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Topic: squeezing every bit of juice from AA batteries (Read 1 time) previous topic - next topic

GoForSmoke


Is it weird this table of voltage regulators list "max INPUT current"?  Isn't OUTPUT current what's important?  Is that a typo?


It's turning current at voltage to less current at higher voltage minus loss due to inefficiency.
The device load is the input current.
I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.

arusr



Is it weird this table of voltage regulators list "max INPUT current"?  Isn't OUTPUT current what's important?  Is that a typo?


It's turning current at voltage to less current at higher voltage minus loss due to inefficiency.
The device load is the input current.



Oh ok, didn't realize they're talking about the intended load and not the regulators themselves.

polymorph

Keep in mind, too, that in my experience, disposable batteries are more likely to leak, the closer they are to fully discharged. Carbon zinc or so-called "heavy duty" batteries leak a corrosive acid. Alkalines leak an alkaline (as expected) that is less corrosive but still damaging.

I'm not saying don't do this, I'm saying don't leave the batteries in after doing this.
Steve Greenfield AE7HD
CET Consumer Electronics and Computer
Please don't read your attitudes into my messages

GoForSmoke

Could a Joule Thief be used to charge rechargeable batteries from the dregs of disposables?
BTW to me, disposable is a dirty word.
I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.

polymorph

I wonder how efficient the average joule thief is.

Why use something less than 100% efficient to charge something that is less than 100% efficient at storing energy which then must power a switching regulator which is also less than 100% efficient? Why not just use a single switching regulator from the disposable battery?
Steve Greenfield AE7HD
CET Consumer Electronics and Computer
Please don't read your attitudes into my messages

BillHo



I'd also recommend pololu.


I'd be interested to know the chips they use, but it seems they're not on the open source bandwagon.


Hi Jack,
The Step-up Voltage Regulators U1V11F3, U1V11F5, and U1V11A using TI TPS61200DRC for Adjustable version (BRR) and TPS61202DRC
for 5V version (BRT)
http://www.ti.com/lit/ds/symlink/tps61200.pdf

Jack Christensen


Hi Jack,
The Step-up Voltage Regulators U1V11F3, U1V11F5, and U1V11A using TI TPS61200DRC for Adjustable version (BRR) and TPS61202DRC
for 5V version (BRT)
http://www.ti.com/lit/ds/symlink/tps61200.pdf


Thanks, Bill! The cryptic markings on tiny packages these days do make it a challenge. We need a package-marking-to-part-number database :D
MCP79411/12 RTC ... "One Million Ohms" ATtiny kit ... available at http://www.tindie.com/stores/JChristensen/

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