Re: [PIC] High Power Consumption for a Battery operated application - Electronic Safe

On Wed, 8 Jan 2025 at 08:17, Francois Robbertze <[email protected]>
wrote:

> Hi,
> I need help with the power consumption on a battery operated project
> (Keypad
> safe)
> I have a lot of safes and the controllers is damaged. I want to create new
> controllers for these safes and try to use what is available
> Details: Current Power is supplied by 4xAA Batteries. Power is dropped to
> 4.8 volt through 2 diodes.
> I used PICBASIC Pro and the software works perfect except the current draw
> is about 1.56mA. The datasheet show on page 167 a current draw of 1uA in
> sleep mode. I use the PIC16F88. That is with the programmer disconnected.(
> I
> measure about 156,8mV volt drop over a 100Ohm resistor )
>
>
A circuit diagram with actual and all components would be a very good idea.
Datasheet links for all relevant components helps.|
Actual test voltage where results are seen helps heaps.
How many safes is relevant.

Good information gets better answers and saves wasting your and others
time.|
I need more sleep :-).

Disconnect solenoid circuitry and anything indeed and determine that the
core circuit sleeps properly.

Unused I/O should be properly initiated. _Either outputs with no load or
inputs and grounded.
Just one of those wrong CAN be enough to do what you see.

At 1 uA a 1N4148 has typical 0.28V drop.
At 10 uA it's 0.38V.
New Alkaline AA are 1.65V.
Four are 6.6V.
Less two diode drops is over 6V at 1 uA and over 5.9V at 10 uA.
This may or may not matter.
All diodes are not created equal.
You may be using other diodes but as you haven't said we cannot tell.\

LDOs that are very very cheap on Aliexpress and will probably work (one's I
get from their do) and somewhat dearer from elsewhere draw in the 1 - 10 uA
range quiescent.

AA Alkaline quality brand are 3000 mAh.
If main load is sleeping at 10 uA then lifetime of 300,000 hours exceeds
shelf life by maybe 5 times.

Peripheral:

Eveready cells quality may be " Made in China, US, Indonesia, Poland in
decreasing order of goodness.
Poilish ones may have under half the capacity of Chinese ones. Indonesian
ones are not much better.
US ones are down somewhat on Chinese.
Some may claim Singapore and should be OK if they are but that's too close
to Indonesia for comfort.|We have brand new on retail shelves Indonesian
ones here that are leaking in their packets.

That factoid is based on a few years old data but leaking Indonesian ones
here say nothing seems to have changed.

Happy New Year :-)


     Russell McMahon