Canadian homebrew battery pack and wrist strap

[MitchellShnier]

I know many long threads have discussed battery packs, but maybe this will help others still. Also, these parts were from RadioShack Canada (much as I hate dealing with them, they are convenient), so this might make it easier for other Canadians to get the parts.

The real find was that they carry the 2.35 mm power plug (part number 273-1704), though as an adapter for their universal power supplies. That is, it has two pins, rather than expecting to be soldered directly to wires.

I soldered two wires directly to the two pins, with heat-shrink tubing over each pin/wire, and another larger diameter piece of heat-shrink tubing over both pins. The second post after this one has a picture (the negative power pin is closer to the camera) ...

[MitchellShnier]

Darn, the forum doesn't let you add a picture when editing a post ...

[MitchellShnier]

Here's the power plug

[GpsMapNut]

Well, what are the other parts of your setup?

[MitchellShnier]

Then I found a 4 x AA cell battery pack with a cover and built-in slide switch. It already has a hole for the wires. I used more heat-shrink tubing as a strain relief for the wires, and used a ty-rap around the heat-shrink tubing and wires on the inside to keep the wires from being pulled or rotated.

I think this was from RadioShack Canada too.

[MitchellShnier]

Here's the battery pack closed.

I measured the no-load voltage from the official Garmin power transformer at 5.2v, and using 4 NiCd rechargeables also provided about 5.2v (no load), so I didn't use a voltage regulator. I measured the current (from the battery pack to charge the iQue -- which was slightly discharged) at about 450 mA with the iQue off, and 650 mA with the iQue on.

[MitchellShnier]

Here's the battery pack under the iQue, held with some elastic bands. I had a wrist strap from a camera and put a little plastic ring on it so I could slide it to make the hand-loop smaller, so the wrist strap wouldn't slip off my hand. I tied a knot at the end of the hand-loop so the ring wouldn't slide off the hand-loop when I wasn't wearing it.

[MitchellShnier]

Finally, here's the wrist strap looped through the wire hinge of the standard Garmin iQue cover (which is under the iQue).

(That's weird, why doesn't my "Posts" counter increment for this flurry of posts.)

[reinbeau]

Originally posted by MitchellShnier
Finally, here's the wrist strap looped through the wire hinge of the standard Garmin iQue cover (which is under the iQue).

(That's weird, why doesn't my "Posts" counter increment for this flurry of posts.) It seems to update the count after you've logged off (at least it seems that way to me).

Your battery pack is nice, but it uses the perilous pin. With the iQue secured to the pack, there wouldn't be much movement, so perhaps you'd have no problems, but I still prefer the Palm UC to using the pin. YMMV.

[YCARON]

I purchased this power pack and is is absolutely fantastic

US site:

http://www.gpscity.com/gps/brados/2762.2.9841855744918613632/ziqueusbpow.html

Canadian Site:

http://www.gpscity.com/gps/brados/68142.2.9586273902915820726/ziqueusbpow.html

[terrier]

Originally posted by MitchellShnier
Finally, here's the wrist strap looped through the wire hinge of the standard Garmin iQue cover (which is under the iQue).


I've had my cover pop off several times with not much force having been exerted. I'd recommend not putting too much trust or force on the stap.

Terrier

[rocket666]

Interesting, your box looks almost identical to the one I purchased w/cable from pc-mobile. Ironically, I too have been trying out some old radio shack power plugs I had available, but in an effort to extend the short cable. I want to create a small extension cable for mine.

Anyway, I need to get a jack to go with the plug I already have.

Also, if the colors on the tip indicate anything, the one I found to fit into my box is not the same as the one you used to plug into the ique. And not wanting to take any chances, I dare not plug it into the Ique.

BTW, the box/cable go for $12.50 + $5 s/h which they sent to me from Hong Kong. It took a week to arive and I had to sign for it.

Slightly O.T. I find that this box has the 4 batteries in series (I get 5 volts on the plug in adapter) and when my ique was at 50% I put my amp meter in series with one of the batteries and read 150 ma. This was the same with the ique on or off. I don't know if there is anything else in this box (e.g. volt reg etc.) but these figures seem to be different from what I have read elsewhere.

