5 ms·

20v@5a! Nice! I can't wait to see USB ports instead of the 13.8v ports we currently have in cars. Sadly my 170w laptop still would need a separate adapter.

morsch 14y ago
Unless your laptop is using 170W all the time, you could still charge it using just 100W. Even a very high powered laptop is probably using <10W in idle.
- beagle3 14y ago
  I used to think that too. But I just measured my ExoPC slate (Tablet, Atom N450, Pine Trail chipset); It draws 0.1W while suspended, 9W idling with screen off, 13W idling with screen on, and 18W with screen on and 100% CPU.
jonknee 14y ago
A decent number of cars have USB ports (usually for audio purposes but they also supply power). Ford Sync comes to mind here.
dspillett 14y ago
Remember that your laptop is unlikely to actually draw 170W at any time unless there is a fault (that it its supply's rated maximum, not what it is expected to draw all the time). Most of the time it'll draw a few 10s of W, maybe stepping up as high as 100W+ when at full tilt (CPU & GPU hammering away, cooling fans on full blast, display at full brightness, all disks spinning & heads flapping, active drives or USB-powered cup warmers in every available port, ...). If you have (or have access to) one of those plug-in power meters give it a try without the battery connected: you might be surprised how little power is being drawn most of the time. A laptop's power system is essentially a UPS: if there is no (or not enough) power coming in from the main source, flip to the battery. This won't be any different for this use: as soon as it wants to draw more than is available it'll see the under-current and switch over. The smoothing capacitors will ensure it can stay alive during the switch-over just as they do when you unplug the charger normally. If it is a little brighter then at times it might be be able to draw as much as it can from the external power and draw the excess from the battery, but I suspect no laptop is currently designed that way (they generally either get more than they need or nothing at all from the external source, so trying to be clever in response to getting half what you need would be over-engineering).
jessriedel 14y ago
> instead of the 13.8v ports we currently have in cars. That's a bit too much precision for that standard. It's only ~13.8 V when your car is running and the alternator is charging the battery. When the car is off, it'll be 13 V or slightly less.
- simcop2387 14y ago
  And even when it's running, you have to expect up to at least 16V, some of the cars and trucks with larger alternators will run a bit higher, I've seen 15V myself but I've always heard that 16V is what to expect.
K2h 14y ago
If you really do need 200W, can't you just plug 2 cables in? I've seen quite a few USB devices that have an extra plug to draw extra juice. wow... just think if every USB3 port needs an extra 100W of potential from the PSU in your computer (plus the overhead of switching effeciency). So if you have 3 USB3 ports that would mean +300W on your supply (to be safe).

morsch 14y ago

Unless your laptop is using 170W all the time, you could still charge it using just 100W. Even a very high powered laptop is probably using <10W in idle.

beagle3 14y ago
I used to think that too. But I just measured my ExoPC slate (Tablet, Atom N450, Pine Trail chipset); It draws 0.1W while suspended, 9W idling with screen off, 13W idling with screen on, and 18W with screen on and 100% CPU.

jonknee 14y ago

A decent number of cars have USB ports (usually for audio purposes but they also supply power). Ford Sync comes to mind here.

dspillett 14y ago

Remember that your laptop is unlikely to actually draw 170W at any time unless there is a fault (that it its supply's rated maximum, not what it is expected to draw all the time). Most of the time it'll draw a few 10s of W, maybe stepping up as high as 100W+ when at full tilt (CPU & GPU hammering away, cooling fans on full blast, display at full brightness, all disks spinning & heads flapping, active drives or USB-powered cup warmers in every available port, ...). If you have (or have access to) one of those plug-in power meters give it a try without the battery connected: you might be surprised how little power is being drawn most of the time. A laptop's power system is essentially a UPS: if there is no (or not enough) power coming in from the main source, flip to the battery. This won't be any different for this use: as soon as it wants to draw more than is available it'll see the under-current and switch over. The smoothing capacitors will ensure it can stay alive during the switch-over just as they do when you unplug the charger normally. If it is a little brighter then at times it might be be able to draw as much as it can from the external power and draw the excess from the battery, but I suspect no laptop is currently designed that way (they generally either get more than they need or nothing at all from the external source, so trying to be clever in response to getting half what you need would be over-engineering).

jessriedel 14y ago

> instead of the 13.8v ports we currently have in cars. That's a bit too much precision for that standard. It's only ~13.8 V when your car is running and the alternator is charging the battery. When the car is off, it'll be 13 V or slightly less.

simcop2387 14y ago
And even when it's running, you have to expect up to at least 16V, some of the cars and trucks with larger alternators will run a bit higher, I've seen 15V myself but I've always heard that 16V is what to expect.

K2h 14y ago

If you really do need 200W, can't you just plug 2 cables in? I've seen quite a few USB devices that have an extra plug to draw extra juice. wow... just think if every USB3 port needs an extra 100W of potential from the PSU in your computer (plus the overhead of switching effeciency). So if you have 3 USB3 ports that would mean +300W on your supply (to be safe).