Lilypad power supply maximum current

Development Boards Arduino
1

I am trying to drive a servo (the small one that comes with the Inventor’s kit for Arduino) by using lilypad + lilypad power supply (the one that takes a single AAA battery).

The servo turns fine when I use power from USB, but when I unplug USB and use the AAA the servo just groans and vibrates slightly. Clearly there isn’t enough current.

With my meter I measured ~70-80 mA when the servo is functioning normally, and the lilypad itself requires ~10 mA based on my previous measurements. Since the lilypad power supply says it can handle up to 100 mA I would expect it to be able to deliver the required current to the servo. However when I checked the servo current in the AAA case I see only 50 mA going through it, which confirms my fear that there isn’t enough current.

When I measured the battery by itself (out of the lilypad power supply) I got ~200 mA closed circuit current, so at first the battery doesnt seem to be the problem. However since the 1.5V is being multiplied by around 3 times, does that mean the total current suppliable by the battery is going to decrease by the same factor? I’m using a duracell AAA.

I even tried using a AA battery or two AAA batteries, but I still can’t get enough current.

Anyone been able to drive a small servo using only a AAA and the lilypad power supply?

2

You might only measure 70 - 80mA, but I bet it draws peak current a lot higher than that (ie, when it starts moving). Also, you’ll be drawing more than 400mA from the AAA cell - some cell types could experience a significant voltage drop with that much current. A couple of NiMh cells in series would give a lot more power than an alkaline cell.