12v to 5v 3a step down power module for USB (1 Viewer)

Oct 14, 2007
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I need a 12v to 5v 3a stepdown/buck converter module with 2 x USB ports. The unit will be on constantly power to a Raspberry Pi and MiFi in my van so needs to be safe and reliable. There are so many on eBay and amazon that I am wondering if anyone has any recommendations. I know I could use the cigarette lighter ones but that would mean wiring in sockets etc.
 
Feb 27, 2011
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I need a 12v to 5v 3a stepdown/buck converter module with 2 x USB ports. The unit will be on constantly power to a Raspberry Pi and MiFi in my van so needs to be safe and reliable. There are so many on eBay and amazon that I am wondering if anyone has any recommendations. I know I could use the cigarette lighter ones but that would mean wiring in sockets etc.

I would be interested in a recommendation for one of these for the same reason. I haven't been able to find one that does 3Amps to a single USB socket. I would also like one that is trust worthy. Don't want it to cause a fire which is a concern with some of the cheaper chinese ones that skip certain safety features.

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Lenny HB

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Most of the 3c ones are in an aluminum case rather than plastic so should be a bit safer.

I've had a couple of the plastic 2amp ones go faulty both times it was the solder joint's that connect and hold the PCB with the USB sockets to the main PCB they rely on the joints as the mechanical connection. I repaired them by resoldering with the addition of TCW to the joint and epoxy.
 
Sep 17, 2017
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I got a pair of 12v to 5v 3A buck convertors to power a MiFi and a Pi. They are potted, so should cope better with movement and vibration. No heatsink though. Only been running for a couple of months, so I can't tell you much about reliability.
Amazon product ASIN B08Q34TYV5

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Diabalo
Oct 14, 2007
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Lenny HB with you lecky hat on does it matter if it's insulated or non-insulated as I have seen both for sale.
 
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Diabalo
Oct 14, 2007
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I got a pair of 12v to 5v 3A buck convertors to power a MiFi and a Pi. They are potted, so should cope better with movement and vibration. No heatsink though. Only been running for a couple of months, so I can't tell you much about reliability.
Amazon product ASIN B08Q34TYV5
I have seen them and you can also get them with dual USBs so not a bad shout. I'm paranoid with putting something in that's poorly manufactured and burning the van down. I have had a couple of the cigarette light plugins that have got hot and failed so thought a proper PCB mounted affair would be better.

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Jan 26, 2017
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I've just bought one of these, mainly to fast charge our phones, seems to be good quality and works well..might be of use for you?
 
Feb 27, 2011
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I got a pair of 12v to 5v 3A buck convertors to power a MiFi and a Pi. They are potted, so should cope better with movement and vibration. No heatsink though. Only been running for a couple of months, so I can't tell you much about reliability.
Amazon product ASIN B08Q34TYV5

I have a couple like that but without the hardwired USB cable, I bought them for some arduino projects. I don't like hardwired cables like that. I would prefer a socket with mounting built in.
 
May 19, 2020
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I got a pair of 12v to 5v 3A buck convertors to power a MiFi and a Pi. They are potted, so should cope better with movement and vibration. No heatsink though. Only been running for a couple of months, so I can't tell you much about reliability.
Amazon product ASIN B08Q34TYV5
I used the same, dedicated one for the Pi and since the MiFi is not nearby a dual version with x2 female USB- gives me an additional port if I need it. I've been using similar for around 10 years to supply a dash cam in the car.

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PP Bear

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I fitted one of these and it’s lovely and flush.

<Broken link removed>
 
Feb 27, 2011
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I fitted one of these and it’s lovely and flush.

<Broken link removed>
You have to be careful with the specs on some of the ebay ones. They say X amps. But when this is split between dual sockets it is half what is quoted. I saw one stating 4.2 amps, but in actual fact is was 2.1 amps x 2 and it wouldn't run a 3 amp device.
 
Nov 4, 2011
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I use one of these to power my Huawei B535 router via the 12volt outlet and that leaves the usb for something else.
<Broken link removed>

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Diabalo
Oct 14, 2007
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I use one of these to power my Huawei B535 router via the 12volt outlet and that leaves the usb for something else.
<Broken link removed>
Yes I like the look of that one but I need 2 usb ports to make it a bit easier, they do a dual port one but none available at a sensible price.
 
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Diabalo
Oct 14, 2007
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This is what you need then.
JZK Car Power Converter DC 12V to 5V/ 3A Voltage Converter with Dual USB Adapter Connectors for phone charging car audio radio etc Amazon product ASIN B06XSCCLCD
Thankyou, that is another option I have looked at but was after recommendations as like Grommet I am wary of cheap Chinese stuff on eBay when it's something that's going to be on all the time and left unattended for long periods while the van is in storage.

