Power bank Issues low power Loads  issue  - Page 1
Forum section: electronics / projects

author: Danielradcliff
author_rank: Contributor
timestamp: February 21, 2021, 04:20:44 am
content: Power bank. Anyone know of a usb power bank Circuit that does not go to sleep when powering light loads like a small radio or an Arduino

author: SilverSolder
author_rank: Super Contributor
timestamp: February 21, 2021, 04:50:52 am
content: I own an older one that works with low loads... but I haven't been able to find one like it since.It seems the newer ones all use the same IC and the people who designed that IC were too clever by half.

author: janoc
author_rank: Super Contributor
timestamp: February 21, 2021, 11:05:08 am
content: That's a good problem to have ... I have a dual output power bank (iGET B-20000) with outputs labeled 2.5A and 2.1A. And I have naively thought - "Yay, good enough for my Raspberry Pi ..." Except RasPi turns off right away.OK, out comes the electronic load and the bloody thing outputs only 4.3V at 2A of current!It is anywhere close to 5V only if you stick to the basic 500mA load. I guess those numbers printed on the bank are "won't start smoking within 10 seconds if you stay below this ..." rating. WTF ...

author: subliti
author_rank: Contributor
timestamp: February 21, 2021, 11:36:18 am
content: IdkBut what you could do to prevent this, is to use a small mcu, load resistor and a mosfet and choose a resistor value so that it pulls lets say 100mA. And than u just programm your mcu to give a 1sec pulse every 20sec or so. Depents on the power bank. So if you know ur power bank deactivates 40s after it detects "no" load, than u just pulse it every 35sec.This would prevent the turning off.You could then for example build a small adapter board with this circuit with 2 female usb sockets (or one male socket that connects straight to the power bank and the other is female), and than this could be used on any power bank

author: mino-fm
author_rank: Regular Contributor
timestamp: February 21, 2021, 06:25:42 pm
content: Please use a translation programhttp://www.mino-elektronik.de/Powerbank/powerbank.htmQuote from: SilverSolder on February 21, 2021, 04:50:52 amNo!

author: Danielradcliff
author_rank: Contributor
timestamp: February 21, 2021, 10:33:17 pm
content: Is there a ready made solution

author: SilverSolder
author_rank: Super Contributor
timestamp: February 21, 2021, 10:47:18 pm
content: Quote from: mino-fm on February 21, 2021, 06:25:42 pmWell, they all behave the same... every single one I've tried for the last several years have refused to cooperate with small loads.Are you aware of any that act differently? I'll be the first to buy!

author: Peabody
author_rank: Super Contributor
timestamp: February 21, 2021, 11:02:51 pm
content: Here's one you might look at:https://www.amazon.com/Voltaic-Systems-Formerly-Battery-Samsung/dp/B07ZS3WYZY/ref=sr_1_1?dchild=1&keywords=voltaic&qid=1613947993&sr=8-1

author: SilverSolder
author_rank: Super Contributor
timestamp: February 21, 2021, 11:07:54 pm
content: Quote from: Peabody on February 21, 2021, 11:02:51 pmQuoteLooks like the Sales department has caught up with the needs of the market! Thanks for the pointer, I'll have a hunt around again now that it appears to be an "upgrade" to go back to how they always used to work!

author: Peabody
author_rank: Super Contributor
timestamp: February 22, 2021, 05:00:57 am
content: At considerably lower cost, there is something called the "18650 battery shield v3" which has the battery holder, a charger, three ganged 3.3V linear regulators, and a 5V boost converter with USB-A output.https://www.ebay.com/itm/18650-Battery-Shield-Micro-USB-Wemos-ESP32-V3-ESP-32-for-Arduino-Raspberry-Pi/293951798138These can be found lots of places - Ebay, Aliexpress, Amazon, Banggood. They also come in 2-cell and 4-cell versions, but I think only the single-cell v3 behaves correctly as an always-on UPS. Andreas Spiess has a video on it:But there's a potential problem with getting charging to terminate properly if you are powering the load while charging:However, if your circuit periodically goes to sleep, that may enough to get charging to terminate.

author: Danielradcliff
author_rank: Contributor
timestamp: February 22, 2021, 08:10:57 pm
content: Thanks everyone but I still don’t have a solution that I can make that will fit space is tight or to buy to solve this issue keep trying everyone I’m listening

author: Peabody
author_rank: Super Contributor
timestamp: February 22, 2021, 10:57:35 pm
content: Well, in theory you could have an 8-pin ATTiny processor, a decoupling capacitor, a transistor, a base resistor and a load resistor. Might not need the base resistor if the GPIO pullup resistor is enough to drive the transistor, which it almost certainly would be. Might not need the capacitor either.

author: SilverSolder
author_rank: Super Contributor
timestamp: February 22, 2021, 11:39:54 pm
content: Quote from: Danielradcliff on February 22, 2021, 08:10:57 pmHow tight is the space?

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 22, 2021, 11:46:13 pm
content: How about just get a boost converter module that doesn't automatically turn off?

author: Danielradcliff
author_rank: Contributor
timestamp: February 23, 2021, 12:06:14 am
content: Seven 3/8 inches deep by 5 5/8 wide 12 Inches tall These measurements are all in inches

author: Danielradcliff
author_rank: Contributor
timestamp: February 23, 2021, 12:16:53 am
content: The inside The center thing is the usb power bank Circuit from Amazon up above is the battery holders for 18 650 cells to the left is a step down converter for the solar panels to take in the 7 V and drop it to 5 V for the Power bank circuit which is one of the issues there’s another issue With the power bank it’s self powering low load device.The thing below the power back circuit is a usb plug thing for the back .

author: SilverSolder
author_rank: Super Contributor
timestamp: February 23, 2021, 02:30:31 am
content: Have you made a circuit diagram / sketch of how the system you are building is meant to work?

author: Danielradcliff
author_rank: Contributor
timestamp: February 23, 2021, 03:23:14 am
content: No I have not made a sketch it’s all in my head currently I’m trying to produce a schematic for you all I’m using an app called iCircuit. Use your imagination on this Schematic picture Are used by components I had available in the app I’ve never made a schematic in my life actually So this is kind a hard i’m good at taking in information but not putting out information it’s complicated

author: Danielradcliff
author_rank: Contributor
timestamp: February 23, 2021, 03:44:05 am
content: More schematic pictures

author: SilverSolder
author_rank: Super Contributor
timestamp: February 23, 2021, 06:32:11 am
content: Keep working on it, it is beginning to make sense!