Reliable 18v to 5v USB voltage converter.

[smilem]

Hello, I have Microtik router that has unpowered USB port that I would like to use.
I want to use a stepdown converter to power it.

The converter obviously needs to be reliable, block inrush voltage when turned on etc.

This would work OK:
http://www.ebay.com/itm/KIS-3R33S-D...1001298808?pt=US_Adapters&hash=item43c1076f78

Notice this one even has red quality cap.

Or use something like this:
http://www.ebay.com/itm/DC-12V-24V-...59?pt=US_Power_Inverters_&hash=item4acaba272b

 

[OLIVE2222]

Hi,

If you want reliable stuff don't buy Ebay Chinese items.
They clone everything, semiconductors, red caps, and even aircrafts!

Here a company that sold reliable genuine stuff:


Olivier


http://www.mini-box.com/DCDC-USB?sc=8&category=981

 

[smilem]

Hi,

If you want reliable stuff don't buy Ebay Chinese items.
They clone everything, semiconductors, red caps, and even aircrafts!

Here a company that sold reliable genuine stuff:

Olivier

http://www.mini-box.com/DCDC-USB?sc=8&category=981

This looks like really reliable PSU, however I can't spend that much on a converter. I'm not from USA and my currency is 2.5x less worth that 1$, so I cant pay 2.5x more I think even you would not pay 150$ for this PSU.

My Arduino however works fine, despite being bought from ebay. You forgot to mention China makes 90% of the stuff, there are clones, but you have to read seller ratings, and actually test seller by asking real questions.

And I got cheated by US company PAYPAL, they do not want to give me back a refund of 50EUR. And that is not some sort CHINA seller. Don't you find it strange that PAYPAL is positioned as reputable company yet they have only very well hidden SKYPE free support number and when you call them they transfer you to EBAY and then EBAY transfers you forever until you reach answering machine, then you leave message and nobody calls you back.

So much for doing business with US companies.

 

[OLIVE2222]

Hi,

I bought exactly the same Ebay down converter and I can tell you that they don't least more than few months. Indeed Arduino Ebay boards, relay boards and others works quite well but power supplies need more demanding components like power diodes, power FETs good capacitors...For mass production when stringent controls are applied they can indeed do good stuff.
One suggestion can to buy those Ebay down converter and to replace the power semi conductors and the caps, they are cheap enough to consider them as PCB+self+heatsink kit.

Olivier

 

[smilem]

Hi,

I bought exactly the same Ebay down converter and I can tell you that they don't least more than few months. Indeed Arduino Ebay boards, relay boards and others works quite well but power supplies need more demanding components like power diodes, power FETs good capacitors...For mass production when stringent controls are applied they can indeed do good stuff.
One suggestion can to buy those Ebay down converter and to replace the power semi conductors and the caps, they are cheap enough to consider them as PCB+self+heatsink kit.

Olivier

I have ordered some relays myself http://www.ebay.com/itm/20098321955...eName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649


Can you post a link what model failed you?

I found this new converter :

http://www.ebay.com/itm/MC34063-DC-...700?pt=LH_DefaultDomain_0&hash=item417600b394

Perhaps it would work better, I would add an electrolytic cap on output.

 

[OLIVE2222]

I will picture it. Ceramic caps are reliable, the problem here is the lacks or transient voltage suppressor at the input. In cars you must deal with cold-crank and Load-Dump Transients !

Olivier

 

[OLIVE2222]

You can maybe go for a Belkin product, those guys have a good rep

http://www.amazon.com/BELKIN-F8Z445ttP-F8Z445ea-Belkin-Charger/dp/B0047T79TA

Olivier

 

[smilem]

I will picture it. Ceramic caps are reliable, the problem here is the lacks or transient voltage suppressor at the input. In cars you must deal with cold-crank and Load-Dump Transients !

Olivier

So I need 12V TVS diode? But wiring shows it connected to ground, and on a car there is no true ground! I'mm use my converter at home, I have neutral and ground same wire.

All there protections that require to connect to ground are nonsense (they offer false sense of protection if you connect to not grounded socket etc.), a poly fuse is better.

 

[smilem]

You can maybe go for a Belkin product, those guys have a good rep

http://www.amazon.com/BELKIN-F8Z445ttP-F8Z445ea-Belkin-Charger/dp/B0047T79TA

Olivier

why there are so many negative reviews?

 

[smilem]

This would work?
http://www.littelfuse.com/products/tvs-diodes/leaded/1_5ke/1_5ke8_2a.aspx

 

[OLIVE2222]

Let's summarize:

-Not a car application, no needs for TVS
-Your proposal http://www.ebay.com/itm/MC34063-DC-D...item417600b394 seems OK so.
-Car lighter type are not suitable (without mods)
-Adding a polyfuse is a good habit

Olivier