I'm looking to do some Arduino projects with a low enough current to be powered by solar panels / rechargeable batteries. My Arduino Uno was drawing too much current for a small solar panel so I decided to try building a bare bones Arduino on a breadboard using the atmega 328 microprocessor. I took out the voltage regulator and replaced with a Dimension Engineering switching regulator DE-SW050 to make power more efficient. I also didn't use any LEDs to indicate power on. My cheap multimeter can't measure low currents so I just started the following test: 1. Arduino Uno running blink sketch with a 9V battery + 2. Bare bones Arduino with switching regulator running blink sketch from a 9V battery. I will see how long each system lasts. No results yet, I just started the experiment a few minutes ago with brand new Radio Shack batteries but if there's any interest I'll post the findings (if I'm home when the batteries run out). If anyone has done similar testing or has any comments please share.
Hopefully..., I ordered a new one online. Should be here in a couple days. Couldn't wait, plus I'm just curious to see how long a 9V can power an Arduino running simple code.
The Arduino Uno circuit just died. That's about 8 1/2 hours, though these are Radio Shack batteries. Well, I'll see if the other circuit is still going when I get up
You could make a sketch that reports an 'alive' status every minute or so to a file on an SD card. That way, even if it has died days ago, you'll be able to retrieve exactly the moment when it stopped working.
jensvanhoof:
You could make a sketch that reports an 'alive' status every minute or so to a file on an SD card. That way, even if it has died days ago, you'll be able to retrieve exactly the moment when it stopped working.
How many Ah were the batteries?
Honestly, I don't think most alkaline battery companies will tell you. Its a little frustrating.
No Ah rating on these batteries. Funny, the package says "performance guaranteed" without indicating what the performance should be. The batteries I used were enercell 9V alkalines. That's a cool idea writing to an SD card jensvanhoof. I think I'm going to try that when I'm further along working with rechargeables and solar panels. I'm glad I decided to work on a project dealing with power efficiency. I'm a beginner at this and looking at efficiency has been forcing me to look at many different aspects of the arduino and microprocessors that I would've otherwise been unaware of.
Honestly, I don't think most alkaline battery companies will tell you. Its a little frustrating.
Some of the 'name brand' battery companies do have datasheets with such information, but they can be difficult to locate. However such ratings are usually expressed at some small current discharge rate and if your actual current draw is at a higher value then that, then the equivalent mAh rating will be lower. Especially for those small 9 vdc batteries, that are really designed for low current draw devices like smoke alarms and the such.
If the batteries are the little rectangular type with the terminals on the top, then typically capacities are around
110 - 150 mah.
Very poor value on a $ per watt hour basis.