@cengland0 I didn’t notice that. I was going to say that my best friend has two of these for when we go camping or whatever and they’re totally sweet. But his are QC compatible, and I think he paid a lot more for them.
@akumax that sound like it was designed for the original Raspberry Pi 4. It didn’t do USB-PD, but it expects 5 volts and it may draw, 3 amps if there are peripherals. It didn’t work with some USB-PD power supplies that correctly followed the spec.
@Fen_Star Wait until you find out that the mAh ratings on these things are actually the LiPo capacity which has a nominal 3.7 volts so it needs to be boosted to 5V for the USB outputs. You will get less mAh at 5V than what is advertised (in all cases that I’ve tested anyway). For this reason, I recommend the standard capacity of these devices should be advertised in mWh or just Wh.
@cengland0@Fen_Star I agree. Watt-hours is more useful, as it is how much energy the battery holds.
Amp-hours is only useful to compare one battery against another when saying “battery X is bigger/smaller than battery Y”.
It’s a bit like using liters/gallons to measure petrol/gas, but that won’t tell you how many miles you can drive on a liter/gallon or how long you can run a snow/leaf blower.
Why be honest when you can mislead with alternate facts?
The bit about using 3.7V numbers instead of 5V numbers is a bit if a crock too. Just like the hard drive and SSD/flash drive manufacturers using the decimal number of bytes when everyone other than them uses binary (i.e. “1MB” is 1,024 bytes to you and me, but they only deliver 1,000 bytes and label it with the same capacity).
For most “normal” customers it doesn’t matter at all-- “bigger is more” is all they know and all they really need to know.
In general, batteries are not heavily current-limited. They’ll give a relatively constant voltage and all the current you’ll try to draw. This makes mAh a very useful descriptor.
A watt-hour is a watt-hour, and it’s a great unit of measuring energy, but without an associated known voltage, you don’t really know what you can do with it. You need a voltage anyway. When you run a device off a battery, you’re pulling current at a specific voltage. You aren’t just pulling watts.
You can’t just swap out a battery with a larger capacity if it’s the wrong voltage.
Tangential, I don’t see it listed, but I would expect this to run on Li-Ion rather than LiPo, just due to issues/safety in charging.
Also a tangent, but the whole memory vs. data storage terminology thing is historic. A MB should be 1000 Bytes. The only reason it computer-architecture specific. When those decisions were being made, they weren’t operating on orders of magnitude where it made much of a difference, so nobody cared.
It works great, but a full pound is a lot heavier than it sounds when it comes to tossing something in your pocket for the day. I found I was frequently leaving it at home, or trying to scam a way for my wife to put it in her purse.