made my own external battery

howdy2k2000 · 11-04-06, 07:13 PM

used 8 AA , 2500mAh, 1.2v rechargable energizer batteries, used a switch between batteries and adjustable switching regulator (or else it drains 1 volt and 20mA) from Dimension engineering http://www.dimensionengineering.com/

part number de-swadj. it has charged my x51v for 2 weeks!!!!!

when it finally gets discharged i just recharge the energizers with their charger and good to go again!

its awesome.

runnr548 · 11-04-06, 07:28 PM

Great job! It's nice to see creative ideas here.

koolman200 · 11-05-06, 10:21 PM

Thats so cool. Could you post some pictures of your invention, just so that we know what does it look like and how do you carry it around. Thanks.

xlimey · 11-06-06, 12:31 PM

I've seen similar DIY external charging units in Aldoid tins for phones etc. Have been looking for a design to charge the battery in my X50v. This sounds like just the thing. Echoing the earlier respondent, pictures of your set up would be most helpful. Do you have your charger in an easily pocketable container such as a small candy tin?
Also do you leave the original battery inside the Axim when using your charger, ie are you actually charging the original battery or powering the Axim directly from your external power source? Specifically how do you attach the lead from the external charger to the Axim - do you use the detachable plug from the original Del charger?
Thanks

howdy2k2000 · 11-12-06, 11:28 PM

i still use the standard plug (got 1 at radio shack) and it plugs into the axim plug which plugs into the axim. i had mad a few different designs but found that i needed a switch between the regulator and batteries. i have now added a dongle to charge my cell phones as well. almost all small electronics sharge at 5-5.5 v!
i just ordered some different enclosures tonight so i can now make it smaller. when i'm done it should be about 3.5x2.75x1.3 inches. i will start selling them when i get it the way i want it. its prototype now of course.
i keep the battery in my axim at all times. it charges as if plugged into the ac adapter and shows the plug at the top and indicates charging on the battery screen. i tested current and voltage output with my fluke 87s3 and it works the same as the factory charger.
i will take some pics of the most recent developments and email to whoever would like them.

frebitz · 11-13-06, 09:24 AM

For those of us not inclined to DIY:
http://www.gomadic.com/dell-axim-x51...-extender.html

gillius · 11-13-06, 01:19 PM

On the site it says the regulator can handle up to 1A but I know the Axim draws more than 1A from the USB (which causes many USB ports to shut off) -- I think at one point I heard 1200mA it can draw -- did you have any problems with current draw on charging or were you charging with the Axim off?

If I understand you correctly you attach to the same connector that the included wall charger plugs into? I was thinking of making a charger with a USB interface then I can charge any USB device -- I think you just need 5V.

coach_ng · 11-13-06, 07:36 PM

Socket Communications mobile power pack pwns!

11-13-06, 08:17 PM

I was going to build one too until I found this... http://www.notebook-laptop-batteries...ry/EDC001U.htm

Works off of 12V, 120V and 0V! I bought one several weeks ago and it works very well.

howdy2k2000 · 11-14-06, 10:07 AM

Originally Posted by gillius

On the site it says the regulator can handle up to 1A but I know the Axim draws more than 1A from the USB (which causes many USB ports to shut off) -- I think at one point I heard 1200mA it can draw -- did you have any problems with current draw on charging or were you charging with the Axim off?

If I understand you correctly you attach to the same connector that the included wall charger plugs into? I was thinking of making a charger with a USB interface then I can charge any USB device -- I think you just need 5V.

no problems to date. it charges with the axim on or off.
it charges just as fast as when plugged in to the wall.
i use a switching regulator so it is very efficient.
frebitzi i tried using 4 batteries but its not efficient at all voltage should be regulated into the axim and 4 batteries dosent allow that.
yes, as coach ng stated, you could buy one...for 109.00!!!
mine cost about 25.00 plus batteries!
i also have a universal power supply for the car (wal mart) that plugs into it.
but most of all, its just awesomer!

ps, i'll get some pics up soon

Pocketbrain · 11-14-06, 12:01 PM

Hey cool, BenHeck uses these!
I might pick one up, I have been looking at increasing efficiency of my external battery packs. Check out Tips from the Trenches (link in my signature).

