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Converting 120v TV to 12v using buck/boost converters
#21
With the buck converters and the cheap capacitors, it basically means even if the IC can handle 3A, the capacitors will limit that max amp rating. Same with the resistors used. As Mike stated, they just seem to randomly pick the cheapest (which, is probably based on the quantity they have on hand). Or they can't handle a surge load like they should be able to.
This is partly why there is under development an Honest buck converter.

As to the 32" vs the 24" @ 1080p, it has to do with the fact that the pixel count is identical, but covers a larger area. So yes, the 32" will look worse than the 24" @ the same resolution. However, I will also state that I do have a 48" 1080p Insignia tv I use as my monitor and it looks great. So, I suppose it depends.
It also depends who the manufacture of the led panel, not the tv, determines the quality as well. There are some Samsung TV's that use a cheaper manufacturer led panel in their lower tier lines. this also works in the other direction. It has been found that Spectre tv's use Samsung led panels. However, they are rejects because of dead pixels, incorrect color, or other issues. So, you get what you pay for, I suppose.
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#22
The 75w converter I linked Feb 26th ended up only being a boost converter. The 12v to 5v buck converter could not reach even 2 amps. I ended up using 2 units of this buck/boost converter. I burnt one out on accident.. So with slow shipping this all took a while.
https://www.ebay.com/itm/60W-DC-Buck-Boo...2749.l2649

I meant to test efficiencies after I read your comment but I forgot while waiting for parts. Hopefully the efficiency loss is minor with the battery usually around 12v but depending on charge could be a little higher or lower. The 12v to 5v buck may not be as efficient. I will still check the total 12v amps used so I can still get an idea of efficiency. Here are "their" test results "24V->12V1A: 86.5%, 12V->16V1.5A: 85%, 8V->16V1.5A: 74%" listed on ebay.

The USB cables I was cutting up were also preventing enough amperage to reach the Raspberry Pi and hard drive. I needed to use the thickest and shortest wire I could find.

I attached a picture I took at the last minute. You can't see the solder/tape to the 2 +12v pins on the power supply. At this point I already had the USB/power strung through the case so I couldn't open it all the way. I added a couple labels to help.

I also attached a picture of the outside. I'm waiting on some inline fuses from China still. I'll fuse the line, add a kill switch, and add some molex connectors.

I've already realized an issue with my setup. The +5v output only works when the TV is connected to +12v DC and not 120vac. I should have wired the 12v to 5v buck converter input from the +12.6v output of the other converter. This way it would take power from the power supply if connected to 120vac. At some point I'll make the change.


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#23
Well I couldn't help but to go back in and fix the USB power issue when connected to 120vac. All better now. You can see the quick wiring change in the attached image. It's also a much better picture from straight above.

I did slide a piece of PVC under both boards. It's clear but should prevent anything from touching the metal case. I used glue on the mounting screws.
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