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Power supply voltage output query

  • Thread starter Deleted member 140690
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Deleted member 140690

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Am back again, I have a power supply rated at 12v 2amp output.

This came with a new laptop, but when the battery in the laptop
is showing 100% charge, the voltage displayed is 8.4

Is it normal for the battery voltage to be this much lower
than the power supply output.

The specs for the laptop state 12 volts, this is why I bought it,
so I could plug it into a car battery with some diodes to bring
the voltage down a little and a 1.5 amp fuse to protect things.

Or do I need to find a 12 volt regulated power supply keeping
in mind I need this to work off a car battery / 12v

I have yet to test the power at the charger outlet to confirm 12 volts.
 


Jarret B

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The power supply voltage may be just a standard power supply that they did not want to have to make a special one for the laptop. The laptop may step down the voltage.
For in a car running off of the power supply, look for an inverter. One end has a cigarette lighter connection. The other has house wall outlet connections. Of course, this assumes you have a cigarette lighter in the car. Most don't anymore.
 

Brickwizard

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Yes it is normal, if you don't have a higher input voltage than that of the Battery then it won't charge
my Dell for example has an 11V battery, but the charger is 19v, if you have ever driven a car with fitted voltmeter [not so common on modern cars, you would have noticed the battery voltage would show around 12v but with the engine running that would increase to between 13.5 & 15V
 
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Deleted member 140690

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Yes it is normal, if you don't have a higher input voltage than that of the Battery then it won't charge
my Dell for example has an 11V battery, but the charger is 19v, if you have ever driven a car with fitted voltmeter [not so common on modern cars, you would have noticed the battery voltage would show around 12v but with the engine running that would increase to between 13.5 & 15V
Yes, I know a voltage above the battery v is required, but that seems a lot, battery reporting 8.4v and a charger putting out 12.
The specs may be wrong for the charger, it does put out 12 v, but
the stated 5 amp on documents is wrong, it states 2 amp on the charger which is more like it.

So the above leads me to believe the laptop actually manages the charging, and cuts the circuit when the battery is fully charged.

But does it handle voltage regulation too, such as cut it down to a level just enough to stay above the battery voltage as it rises during charging, or does it just let the full 12 volts at it, and cut that when the battery is charged.

On another note, would the 9 volts from a 9 volt battery not adequately run this laptop in an emergency.

I do not want to buy an inverter, just one more thing to break when
you need it most. Batteries are a lot cheaper and in general are always knocking about or can be purchased.
 
OP
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Deleted member 140690

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The power supply voltage may be just a standard power supply that they did not want to have to make a special one for the laptop. The laptop may step down the voltage.
For in a car running off of the power supply, look for an inverter. One end has a cigarette lighter connection. The other has house wall outlet connections. Of course, this assumes you have a cigarette lighter in the car. Most don't anymore.
The power supply has a small barrel jack, and resembles he ones not usually used with computers, this is a Dynabook E10 106 11.5 inch device. I get 12 volts at the output, that's a lot above the battery voltage.
 

Brickwizard

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All OEM power supply units for Dinabooks are 19V there are 2 different outputs depending on age, either 45W or 65W
they all need an input of 100/220V at 5amp
 
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Confusing info, it states 12 volts here
from the site I purchased from.

System memory:​

  • Standard : 4,096 (onboard) MB
  • Maximum expandability : 4,096 MB

Display:​

  • Type : HD IPS non-reflective WLED-backlit display with 220 nit

Interfaces:​

  • 1 × External Headphone (stereo) / Microphone combo socket
  • 1 × HDMI-out supporting 1080p signal format
  • 1 × RJ-45
  • 3 × USB 3.0
  • 1 × 1 x USB 3.0 Type-C Gen 1 port (supporting USB sleep & charge)

Wireless communication:​

  • Network Support : 802.11ac, agn (Dual Band)
  • Wireless Technology : Wireless LAN
  • Wireless Technology : Bluetooth 4.1
  • Version : 4.1

Wired communication:​

  • Topology : Fast Ethernet LAN
  • Speed : 100BASE-TX

Keyboard:​

  • Keys : 78
  • Windows keys : Yes
  • Special features : Black tile keyboard

Pointing Device:​

  • Type : Touchpad with multi-touch gesture support

Battery:​

  • Technology : Lithium-polymer, 2 cell
  • Maximum life : Up to 12h10min (MobileMark 2014 running Windows 10)
  • MobileMark is a trademark of Business Applications Performance Corporation

AC Adapter:​

  • Input voltage : autosensing AC adapter (100/240 V) for worldwide usage
  • Output voltage : 12 V
  • Output current : 2.5 A

Security Features:​

  • User password
  • Supervisor password
  • Firmware Trusted Platform Module (FTPM)

Certification:​

  • The manufacturer declares that this product complies with the following directives and regulations for the CE-marking. Responsible for CE marking is Dynabook Europe GmbH, Stresemannallee 4b, 41460 Neuss, Germany

Bundled Hardware:​

  • AC adaptor

Bundled Software:​

  • Microsoft 365 - 1 month trial for new Microsoft 365 customers

Product Features:​

  • Sound system: Stereo speakers
  • Keyboard: Keys : 78, Windows Keys, Special features : Black tile keyboard
  • Pointing device: Type : Touchpad with multi-touch gesture support
 
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Deleted member 140690

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These are small educational models, Sharp now own the Dynabook brand and are manufacturing these, here is the supplied charger, make it full size, 12 volts 2 amp is what I make it.
Dyna-.jpg
 
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