run a 20 Volt Laptop from 26V car battery?

Lenovo 3000 n200
November 27, 2010 at 07:09:50
Specs: Windows Vista
I'd like to use two car batteries in series (~26V) to run my Lenovo Laptop (20V is written on its DC supply); is it safe?

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#1
November 27, 2010 at 07:28:19
What is the purpose of that exercise? Certainly not mobile anymore.

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#2
November 27, 2010 at 08:44:59
Put 26V into a device expecting 20V and you will allow the smoke to escape. When the smoke escapes everything stops working. I would stick with the recommended power supply.

Unless the battery was on a trickle charge, as soon as it started to run down all sorts of strange things could start happening. Bear in mind also a car battery only shows 14-13 V when not under load. When under load the voltage can drop to below 12V. This is not a problem with cars as car eclectics are not that sensitive to voltage fluctuations. Computers are very sensitive to variations in voltage.

There are adapters that you can get to run electronic devices like sat-navs and mobile phones from a car battery with there own built in voltage regulator but they are usually only rated for 12V. The recommended power supply will also incorporate a voltage regulator.

Stuart


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#3
November 27, 2010 at 10:31:24
Purpose?: we have (in Mexico) extended periods of power outage.
As to "smoke": many modern power supplies can handle out of spec voltages. But not sure about the technology used in Laptops, therefore my original question.

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Related Solutions

#4
November 27, 2010 at 10:45:30
You need a battery/mains inverter, like:

http://cgi.ebay.co.uk/12V-DC-AC-Mai...


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#5
November 27, 2010 at 11:02:20
The inverter makes much more sense.

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#6
November 27, 2010 at 11:16:45
The thing is with desktop is the the power supply has all-sort of voltage regulators to accommodate variations in main voltage. What you are doing with a battery is feeding an unregulated voltage where a regulated voltage is expected.

A mains inverter as described in the previous post should do the trick but make sure you get the right type. The one described if 240v for European use and I suspect the mains voltage in Mexico is 120V, the same as the USA. You should get a few hours use from two 12V batteries wired in series.

Stuart


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#7
November 27, 2010 at 13:19:51
I do have a 12V to 120 inverter (not powerful enough for feeding the Lap top, though) and I am not encouraged because of the terrible performance in terms of the load dependence of its output voltage (120 nominal). But I guess the laptops a/c-d/c would take care of that(?) Thanks everybody for their input!

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#8
November 27, 2010 at 18:49:04
Seems like all you need is one battery, a car charger/adapter for the laptop and one of these:

http://www.o-digital.com/uploads/21...

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#9
November 27, 2010 at 23:42:30
A proper inverter should have adequate capacity to run a laptop for a day. Either the regular 12vdc to 120vac inverter or a 12vdc to laptop (Targus APM62).

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