found datasheet of the chip:
https://www.richtek.com/assets/product_file/RT2808A/DS2808A-00.pdf
Thought lifting pin 5 would work but sadly the module won't start anymore.
So after another more careful reading; 100 ohms pulls about 30mah
Max load on a arduino pin is 40mah
So next step will be trying to put a 100 ohm resistor on 2 pins and set these to LOW and HIGH for respectively 5 seconds.
Will report back.
https://www.richtek.com/assets/product_file/RT2808A/DS2808A-00.pdf
That does not look at all like a powerbank controller. It's a buck converter so it can only produce voltages below the battery voltage (2.95V to 4.2V). The recommended input range is 5.5V to 36V. The HOTCHIP HT4928S appears to be a MUCH closer match.
Looking at this picture:
I can read SW2808S
Something totally difrent again.
For now the resistor solution works. But i'll research a bit more since i have more of these modules laying around already and a work around would be handy for future projects. So if there are other solution you guys can think of please let me know i really appreciate all the help and thinking along.
Yes, that is what I read, too. But a search for "SW2808S", and "SW2808" turned up no USB Power Bank controllers. After searching for pictures of "5V Step-Up Power Module Lithium Battery Charging Protection Board Boost Converter LED Display USB For DIY Charger 134N3P" I found a picture of an identical board but containing the "HOTCHIP HT4928S" chip:
https://www.aliexpress.com/item/5V-Boost-Step-Up-Power-Module-Lithium-LiPo-Battery-Charging-Protection-Board-LED-Display-USB-For/32818182292.html
This tends to indicate that the two chips are functionally equivalent. If you find other chips in that same board you might be lucky enough to find one with a datasheet in English.
johnwasser nice find thank you for all the effort. I'll keep on searching and see what we may find thank you for pointing me out in this direction
So in the end i ended up placing 5 resistors in parallel and have a 50 something ohm load using just about 60mah.
Beware the heat buildup.
Thanks for the warning.
That's the reason why i did use 5 resistors. This way heat will be divided. One single resistor was to hot to hold on to.
These 5 resistors are getting slightly warm, the wallplug to power the arduino is "warmer"
In the end i just used a different booster that did not have the cutout at low current.
5V DC-DC Booster- CE8301
Model : PCH8301C
I'm glad you found the new board. The low-current cutoff issue with powerbanks just about kills them for a real world use. I just use them for demonstration. 60 milliamps is really huge for a long term, battery/solar powered project.
True that. Another question kind of related here, since we are talking about saving energy, removing leds is somethng i see popping up everywhere.
Just desolder them would be enough?
Desoldering is good, or you can use an exacto knife to gouge through the circuit trace.
How did you charge the battery form solar since that last chip you provided only steps up the battery to 5V
Was it with this one (TP4056) getting this:
This is the data:
The input voltage: 4.35-6 v (recommended voltage 5 v)
Charge cut-off voltage: 4.2 V + / - 1%
Maximum charging current output: 1000 ma
The battery overcharge protection voltage: 4.28 V
Battery overcharge lifting voltage: 4.00 V
The battery discharge protection voltage: 3.0 V
Battery discharge termination voltage: 3.2 V
Battery: over-current protection current 3 a
The board size: about 2.5 * 1.65 CM
Light state: no load the light not bright, red light for recharging, is full of green light.
I have a setup like that too yeah
I know its a late response but I have a solution when using the ht4928s chip.
I use a 50 Ohms resistor to generate some load the keep the "powerbank" chip enabled. But it is switched on and off by a transistor (PN2222). The transistor is controlled by the arduino. After some experimentation I found out the load only has to be enabled for 0.01 seconds every 3 seconds to keep the "powerbank" on. Effectively this will only 0.333 mAh.
It's not a perfect solution but for most applications it is acceptable.
paulusbrand:
I know its a late response but I have a solution when using the ht4928s chip.
I use a 50 Ohms resistor to generate some load the keep the "powerbank" chip enabled. But it is switched on and off by a transistor (PN2222). The transistor is controlled by the arduino. After some experimentation I found out the load only has to be enabled for 0.01 seconds every 3 seconds to keep the "powerbank" on. Effectively this will only 0.333 mAh.
Great! Can you please send a picture or schematic of how did you wire this? I´m having the same issue as Bringamosa did, with a Nano that keeps shutting down when powered by a T6845 step-up/charger.
Thanks!
Bringamosa:
So in the end i ended up placing 5 resistors in parallel and have a 50 something ohm load using just about 60mah.
Hi Bringamosa! How did you connect them? I have the same issue with the T6845 and my Nano. I only have 120 ohm resistors at hand, so I would divide them into 2 or 3 to get 60 / 40 ohm load, or maybe put some Rs in series.
Thanks!
Bringamosa:
True that. Another question kind of related here, since we are talking about saving energy, removing leds is somethng i see popping up everywhere.Just desolder them would be enough?
