Retropie in my Mazda-- Low voltage problem
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I bought this 12v dual socket 5V/ 4.2A (2.1A+ 2.1A) that I connect my Pi to.
https://www.ebay.com/itm/12V-Car-Cigarette-Lighter-Socket-Dual-2-1A-USB-Port-Charger-Power-Outlet-LED/232777005143?ssPageName=STRK%3AMEBIDX%3AIT&var=532289411310&_trksid=p2057872.m2749.l2649But I have a problem, When I connect 12v directly to the power supply I have no voltage problems. but as soon as I put a switch in the circuit I immediately have problems. The switch is necessary because the Pi has continuous power going to it so if someone unthinkingly turns off the car the pi can still be safely shutdown later. I need to be able to turn off the power so it doesn't drain the battery since the USB outlet also has a built-in light.
What I'm asking is there some switch that I can use that has very low voltage drop across it?
I'm connecting to it with crimped spade connectors would it help If I soldered the spades to the wire or should I directly solder it to the outlet?
May be I need a different power supply since that one says 2.1 per USB I don't know if it is limited to 2.1 or it is 4.2 overall.Thank you
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@Maskedsquirrels I think this would fullfill all your needs ;)
https://mausberry-circuits.myshopify.com/collections/frontpage/products/3a-car-supply-switch-1 -
@maskedsquirrels I think power supplies like that are 2.1A max per USB. I have used one similar and they cannot power the Pi correctly.
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looks a bit pricey but that should do the job, but I take my pi in and out of the house and it is in a NESpi case. I don't think that would fit inside of it. Would it be possible to mount that somewhere on the car? I guess the GPIO shutdown function would go away.
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@maskedsquirrels Buy a second Pie and let it permanent installed into your car. Just this makes sense imho if you think about buying that device ;)
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@rbaker
Thanks I think you are right. -
I guess, but then my save games won't match up. I need to figure that out, any links for that? That might need another thread. Thanks all for helping me out.
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@maskedsquirrels run roms from usb. Then all your saves and games will be on the usb stick that can easily move back and forth.
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I know there are twin USB power cables for external hard drives, so after a few minutes digging found this. It shows they are out there, and a lot cheaper than that power supply
After more digging, found this that claims to supply 3A
and this one that claims to supply 5V at 5A
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Pi3b+ need 5,1 volts. standart usb charger only have 5 volts.
i have with 5 volts the same problem. 5.1 volt 2 amps works -
i got a 2.4 amp charger for the car from b&m that should be enough to run the pi with a decent usb cable the cheap ones loose too much current
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@grant2258 Also shorter the cable better. I can run a pi3 off a external USB battery, but using a short 6 in cable, otherwise i get the dreaded low voltage warning.
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well longer cables should be fine that why some are cheaper than others.
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@grant2258 wire has resistance. the longer the cable, the greater the voltage drop. for charging a battery, not a big deal, but for a pi that requires the full 5V, it can cause issues. the official pi power supply cables are at least twice as thick than what i usually see in a standard charging usb cable.
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exactly anything 1m and below should be fine if its using the right awg wire the budget ones are far too thin. https://www.engineeringtoolbox.com/wire-gauges-d_419.html
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I recommend you get a Power adapter capable of outputting 5V at 3 amps. It's had my Pi running without power issues, although i should mention that I've got nothing plugged into the USB ports (...on the Raspberry Pi) that would draw additional power. I'll post the items I used if we're allowed. If linking is frowned upon, I'll delete them or a Mod can remove them. Note that I AM using the USB ports on the 3-socket car adapter to power other devices. I'm charging my cheap-o Shanwan PS3 Dualshock 3 Controllers through the socket with the 5V, 1amp ports but nothing goes in the Pi USB ports. It should also be noted that I had this setup with a NESPi+ case before switching and kept getting the low power icon. It still worked but the icon drove me crazy. Case swap made that go away and it didn't matter since the Pi is hidden under the passenger front seat.
Smarza case (Great Airflow and stays below 43 degrees in the car)
Choetech Car adapter (it says the USB-C port outputs 5V at 3amps)
3-Socket 12V Splitter To connect peripherals and add kill switch to Pi.
Generic HDMI Splitter Because 2 headrests...
3-input HDMI Switcher (replacing as I now realize I'll need a remote for when it's tucked away)I'll include images of the madness I've made and hopefully it's not too far off from your Mazda setup.
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Here is the 3 Socket adapter with Power running through the ChoeTech adapter.
Car Charger to supply enough power to Pi without bolt issues
Running to Pi 3B+ with a generic braided USB-C to MicroUSB cable
HDMI out from Pi to an HDMI Switcher (additionally a Firestick is there but removed to minimize confusion)
HDMI Switcher to HDMI Splitter...
And Lastly.... HDMI Splitter to Car Headrests (Sending them back as they aren't comfortable; Awesome monitors, lousy headrests)
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Look Ma... No Lightning Bolt!
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