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Old 08-02-2014, 09:51   #1
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How exact do electronics need 12 volts?

Hi,

I bought a non-marine computer modem with a 120/220 volt power plug that converts it to 12 volts 1.67 amps. The actual modem input says 12 volts 1.66 amps.

I want to cut the power plug off and connect it into my 12 volt system which goes up to 14.4 volts day time.

Should the extra 2 volts be OK? Or will it blow the bloody thing to Kingdom Come?


Thanks for your advice.


Mark
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Old 08-02-2014, 10:00   #2
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Re: How exact do electronics need 12 volts?

Mark, I always designed 12v stuff to continue working at 10v and to withstand 16v with no problem. I did not design your stuff but I bet it will be ok! Go ahead, you try it!
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Old 08-02-2014, 10:16   #3
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Re: How exact do electronics need 12 volts?

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Originally Posted by Cowboy Sailer View Post
Mark, I always designed 12v stuff to continue working at 10v and to withstand 16v with no problem. I did not design your stuff but I bet it will be ok! Go ahead, you try it!
I have not seen many competent designers ( such as Cowboy Sailer ) that allow such a wide variation. At times, one can get the exact tolerance from the manufacturer.

Or, if the manufacturer decided to eliminate some components to save $, and 'assume' the input is a regulated 12V, one can construct/buy a regulation circuit that allows a voltage fluctuation on the input and smooths it out on the output.
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Old 08-02-2014, 10:17   #4
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Re: How exact do electronics need 12 volts?

Seems like most 12v devices have a wide variation, I have seen up to 18 volts allowable. My old Fujitsu Laptop says to 16v right on the label. Maybe pull your battery pack and see if it 's label has a range?
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Old 08-02-2014, 10:24   #5
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Re: How exact do electronics need 12 volts?

I bought a load of these for the various bits which have different input voltages and anything which might be a bit fragile...
Handy to have a variable voltage source onboard Sometimes as well.
http://www.ebay.co.uk/itm/3-5-28V-to...item51ab7d061a
Rf noisy but a Capacitor each side seems to clean that up.

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Old 08-02-2014, 10:27   #6
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Re: How exact do electronics need 12 volts?

Mark,

Bet it would be just fine... BUT... I would use one of these two things... CHEAP!

Amazon.com: RioRand LM2596 DC-DC Buck Converter Step Down Module Power Supply Output 1.23V-30V (1 Pcs-LM2596): Car Electronics

Amazon.com: DROK Waterproof 60W/5A 17-35V 24V to 12V DC Car Power Converter Step Down Buck Voltage Regulator: Electronics
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Old 08-02-2014, 10:35   #7
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I can tell you from first hand experience that led lights that don't have a built-in current regulator will wear out very quickly If used at 14.4. I agree that regulators for that low amperage are pretty cheap and well worth the money.
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Old 08-02-2014, 11:21   #8
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Re: How exact do electronics need 12 volts?

Regulator in the Budget Marine catalogue for only $65!

Thanks for the advice. I will see if i can find a cheapy. The whole unit is only worth $125.
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Old 08-02-2014, 11:35   #9
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The one on Amazon is two for 3.99 free shipping just ordered one or two that is.
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Old 08-02-2014, 11:41   #10
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Re: How exact do electronics need 12 volts?

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The one on Amazon is two for 3.99 free shipping just ordered one or two that is.
Bear in mind that you lose some voltage with a buck converter.
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Old 08-02-2014, 11:52   #11
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Bear in mind that you lose some voltage with a buck converter.
Thanks they also have one for about nine bucks that can step voltage up or down. But I'm going to use it for LED anchor lights and they're very bright. I think if the voltage is a little low they should just last a lot longer. Edit. Do you know what the voltage drop off would be?
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Old 08-02-2014, 12:00   #12
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Re: How exact do electronics need 12 volts?

I'm no EE, but my friend who is one told me that if the voltage requirement is higher (like commonly 18.5 - 19 for computers) you need to step it up... so I bought a 12v to 19v dc converter for about $10 on Amazon. HOWEVER, he said if it draws less than 12 volts, I could plug it directly to my DC power distribution and it should only draw what it requires.
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Old 08-02-2014, 12:08   #13
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Re: How exact do electronics need 12 volts?

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Originally Posted by sparrowhawk1 View Post
Thanks they also have one for about nine bucks that can step voltage up or down. But I'm going to use it for LED anchor lights and they're very bright. I think if the voltage is a little low they should just last a lot longer. Edit. Do you know what the voltage drop off would be?
Think voltage drop is about 1.5v. For low current the buck/boost ons from eBay work fine for me, very stable output if a bit radio frequency noisy. If your anchor light has a regulator in it already it might not work so well for dimming..
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Old 08-02-2014, 12:23   #14
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Quote:
Originally Posted by conachair View Post

Think voltage drop is about 1.5v. For low current the buck/boost ons from eBay work fine for me, very stable output if a bit radio frequency noisy. If your anchor light has a regulator in it already it might not work so well for dimming..
No regulator they're actually waterproof strip lights and I wrapped a band around the mast. they are very bright but made for regulated power supply. Worst case scenario I will buy the one that will hold the voltage steady "regardless" of input
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Old 08-02-2014, 12:38   #15
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Re: How exact do electronics need 12 volts?

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No regulator they're actually waterproof strip lights and I wrapped a band around the mast. they are very bright but made for regulated power supply. Worst case scenario I will buy the one that will hold the voltage steady "regardless" of input
Good idea
These are the ones I've used..
http://www.amazon.com/Converter-3-5-...ref=pd_sim_e_6
Reliable so far, buy few, very handy.
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