But the fact that the current is the same on/off would indicate to me that when the ique is on, I am not actually charging the battery, just powering it. I thought it would be otherwise, i.e. power and charge at the same time. Maybe my EE days are too long ago and I have something wrong in my calculations and measurments.

[rocket666]

Originally posted by YCARON
I purchased this power pack and is is absolutely fantastic

US site:

http://www.gpscity.com/gps/brados/2762.2.9841855744918613632/ziqueusbpow.html

Canadian Site:

http://www.gpscity.com/gps/brados/68142.2.9586273902915820726/ziqueusbpow.html

This is probably a dumb question, but how do you get the wires back into the holder when you want to shorten it up. Is it spring loaded or something? Like a tape measure or something? And how much pulling force is needed to lengthen it again? I had looked at this combo deal but worried that the wires would break after some number of times pulling on them.

[MitchellShnier]

That retractable cable thing in the GPScity picture winds the cable by starting at the middle of the cable and winding, not like a tape measure where it winds from one end. I think it is spring-loaded though, and you press a button on the winder to get it to wind up. I've got one for a phone cord, and it does not wind with much force, you need to help the cable back into the winder.

About your current measurements. If you're only providing 150 mA, I agree you're not both charging the batteries and charging your batteries. Your ammeter might have too great an internal resistance (maybe try a higher range, like a 2 amp range, rather than a 200 mA range) and this is limiting the current the batteries provide.

[rocket666]

Originally posted by MitchellShnier


About your current measurements. If you're only providing 150 mA, I agree you're not both charging the batteries and charging your batteries. Your ammeter might have too great an internal resistance (maybe try a higher range, like a 2 amp range, rather than a 200 mA range) and this is limiting the current the batteries provide.

You got that right. When I set the range to 10amp, I read about 0.3 amps.

[Adam Helberg]

I don't see too much new here.

I have the standard battery back that plugs into the universal connector.

What I would like is a battery pack with rechargable batteries that can be recharged in the pack without taking the batteries out. Yet I still want to be able to open the pack to exchange the batteries.

Adam

[Robertp366]

What I really want is a battery pack with an iQue interface like the auto mount - a conformal connector that doesn't stick out an inch and wobble too much ( like all the palm universal connectors do), and includes a latch that hooks into the Que like the auto mount does.

HEY GARMIN!!! ARE YOU LISTENING YET????

Maybe I'll try a second auto mount and scarf it up to become the cover of one of these 4 AA packs. Or maybe I can mount a spare Garmin replacement battery in it. Add a USB connector so I can charge from a USB charger or USB port perhaps.......

(yes, I know Garmin doesn't sell a replacement battery, but the forum has links to a good supplier of the exact internal battery.

BTW, this is a 3.7 volt battery, as used in the Que and other Palm 5 devices.

Robert

[reinbeau]

Originally posted by Robertp366
What I really want is a battery pack with an iQue interface like the auto mount - a conformal connector that doesn't stick out an inch and wobble too much ( like all the palm universal connectors do), and includes a latch that hooks into the Que like the auto mount does. I appreciate what you're looking for, but I have to say the connector I got from Gomadic (http://www.gomadic.com/pacoplas.html) is an excellent fit and doesn't wobble at all.

[jonasolof]

Two questions raised here

Recharging in batterypack: Chargers charge batteries in pairs or individually. Rewire your batterypack so that you can choose between charging them or use them for the iQue. Then modify a charger to connect.

A better power connector: The best UC connector I've seen comes with the Gomadic cell phone-PDA cable. Much better than the UC connectors that Gomadic sells over the net (they break to easily, the hooks are thin steel wires).

There are 2.35 mm plugs that one can use. But they are all 3 mm too long, so they also protrude.

The problem with the UC connector is taht all the cable varieties use the small steel hooks to attach to the bottom of the iQue. That's too vulnerable for field use.

What I'd like to find is a UC connector like in the cradle or the auto nav cradle. Probably should be one for a printed circuit board. If we could get hold of these, one could develop a battery pack that holds on to the holes in the back of the iQue like the auto nav cradle.

