The Asus P3B is a bright Mini LED projector rated 800 ANSI lumens with an internal 45Wh battery. I had the chance to test an Asus P3B portable projector briefly before it was sent off to it’s new owner in Africa. I measured it’s power consumption and did a short subjective evaluation of it.

Test Date: 29 March 2019

When plugged into the wall, only full brightness is available; you can’t dim it to save power. At 1280 x 800 native resolution, computer text was clear and easy to read.

When on battery there are 3 brightness levels to choose from. All quite a bit dimmer than full, with a very green tint to everything. The tint was quite annoying but for computer work is probably tolerable. Movies will look sick. Internal battery is ~45Wh. When you pull up the on-screen menu, It predicts the run time left when running on battery. Run time on a full battery is estimated ~2 hours on highest brightness, ~4 hours on dimmest setting (very dim)

It has an extremely short throw distance. 3ft projector-to-screen distance gives an over 4ft diagonal. In our well-lit office environment ~48 inch diagonal was the upper limit with good contrast for computer programs (black text on white background). For watching movies the maximum size was about 32” diagonal.

Power draw @19V when full bright and charging battery is 35.7W, when internal battery is full, 31W. When the projector was turned off and charging the internal battery it drew about 22W, taking about 2 hours to recharge from empty.

The included power brick is rated 19V 3.42A. But the projector never drew more than 1.9A (36W) in all my testing. The projector appears to limit the charge power into the internal battery to 5W while the projector is running, and bumping up to 22W when the projector lamp is turned off. This means that the internal battery charges extremely slowly while you are running the projector.

Efficiency: Assuming the rating of 800 Lumens is accurate = 25.8 ANSI Lumens / watt

Summary of Impressions: Very hefty, impressive build quality, large diameter optics. 1.73 lbs = 0.787 kg Nice buttons on the projector. Overall impressive quality. Exception: The remote control is tiny and cheap feeling with membrane buttons. Image Evaluation: Very nice image when plugged in. Disappointing image when running on battery.

This projector is very efficient with power and a good choice for running on solar power. You could run a 2 hour movie from a fully charged Half-Pint without ever using the projector’s internal battery. It is unfortunate that you can’t choose to conserve power by running on lower brightness and there are cheaper projectors with similar specs on the market.