Tyre inflator modification. Currently powered by cigarette lighter, want to add mains power option.

[TheJay]

The yellow and black wires run from the point the cable plugs in to supply power. I'd like to add an DC power jack and figure I just need to mount it to the outside and then use two wires to join up with the points that are soldered on.

How do I safely detect what voltage is required without breaking it? Would it be 12v, can I just get a 12v adapter plug?

 

[Nigel Goodwin]

It's 12V (obviously, as it plugs in the 12V on the car), but it's fairly high current - a car socket is capable of about 10A.

 

[TheJay]

How do I check that or do I assume 10A?

Would this do?

https://www.ebay.co.uk/itm/26619031...aZIty1hf6TjDrWoTP+8+zpRg==|tkp:Bk9SR7iJ6v_eYw

12V 10A 120W Switch Power Supply | eBay

Rated Power: 120W. We'd like to settle any problem in a friendly manner. It's just take you 1 minute. Because the unpaid dispute will not be closed automatically, and we may ignore it.

www.ebay.co.uk

https://www.ebay.co.uk/itm/276394988336?itmmeta=01HVVZTGJ4TYHB80V181Y9SWWK&hash=item405a6cd330:g:~fkAAOSwMy1l~vhY&itmprp=enc:AQAJAAAAwB+sSZbNFETETyeFPGqFfyliCtGR2fkUf+RDa6PYjuEsYZf8I1b15oPhkjn1geDg+QbnKPEGzVkRQmzdTOjna1VXniL+hU/gTeGcC/y/PhQ3cy6C06TkEoPsV80RXspdROH4MeMpBp3LnJViKfPW3PQZgInc92P9oogoPatJSnSJsvWWesYi4Lwj6VfMb5cHqMHeqfzyY34w724YSshCdxJyzUjMM4q4Zq2IFGEd47xmSGxgpUnF4aRuMnecnCr76Q==|tkp:Bk9SR7CJ6v_eYw

https://www.ebay.co.uk/itm/28492893...lp:4429486&itmmeta=01HVVZAD04JQ6D98RZHGNBKB1G

12V 5-10A AC to DC Adapter Car Cigarette Lighter Charger Power Supply Adapter UK | eBay

Plug: Car cigarette lighter socket. Converts 100-240V AC household current to 12V DC power. 12V Car to Mains Converter. Powerful 12V 5A/10A 60W/120W max current draw. Suitable for devices up to 120W/60W Only.

www.ebay.co.uk

Is there another way to do this without an adapter like adding components inside the inflator enclosure?

 

[crutschow]

Is there another way to do this without an adapter like adding components inside the inflator enclosure?

That would be difficult unless you can fit the converter inside the inflator, since the components you would need would likely occupy a similar volume..

Just buy the external converter.
The bottom one would likely work.

Does the inflator label say how much current it takes?

 

[Beau Schwabe]

Or just get a small air compressor that is designed to plug into AC

 

[Tony Stewart]

How do I check that or do I assume 10A?

Would this do?

Yes

Is there another way to do this without an adapter like adding components inside the inflator enclosure?

No. Power conversion to match the pump power required takes more space than the pump.
If you just want an AC pump, get an AC air pump.

 

[Diver300]

Compressors for inflating car tyres can take around 5 times the running current as they start up. With a car battery or a linear unregulated power supply that current is less likely to be a problem as the compressors will start in around 200 ms.

However on a switch-mode supply or a regulated supply there is likely to be a current limit. The simple compressors are only single cylinder so the torque varies a lot as they rotate. If they are starting with the air pressure already high, they need a lot of current to start. With a current-limited supply or too much resistance in the wires they may fail to start at all unless the pressure is removed before starting.

I did some work on compressors designed to run from a cigar lighter supply. They took about 12A when running. Starting current was about 70A and 100 milli-Ohms of wiring resistance would make starting difficult.