Running the Prime with AAA batteries
01-31-2014, 12:29 AM (This post was last modified: 01-31-2014 01:12 AM by eried.)
Post: #1
 eried Senior Member Posts: 741 Joined: Dec 2013
Running the Prime with AAA batteries

PS: The adaptor is mainly designed to bypass the battery, because I was unable to securely intercept the pins with another method to measure the batt current

My website: erwin.ried.cl
01-31-2014, 06:08 PM
Post: #2
 Stefan Member Posts: 87 Joined: Dec 2013
RE: Running the Prime with AAA batteries
Nice one! And good to see that you did not have to sacrifice your (or mine ) calc.

If you intend to run it for a longer time of batteries (not just for measuring) you maybe should consider using a switching regulator. Otherwise you burn most of the energy in the LDO.
I know that TI (I guess other manufacturers have similar devices) makes some regulators which are pretty much drop in devices, they even include the inductor already. Look for their "Simple Switcher" series. Maybe you even want to use the "Nano" ones to fit everything in the battery adapter.

And then you can print a battery cover
01-31-2014, 10:57 PM
Post: #3
 eried Senior Member Posts: 741 Joined: Dec 2013
RE: Running the Prime with AAA batteries
(01-31-2014 06:08 PM)Stefan Wrote:  Nice one! And good to see that you did not have to sacrifice your (or mine ) calc.

Scratches are sacrifice :/ you should have hated the device! haha

I use cheap buck converters, but they are too bulky and they add a bit of noise so for this kind of project linear regulator suit well in my opinion. In this case the drawback is exactly:
Code:
Power Dissipated (Watts) = (Vin - Vout) * IL Watts = (6.2-3.98)*0.068 (idle low brightness) W= 0.15W

So, waste is 0.038A from the loss, so the calculator uses in total 106mA in low brightness = near the consumption of idle-high brightness.

My website: erwin.ried.cl
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