5 ms·

One should be careful evaluating the claims. A good boost converter will be ~90% efficient (it can be more efficient, but not miniaturized like the pictures sh

by jwr 11y ago

One should be careful evaluating the claims. A good boost converter will be ~90% efficient (it can be more efficient, but not miniaturized like the pictures show). So, to begin with, you'll discard ~10% of your energy. Now look at AA alkaline discharge curves: http://www.powerstream.com/AA-tests.htm http://www.powerstream.com/AA-tests.htm Indeed if you gadget reports the batteries as dead at 1.25V, you can still get ~40% more usage. But most gadgets don't work that way. 1.25V is the normal voltage of a fully charged NiMH rechargeable AA, so if you gadget works with those, the real cutoff point is likely closer to 1.15V or so. The booster will boost the voltage (at the expense of current, obviously, plus losses) so that even though the battery will be below 1.15V, output voltage will be at 1.5V. Looking at the graphs, this buys you less than 1/5th, and if you consider the losses in the boost converter, probably half that. The "800%" claim seems totally bogus. Perhaps with a gadget that stops working when the voltage falls below 1.45V per cell. I'm not saying it's not a useful gadget (and I'm very impressed by the miniaturization: where is the inductor? This thing must run at several MHz at least!) — just that the claims should be taken with a large grain of salt.

amelius 11y ago
Also, I'm wondering if the maximum current output will drop over time. Or in other words, if the battery can maintain its power output.
- VLM 11y ago
  The word you're looking for is internal resistance. Here's an on topic application report from (one of many) manufacturer of single cell upconverter chips. http://www.ti.com/lit/an/slva194/slva194.pdf http://www.ti.com/lit/an/slva194/slva194.pdf Internal resistance rises ridiculously fast with depth of discharge but even in the range of "ohms" you can still squeeze out a good fraction of an amp, a decent fraction of a watt. Its surprising how much you can do with a tenth of a watt or whatever, this will work quite well with a remote control or wireless game controller or a kitchen timer, maybe not so well with RC cars or laptop power supplies or the stereotypical "charge your cellphone with a AA battery" product or 1000 lumen flashlights. In the long run nobody's ever going to use cells in series so as to avoid depolarization / cell reversal type stuff. Its feasible now for low current stuff, what I'm getting at is "someday" people will be running portable drills off single cells. Its a long term trend in power conditioning.
danmaz74 11y ago
Regarding efficiency, you should simply add the batterizer thing only after your new batteries became "dead" for your appliance. This way you use the normal run of the battery at 100% efficiency, and everything extracted after that is pure gain.
- asddubs 11y ago
  that's pretty fiddly and impractical though. By the time the batteries are dead, the batteriser will be long lost in some drawer
  - cmwright 11y ago
    This may be naive, but would it be possible for the voltage booster to only start 'boosting' after the battery falls under a certain voltage threshold? That would be seem to solve both of your concerns.
    - tlrobinson 11y ago
      But then you would of course need circuitry to measure the voltage and switch the booster on, and it wouldn't know what the correct threshold is.
    - 3JPLW 11y ago
      The trouble is that the battery doesn't know the voltage requirements of the device it's powering. Should it start boosting at 1.4V? Or 1.25V? I have a hunch that it already does this for voltages near 1.5. The trouble is determining where you draw the line.
      - wodenokoto 11y ago
        That's easy. You license the batteriser technology to the gadget creators, they build it into their gadget and set the limit!
        11y ago
userbinator 11y ago