.

xlimey · 11-22-06, 07:51 PM

I've read the string on this and I was going to make my own external charger for my x50v using the suggestion from howdy2k2000 to purchase the switching voltage regulator DE-SWADJ from http://www.dimensionengineering.com/. When I saw that it cost $15.00, I checked out the suggestion of frebitz to look at http://www.gomadic.com/dell-axim-x51...-extender.html. There I found a sleek matt black case for 4 x alkaline batteries ready fitted with the plug to fit directly into my x50v. This cost $20.00. Considering it comes ready to use, with an integral 'on' LED and a switch, it was basically cheaper than any set-up I could begin to cobble together starting from the DE-SWADJ regulator. Frankly, if you are using a 9v battery to charge then I can see you need to regulate that voltage down a bit to safeguard your x50v internal battery, but if you have a (steady) charging output voltage that is close to the original equipment Dell AC adapter charger output (5.4v) then it seems to me that you don't need the added complication (and price) of a voltage regulator whether it be a linear or switching type.

I thus went with the Gomadic 4 x battery holder & its included x50v plug. I checked out the electrics & best I can tell there is a rectifier, or at least circuitry that behaves like a rectifier, housed within the enclosed top end of the case, in addition to the LED & switch. (The resistance is about 28 ohms in one direction & infinite in the other direction.) Not wanting to damage the case I did not go for a confirmatory visual.

Now the story doesn't end there. I found that the Gomadic case does indeed hold 4 alkaline batteries (very snugly) and they do charge my x50v. HOWEVER I wanted to use rechargeable NiMH batteries. When I tried to insert 4 NiMHs, the case top would not completely shut because, hello, NiMH batteries are slightly larger in diameter than regular alkaline batteries and so won't stay fully in place. FURTHERMORE, 4 NiMHs only provide 4 x 1.2v = 4.8v which turned out to be insufficient to charge the x50v. (Four alkaline batteries provide 4 x 1.5 = 6v which did do the job.)

Thus I was the owner of a case that was too small & wouldn't even charge when I left the top off. Well, what I did was rummage through my old electronic stuff & find a 2 battery holder I'd got years ago from Radioshack and I wired it in series with the Gomadic case. To do this I made a dummy battery by cutting a piece of wooden dowel slightly smaller than the length of a battery and screwing a round head screw, with a washer, into each end (pre-drilling the hole so that the screw would not split the dowel end). I attached the wires from the Radioshack dual battery holder beneath each washer (observing the correct polarity) and tightened each screw. By inserting this dummy battery into the end slot of the Gomadic case (so that the wires conveniently exit at the edge of the case) I now had a set-up that took 5 batteries in series. The Gomadic case will close with 3 NiMHs and the wooden dummy, and the Radioshack dual case does close with 2 NiMHs. This set-up now provides 5 x 1.2 = 6.0v which charges my x50v perfectly in less than 1 hour. As far as I know I am using unregulated voltage, but since the voltage from NIMHs is a very steady 1.2v each right up until they become discharged, I see no problems, only money saved. The first charge using the 5 fully charged NiMHs (I actually use 2650 mAh Duracells) caused the charging light on the x50v to alternate between green and orange for about 15 minutes. This concerned me for those 15 minutes but then the light changed to a steady orange until the PDA was fully charged and then went green in the usual way. I suspect the alternating colors were due to the slightly higher voltage NiMHs provide right after being charged (1.25v each), which then quickly drops under load to their relatively constant 1.2v. I have recharged the x50v half a dozen times so far and the NiMHs are still on their first charge so I can't yet say how many recharges one set up will provide. Hope this helps the undecided to decide.

satnav4 · 02-05-07, 01:52 PM

Originally Posted by xlimey

I've read the string on this and I was going to make my own external charger for my x50v using the suggestion from howdy2k2000 to purchase the switching voltage regulator DE-SWADJ from http://www.dimensionengineering.com/. When I saw that it cost $15.00, I checked out the suggestion of frebitz to look at http://www.gomadic.com/dell-axim-x51...-extender.html. There I found a sleek matt black case for 4 x alkaline batteries ready fitted with the plug to fit directly into my x50v. This cost $20.00. Considering it comes ready to use, with an integral 'on' LED and a switch, it was basically cheaper than any set-up I could begin to cobble together starting from the DE-SWADJ regulator. Frankly, if you are using a 9v battery to charge then I can see you need to regulate that voltage down a bit to safeguard your x50v internal battery, but if you have a (steady) charging output voltage that is close to the original equipment Dell AC adapter charger output (5.4v) then it seems to me that you don't need the added complication (and price) of a voltage regulator whether it be a linear or switching type.

