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12v ac dc converter

Printed From: the12volt.com
Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=121728
Printed Date: May 16, 2024 at 9:44 AM


Topic: 12v ac dc converter

Posted By: wuzin
Subject: 12v ac dc converter
Date Posted: May 07, 2010 at 4:27 PM

Hello,

I'm trying to power up the Valentine1 radar detector at home to do some custom work, and I'd like to use my cigarette lighter charger for the power source.

I purchased AC-DC adapter from ebay (Input 110-240V~50/60Hz 0.1A, Output : DC 12v 500mA) but it doesn't turn my V1 up.

Power requirements for V1 is

11.0-16.0 Volts DC negative ground
225 mA typical standby
425 mA maximum alarm condition

Could you please let me know which AC-DC adapter/converter should I get or need?

Thank you!




Replies:

Posted By: oldspark
Date Posted: May 07, 2010 at 5:44 PM
That AC-DC adaptor should work.

It supplies 500mA and the detector only needs a max of 425mA.

Hence either the AC-DC adaptor is faulty or you have + & - interchanged or your detector draws more current on switch-on. (I assume the detector still works in a car?)

If you can't figure out which of the above, maybe try a larger 1A output rectifier (ac-dc adaptor).




Posted By: wuzin
Date Posted: May 07, 2010 at 5:59 PM

Thanks for the reply oldspark,

That detector still works in a car and AC-DC adaptor works fine with other chargers, but not it just doesn't power up the detector..

Will this one work?





Posted By: wuzin
Date Posted: May 07, 2010 at 6:10 PM

Somehow I can't link the product..

It's ebay item# 230345927313 - 110V To 12V Power Cable Adapter Converter, SEM-AC/DC





Posted By: oldspark
Date Posted: May 07, 2010 at 6:42 PM
Yeah - this site blocks eBay links. Just supply the item number - but a title/description is a handy confirmation!!

Maybe you have an old computer supply hanging around... that has AMPle 12V capacity...


But that #230345927313 is a cute plugpack.

Yes - it should work. It's 1A is more than double the detector's "max average" consumption.
And I should think it will handle the inrush current....

But if the inrush (power up) demand is higher than what that unit can supply...

Have you tried using a capacitor on the output of the 500mA unit? (EG - PSU on with capacitor BEFORE connecting the detector.) That should solve inrush problems.... providing the inrush for the charging of the cap doesn't blow the PSU....
The cap should be at least 16V rated - preferably 25V.
As big as possible for inrush ride-thru, but....
As small as possible to not overburden the PSU upon initial charge up....
Probably around 470uF?
But I reckon whatever you have - whether 10uF or 10,000uF - give it a try.
A big cap might blow the PSU if it isn't self limiting, but if it's useless anyway.... (or cheap enough to replace).




Posted By: wuzin
Date Posted: May 11, 2010 at 5:00 PM

I ended up buying this converter, it arrived today and works perfect! posted_image

https://www.amazon.com/gp/product/B000P7O5DG/ref=ox_ya_os_product





Posted By: oldspark
Date Posted: May 11, 2010 at 6:54 PM
WOW! If I found 5A units like that - and that cheap - I wouldn't have bought my $10 PC supplies. (I use them for 12V watertank and sump pumps using the 2 level-limit switches in a simple SPST latching relay configuration.)

But yeah - 5A should definitely do it LOL!

I'm curious as to why the other did not work - faulty PSU or connection; sensitive PSU; or undocumented inrush current?
But I'll leave that for the cats.... it'll be one of the above; big deal....

For that price and its nice beefy over-rating, I think you got your best solution!





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