Tag Archives: Scrolling text message mode

Phase 1 LEDC life test complete

The LEDC battery life test concluded with an error (reset) after 735 hours (30+ days), 217 hours greater than predicted. My prediction assumed a higher current load than actual. In addition battery chemistry and the ability for it to recover seems to have also been a factor.

The LEDC actually continued to operate and keep time, but the processor reset when the hourly chime occurred, the chime can draw up to 90mA and the processor browned-out.

With the chime disabled the clock continued to operate, but I concluded the test. Now to the next test, which is continuous operation without sleeping, and chime on the hour. This will not last as long, probably 72 hours or so.

LEDC battery life 400 hour update


After 400 hours of observation, my predicted battery life for the LEDC with settings to wake every minute and chime on the hour of 518 hours now appears to be a bit low. My prediction was based on observed current demand seems to be a bit pesimistic, it’s still going strong and may well go past the predicted time. Also battery chemistry be a bigger factor than I thought as there is a bit of a flat spot developed at around the 350 hour mark which I can’t explain.

LEDC battery life

I designed the LEDC as a battery powered desktop clock that is the size of a business card. The size was a design choice, I wanted to be able to put it in standard business card holders. It seems to work fine, now I’m measuring how long it will operate. This will consist of several battery life tests as follows:

Mode Predicted hours
Wake every minute, Chime the hour 518
Wake every 10 minute, Chime the hour 5002
Don’t sleep, Chime the hour 52

The first test seems to be tracking fairly well to the prediction as shown in the chart below: