest run-time between changes (as it's a PITA to re-pair them and re-set the clock in >the receiver too often). I though of converting the receiver to run on a single 14500 Li-Ion cell >(AA size) and a buck regulator or even a wall-wart but that still doesn't solve the issue of the >sender. > >I dislike throwing good quality alkalines away when they still have ~65% of their capacity >remaining but have had enough leak-disasters to not want to put already semi-discharged cells in >remote controllers etc. where they then get forgotten about until things stop working. (I've never >had an Eneloop leak and they run my remotes for about 3 years between charges.) > >So I'd like to make a gizmo that takes a single alkaline and pushes out ~5v through a USB cable for >as long as the cell has juice, preferably at a reasonable current. I have a few different pre-made >boost modules from the usual suspects but when I tested one the output voltage curve dropped with >the input so that it wasn't very successful. > >If anyone has any ideas for something I can put together with a bit of veroboard or similar I'm all >ears. I'm tired of having loads of half-used cells sitting around but don't want to just chuck them >away. I've thought of this before but it's fresh in my mind as I've just bought a 32-pack of each >size cell and they cost quite a chuck of change. > >TIA.
If there is room for two AA cells in the sender why not substitute a lithium pouch cell and a regulator? Then you could charge the pouch cell while in the sender and never worry again about pairing the devices? Eric
On 30/09/2019 1:20 AM, default wrote:
> On Mon, 30 Sep 2019 00:19:07 +1300, ~misfit~ > <shaun.at.pukekohe@gmail.com> wrote: > >> ... that I can use to drain alkaline cells and push the 'charge' into either a lithium-Ion cell >> (for a flashlight), a phone or a powerbank. >> >> I have a combined wireless doorbell - inside/outside thermometer that I quite like. Unfortunately >> it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's the only thing I have that >> doesn't run on rechargeable cells.) >> >> The sender uses AAA cells and the receiver uses AA cells and I buy good quality (expensive) cells >> to get the longest run-time between changes (as it's a PITA to re-pair them and re-set the clock in >> the receiver too often). I though of converting the receiver to run on a single 14500 Li-Ion cell >> (AA size) and a buck regulator or even a wall-wart but that still doesn't solve the issue of the >> sender. >> >> I dislike throwing good quality alkalines away when they still have ~65% of their capacity >> remaining but have had enough leak-disasters to not want to put already semi-discharged cells in >> remote controllers etc. where they then get forgotten about until things stop working. (I've never >> had an Eneloop leak and they run my remotes for about 3 years between charges.) >> >> So I'd like to make a gizmo that takes a single alkaline and pushes out ~5v through a USB cable for >> as long as the cell has juice, preferably at a reasonable current. I have a few different pre-made >> boost modules from the usual suspects but when I tested one the output voltage curve dropped with >> the input so that it wasn't very successful. >> >> If anyone has any ideas for something I can put together with a bit of veroboard or similar I'm all >> ears. I'm tired of having loads of half-used cells sitting around but don't want to just chuck them >> away. I've thought of this before but it's fresh in my mind as I've just bought a 32-pack of each >> size cell and they cost quite a chuck of change. >> >> TIA. > https://www.eleccircuit.com/wp-content/uploads/2018/09/step-up-dc-converter-12v-to-5v-fo-micro-computer-min.png > https://www.electroschematics.com/portable-5v-power-box/ > http://electronics-diy.com/electronic_schematic.php?id=742
Brilliant! Thanks. -- Shaun. "Humans will have advanced a long, long way when religious belief has a cozy little classification in the DSM" David Melville This is not an email and hasn't been checked for viruses by any half-arsed self-promoting software.
