Connect with us

dc car charger

Discussion in 'General Electronics Discussion' started by stevenk, Mar 11, 2013.

Scroll to continue with content
  1. stevenk

    stevenk

    5
    0
    Mar 11, 2013
    im not a hobbyist nor profesional thats why im here to ask yo guys and girls. Question 1: looking to replace a car charger which is rated output 5.5V 750mA but cant find anythings with exact output. saw stuff with rating of 5 through 8 V and no mA rating anywhere. not sure what that stuff is and how important it is so i need your help. question 2: when plugged in charger interferes with radio reception in my car. remedy? any help would be apreciated!
     
  2. Electrobrains

    Electrobrains

    259
    5
    Jan 2, 2012
    1. What do you mean with "car charger"? Do you charge batteries or something else inside your car? Is it supplied with the 12V from your car?
    If yes, you can buy cheap adjustable DC/DC converters at many places, for instance on Ebay:
    http://www.ebay.com/itm/DC-7-35V-to...ly-Charger-LED-Driver-Regulator-/390546327147

    2. If you buy a good finished charger or power supply, it should conform to the emc standards and not disturb your radio.
    If you buy a cheap switched mode charger/supply (like the Ebay type above), you might have to put it in an earthed metal box. If that wouldn't be enough, you could add a simple filter or ferrite snap to the supply input.
    If you would buy or build a linear circuit (for instance with the ic L200), you would not have any radio interference problems (but quite much power loss - approx. 5W).
     
  3. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    You would probably find it best to simply use a cheap linear voltage regular (as Electobrains suggest) like the adjustable LM317 since I doubt efficiency is that much of a concern in your design... You should install a heatsink on the LM317 in this application to keep it running cooler, because again as Electobrains suggest it's wasting a decent amount of power as heat...

    All the parts can be had at Radio Shack... If you use Radio Shack get a 5 pack of 220 Ohm and a 5 pack of 100 Ohm resistors, that way you can use a 220 Ohm for R1 in the below link and three 220 + one 100 Ohm to get a value of 760 for R2 that should dial you in to a nominal 5.5V out...

    http://www.electronics-lab.com/articles/LM317/

    The linear regulator setup above should not cause any significant radio interference, get you about 5.5V out with the resistor values I suggested and can be assembled pretty easily and even put in a small enclosure (Altoids tin, that can also serve as the heat sink if you bond the regulator it it with a screw) if you want...
     
  4. BobK

    BobK

    7,682
    1,688
    Jan 5, 2010
    And you get a free hand warmer as a bonus.

    Bob
     
  5. stevenk

    stevenk

    5
    0
    Mar 11, 2013
    im not relly looking to make anything from scratch. what i really need is a quality replacement that wont damage the camera in the process. this is what charger is for . one it came with. http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=130455460442

    specs posted on charger are the ones i've posted in my original post. thanks
     
  6. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    Chances are real good you can use a 5V power adapter, and that pretty much opens you up to any of the current 'USB' style car phone chargers on the market... Most new phones want in excess of 750mA @ 5V so as long as you get a charger for a new smart phone it should work... You will likely need to install the proper plug on it though... You can also look at GPS power cords most of them are also 5V...
     
  7. stevenk

    stevenk

    5
    0
    Mar 11, 2013
    thank you for reply, original charger is 5.5 v,5v will work anyways? also as long as it can supply over 750mA its ok? so is it one of those things that will either work or will not or am i looking at any psssible damage to the device?
     
    Last edited: Mar 13, 2013
  8. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    I would hazard an educated guess that yes, 5.0V will work but I can't guarantee that... There is nil to no chance of damage using the lower voltage, the battery from the pictures you linked shows it runs on 3.7v the 5.5V overhead is likely just that a little overhead to properly charge the battery... The good thing is that it's a low cost investment to try out, if it doesn't work you are only out a few dollars...

    And yes anything 750mA or above will work...
     
  9. stevenk

    stevenk

    5
    0
    Mar 11, 2013
    thank you very much! i found a charger rated 650mA will that work?
     
  10. CocaCola

    CocaCola

    3,635
    5
    Apr 7, 2012
    You want to go at least what the original is, in this case 750mA or more... 650mA is less...
     
  11. stevenk

    stevenk

    5
    0
    Mar 11, 2013
    gotcha. thanl you for all the lelp
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Similar Threads
There are no similar threads yet.
Loading...
Electronics Point Logo
Continue to site
Quote of the day

-