I recreated an Amazon Product to make it better & cheaper! (Fire TV Stick)
video description
So yeah, the Li-Ion version is completely overengineered, no doubt. But your version is completely overengineered and not really that much better. Sure, Li-Ion batteries have limited charge cycles, but you are barely using the capacity of the Li-Ion battery, so it will probably never even complete a single charge cycle.
Interesting project and all. But I'm not entirely sure what the point of the video is. I'm also not entirely sure why Amazon didn't just add a god damn capacitor to the Fire TV stick themselves.
Date: 2022-03-27
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Comments and reviews: 9
Mike
Maybe it's too much to ask, but this circuit reminded me:
I'd like to build a giant UPS. Something that can be configured to host a single or multiple LiFePO4 12 V batteries.
For example, a 3 kWh system.
It needs to pass AC power through, then very rapidly switch to inverter function if there's a black/brown-out.
I've been hoping that something like this would be available commercially, but still isn't. The solar generators out there with UPS function are starting to serve the purpose but they switch too slowly, and are nowhere near as configurable as needed.
Yeah, tall order, I know, and dangerous, so maybe not, but I can dream: )
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Maybe it's too much to ask, but this circuit reminded me:
I'd like to build a giant UPS. Something that can be configured to host a single or multiple LiFePO4 12 V batteries.
For example, a 3 kWh system.
It needs to pass AC power through, then very rapidly switch to inverter function if there's a black/brown-out.
I've been hoping that something like this would be available commercially, but still isn't. The solar generators out there with UPS function are starting to serve the purpose but they switch too slowly, and are nowhere near as configurable as needed.
Yeah, tall order, I know, and dangerous, so maybe not, but I can dream: )
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spaideri
Cool idea. Though I have couple of ideas to consider. Since you are charging the 2 capacitors to a combined higher voltage that they can tolerate by themselves, I would put in some protection for too high cell voltage. Supercapacitors (at least in the range of 100s of Fs) can be easily be damaged with too high voltage. Also the op. Amp used to turn the load on does not have any feedback to prevent oscilation when reference voltage is near the compared voltage. Just a small amount of feedback to the compared voltage would made the operation to work a bit like a schmitt trigger.
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Cool idea. Though I have couple of ideas to consider. Since you are charging the 2 capacitors to a combined higher voltage that they can tolerate by themselves, I would put in some protection for too high cell voltage. Supercapacitors (at least in the range of 100s of Fs) can be easily be damaged with too high voltage. Also the op. Amp used to turn the load on does not have any feedback to prevent oscilation when reference voltage is near the compared voltage. Just a small amount of feedback to the compared voltage would made the operation to work a bit like a schmitt trigger.
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Anna
I see there one big problem: You did all the switching and sensing on the GND side. That means as it works (the current sensing, current limitting, load switching, it will make voltage differences between these grounds.
But this GND is common with the USB communication, connected inside of the TV. That means the fire stick supply output GND is shorted out with the power input GND, once it gets connected together into one TV.
You should just have made all the current sensing and regulation on the positive side (so using PMOS devices, keeping the one single common GND.
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I see there one big problem: You did all the switching and sensing on the GND side. That means as it works (the current sensing, current limitting, load switching, it will make voltage differences between these grounds.
But this GND is common with the USB communication, connected inside of the TV. That means the fire stick supply output GND is shorted out with the power input GND, once it gets connected together into one TV.
You should just have made all the current sensing and regulation on the positive side (so using PMOS devices, keeping the one single common GND.
reply
sanji
Maybe u can add a balancing net for those 2 super caps since over time they might go out of sinc.
Also maybe u can measure the effective capacitance since honestly i dont trust cheap chinese parts if the original part is expensive on main sites like mouser / farnell. but still even it it is 20 not 25F it is a nice find. Also some indicator leds would be nice. And a proper PCB but that is not that hard if u have the schematic.
Also maybe do a vid how to find good non fake parts on the Ali market.
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Maybe u can add a balancing net for those 2 super caps since over time they might go out of sinc.
