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

[~misfit~]

.... 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.

 

[default]

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

 

[~misfit~]

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.

 

[~misfit~]

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.

 

[Jasen Betts]

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.

 

[Charlie+]

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

 

[~misfit~]

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.

 

[~misfit~]

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.

 

[~misfit~]

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.

 

[~misfit~]

On 1/10/2019 3:08 PM, ~misfit~ wrote:

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.

I just ordered 5 of these <https://www.aliexpress.com/item/32830275320.html> They're cheap enough
and claim a higher efficiency than the one you linked. If I don't use them for this 'project' they
will likely be useful down the track sometime. I can put them in my 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.

 

SEPIC

WIKI has a page on it that isn't too bad.

 

[Jasen Betts]

On 2019-10-01, ~misfit~ <shaun.at.pukekohe@gmail.com> wrote:

On 30/09/2019 8:17 PM, Jasen Betts wrote:

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,

3 AAAs are smaller than an 18650 and the voltage is about
right. you can get adaptors.

https://www.aliexpress.com/item/32973004084.html

On the other hand the torch may work just fine off a single cell, I've
got mostly AA/14500 torches here, they have some sort of buck/boost
device.

--
When I tried casting out nines I made a hash of it.

 

[whit3rd]

On Sunday, September 29, 2019 at 7:07:22 PM UTC-7, ~misfit~ wrote:

On Mon, 30 Sep 2019 00:19:07 +1300, ~misfit~
shaun.at.pukekohe@gmail.com> wrote:

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.

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.

It's bad design if it requires 1.33V; either bypass the battery terminals with a capacitor
(that'll lower the impedance, if it's a logic-glitch that makes it malfunction) or consider
using three cells in series (if it works on 3V, it should be OK for 4.5... maybe). A
redesign of the circuit might be in order, except it's a consumer-grade package with
cryptic labels and 'instructions'.

Gluing it into a bigger waterproof box isn't too hard.

 

[Robert Roland]

On Mon, 30 Sep 2019 00:19:07 +1300, ~misfit~
<shaun.at.pukekohe@gmail.com> wrote:

>it won't run on NiMH cells and only uses alkalines down to 1.33v.

You need a batteriser!
--
RoRo

 

[~misfit~]

On 5/10/2019 6:12 AM, Robert Roland wrote:

On Mon, 30 Sep 2019 00:19:07 +1300, ~misfit~
shaun.at.pukekohe@gmail.com> wrote:

it won't run on NiMH cells and only uses alkalines down to 1.33v.

You need a batteriser!

.... like I need a hole in the head.
--
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.