I just bought a strip of 5 boost converters from Amazon:
I'm interested in reading the datasheet for the only device with more than two leads, which hopefully is the boost converter chip. I've taken these photos:
Dave
Hi, @Dave_Lowther
I've also done a check, even got chatGPT to trawl the data sheets.
It looks like it is an OEM in house number.
Can you please post a link to the Amazon page please?
Tom.... 
Thanks for the quick reply. Here’s the link you asked for.
FWIW I did some tests on one of them. They work within some limits, which are different to the headline ‘spec’ in the link.
Amazon5VBoostTestResults.txt (1.2 KB)
I just found this:
With datasheet
The markings "E50H" and "E50P" maybe also match
and
https://www.sunrom.com/p/bl8530-501sm-e5-5v-sot89
(the 0H / 0P / 0H might be a date code or fab code).
I bought 5 of these recently from Aliexpress. https://de.aliexpress.com/item/32809095271.html
The datasheet is probably this one from Nanjing: https://archive.espec.ws/files/ME2108%20Series.pdf
Thanks Max. I assume you are the same maxgerhardt from the platformio forum where you’ve done so much to help me and others. Welcome to here. I’ll have a look at the info you provided some time over the weekend. I’ve got to go out shortly.
@6v6gt Thank you to you too.
I used a Pololu U1V11FS in a recent project Basic single AA cell powered thermometer, powered only by a 1.5v cell, which is relatively expensive, however, it does have the advantage of an enable pin so it can be fully switched off. I have a similar breadboard experiment in front of me with one of the cheap Chinese boost converters, as you have, but added a high side switch to cut power when not required.
That’s a nice project. In my case the project is something that’s used very infrequently. It has a physical on/off switch to isolate the battery from the boost converter. ATM it’s using a boost converter stolen from a Minty Boost. It’s a shame that the LT1302 is so expensive these days. I need to make upto 5 PCBs next.
It’s part of a STEM activity. Students assemble a propeller and gearbox to drive a small DC motor which is used as a generator. It’s then fitted to a raft that goes on a lake and the students tow it with a rope from the path next to the lake. It records time, voltage, speed (from the GPS). It has a WiFi hotspot and a web server. A number (up to 4) of devices can connect to the hot spot and view the data on a browser. The logging can also be controlled from the browser. Logged files can be downloaded in csv format for later analysis. The ESP32 carrier shown in the photo is from an earlier ESP32 project that just happened to be suitable for this. Hence the silk screen jumper text doesn’t match the use of the GPIOs here.
It looks like you have an interesting project for your students (I'm guessing that you are not one of the students ?)
Anyway, with a starting point of 2 lithium AA cells in series, the boost to 5v is not such a challenge and maybe at least some of those devices can be driven at 3v3, for example the ESP32. So your choice of boost converters is quite wide. The speciality of the one you have featured in the OP is that it can work at a very low voltage (~0.9v). Lithium batteries appear, however, to maintain a reasonably stable voltage under load then quickly die so there is probably not much capacity to salvage towards the end of their life. https://data.energizer.com/pdfs/l91.pdf
I’m not one of the students :-). Yes I’ve considered a 3.3V converter, and may go that way. ATM the GPS has a 5 → 3.3V regulator on board, which is why I’m using 5V for this instance of the prototype. For the PCB version I may get GPS modules which run off 3.3V directly. My soldering skills are mainly with through hole components. I’m okay with soldering SOP8 packages for example, but some of the boost chips have a solder pad under the chip for heat sinking, which I don’t think I can do. So I’m mainly going to use modules on the PCBs. Only getting 5 PCBs made, and initially only building 2 of them. It’s not worth me going bare ESP32 chip / GPS chip. If I can find a suitable boost converter chip that I can solder to the PCB then I may not use a boost module. That’s the stage I’m at ATM
Doesn't that GPS have supply range of 3-5V?
I tried powering it off the ESP32 3.3V pin and it didn’t work well. The spec for the GPS chip says it needs about 45mA. I can’t remember exactly how it didn’t work. IIRC some messages from the GPS passed validation checks, but many didn’t. Whereas when I run it off 5V all the messages are fine. I’m using the default set up it came with where it’s using UBX format and I wrote my own message decoder for it, and I can see the counts for valid / corrupted GPS messages in the ESP32 web server ‘stats’ page. The GPS module has a 5 → 3.3V regulator on it. I’m assuming that regulator won’t pass through 3.3V. I suppose it could be that the 3.3V from the ESP32 can’t handle the extra 45ma, but when it was connected to the ESP32 3.3V the ESP32 continued to work fine. Sorry for being a bit vague, it was a couple of months ago when I tried to run it off 3.3V and I didn’t take any notes
I have no experience with it. Ublox gives 3-5V.
If it doesn't work with 3.3V from Esp, you might want to measure the actual voltage. Some esp boards have very shy voltage regulator..
