Laughable power bank - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: January 07, 2018, 02:23:57 pm
content: Bought a couple of cheap power banks off EBay before xmas for presents. Kept myself 2 of them.They have a solar panel, 2 LED bulb torch and claim to be waterproof.Now for the LOL part. The description claims "300000mAh", aka 300Ah. A lead acid battery would need to be the size of a suitcase to deliver that much capacity. The product blurb tries to bullshit about this being a derived value based on the solar panel working at the same time or some rubbish.https://www.ebay.co.uk/itm/Waterproof-300000mAh-Solar-Power-Bank-2USB-Battery-Portable-Charger-for-Phone-UK/152214561530?hash=item2370b1e2fa:m:mz_Pr8pZEPBulwPTvfEnxfwI tested it multiple times from it rejecting anymore charge to powering off 5 times with a 5 minute rest in between, to get it fully discharged. 2000mAh. Confirmed in discharge and charge (using the same analyser admittedly).However now I have taken it apart I can see it has a single LiPo pouch cell that it very likely to be a 2200mAh cell. It's unlaballed.The solar panel is a nice idea, though they of course claim it's theoretical output of 200mA.Now it's not all that bad. I tested it in afternoon winter sunlight today, indoors with a window in the way by running the 2 LEDs from the torch unit on it.Open circuit it was producing 5.4VRunning the LEDs it was producing 2.6V and 25mA.I could gather in direct summer sunlight, directly angled to the sun it could produce 50mA, 100mA tops, but I'm guessing here. 200mA, I doubt it. 200mA @ 5V would make it a 1W panel. It's only 2" and 4" in size.Now for another LOL. While in the unit, should the solar panel get enough light the unit displays a number of LEDs, a green "solar" light and then a chaser lighting up another 5 blue charge LEDs.You can see the problem. While running all those LEDs + the Micro to run them there is no power left to charge the battery. Over Christmas I drained it and left it in the window for a full week and tested how many more mAh I got out of it after that and achieved 12mAh before it power off.My brother claims he left one in the window for the whole summer and it fully charged. I'm not convinced. I think he forgot it was charged when it left it there.Well, in the end I have a nice board with 2 torch LEDs on it, a LiPo pouch cell with a power bank board hanging off it and a 0.5W solar panel which I'm not sure what I can do with. 20mA is enough to power an arduino, but not at 2.6V. Better sunlight and outdoors it might stand a chance of running an Arduino and a few very dim LEDs.Can I get it to charge the LiPo cell using a TP4056 with it's LEDs removed I wonder.

author: Audioguru
author_rank: Super Contributor
timestamp: January 07, 2018, 03:59:57 pm
content: A good solar panel has a glass face. A cheap solar panel has a plastic face that gets sunburned and fails soon so don't put a cheap solar panel in sunlight.

author: Cyberdragon
author_rank: Super Contributor
timestamp: January 07, 2018, 07:32:11 pm
content: QuoteDoes it even have a battery protecter? From the sound of it, it's totally unregulated and has 112of resistance from the converter to the output. Utter trash! I wouldn't trust it, if it even has battery protection it would be very dodgy using phony chips and could even explode!Verdict: Destroy this POS immediately! Go outside and give it mains or something (have an extinguisher ready). Share some photos of the carnaige when you're done abusing it.

author: soubitos
author_rank: Frequent Contributor
timestamp: January 07, 2018, 08:14:21 pm
content: Quote from: Audioguru onTodayat 05:59:57 PM

author: soubitos
author_rank: Frequent Contributor
timestamp: January 07, 2018, 08:16:41 pm
content: Quote from: Cyberdragon onTodayat 09:32:11 PM

author: soubitos
author_rank: Frequent Contributor
timestamp: January 07, 2018, 08:17:50 pm
content: Quote from: paulca onTodayat 04:23:57 PM

author: paulca
author_rank: Super Contributor
timestamp: January 07, 2018, 10:06:15 pm
content: Those figures where the raw solar panel, I cut it out.The power bank control board works fine. Most I've loaded it to was about 2A. It chargers at about 1A. The board has two ICs, I'm assuming those are an MCU and a BMS. I didn't have a magnifying lens to look at the time.The torch LEDs where extremely bright in the unit, not that bright on the solar panel, but I was surprised they lit at all.Now I'm wondering if I can play with some form of solar controller PWM stuff on an Arduino and call it my "breadboard" solar panel. Micro-solar. Sill 100mW of power isn't much use to much.