ViewSonic M1 Mini Pico Projector

Short review: Do not buy this if you expect to keep it plugged in long-term. The charging will not always work and require you to unplug and plug it in. I've tested this with 3 devices and a USB multimeter. This is confirmed to me through Viewsonic customer service and Viewsonic engineering. Viewsonic Customer Service: "I did get confirmation from our engineering dept that this is not a defect, but a hardware limitation that has to do with the main board as this unit is more meant for portable use. Charging this device cannot keep up with the ongoing usage and will eventually drain the battery." Full story: I originally bought this because I wanted a compact, quiet projector that could project an image on my desktop or wall in my home office -- on occasion, I expected to take it out for portable use. This use case is impossible with this model device because the micro-usb charging cannot keep up with continual charging. What happens if you keep the unit plugged in and try to use it continually for 6-8 hours? I've found that the unit will start resetting constantly because the batter has drained. And, there is a deeper problem: it is unpredictable. After 3 RMAs (Yes, I've tested 3 devices) , buying an Anker charger, and buying a USB voltmeter (see picture), I've found that the ViewSonic M1 Mini, when charging indefinitely, will suddenly drop the wattage that draws from the charger down to a fraction of an ampere (less that 1 Watt of power). This can only be solved manually by unplugging and plugging the device in. Then, miraculously, it will start drawing up to 8-10 Watts of power. As long as it draws this much power, I've seen that it will both project an image and charge the battery. But, unpredictably, then device can drop in power draw again. This is possibly a safety measure, but it is undocumented and unpredictable. Without a multi-meter, the only way to anticipate this is to stop projecting, switch to the main menu, and see if the battery has been draining. This is because the device doesn't know to warn you that it is no longer charging correctly, it just thinks that it's plugged in, so everything is fine (everything is not) This means that * I cannot use it to project indefinitely (6-8 hours) because I cannot predict if and when it'll stop drawing power and no one wants to babysit the projector by unplugging it and plugging it in again every 2 hours. * I cannot have it plugged in and only project for short amounts of time because leaving it plugged in means that it might stop drawing power and have a drained battery.