On 30/09/2019 7:38 AM, etpm@whidbey.com wrote:
> On Mon, 30 Sep 2019 00:19:07 +1300, ~misfit~ > <shaun.at.pukekohe@gmail.com> wrote: > >> ... that I can use to drain alkaline cells and push the 'charge' into either a lithium-Ion cell >> (for a flashlight), a phone or a powerbank. >> >> I have a combined wireless doorbell - inside/outside thermometer that I quite like. Unfortunately >> it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's the only thing I have that >> doesn't run on rechargeable cells.) >> >> The sender uses AAA cells and the receiver uses AA cells and I buy good quality (expensive) cells >> to get the longest run-time between changes (as it's a PITA to re-pair them and re-set the clock in >> the receiver too often). I though of converting the receiver to run on a single 14500 Li-Ion cell >> (AA size) and a buck regulator or even a wall-wart but that still doesn't solve the issue of the >> sender. >> >> I dislike throwing good quality alkalines away when they still have ~65% of their capacity >> remaining but have had enough leak-disasters to not want to put already semi-discharged cells in >> remote controllers etc. where they then get forgotten about until things stop working. (I've never >> had an Eneloop leak and they run my remotes for about 3 years between charges.) >> >> So I'd like to make a gizmo that takes a single alkaline and pushes out ~5v through a USB cable for >> as long as the cell has juice, preferably at a reasonable current. I have a few different pre-made >> boost modules from the usual suspects but when I tested one the output voltage curve dropped with >> the input so that it wasn't very successful. >> >> If anyone has any ideas for something I can put together with a bit of veroboard or similar I'm all >> ears. I'm tired of having loads of half-used cells sitting around but don't want to just chuck them >> away. I've thought of this before but it's fresh in my mind as I've just bought a 32-pack of each >> size cell and they cost quite a chuck of change. >> >> TIA. > If there is room for two AA cells in the sender why not substitute a > lithium pouch cell and a regulator? Then you could charge the pouch > cell while in the sender and never worry again about pairing the > devices? > Eric
The sender uses two AAA cells and is very tightly packaged. Also it's waterproof as it's outside in the elements so I don't want to mess with it too much. Cheers, -- Shaun. "Humans will have advanced a long, long way when religious belief has a cozy little classification in the DSM" David Melville This is not an email and hasn't been checked for viruses by any half-arsed self-promoting software.
On 2019-09-29, ~misfit~ <shaun.at.pukekohe@gmail.com> wrote:
> ... that I can use to drain alkaline cells and push the 'charge' into either a lithium-Ion cell > (for a flashlight), a phone or a powerbank. > > I have a combined wireless doorbell - inside/outside thermometer that I quite like. Unfortunately > it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's the only thing I have that > doesn't run on rechargeable cells.) > > The sender uses AAA cells and the receiver uses AA cells and I buy good quality (expensive) cells > to get the longest run-time between changes (as it's a PITA to re-pair them and re-set the clock in > the receiver too often). I though of converting the receiver to run on a single 14500 Li-Ion cell > (AA size) and a buck regulator or even a wall-wart but that still doesn't solve the issue of the > sender. > > I dislike throwing good quality alkalines away when they still have ~65% of their capacity > remaining but have had enough leak-disasters to not want to put already semi-discharged cells in > remote controllers etc. where they then get forgotten about until things stop working. (I've never > had an Eneloop leak and they run my remotes for about 3 years between charges.) > > So I'd like to make a gizmo that takes a single alkaline and pushes out ~5v through a USB cable for > as long as the cell has juice, preferably at a reasonable current. I have a few different pre-made > boost modules from the usual suspects but when I tested one the output voltage curve dropped with > the input so that it wasn't very successful.
these are cheap and will do it https://aliexpress.com/item/32786144773.html how often do you need an unreliable portable USB charger? the cost to run that thing will not be much less than the cost to run a plug-in usb charger, but the hassle will be greater.
> If anyone has any ideas for something I can put together with a bit of veroboard or similar I'm all > ears. I'm tired of having loads of half-used cells sitting around but don't want to just chuck them > away. I've thought of this before but it's fresh in my mind as I've just bought a 32-pack of each > size cell and they cost quite a chuck of change.
