Author Topic: Power Supply on the road  (Read 6824 times)

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Offline bud16415

Power Supply on the road
« on: July 20, 2011, 12:52:11 pm »
Hello all:
 Long time reader, first time poster here.
To the old timers here let me say your posts are both informative and inspiring to us newbie's.

As of late I have been reading a lot of posts about taking  electronic devices along on the journeys and although my one or two day treks don’t compare with the TA's I have read about maybe some of my tinkering might help others. I have basically 5 powered devices, two cheep blinker lights one on the back of the bike and one helmet mounted. I run a regular old cheep wired bike speedometer and I have a DIY headlight that can be recharged with a wall charger or a DIY system I built and my connection to the world around, my iPhone. The photos show my iPhone 3GS but I now run with a iPhone-4. The mounting is different now but the concept the same. The iPhone gives me phone, GPS, cycle computer, email, camera, weather, news, and music / entertainment all in a small package. The application I use is Cyclemeter and is very amazing to me all it does for a $4.99 app. If anyone wishes to discuss any of this feel free to ask questions.
What I mainly wanted to post was the DIY battery recharger I made for under $10 that uses 8 AA batteries. The setup will recharge the phone at least 40 times and can be used as backup to recharge or power my light for days. With using AC to supplement the charging when available, I would think a person could go months without power worries setup this way. I might add the bike light is removable and doubles as a tent light / flashlight and also has a blink mode and with 20 LED's it throws amazing lumens to be seen but also to see when riding at night. The 8 AA batteries are configured 2 ways to give 6 or 12 volts. I use the 6vdc for the light and the 12vdc powers a lighter adapter thus you can charge any device that has a usb or other car adapter. The advantage of doing it this way is the car chargers have built into them voltage and current regulators and you don’t have to worry about damage to the sensitive electronics like you might with the generator setups.
Below are a few photos as this post is getting long winded. I will be happy to take more if someone wants to build one. Radio Shack has all parts.
Bike and handlebar bag that hold the unit:

View of cockpit:

Unit storage:

Charger and adapter: (much smaller car charger now with iPhone-4)

All the claptrap on bars:

That’s all folks, sorry for a long first post. :)
« Last Edit: July 20, 2011, 01:17:10 pm by bud16415 »

Offline jsieber

Re: Power Supply on the road
« Reply #1 on: July 20, 2011, 01:15:02 pm »
Welcome to the Adventure Cycling forums! It looks like a really interesting setup you have and I think others will be interested as keeping smartphones charged on extended trips seems to be a problem that long distance cyclists face. Is the phone essentially running off the external power throughout the day, or do you only use the external power for charging when the device power becomes low? This seems like an interesting alternative to the solar panel charging option that has its own limitations.

Offline bud16415

Re: Power Supply on the road
« Reply #2 on: July 20, 2011, 01:47:34 pm »
Thanks for the welcome.
I actually run it using both methods but for all practical purposes you could leave it stowed until needed. The phone will maintain power a very long time in standby mode (screen blank, waiting for a incoming call and mapping my route) If it's being actively used the charge time diminishes, the screen uses a fair amount of power as do the speakers. On the other hand the phone only charges as needed so I don’t think leaving it plugged in would run your batteries down a great deal.

What I do is have the phone set to auto dim after 30 seconds so if I want to see where I am at on my route or look ahead for route changes etc. I just hit the start button on the face and the phone comes alive. It is so much fun watching the map progress one is tempted to leave it on but eyes are better left to watch the road.

I went with this design because it uses the old batteries you can find anyplace along the way. The power packs that need to be recharged just came back around to the same problem, when do I plug in? Also recharge batteries are great for many things but one drawback is in storage they discharge rather fast. Solar is a great thing but living in Northern Pa on lake Erie it might take me a month to get enough sun to charge a phone.
I will try and take a few new photos in the next few days and also weigh everything for those that are counting ounces. It is a bit of a prototype still.

Below is a link to a typical ride report that the iPhone emails automatically after each day's journey or any time span you wish.

You can have as many email's as you wish posted to. Might be nice for a solo traveler wishing to keep folks at home involved. Elevation graphs are also made and I find they are very helpful. None of this is possible if you are turning your device on and off to save power.
« Last Edit: July 20, 2011, 02:14:01 pm by bud16415 »

Offline cgarch

Re: Power Supply on the road
« Reply #3 on: July 20, 2011, 05:33:09 pm »
I like what you've done here. I've used the same battery holder but with an LM380A voltage regulator and a mini-USB connector to power a Garmin Edge 305. But looking at this it makes obvious sense. I'm changing my set up when I get home. Thanks much.

