Powering my mirror?

[The Bean]

@MadScientist ok awesome! That really did help I wasn’t thinking of doubling them up in the terminal.

[The Bean]

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F191903753580
This converter isn’t adjustable and it’s only 5.0 v would this work?

[MadScientist]

https://www.ebay.com/itm/1PCS-DC-DC-LM2596-power-Supply-Buck-Converter-step-down-module-NEW-CA/142147326064?hash=item2118a41070:g:L1kAAOSwvzRXzOBg
or
https://www.ebay.com/itm/DC-DC-Buck-Step-down-Regulator-Converter-4-2-23v-to-3V-3-3V-5V-9V-12V-24V-Module/112472493337?hash=item1a2fe20d19:g:dCsAAOSwdd9aVjD6
should do. They are adjustable via a potentiometer. Iam using the latter one for a Pi Zero but the 3A are enough to power a Pi3 easily. You should check aliexpress.com since most of the low priced parts already come from China. They will be even cheaper and are the very same product.

[The Bean]

How do these look?
http://s.aliexpress.com/67rmau6V?
http://s.aliexpress.com/vuaEjyAR?

[MadScientist]

Yeah, that should do.

[The Bean]

before i buy a power supply i wanted to ask if the one i had for it would work, if i spliced the adapter into it?

https://www.ebay.com/itm/112168199465

[MadScientist]

Sure it works. I just proposed the other one because it’s very compact and I thought that was important. Use the once you already have to save costs as long as it suits you. It’s powerful enough if those values are correct.

Especially those black power bricks can be of very bad quality. Run your mirror setup for a few hours and check that the power supply isn’t getting too hot.

[The Bean]

My problem with it was that I didn’t want to have the brick of it out side the case. Or 3 foot of wire looped inside but I’ll have to cut it to add the step down anyway. So I may as well try it that way first. But I also didn’t know if it was big enough for both To run off of.

[The Bean]

i ran into this problem awhile back but got put on the backburner.

[maxbachmann]

@The-Bean Whats the buck down converter? I guess the pi is just a to big load for it

Never expect those china buck down converters to achieve more than 50% of what they say they will do (especially without additional cooler)

[maxbachmann]

@The-Bean you might want to try with a additional cooler on the converter since the pi is not constantly pulling 2A, so it might work

[The Bean]

http://a.co/4qRQUQJ

[maxbachmann]

@The-Bean When it gets really hot I would try with a heatsink
and what happens when you connect it and then turn up the voltage until you reach 5V?

[The Bean]

the converter its self doesnt really get hot.(that i have noticed) it just the wire to the pi. and once it drops, it doesnt adjust anymore.

[maxbachmann]

hm strange I mean I don’t know the cable size you use, but 5V 2A is pretty much nothing for any cable. Should not really get hot for sure

[The Bean]

thats what i thought… i will continue to investigate and post back if i find anything.

[MadScientist]

2A is not nothing for a thin cable. What kind of cable are you using? If it is just a very thin one, it would also explain the huge voltage drop. Try using a thicker one.
I am running the Pi with a SSD with one of those very cheap china buck converters without any issues for 6 months now.

[maxbachmann]

Yep thats why I write I don’t know what siye of a cable you use ;)
but since I expected the cable to be very short (step down converter directly in front of the pi and the cable is probably open to all sides
VDE rules say you should use at least 0.5mm² up to 2.5A 2m
and at least 0.1mm² up to 1A 2m

So you should use 0.5mm² to be on the safe side.

0.25mm² should probably work aswell when you do not have long cables and do not stress the pi fully out to 2A ;)
But yes @MadScientist is right you should definetly not get below this

and keep in mind those values are for copper cables. If you use aluminium cables you obviously need thicker cables