It seems like a waste of time to use batteries, even free batteries, where mains power is available. can you run a wire to power the door button? maybe you can find some device to run off the partly used batteries, a portable radio perhaps. -- When I tried casting out nines I made a hash of it.
On Mon, 30 Sep 2019 15:07:18 +1300, ~misfit~
<shaun.at.pukekohe@gmail.com> wrote as underneath :

>On 30/09/2019 7:38 AM, etpm@whidbey.com wrote: >> On Mon, 30 Sep 2019 00:19:07 +1300, ~misfit~ >> <shaun.at.pukekohe@gmail.com> wrote: >> >>> ... that I can use to drain alkaline cells and push the 'charge' into either a lithium-Ion cell >>> (for a flashlight), a phone or a powerbank. >>> >>> I have a combined wireless doorbell - inside/outside thermometer that I quite like. Unfortunately >>> it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's the only thing I have that >>> doesn't run on rechargeable cells.) >>> >>> The sender uses AAA cells and the receiver uses AA cells and I buy good quality (expensive) cells >>> to get the longest run-time between changes (as it's a PITA to re-pair them and re-set the clock in >>> the receiver too often). I though of converting the receiver to run on a single 14500 Li-Ion cell >>> (AA size) and a buck regulator or even a wall-wart but that still doesn't solve the issue of the >>> sender. >>> >>> I dislike throwing good quality alkalines away when they still have ~65% of their capacity >>> remaining but have had enough leak-disasters to not want to put already semi-discharged cells in >>> remote controllers etc. where they then get forgotten about until things stop working. (I've never >>> had an Eneloop leak and they run my remotes for about 3 years between charges.) >>> >>> So I'd like to make a gizmo that takes a single alkaline and pushes out ~5v through a USB cable for >>> as long as the cell has juice, preferably at a reasonable current. I have a few different pre-made >>> boost modules from the usual suspects but when I tested one the output voltage curve dropped with >>> the input so that it wasn't very successful. >>> >>> If anyone has any ideas for something I can put together with a bit of veroboard or similar I'm all >>> ears. I'm tired of having loads of half-used cells sitting around but don't want to just chuck them >>> away. I've thought of this before but it's fresh in my mind as I've just bought a 32-pack of each >>> size cell and they cost quite a chuck of change. >>> >>> TIA. >> If there is room for two AA cells in the sender why not substitute a >> lithium pouch cell and a regulator? Then you could charge the pouch >> cell while in the sender and never worry again about pairing the >> devices? >> Eric > >The sender uses two AAA cells and is very tightly packaged. Also it's waterproof as it's outside in >the elements so I don't want to mess with it too much.
Trouble is that the boost circuit takes a proportion of the available battery power to run, so trade off calculation required! See: https://www.ebay.co.uk/itm/DC-DC-1V-1-2V-1-5V-1-8V-2-5V-3V-to-DC-3-3V-Step-UP-Boost-Power-Supply-Converter/192311866315?hash=item2cc6ae33cb:g:ho0AAOSw-QZZwnWh
On 30/09/2019 8:39 PM, Charlie+ wrote:
> On Mon, 30 Sep 2019 15:07:18 +1300, ~misfit~ > <shaun.at.pukekohe@gmail.com> wrote as underneath : > >> On 30/09/2019 7:38 AM, etpm@whidbey.com wrote: >>> On Mon, 30 Sep 2019 00:19:07 +1300, ~misfit~ >>> <shaun.at.pukekohe@gmail.com> wrote: >>> >>>> ... that I can use to drain alkaline cells and push the 'charge' into either a lithium-Ion cell >>>> (for a flashlight), a phone or a powerbank. >>>> >>>> I have a combined wireless doorbell - inside/outside thermometer that I quite like. Unfortunately >>>> it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's the only thing I have that >>>> doesn't run on rechargeable cells.) >>>> >>>> The sender uses AAA cells and the receiver uses AA cells and I buy good quality (expensive) cells >>>> to get the longest run-time between changes (as it's a PITA to re-pair them and re-set the clock in >>>> the receiver too often). I though of converting the receiver to run on a single 14500 Li-Ion cell >>>> (AA size) and a buck regulator or even a wall-wart but that still doesn't solve the issue of the >>>> sender. >>>> >>>> I dislike throwing good quality alkalines away when they still have ~65% of their capacity >>>> remaining but have