Perhaps with a gadget that stops working when the voltage falls below 1.45V per cell. And such a gadget is one that no one would buy, and consequently no one would produce. Electronics designed to run off AA batteries already extract as much energy as is practical from them. From those discharge curves you can see that there is a gentle downward-sloping section, followed by a distinct "knee" at the end where the voltage falls rapidly. That is where the gadget would be designed to work down to. Sure there's a few percent more beyond that, but adding a boost converter which attempts to extract that energy won't work - the boost converter itself will be consuming energy, and likely far more than is available past the knee, so this device could actually reduce how long your batteries last! As for the miniaturisation - this isn't that small; similar boosters have been present in MP3 players, cellphones, and other battery-powered electronics for years. Fitting everything on a PCB with the diameter of an AA and less than 1mm thick is not that hard. Look at the ISL9113A for one example. I haven't laid out a boost converter in a design with that space constraint, but it turns out to be roughly of that area anyway and I'm sure if you did things like cutouts to sit the passives into the board, it'll be thin enough.
- ansible 11y ago
  And such a gadget is one that no one would buy, and consequently no one would produce. Electronics designed to run off AA batteries already extract as much energy as is practical from them. Indeed. If your gadget can make use of NiMH rechargables, then you're already having to deal with about 1.2V per cell, and that's when they're fully charged! So if you need 3.0V or 3.3V nominal for your main supply, you are probably already using a buck/boost switching regulator. As long as the battery can supply enough current, your gadget will keep going, and drain pretty much all the useful energy from it.
chisleu 11y ago
Yup. Also, isn't there a problem with batteries leaking nasty acid when they are fully discharged?
- strictnein 11y ago
  The batteries don't become fully discharged with this device, just more so than normal.
larrys 11y ago
> The "800%" claim seems totally bogus. Maybe "bogus" is to strong but I would say "suspect". The "proof" in the article could be summed up as: 1) A demo to the writer which (and I'm not suggesting this is what happened) any magician could have pulled off 2) A statement from an authority source "Dr. Kiumars Parvi" "with the physics department of San Jose State University" who said "we confirmed that the Batteriser taps into 80 percent of energy that is usually thrown away" Neither item confirms anything like 800% nor do I remember seeing any independent testing to prove that point.
- wlesieutre 11y ago
  "taps into 80 percent of energy that is usually thrown away" is at least in the right ballpark. If you typically use 20% and throw away 80%, then using the 80% would extend your battery life by 4x over the original. So 400%. I'm very skeptical of this.
  - dragontamer 11y ago
    5x actually. (4x PLUS the original 1x for 5x total). I agree with you, just arguing a technicality.
    - wlesieutre 11y ago
      Increased by 4x the original, or increased to 5x the original. I'd tend to read "extends battery life 800%" as 100%+800%, but they left out the word that would specify one or the other. Still, I'd interpret the numbers the same way as I would "extends battery life 50%," which I can easily imagine someone writing.
s73v3r 11y ago
"The "800%" claim seems totally bogus. Perhaps with a gadget that stops working when the voltage falls below 1.45V per cell." Reading the article, that's what they were using as the benchmark.
mutagen 11y ago
The article briefly mentions using them with rechargeable batteries. While I'm sure the boost to 1.5V allows more devices to use the rechargeable batteries, I'd be concerned about over-discharging [1] NiMH batteries. [1] https://en.wikipedia.org/wiki/Nickel%E2%80%93metal_hydride_battery#Failure_modes https://en.wikipedia.org/wiki/Nickel%E2%80%93metal_hydride_b...
torgoguys 11y ago
I am similarly skeptical. I contacted the physicist quoted in the article and inquired about the tests they did in their lab. I wanted to see if the quote is out of context, relates to a specific use case or what. He sent a brief, friendly reply (from his iPhone). Here it is: Dear [redacted] Thank you for your email concerning the Battereiser. The product is sound and we will disclose additional information in the coming weeks. Best, Kiumars Parvin So he is apparently still endorsing it. I still suspect the article is grossly misrepresenting its usefulness. I am willing to be swayed by solid data, but I'm not holding my breath.

