Doogals
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In-Car Power: DC-DC Converter? [Video]

Thu Mar 15, 2018 12:24 am

Looking for a temporary in-car power solution and wondering if this 12V to 5V 3A converter would power a RPi 3?

https://www.amazon.ca/DROK-Converter-St ... B00C63TLCC

How would this compare to usig the official power supply and a 12V AC inverter?
Last edited by Doogals on Mon Mar 19, 2018 5:14 am, edited 1 time in total.

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Imperf3kt
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Re: In-Car Power: DC-DC Converter?

Thu Mar 15, 2018 12:37 am

If it comes from China, its nothing but landfill.
I recently bought a 2.1A 'lighter socket' buck converter.

After opening it, I found not only could it not deliver 2.1A due to the internal wiring being incapable of more than 1.5A, but the chip performing the buck was only rated to 1000mA peak, with 700mA under normal operation.
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Doogals
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Re: In-Car Power: DC-DC Converter?

Thu Mar 15, 2018 12:50 am

Imperf3kt wrote:
Thu Mar 15, 2018 12:37 am
If it comes from China, its nothing but landfill.
I recently bought a 2.1A 'lighter socket' buck converter.
This could be checked using a digital multimeter before connecting the RPi correct?

Would you recommend using a DC inverter and the official power supply instead of this?

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Imperf3kt
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Re: In-Car Power: DC-DC Converter?

Thu Mar 15, 2018 1:07 am

No need. I'd just recommend you use a reputable brandname product. (I haven't looked at the link yet) and not trust the "specs" of Ebay or Amazon (or even your local bazarr) listings.

E: link shows a UBEC, I would expect that to work well given sufficient airflow for cooling.
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Doogals
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Re: In-Car Power: DC-DC Converter?

Thu Mar 15, 2018 2:06 am

Imperf3kt wrote:
Thu Mar 15, 2018 1:07 am
E: link shows a UBEC, I would expect that to work well given sufficient airflow for cooling.
Thanks for checking, much appreciated. So it sounds like this DC-DC converter would be a better choice for powering the Pi than the inverter/AC adapter route? No sense going from DC to AC then back to DC correct?

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Imperf3kt
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Re: In-Car Power: DC-DC Converter?

Thu Mar 15, 2018 3:00 am

If the Pi is the only thing you are powering, sure. But if you have other stuff, the inverter may be more desireable.
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Doogals
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Re: In-Car Power: DC-DC Converter?

Thu Mar 15, 2018 4:44 am

Imperf3kt wrote:
Thu Mar 15, 2018 3:00 am
If the Pi is the only thing you are powering, sure. But if you have other stuff, the inverter may be more desireable.
I actually have two 10.1” screens connected to the Pi via HDMI (for an in-car entertainment system running LibreELEC) and they are both powered by 12V...

Maybe the best option here is this cigarette splitter (see link below) that will accommodate the 12V power adapters for the both screens and also has 5V 3A USB ports for powering the Pi? This seems like it might be the perfect fit for my application?

https://www.amazon.ca/Cigarette-Splitte ... B01D5WRL9C

Doogals
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Re: In-Car Power: DC-DC Converter?

Fri Mar 16, 2018 3:59 pm

Imperf3kt wrote:
Thu Mar 15, 2018 3:00 am
But if you have other stuff, the inverter may be more desireable.
So it turns out “QC 3.0” charging ports only output higher amperage to supported devices that have a proprietary Qualcomm chipset, and non-supported devices receive 1A-2.1A, so that’s not going to cut it.

Here is another idea, would it make more sense to install LibreELEC on a Pi Zero that only needs 1.2A? Should be able to use almost any USB charger for that, correct?

Doogals
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Re: In-Car Power: DC-DC Converter?

Fri Mar 16, 2018 9:24 pm

Imperf3kt wrote:
Thu Mar 15, 2018 3:00 am
If the Pi is the only thing you are powering, sure. But if you have other stuff, the inverter may be more desireable.
Here is a basic component layout of the setup:
2E7E4EF2-34F7-487F-8851-EBE3A81400FC.jpeg
2E7E4EF2-34F7-487F-8851-EBE3A81400FC.jpeg (60.38 KiB) Viewed 1796 times

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Lob0426
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Re: In-Car Power: DC-DC Converter?

Fri Mar 16, 2018 10:53 pm

http://www.mini-box.com/s.nl/sc.8/category.13/.f

I found this site has number of vehicle solutions. Should give you some ideas.
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Doogals
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Re: In-Car Power: DC-DC Converter?

Mon Mar 19, 2018 5:12 am

I've started testing this setup (see video link below) RPi 3 is connected to USB multimeter, which is connected to Quick Charge 3.0 USB port on 12V DC splitter.

Note the DC splitter is connected to an AC/DC converter for testing purposes only, and the 10.1" screen is also connected to AC outlet but both will be powered in-car by the 12V DC splitter.

So far I've had no issues, but would like some input on the voltage and current readings in the video (voltage red, current blue), thanks!

https://streamable.com/t55ya

ignis627
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Re: In-Car Power: DC-DC Converter? [Video]

Sat May 12, 2018 2:05 am

PowerStream makes the PST-DAA1205-2, 5 volt 2 Amp DC/DC Converters fully isolated, for automobile voltage stabilization for abou $30 USD

https://www.powerstream.com/dda.htm

Hope it helps...

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