had enough leak-disasters to not want to put already semi-discharged cells in >>>> remote controllers etc. where they then get forgotten about until things stop working. (I've never >>>> had an Eneloop leak and they run my remotes for about 3 years between charges.) >>>> >>>> So I'd like to make a gizmo that takes a single alkaline and pushes out ~5v through a USB cable for >>>> as long as the cell has juice, preferably at a reasonable current. I have a few different pre-made >>>> boost modules from the usual suspects but when I tested one the output voltage curve dropped with >>>> the input so that it wasn't very successful. >>>> >>>> If anyone has any ideas for something I can put together with a bit of veroboard or similar I'm all >>>> ears. I'm tired of having loads of half-used cells sitting around but don't want to just chuck them >>>> away. I've thought of this before but it's fresh in my mind as I've just bought a 32-pack of each >>>> size cell and they cost quite a chuck of change. >>>> >>>> TIA. >>> If there is room for two AA cells in the sender why not substitute a >>> lithium pouch cell and a regulator? Then you could charge the pouch >>> cell while in the sender and never worry again about pairing the >>> devices? >>> Eric >> >> The sender uses two AAA cells and is very tightly packaged. Also it's waterproof as it's outside in >> the elements so I don't want to mess with it too much. > > Trouble is that the boost circuit takes a proportion of the available > battery power to run, so trade off calculation required! > See: > https://www.ebay.co.uk/itm/DC-DC-1V-1-2V-1-5V-1-8V-2-5V-3V-to-DC-3-3V-Step-UP-Boost-Power-Supply-Converter/192311866315?hash=item2cc6ae33cb:g:ho0AAOSw-QZZwnWh
Yep. My plan probably isn't worth how much I'd 'save' by not mains-charging whatever I use this for. However I dislike waste, especially energy waste. I'm probably better to just get a flashlight that uses 2/4 AA/AAA cells and use them up that way. I remember over a decade ago I had a cell phone (not a smart phone) that had an alternate battery cover / adapter that took 3 x AA cells (and had a bulge in it that made the phone a bit bigger). It was designed more as an 'emergency solution' to not having a charged battery than a day-to-day option. Anything would be better than having a drawer half-full of 65% good AA / AAA cells... -- Shaun. "Humans will have advanced a long, long way when religious belief has a cozy little classification in the DSM" David Melville This is not an email and hasn't been checked for viruses by any half-arsed self-promoting software.
On 30/09/2019 8:17 PM, Jasen Betts wrote:
> On 2019-09-29, ~misfit~ <shaun.at.pukekohe@gmail.com> wrote: >> ... that I can use to drain alkaline cells and push the 'charge' into either a lithium-Ion cell >> (for a flashlight), a phone or a powerbank. >> >> I have a combined wireless doorbell - inside/outside thermometer that I quite like. Unfortunately >> it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's the only thing I have that >> doesn't run on rechargeable cells.) >> >> The sender uses AAA cells and the receiver uses AA cells and I buy good quality (expensive) cells >> to get the longest run-time between changes (as it's a PITA to re-pair them and re-set the clock in >> the receiver too often). I though of converting the receiver to run on a single 14500 Li-Ion cell >> (AA size) and a buck regulator or even a wall-wart but that still doesn't solve the issue of the >> sender. >> >> I dislike throwing good quality alkalines away when they still have ~65% of their capacity >> remaining but have had enough leak-disasters to not want to put already semi-discharged cells in >> remote controllers etc. where they then get forgotten about until things stop working. (I've never >> had an Eneloop leak and they run my remotes for about 3 years between charges.) >> >> So I'd like to make a gizmo that takes a single alkaline and pushes out ~5v through a USB cable for >> as long as the cell has juice, preferably at a reasonable current. I have a few different pre-made >> boost modules from the usual suspects but when I tested one the output voltage curve dropped with >> the input so that it wasn't very successful. > > these are cheap and will do it > https://aliexpress.com/item/32786144773.html
I've actually already got some of those in my 'module collection'.