by jwr 11y ago

amelius 11y ago

Also, I'm wondering if the maximum current output will drop over time. Or in other words, if the battery can maintain its power output.

VLM 11y ago
The word you're looking for is internal resistance. Here's an on topic application report from (one of many) manufacturer of single cell upconverter chips. http://www.ti.com/lit/an/slva194/slva194.pdf http://www.ti.com/lit/an/slva194/slva194.pdf Internal resistance rises ridiculously fast with depth of discharge but even in the range of "ohms" you can still squeeze out a good fraction of an amp, a decent fraction of a watt. Its surprising how much you can do with a tenth of a watt or whatever, this will work quite well with a remote control or wireless game controller or a kitchen timer, maybe not so well with RC cars or laptop power supplies or the stereotypical "charge your cellphone with a AA battery" product or 1000 lumen flashlights. In the long run nobody's ever going to use cells in series so as to avoid depolarization / cell reversal type stuff. Its feasible now for low current stuff, what I'm getting at is "someday" people will be running portable drills off single cells. Its a long term trend in power conditioning.

danmaz74 11y ago

Regarding efficiency, you should simply add the batterizer thing only after your new batteries became "dead" for your appliance. This way you use the normal run of the battery at 100% efficiency, and everything extracted after that is pure gain.

asddubs 11y ago
that's pretty fiddly and impractical though. By the time the batteries are dead, the batteriser will be long lost in some drawer
- cmwright 11y ago
  This may be naive, but would it be possible for the voltage booster to only start 'boosting' after the battery falls under a certain voltage threshold? That would be seem to solve both of your concerns.
  - tlrobinson 11y ago
    But then you would of course need circuitry to measure the voltage and switch the booster on, and it wouldn't know what the correct threshold is.
  - 3JPLW 11y ago
    The trouble is that the battery doesn't know the voltage requirements of the device it's powering. Should it start boosting at 1.4V? Or 1.25V? I have a hunch that it already does this for voltages near 1.5. The trouble is determining where you draw the line.
    - wodenokoto 11y ago
      That's easy. You license the batteriser technology to the gadget creators, they build it into their gadget and set the limit!
      - 11y ago

userbinator 11y ago

Perhaps with a gadget that stops working when the voltage falls below 1.45V per cell. And such a gadget is one that no one would buy, and consequently no one would produce. Electronics designed to run off AA batteries already extract as much energy as is practical from them. From those discharge curves you can see that there is a gentle downward-sloping section, followed by a distinct "knee" at the end where the voltage falls rapidly. That is where the gadget would be designed to work down to. Sure there's a few percent more beyond that, but adding a boost converter which attempts to extract that energy won't work - the boost converter itself will be consuming energy, and likely far more than is available past the knee, so this device could actually reduce how long your batteries last! As for the miniaturisation - this isn't that small; similar boosters have been present in MP3 players, cellphones, and other battery-powered electronics for years. Fitting everything on a PCB with the diameter of an AA and less than 1mm thick is not that hard. Look at the ISL9113A for one example. I haven't laid out a boost converter in a design with that space constraint, but it turns out to be roughly of that area anyway and I'm sure if you did things like cutouts to sit the passives into the board, it'll be thin enough.

ansible 11y ago
And such a gadget is one that no one would buy, and consequently no one would produce. Electronics designed to run off AA batteries already extract as much energy as is practical from them. Indeed. If your gadget can make use of NiMH rechargables, then you're already having to deal with about 1.2V per cell, and that's when they're fully charged! So if you need 3.0V or 3.3V nominal for your main supply, you are probably already using a buck/boost switching regulator. As long as the battery can supply enough current, your gadget will keep going, and drain pretty much all the useful energy from it.

chisleu 11y ago

Yup. Also, isn't there a problem with batteries leaking nasty acid when they are fully discharged?

strictnein 11y ago
The batteries don't become fully discharged with this device, just more so than normal.

larrys 11y ago

> The "800%" claim seems totally bogus. Maybe "bogus" is to strong but I would say "suspect". The "proof" in the article could be summed up as: 1) A demo to the writer which (and I'm not suggesting this is what happened) any magician could have pulled off 2) A statement from an authority source "Dr. Kiumars Parvi" "with the physics department of San Jose State University" who said "we confirmed that the Batteriser taps into 80 percent of energy that is usually thrown away" Neither item confirms anything like 800% nor do I remember seeing any independent testing to prove that point.

wlesieutre 11y ago
"taps into 80 percent of energy that is usually thrown away" is at least in the right ballpark. If you typically use 20% and throw away 80%, then using the 80% would extend your battery life by 4x over the original. So 400%. I'm very skeptical of this.
- dragontamer 11y ago
  5x actually. (4x PLUS the original 1x for 5x total). I agree with you, just arguing a technicality.
  - wlesieutre 11y ago
    Increased by 4x the original, or increased to 5x the original. I'd tend to read "extends battery life 800%" as 100%+800%, but they left out the word that would specify one or the other. Still, I'd interpret the numbers the same way as I would "extends battery life 50%," which I can easily imagine someone writing.

s73v3r 11y ago

"The "800%" claim seems totally bogus. Perhaps with a gadget that stops working when the voltage falls below 1.45V per cell." Reading the article, that's what they were using as the benchmark.

mutagen 11y ago

The article briefly mentions using them with rechargeable batteries. While I'm sure the boost to 1.5V allows more devices to use the rechargeable batteries, I'd be concerned about over-discharging [1] NiMH batteries. [1] https://en.wikipedia.org/wiki/Nickel%E2%80%93metal_hydride_battery#Failure_modes https://en.wikipedia.org/wiki/Nickel%E2%80%93metal_hydride_b...

torgoguys 11y ago

I am similarly skeptical. I contacted the physicist quoted in the article and inquired about the tests they did in their lab. I wanted to see if the quote is out of context, relates to a specific use case or what. He sent a brief, friendly reply (from his iPhone). Here it is: Dear [redacted] Thank you for your email concerning the Battereiser. The product is sound and we will disclose additional information in the coming weeks. Best, Kiumars Parvin So he is apparently still endorsing it. I still suspect the article is grossly misrepresenting its usefulness. I am willing to be swayed by solid data, but I'm not holding my breath.