Also maybe u can measure the effective capacitance since honestly i dont trust cheap chinese parts if the original part is expensive on main sites like mouser / farnell. but still even it it is 20 not 25F it is a nice find. Also some indicator leds would be nice. And a proper PCB but that is not that hard if u have the schematic.
Also maybe do a vid how to find good non fake parts on the Ali market.
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Matthew
Might be better if the output voltage cutoff had some hysteresis, so it gets to a decent level, but will then allow it to drop to the minimum working level, otherwise it may cut off prematurely as the capacitor discharges.
Could also use a boost converter so that the voltage does not fade with capacitor discharging.
Finally, it appears that the switching and any drop is in the 0V side, not the +V, this would be bad if the USB ground is not isolated from the HDMI ground
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Might be better if the output voltage cutoff had some hysteresis, so it gets to a decent level, but will then allow it to drop to the minimum working level, otherwise it may cut off prematurely as the capacitor discharges.
Could also use a boost converter so that the voltage does not fade with capacitor discharging.
Finally, it appears that the switching and any drop is in the 0V side, not the +V, this would be bad if the USB ground is not isolated from the HDMI ground
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Rhian
A cheap li-ion battery bank would produce 5v at 1 amp if chosen for the purpose. The battery terminals could also be connected to a TP4056 set to provide 500ma towards the battery and thus, via its inverter, about 400ma contribution to the 5v load. The lithium ion battery will sit at 4. 2v except for short periods when the load is demanding more than the TP4056 is set to provide so the number of full charge cycles is not going to be approached.
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A cheap li-ion battery bank would produce 5v at 1 amp if chosen for the purpose. The battery terminals could also be connected to a TP4056 set to provide 500ma towards the battery and thus, via its inverter, about 400ma contribution to the 5v load. The lithium ion battery will sit at 4. 2v except for short periods when the load is demanding more than the TP4056 is set to provide so the number of full charge cycles is not going to be approached.
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GoPro
I still prefer the battery build because I happen to have too many 18650s lying around here also they're much cheaper than a super caps at half a dollar (refurbished cells from dead laptops etc) it helps with recycling. If one or two of the components/modules no longer work, one could just Frankenstein from another cheap device and put it there. I also like the idea that it can work as UPS for a longer period of time compared to super caps
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I still prefer the battery build because I happen to have too many 18650s lying around here also they're much cheaper than a super caps at half a dollar (refurbished cells from dead laptops etc) it helps with recycling. If one or two of the components/modules no longer work, one could just Frankenstein from another cheap device and put it there. I also like the idea that it can work as UPS for a longer period of time compared to super caps
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LordHonkInc
Hmm, now this makes me want to try a similar solution for my 3D printer. I've got a raspberry pi hooked up directly to the printer's PSU, so I have to make sure to shut down the pi before I turn off the power (if just for good practice's sake. Would love to read the state of the PSU and shut down the pi automatically, but obviously that would mean it'd have to be on for just slightly longer than the rest of the system.
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Hmm, now this makes me want to try a similar solution for my 3D printer. I've got a raspberry pi hooked up directly to the printer's PSU, so I have to make sure to shut down the pi before I turn off the power (if just for good practice's sake. Would love to read the state of the PSU and shut down the pi automatically, but obviously that would mean it'd have to be on for just slightly longer than the rest of the system.
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Richard
The rule of thumb for artists is that you should charge at least 3 times your materials costs for the finished product. I've read a few times that that same ratio works well for small electronics products, too. By that rule, your 10-in-parts should sell for about 30, which is 50% more than the buy version.
But I agree about the LiPo. Wrong application, and built in a way that makes it not user-serviceable.
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The rule of thumb for artists is that you should charge at least 3 times your materials costs for the finished product. I've read a few times that that same ratio works well for small electronics products, too. By that rule, your 10-in-parts should sell for about 30, which is 50% more than the buy version.
But I agree about the LiPo. Wrong application, and built in a way that makes it not user-serviceable.
reply
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