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Can I use battery w/ higher voltage than specified?

  1. Oct 14, 2016 #1
    I've got two monitors I am trying to power with a battery. They accept 19V @ 1.3A each, and I'll have them in parallel off a single battery, so they'll need 19V @ 2.3A from the battery. I'm looking at this battery on HobbyKing. The specifications say 22.2V. Can I still use this directly with the monitors? Or would I have to use some resistors to lower the voltage before it got to the monitors?
     
  2. jcsd
  3. Oct 14, 2016 #2

    berkeman

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    Staff: Mentor

    Welcome to the PF.

    Their datasheets or User's Manuals don't show a range of input voltages allowed? Have you tried calling their Technical Support folks to ask for advice?
     
  4. Oct 14, 2016 #3

    nsaspook

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    What is the exact monitor type and specification. Usually a 19 volt supply is used to keep a 4 cell Lithium Ion powered system charged. The 4 cell pack voltage is about 16.8 V so you need the extra voltage for a direct (without another DC-DC switcher) connection to the internal charger electronics but I have seen that voltage used in some LCD monitors with external power bricks.
     
  5. Oct 14, 2016 #4
    Thanks for the welcome!

    I'm using this Acer R240HY bidx monitor. I'll try their support now. There doesn't seem to be specifications for input power on the Internet, but the power brick and sticker on the monitor state 19V at 1.3A DC power.
    Perhaps I should've been more specific in my original post - sorry about that! As stated above, I'm using the Acer R240HY bidx. This monitor has an external power brick, so the screen accepts straight DC power. The output on the brick (and the sticker on the monitor) state 19V at 1.3A.
     
  6. Oct 14, 2016 #5

    nsaspook

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    I just looked at a similar type Acer service manual online. The 19 volt circuit is a direct tie into some of the electronics so I would suspect the nominal voltage tolerance would be fairly tight (maybe 10%). The safe way to handle the voltage difference would be to use a DC-DC converter to deliver the correct voltage to the monitor.

    They sell fairly cheap ones designed for a car 12vdc battery input.
    https://www.amazon.com/Step-up-Regulator-Vehicle-Supply-Converter/dp/B00S0UFR14

    100_0229.png
     
    Last edited by a moderator: May 8, 2017
  7. Oct 14, 2016 #6
    Unfortunately the Amazon link is for 12V, not 22.2V, and I don't know enough to follow the circuit schemata you've got there. I found this DC-DC regulator on batteryspace, which I might be forced to buy given my time constraints and the current state of my project. This has a max throughput of 4A, which should be fine (the LCDs should draw 3.6A), so if I buy that and a power distribution board, everything with the battery I'm looking at should work, right?
     
  8. Oct 14, 2016 #7

    nsaspook

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    That should work.
     
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