electric trailer brakes 12v and 24v vehicles

Discussion in 'General Electronics Chat' started by spatsupply, Feb 3, 2012.

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  1. spatsupply

    Thread Starter New Member

    Feb 3, 2012
    Electric circuits are definitly not my strong point. I need to use trailers with electric 12v systems behind both 12 and 24v vehicles. I am trying to work out a way to do this so that the driver does not have to switch anything on or off ... ie no silly beggar is going to forget and fry the circuit.
    I am using a standard 12v brake controller and a 12v battery on the trailer and a solid state multivolt input relay to control the braking from the 12/24v brake light. So far so good. The problem comes when I am keeping the 12v battery charged. I have put in a small solar panel battery charger controller thinking that it would handle the input voltage from a park light circuit and automatically charge the 12v battery. Unfortunately it automatically uses the input voltage to determine if it should be charging a 12v or a 24v battery. I figured maybe I could use a DC DC buck to bring the voltage down, but then it drops too far when using a 12v vehicle. Any ideas?
  2. PaulEE


    Dec 23, 2011
    1) we'd need a schematic
    2) AAC prohibits the discussion of automotive anything because of legal issues
  3. spatsupply

    Thread Starter New Member

    Feb 3, 2012
    Thanks PaulEE ...I guess the problem really is not automotive. It is how to keep a 12v battery charged with an input that can vary between 28v and 13.2 V. Without knowing enough about it I can only guess that it would be something similar to the circuitry used in a cell phone charger that will plug into either 12v or 24v and still deliver about 5.2v.
  4. SgtWookie


    Jul 17, 2007
    And if that 12v battery doesn't get charged, then the braking system on the trailer fails to work with no warning - and brakes are a critical safety system.

    Paragraph 6 of the Terms of Service has a list of topics which are not to be discussed on this forum, and "Automotive Modifications" is on that short list. Since your project is in that category, and definitely involves a critical safety system, we simply cannot discuss it here.
  5. bertus


    Apr 5, 2008

    I am closing this thread as it violates AAC policy and/or safety issues.

    6. Restricted topics. The following topics are regularly raised however are considered “off-topic” at all times and will results in Your thread being closed without question:

    Any kind of over-unity devices and systems
    Automotive modifications
    Devices designed to electrocute or shock another person
    LEDs to mains
    Phone jammers
    Rail guns and high-energy projectile devices
    Transformer-less power supplies

    This comes from our Tos:
    Terms of Service
    There will be enough sites where automotive questions can be discussed :
    Member selected automotive forums

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