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Diabalo
Oct 14, 2007
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Jaws

John as you are an electronics wizard, do you have any recommendations?
 
Aug 25, 2016
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Thankyou, that is another option I have looked at but was after recommendations as like Grommet I am wary of cheap Chinese stuff on eBay when it's something that's going to be on all the time and left unattended for long periods while the van is in storage.
I have used these for years on defender to Porsche Boxsters and motorhomes. Never had any problems with them. And easy to hide 👍🥃
 
Feb 27, 2011
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This is what you need then.
JZK Car Power Converter DC 12V to 5V/ 3A Voltage Converter with Dual USB Adapter Connectors for phone charging car audio radio etc Amazon product ASIN B06XSCCLCD
That doesn't look like it would work for our needs.

* Output power: 15 W
* Output current: 3A max. In the ambient temperature of 30 °, long-term work using 2A current , no need heat dissipation

So maximum of 15 watts (3 amps) across the entire module.
2A maximum sustained.

so that is effectively a 1 Amp per connected device for long term use.

Probably ok for a car where you will just be plugging your phone or tablet in for relatively short periods.

No good for long term use to supply a raspberry Pi 4 and permanently supply a Wifi Router :(

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Two on Tour

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I'm using a couple of these to power the Rasp Pi's on our van.

They have remained stable and accurate going by the LED readout and are easy to set the output voltage via the trimmer, plus the seller is UK and in the UK. (y)
Mine are on 24/7 and have been for the past 6 months or so.

<Broken link removed>
 

RM_Marine

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2PCS Quick Charge Car Dual USB Charger Socket Panel, 12V/24V Power Outlet Waterproof Adapter with On/Off Switch & Blue LED Voltmeter for Vehicles Car Boat Motorcycle SUV RV Truck Caravan Marine Amazon product ASIN B092ZT186S
 
Sep 17, 2017
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I'm using a couple of these to power the Rasp Pi's on our van.

They have remained stable and accurate going by the LED readout and are easy to set the output voltage via the trimmer, plus the seller is UK and in the UK. (y)
Mine are on 24/7 and have been for the past 6 months or so.

<Broken link removed>
What's the efficiency of these like? Would they have an bigger baseline draw than a lower power device? If they are on 24/7, those milli-amps add up to a lot of Amp Hours on the battery.

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Diabalo
Oct 14, 2007
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Got plenty of heatsink, so that's looking good. What did you do for the output leads, I suppose I could cut the ends off 2 usb c charging leads and use those.
 
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Diabalo
Oct 14, 2007
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Guigsy Good point but at least you will be able to see the draw:LOL:

Joking aside that's why I am looking for recommendations, does efficiency necessarily come with quality? It's a bleedin nightmare.
 
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Sep 17, 2017
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2PCS Quick Charge Car Dual USB Charger Socket Panel, 12V/24V Power Outlet Waterproof Adapter with On/Off Switch & Blue LED Voltmeter for Vehicles Car Boat Motorcycle SUV RV Truck Caravan Marine Amazon product ASIN B092ZT186S
I've got a few of these in the van. They are OK for plugging stuff in to charge. But I wouldn't trust them for 24/7 operation. I've had a couple just fall apart because there wasn't enough glue. The electronics inside are pretty scary. With the ones I've seen, the pins on the back are held against the circuit board pickups with non-captive springs. If the back falls off the springs are free to short circuit things.

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Lenny HB

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I've got a few of these in the van. They are OK for plugging stuff in to charge. But I wouldn't trust them for 24/7 operation. I've had a couple just fall apart because there wasn't enough glue. The electronics inside are pretty scary. With the ones I've seen, the pins on the back are held against the circuit board pickups with non-captive springs. If the back falls off the springs are free to short circuit things.
I think those ones are a bit better they are the aluminum body ones.

I've been trying to find some with 2 x 3A output without the 12v display, also keep hoping someone will bring out some higher power ones as my phone can charge at up to 6 amps.
 

Two on Tour

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Got plenty of heatsink, so that's looking good. What did you do for the output leads, I suppose I could cut the ends off 2 usb c charging leads and use those.

I boxed the PSU's and wire one of the USB breakout PCB's to each PSU and then covered the USB PCB and cabling back to the box.
You can then use a USB cable of your choice to your Pi as I have.

 
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Two on Tour

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What's the efficiency of these like? Would they have an bigger baseline draw than a lower power device? If they are on 24/7, those milli-amps add up to a lot of Amp Hours on the battery.

280Ah of lithium and 410watts of solar, it copes with the milli-amps. :wink:

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