Handtops, UMPC - Proprietary power supply?

10/11/04 + vadsoom

Greetings,

Do any of you with hands-on OQO experience have any knowledge about the power supply? Will the OQO require it's own or will an off-the-shelf replacment function?

Like some PDAs, is it possible to charge the OQO through it's USB port?

Thanks in advance!

Recent Blog: I finally did it.., went on a business trip with only my OQO

edited: Nov 20 2004 + DoC

It runs with only the 2 pins connected and switches between battery or mains power icons in windows but it doesn't charge the battery.

That's actually what the airlines would want (They tell you to disconnect your battery while using the air power) but it wouldn't be good for car use or for recharging from an external pack. :/

Doing that might not be good for the battery, though.

11/22/04 + Troy

DoC:

I find this thread interesting, and appreciate you posting this power/battery info.

If the power supply does not charge the battery while the unit is in use, this seems encouraging for those who might want to use the OQO for extended periods of time plugged in (at home), without having to worry about battery implications. Would you concur?

I ask, because I envision myself parked on the couch in front of the TV working in the evenings, and would like to plug the unit in and not worry about getting everything done within a couple hours.

11/24/04 + DoC

There shouldn't be any issues with leaving it plugged in and running. I've done it several times and once the battery is charged the ACPI system tells the OS that it's running only on mains power instead of charging. Not that what the ACPI controller tells the OS is necessarily true but seeing that it doesn't appear to change the charge level when only 2 wires from the power supply are plugged in makes me think it's smart enough to pull only from mains power and switches instantly to battery when you unplug it.

11/24/04 + cOoLAid

Doc,

Are you certain that the OQO does NOT use up the battery while plugged into the wall and running it at the same time?

If what your saying is the unit runs off the feed from the wall when pluged in, but does not use the battery and at the same time it does NOT charge the battery, Why would they do this?

That means the only time you can charge the unit is when its off? That does not make any sense.

Does this mean you can use the oqo plugged into the wall without the battery pack?

Recent Blog: FIX OQO 3D directX not supported

edited: Nov 25 2004 + DoC

The OQO does charge the battery if it's run down. Once it's topped up it stops charging and runs entirely off the mains to avoid a continuous trickle-charge to the battery which can be bad for lithium. A fast switching mechanism can be designed that allows the battery to only receive power from the charger circuitry when it's not full and to limit current draw from the battery when mains power is connected. It charges both while on and off but only if the battery is not full.

You can use the OQO plugged into the wall without the battery pack, yes. That's fairly important as it provides a way to quickly change batteries without shutting down.

What I was saying, though, is that it doesn't charge at all if you only connect the two power pins and not the 3 additional pins on the connector that are likely an i2c bus similar to the 3 additional pins on the battery.

edited: Nov 28 2004 + DoC

I posted this in the mini port replicator thread but it's relevant to this discussion as well:

The large pins on the power connector are 17awg and the small pins are 20awg. Center-to-center spacing on all pins is 0.175 inch.

The top row is .075 inch from the top edge to the center of the pins. The bottom row is 0.055 inch from the bottom edge to the center of the pins. There is .085 inch between the center of the top and bottom row of pins.

The connector, if the edges weren't rounded, is .550 inch wide and the sides are slanted in 15 degrees (285 degrees on the left and 255 degrees on the right) and the corner rounding is .050 inch radius. The connector is .215 inch tall.

The insertion depth of the connector is .230 inch. The edges are all chamfered at 45 degrees.

I've put all this together in a mechanical drawing and printed it to scale and it looks accurate.

I've now got a 3d model of both the plug and socket. As soon as I find the right 3rd party pins I can finalize the design and have them molded.

Oddly enough there is some variation in the sockets. The one on the docking cable is .190 inch deep so the plug on the power cable doesn't go all the way in. The one on the OQO itself is 0.215 inch which again isn't quite deep enough.

11/28/04 + garylm

DoC,

Do you think it's important that the top two pins make contact before the bottom three?

Recent Blog: Travelling With the OQO

edited: Nov 28 2004 + DoC

It doesn't appear to make any difference. I believe the bottom 3 are part of an i2c bus which allows things to be hot connected and the top two provide power no matter what. It just won't charge until the bottom three are connected and instructing the charger circuitry. The OQO detects power on the top two pins and informs the OS about it without the bottom three being connected so I'm sure any power switching is based on that. The connector design makes no attempt to ensure any pins are connected prior to others. The tricky bit is going to be figuring out how to listen in on the i2c bus to figure out what they say to each other to make a DC-DC charger.

I'm hoping that if I dissect one of the power supplies I'll have a better idea of what it's trying to do. I'm also hoping I can dissect one without breaking it so I can bypass the transformer and give it a DC input for car/airline use since it doesn't look like anyone is going to come out with one in time for my trip the end of december and I doubt I'll be able to manufacture one from scratch by then since I can't find any prefabricated connectors. It's very similar to Mixed D-Sub connectors but smaller and no one I can find makes a 5w2 Mixed D-Sub anyway. It's also slightly larger than a Micro-D connector and I've never seen a Micro-D with mixed pin sizes.

And hopefully OQO won't get upset with me for doing all this. ;P

04/27/05 + volker

I am desperately looking for a car charger for the OQO. All suggestions in this topic (links) - like "Belkin" or "StayOnline" are MODIFIED sine converters, not pure sine converters. Has anybody found a well functioning pure sine converter for the OQO that I can use with my cigarette lighter in the car and fits in the OQO (or gives the connection to the power supply of the OQO)?

04/27/05 + store

I have this one for my truck. Made by Wagan part number 9754. Got it on ebay for $99 buck. 150 watts 100% pure sine wave.