nkedel

Interesting news!

I'll be in J on an AA 77W (and a couple of CX planes, one in Y and one in J) and will be trying the 130W supply at least on the longer AA legs (although I'll have a 90W for backup just in case.)

I also wonder if there is some variance in the 130W supplies; I've got some older ones that came with my M3800 (bought at various points during its useful lifetime), and a newer one that came with my XPS 15 (9560.) They looked the same on the outside, but I wonder if there are internal differences.

tentseller

I don't know about now but one of my summer jobs was servicing airplanes.
The power for the service crew is hooked up to airport power.

docbert

And another success - this time on a United/Skywest ERJ175 in F.

Edit: And of course about 30 seconds after I posted that, it tripped. Light on the socket went orange rather than green, and the laptop started running on battery. Unplugged and replugged and it's working again, but it's obviously right on the edge of what is allowed...

SuperFlyBoy

Has anyone tried doing so on the long-haul 772-ERs? (EWR-BOM/DEL/NRT/etc.-EWR)

I would think as the seats are pretty old (ex-CO BF), then probably not...

jackal

So I think I've figured the secret out.

After forgetting my smaller adapters on my most recent trip, all I had to use was my 180W adapter.

Since it's the high-capacity capacitor that seems to trip the socket's circuit as soon as you plug it in, the secret seems to be that you need to let the capacitor in the charger charge up. Once it's full, the actual draw is usually less than 100W, so it's not enough to trip the circuit.

The way to do that is to repeatedly plug and unplug the charger into the socket (without a computer attached to the other end) until the light stays solid. Once the light is on solid, then you can plug your computer into the charger and proceed as normal.

First up was a VX A321. I plugged the adapter in and it went out, but the light on my adapter lit up a bit and stayed glowing. I plugged it in again and voila: all was well.

Next was an AS 738. This one was a little more difficult and required me to plug and unplug the power adapter about five or six times before it charged the capacitor enough to stay on. Once that happened, everything was smooth sailing.

Of course, if you are running right on the edge of the circuit's capacity such that a power spike in your laptop triggers the circuit to knock out, try putting the computer in sleep mode and charging the battery. Once the battery is full, then use the computer. That should reduce the power consumption enough to keep it below the circuit's max.

Edit: the AS 739 I flew last night took a good 10 or so plug-in-unplug cycles before it worked, but after that, no troubles at all.

nkedel

Interesting. I've got a flight on a newer-config AA 772 in their new PE next month, and will give that method a try with the Dell 130W slim adapter.

(Also, I realized I never followed up on my point about the 77W above, but to follow up, the Dell 130W definitely trips those. I did not notice whether the LED came on before it tripped.)

I wonder if one could find an airline-legal (< 99Whr) powerbank with a 120V outlet that had sufficient momentary current capacity. It wouldn't charge a big laptop supply for long, but it would certainly be plenty to pre-charge the capacitors. I suspect they most have current limiters that would have the same problem as the outlet, e.g. http://amzn.to/2AjioxF

diburning

Which US airlines have restrictions or outright disallow powerbanks with more than 100Whrs? I have such a powerbank and so far, Jetblue and Southwest don't seem to have any restrictions on them. I haven't looked into whether the legacy carriers have any rules against them. TSA says to refer to the carriers for their policies.

nkedel

So far, I've only had power banks checked at non-US airports. It is technically an FAA limit but if airlines and the TSA aren't enforcing it, then you're in luck. (Apparently, you can have a limited number of 101-160Wh batteries, as well, but most manufacturers are treating 100 as a hard limit AFAICT)

KRSW

It'd be a colossal waste of electrons to make a battery bank which output 120v, only for someone to plug in another DC transformer in. The conversion losses between battery DC -> inverter AC -> DC power supply -> Laptop's internal DC circuitry would be pretty high (>50%), making runtime minimal. I guess this is where the future USB-C battery banks could play a role, but not many of those out there yet.

SuperFlyBoy

My question would be whether the output (DC) voltage of the (USB-C) battery should match the input requirement of the DC input for the laptop?

Pros/cons?

nkedel

I have a Dell-specific 19.5V battery bank that works great with my lower-power Dell machines -- unfortunately, it reports itself as 65W, which means throttling on the 95x0/M3800/M55x0. There are a number of other non-branded 20V battery backups, some of which show a 90W supply. Given how many other machines run in the 18-20V range (pretty much all Thinkpad and recent Dell models, at least some HPs, 15" Macs, etc)

My point was just to use the battery to pre-charge the capacitors so as to keep the supply from tripping the overcurrent protection on in-seat power, since it would be a bit less timing-dependent than hoping that the capacitors stay charged for longer than the outlet takes to reset. You wouldn't need a lot of capacity, jut a reasonably high-ish current briefly.

EuropeanPete

I had no idea this was a thing. I have a small but powerful Razor Blade drawing 165W which I assumed I'd be able to charge online. I was going to charge it tomorrow, but looks like I'll have to be a bit careful.

nkedel

At least for the combination of a Dell thin 130W supply and an AA 772 new-style business class seat, the "plug/unplug repeatedly" to pre-charge the capacitors worked! It took several rounds, and the outlet went on again quicker than I remember some others doing, so I'm not sure I'd want to bet on it working everywhere (I have a 90W with tip adapter in my bag just in case) but it looks like I'll be at full, unthrottled speed for this flight

yangotang

I kept a list this year, high power requirements are kind of a pain!

Here's my successes and failures this year thus far with a Slim 130W Dell on a Precision M5510:

AC (QK) CRA / CRJ-705 / CRJ-900 J: Trips every time, doesn't work.
UA 738 E+: Trips every time, replug doesn't work.
UA 739 E+: Trips every time, replug doesn't work.
UA 73* F: Works on almost all configs with Sky interior
UA 752 pmCO Int'l Config E+: Works
UX E175 F: Works
DL (OO) E175 F: Works
DL 752 F (new bins): Works
DL MD88 F: Works