road-runner wrote:
You can buy universal 12V laptop supplies which will have different laptop plug adapters and is switchable to the voltage your laptop needs..
....if your laptop doesn't require a specific charger. A Dell laptop, for example, communicates with the charger, and if it's not a Dell charger, it's not happy. It will run the laptop from the charger, but will not charge the battery.
:R
I guess YOU better call my IT dept and tell them this.. They have for many years replaced the Dell Laptop chargers with GENERIC UNIVERSAL power bricks whenever someone loses one or they need an extra one..
Dell uses the same coaxial plug as the rest of the laptops, it is a DC only output on the charger and is typically 19V to 21.5V DC depending on the model.
While it "may" be possible they could make the power supply "communicate" by imposing a AC signal over top the DC voltage of the power supply it would COST MORE MONEY TO DO SO.. Dell and most of the other manufacturers are not going to waste money on non value added features..
What you may have seen as a characteristic of not charging most likely was from the INCORRECT VOLTAGE SELECTED OR TOO LOW OF WATTAGE RATING OF THE POWER SUPPLY..
Too low of a voltage or not enough wattage will result in the battery not charging while the laptop is turned on (IE not enough power to supply the PC AND battery charge functions at the same time).
Besides, Dell DOES offer their own 12V to laptop power supplies for most if not all of their laptop models so really THERE IS NO EXCUSE to use an inverter even for a Dell..
Even if you bought a generic universal supply, 99% of the vendors WILL be willing to refund your money if it doesn't work within 30 days NO QUESTIONS ASKED(provided you buy it from non ebay sources)..
Conservation is cheaper than buying bunches of 12V batteries, and you can really save on Ahrs by skipping just one of the "conversion" steps..
Heck even folks that are into building "car PCs" get it.. They will build a mini PC based on a Mini ITX form factor system board (6"x6") and run it off a ATX power supply that is designed to operate from 11V DC to 16V DC.. No 12V to 120 inverter to a 120V ATX power supply..
I even did that myself for our camper PC, using a Intel dual core Atom system board, all told with HD, DVD drive that PC draws a mere 27W at full bore (20W idle), add in a 12V LCD monitor and my PC was only using 36W! Which is about half of what a laptop uses sitting idle..
