What does this do?

It appears to have a power input USB and a power output USB - probably similar to more "canned" commercial USB power packs. I'll often daisy chain my phone and tablet off the outputs of mine while feeding the input, and they all seem to stay topped up.

Run some tests? Hook up a voltage source and sink and see if it does what you want? 

@binaryrhyme That is a reasonable approach, but to do it I have to decode the USB pin connections, sacrifice some USB cables to get access to the leads, find a harmless sink (I certainly will not risk any of my devices). I was hoping somebody else here already did that. 

I went back to AliExpress and just out of boredom scrolled down the page and see there are reviews and some more technical information. One other person had a similar question and the answer is it is a UPS.

Part of my questioning is Bill's remarks about the dangers of charging these types of batteries. Part of the problem is I don't really know if mine are the dangerous ones or not. The safe assumption is they are dangerous, so a proper charger is mandatory. I just don't see that much circuitry on these battery holders that tell me they are smart enough to not blow the battery up.

The small chips/boards on the other hand do appear to my uneducated eye to be more likely proper chargers, but I could be wrong. At least one of the two has progress LED's.

Another reason for my concern, is that boards/devices that do the same thing offered for sale on PiShop.ca cost $75 and seem to have more components.

Thoughts?

Here are the Pishop boards

Yeh, the vagueness of the description is a bit weird. It didn't ship with a website link to specs or examples or the like?

The 'harmless' source could be a USB battery pack. I suppose conduct the experiment somewhere exploding batteries won't be bad news.

@binaryrhyme My suspicion is the AliExpress board is just connecting the USB power in to the batteries but until I can get a meter on it it's just a hunch. There is some sort of switch they talk about that I don't really get but has no purpose in a true UPS so I think the board is not actually doing very much at all.

I have to finish the LED light strip project first to keep the boss happy. YES @will I am using the mag switch to sense the door opening.

@ronalex4203 

🙂

@ronalex4203 Well, a true commercial UPS senses the power loss and only engages the battery when the power goes out, and has some manner of optimal battery charge maintenance over a long period of time - and additionally can notify devices so they can shut down. I have one on my router/NAS array - checking model... Schneider APC Pro 1500 S. Overkill here, though. 😉

Did some digging, and Andreas has a couple pertinent vids:

#250 Universal Power Source (UPS) for only 2$. Is this possible? (Raspberry Pi, Arduino, ESP32) - YouTube

#351 10 Battery Power Boards for Raspberries and ESPs. Start of “SuperPower” project - YouTube

@binaryrhyme Yah call that overkill, I have 7,200 Wh of LiFePO4 driving, a 3,000W, 2,400VA inverter, now that is a UPS! I have 6 x 180 W solar panels on tilters to keep everything going in the summer, not much power at these latitudes at this time of year though.

@binaryrhyme Gawd, I am getting old. Of course, that is where I first saw the UPS (Uninterruptible Power Supply) modules. In fact I was part of the discord group for a short while (Never figured out how it worked, seemed to be just full of jokers and angry folks)

I will go over those videos to see what I have and get back here with answers when I am done. 

@binaryrhyme, The "SuperPower" project sounds interesting!.. The author of the Video makes a lot of valid points about Battery power supplies charging systems, and UPS in general..I think I will continue to monitor that channel to see what he comes up with.. the open source is really appealing...lol

Thanks for posting the links..

regards,

LouisR

@inst-tech @ronalex4203 - yeah, I jumped into the Superpower Discord and looked around. My first thought was a brute force approach using an MPC to monitor two separate charging units, and use optocouplers to switch one to charge while the other discharges based on some optimal algorithm or other. Brute Force R Me, lol.

P.S. MPC control would allow for notifications to go out, remote status checks, yada yada, - I'm basically implementing a proper UPS at that point.

@binaryrhyme What is MPC ?

@binaryrhyme Why so complicated, 2 batteries in parallel gives you same power with half the parts.

@ronalex4203 MPC - microprocessor controller - perhaps the correct acronym is MC? Still kitting up on the latest jargon. 😉 Agree that it is pretty heavy handed to go that route, but my thinking is, if the battery won't charge below a certain voltage unless the load is disconnected, you could accommodate that corner case by having a switch to offload one bank in that circumstance. Is a pre-napkin level thought - will ponder. 😉