I thus went with the Gomadic 4 x battery holder & its included x50v plug. I checked out the electrics & best I can tell there is a rectifier, or at least circuitry that behaves like a rectifier, housed within the enclosed top end of the case, in addition to the LED & switch. (The resistance is about 28 ohms in one direction & infinite in the other direction.) Not wanting to damage the case I did not go for a confirmatory visual.

Now the story doesn't end there. I found that the Gomadic case does indeed hold 4 alkaline batteries (very snugly) and they do charge my x50v. HOWEVER I wanted to use rechargeable NiMH batteries. When I tried to insert 4 NiMHs, the case top would not completely shut because, hello, NiMH batteries are slightly larger in diameter than regular alkaline batteries and so won't stay fully in place. FURTHERMORE, 4 NiMHs only provide 4 x 1.2v = 4.8v which turned out to be insufficient to charge the x50v. (Four alkaline batteries provide 4 x 1.5 = 6v which did do the job.)

Thus I was the owner of a case that was too small & wouldn't even charge when I left the top off. Well, what I did was rummage through my old electronic stuff & find a 2 battery holder I'd got years ago from Radioshack and I wired it in series with the Gomadic case. To do this I made a dummy battery by cutting a piece of wooden dowel slightly smaller than the length of a battery and screwing a round head screw, with a washer, into each end (pre-drilling the hole so that the screw would not split the dowel end). I attached the wires from the Radioshack dual battery holder beneath each washer (observing the correct polarity) and tightened each screw. By inserting this dummy battery into the end slot of the Gomadic case (so that the wires conveniently exit at the edge of the case) I now had a set-up that took 5 batteries in series. The Gomadic case will close with 3 NiMHs and the wooden dummy, and the Radioshack dual case does close with 2 NiMHs. This set-up now provides 5 x 1.2 = 6.0v which charges my x50v perfectly in less than 1 hour. As far as I know I am using unregulated voltage, but since the voltage from NIMHs is a very steady 1.2v each right up until they become discharged, I see no problems, only money saved. The first charge using the 5 fully charged NiMHs (I actually use 2650 mAh Duracells) caused the charging light on the x50v to alternate between green and orange for about 15 minutes. This concerned me for those 15 minutes but then the light changed to a steady orange until the PDA was fully charged and then went green in the usual way. I suspect the alternating colors were due to the slightly higher voltage NiMHs provide right after being charged (1.25v each), which then quickly drops under load to their relatively constant 1.2v. I have recharged the x50v half a dozen times so far and the NiMHs are still on their first charge so I can't yet say how many recharges one set up will provide. Hope this helps the undecided to decide.

Quick clarification: Does the Gomatic not work at all, or does it just work more slowly when not modified?

I would like to get one for an Axim and a Mio GPS.

Thanks

S.

mitch1063 · 02-15-07, 06:34 AM

Originally Posted by frebitz

For those of us not inclined to DIY:
http://www.gomadic.com/dell-axim-x51...-extender.html

Nice Find!!! I just placed my order.
I will let you know how it works.

I'm a Licensed Ham Radio Operator here is NYC and a Emergency Coordinator for a Emergency Communications group called ARES. and anything that will keep my portable electronics charged during a black out or in the field is a great find.

Mitch
N2RGA
www.kingscountyares.org
AXIM x51v

mitch1063 · 02-15-07, 06:50 AM

Originally Posted by xlimey

Now the story doesn't end there. I found that the Gomadic case does indeed hold 4 alkaline batteries (very snugly) and they do charge my x50v. HOWEVER I wanted to use rechargeable NiMH batteries. When I tried to insert 4 NiMHs, the case top would not completely shut because, hello, NiMH batteries are slightly larger in diameter than regular alkaline batteries and so won't stay fully in place. FURTHERMORE, 4 NiMHs only provide 4 x 1.2v = 4.8v which turned out to be insufficient to charge the x50v. (Four alkaline batteries provide 4 x 1.5 = 6v which did do the job.)

I wish I read the rest of the thread before ordering mine.

Now to find out how to cancel it.

Mitch