> how often do you need an unreliable portable USB charger? > the cost to run that thing will not be much less than the cost to run > a plug-in usb charger, but the hassle will be greater.
True.
>> If anyone has any ideas for something I can put together with a bit of veroboard or similar I'm all >> ears. I'm tired of having loads of half-used cells sitting around but don't want to just chuck them >> away. I've thought of this before but it's fresh in my mind as I've just bought a 32-pack of each >> size cell and they cost quite a chuck of change. > > It seems like a waste of time to use batteries, even free batteries, > where mains power is available.
Yeah, it's more the principle and not liking waste.
> can you run a wire to power the door button?
Not easily - and I rent so I don't want to go drilling holes in walls etc.
> maybe you can find some device to run off the partly used batteries, > a portable radio perhaps.
Radio? I haven't used one of those in years! However you're right, I think I'll use them in a flashlight or something that I *do* use. ;) Now I need to decide if buying a new flashlight (when I have several perfectly fine 18650-powered flashlights) works out better than wasting alkaline cells. Cheers, -- Shaun. "Humans will have advanced a long, long way when religious belief has a cozy little classification in the DSM" David Melville This is not an email and hasn't been checked for viruses by any half-arsed self-promoting software.
On 1/10/2019 3:04 PM, ~misfit~ wrote:
> On 30/09/2019 8:17 PM, Jasen Betts wrote: >> On 2019-09-29, ~misfit~ <shaun.at.pukekohe@gmail.com> wrote: >>> ... that I can use to drain alkaline cells and push the 'charge' into either a lithium-Ion cell >>> (for a flashlight), a phone or a powerbank. >>> >>> I have a combined wireless doorbell - inside/outside thermometer that I quite like. Unfortunately >>> it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's the only thing I have that >>> doesn't run on rechargeable cells.) >>> >>> The sender uses AAA cells and the receiver uses AA cells and I buy good quality (expensive) cells >>> to get the longest run-time between changes (as it's a PITA to re-pair them and re-set the clock in >>> the receiver too often). I though of converting the receiver to run on a single 14500 Li-Ion cell >>> (AA size) and a buck regulator or even a wall-wart but that still doesn't solve the issue of the >>> sender. >>> >>> I dislike throwing good quality alkalines away when they still have ~65% of their capacity >>> remaining but have had enough leak-disasters to not want to put already semi-discharged cells in >>> remote controllers etc. where they then get forgotten about until things stop working. (I've never >>> had an Eneloop leak and they run my remotes for about 3 years between charges.) >>> >>> So I'd like to make a gizmo that takes a single alkaline and pushes out ~5v through a USB cable for >>> as long as the cell has juice, preferably at a reasonable current. I have a few different pre-made >>> boost modules from the usual suspects but when I tested one the output voltage curve dropped with >>> the input so that it wasn't very successful. >> >> these are cheap and will do it >> https://aliexpress.com/item/32786144773.html > > I've actually already got some of those in my 'module collection'.
My bad, just checked and I don't have those. I have some of these <https://www.aliexpress.com/item/32450571426.html> and at first glance I thought they were the same thing. I really need to 'index' my module collection. -- Shaun. "Humans will have advanced a long, long way when religious belief has a cozy little classification in the DSM" David Melville This is not an email and hasn't been checked for viruses by any half-arsed self-promoting software.