Who finds a minimal universal connector like in the cradles?

[jonasolof]

It's easy to take apart the auto nav cradle. At the bottom, there is a small printed circuit board that holds a the universal conenctor. It comes out easily. It would be possible to use this piece only for a battery holder.

It protrudes about 8 mm under the bottom of the iQue.

Next solution for applying power: Modify a 2.35 mm plug (sold at DigiKey with cables attached.) I cut of the hard rubber coating to get to the metal parts. The cable is soldered to the outer and the inner conductor. If you use only the metal plug, it won't protrude more than 10 mm south of the iQue. It would be possible to add a sidesways support that dips into the rectangular recesses for the UC horns in order to get sideways stability. But the simlest way to get that is to increase the diameter of the outer tube of the plug where it inserts into the iQue. I have used Cu-tape or shrink tube for this.

I can't come up with a smaller connector right now. But it would be possible to make a plug that dips into the jack barell and hardly protrudes at at all except for the cable. The problem would be to ensure the insulation of the inner tube from the outer tube.

Just to know, I cut a plug at half length. In fac, the inner tube isn't a tube but consists of two metal strips that connect towards the end of the plug in an orifice shaped circle. It would be possible to solder a connector to the inner core and then solder another connector to the outer tubing and thus get a really small 2.35 mm plug. It takes a few plugs (at less than 2 dollars each) and a very fine saw plus a precision soldering iron. I got all that plus the microsurgery experience but not the time for now. However, it appears to be a feasible project which would solve the connector problem.

Two details: The center pin of the barrell is made up of two rectangular pieces of metal pressed together. So it is square when seen from below. That's why there is too much friction as the plug is inserted. But if one uses a 0.6 and then a 0.7 mm drill the plugg inner opening (orifice mentioned above) can be opened up so that the plug inserts easily without undue friction. Lubrification helps a bit also.

Next: The minus pole in the barrel is a spring metal coming in at half depth of the barrell from the lateral side (outward side) and goes further in. It will be pressed in towards the wall of the barrell as the plug is inserted.

You can get the 2.35 mm plugs at www.digikey.com item CP-012-ND. Now that's the plug only. You get ten for a total of USD 7.80

They also sell a right angle plug with a cable attached, item number CP-2196-ND. Ten for USD 10.92 (plus handling).

[whk]

Here (http://www.pbase.com/brianwu/iqu3600_backpack) is second battrey pack I made, also with a heavly modified power plug.
I use it for hiking, so far works well, this version only use external ant and is not water resistant.

[JMckie]

Originally posted by whk
Here (http://www.pbase.com/brianwu/iqu3600_backpack) is second battrey pack I made, also with a heavly modified power plug.
I use it for hiking, so far works well, this version only use external ant and is not water resistant.

Let me be the first to say: OUTSTANDING work! I am green with envy.

How much did the whole thing set you back in parts alone?

[whk]

Originally posted by JMckie
How much did the whole thing set you back in parts alone?
Thanks, if you have to buy everything, it'll cost about $30, but my case is about $12 (Li-Ion, plug and vinyl fabric).

[Curious Cat]

Great job and nice photography!

[jonasolof]

I talked about a modified connector and you did it! Great job! A very well studied project. Thanks for the generous documentation.

What about the Li-Ion protective circuit, can you buy that or did you build it?

Let me ask about the connector. Does it sit well in the plug or have a tendency to come off axially (I see the square contraption that goes down into the UC recess which would prevent it from moving laterally)?

Really nice that you could get all that into the footprint of the iQue.

[whk]

Thanks, Mr. Cat and Jonas.
Li-Ion protective circuit is left over from an old cell phone battery pack used for my first iQue batt pack, I did not built it, use it because I just have it, a regular fuse plus a thermo fuse will do fine (less over charge/discharge protection).
The power plug sit in jack nicely (it is standard 2.35mm plug from Radio Shack ), the little key tab is used for enforcement incase cable gets pulled, also plug can only insert one direction.