Offline mcparsons

Re: Power Supply on the road
« Reply #4 on: July 20, 2011, 11:52:03 pm »
Brilliant idea.  Especially with the built in voltage regulation of the car adapters.  Can you post a parts list?

Offline cgarch

Re: Power Supply on the road
« Reply #5 on: July 21, 2011, 01:11:56 am »
I just tried this as I had all the parts and I'm going to say that I think it is a non-starter for at least an iPhone G4. With a nominal set of batteries it drained the batteries in a few minutes and I can say I've never felt a battery pack as hot as this one. I tried again with a full fresh set and it dropped a solid 2 volts in about 5 minutes and the batteries were sweating. What got my attention was the loud pop from some part of the setup (at least it wasn't the phone).  I think folks need to try this setup before going on the road with same. I had better luck charging the iPhone with the Power Monkey.

The voltage regulation from the power adapters works fine but with car batteries the voltage tends to remain level due to the amp-hour capacity of the car battery. With AAs the voltage drops relative to the demand of the unit. My Garmin doesn't take that much to charge, and certainly nothing like the iPhone.

My setup for charging a Garmin
The battery pack can be found here
The 9v snap clip is here:
The socket is here

Bud may have a better parts list - his looks nicer than the one's I've listed.


Offline bud16415

Re: Power Supply on the road
« Reply #6 on: July 21, 2011, 10:59:25 am »

Sorry to hear you had that problem.  :'(

I looked around quite a bit for a system (commercial) to do this a year and a half ago and the only ones I found were high dollar and required plugging in to charge. At that time I was riding with a iPhone 3GS and built the prototype I showed the forum yesterday. I charged my phone many times last year with no issues. One thing annoying about the iPhone was any time I plugged a charger or device into it made for an iPhone by a third part I would get the Apple message that this "product is not supported". and I would hit ok and it would work fine. I used it a couple times last fall with the iPhone-4 and no issues. I was at 60% charge on phone this morning and after reading your reply I checked the voltage on the booster pack and it was at 8.8v. Batteries are about a year old. USB charging needs 5v I believe so I gave it a try and it gave me the error message again and then charged my phone to 100%. No overheating of batteries at all.

I then did some research and found a interesting web page where someone else is working on something similar to what you were building.
The link might help.
The other thing I discovered is there are a lot more units out there now than a year ago, some getting great reviews and some getting mixed reviews similar to mine it seems.
Few links below; Most of the AA battery units used 3 or 4 batteries  and had mixed reviews.

I'm not sure what happened in your test. I haven't at any time seen overheating or popping or anything like that. I'm thinking maybe you had something shorting someplace in your setup.

I just replaced all batteries with new and measured at 12.3v my phone had run down to 95% and I tried charging. No error message this time and took about 5 minutes to reach 100%. Batteries, car adapter and phone no heat to the touch. What I think I'm finding is this setup with fresh batteries will work fine down to 9v and then the charger reads a low voltage condition and starts giving error messages and eventually will reject charging. with a 3v drop I don’t know what that means in terms of battery life percentage??? I just switched the 8 batteries that made 8.8v in my phone charger to the charger that’s configured to make 6v, (2 sets of 4 series/par)  assuming they are doing 4.4v in that. They are working fine charging my headlight at this point. That might have to be my method of battery management first usage to charge electronics then finish them off making light a less voltage sensitive application.

Again this was shown as a DIY project that I felt was well proven. Please use caution I would hate to hear of someone damaging their smart phone or hurting themselves doing this.

I plan on evaluating some of the battery management apps for the iPhone to use in conjunction with this. I just looked quickly at some of them and they look like they may also help.

Offline cgarch

Re: Power Supply on the road
« Reply #7 on: July 21, 2011, 01:50:27 pm »
Appreciate your reply. I also received the "This charging product is not supported" and after dismissing, it no longer charged - batteries were at 9.6V. Retrying didn't work either. My suspicion is that the 4G has a larger battery (more AH) with a greater demand [research required]. It could also have been an issue with the plug-in charger (it isn't handy at the moment, so I can't give the model name). The more interesting item too was the crinkling noises the batteries were making, even after disconnecting. I doubt i have a any shorts, but I will take another look. The small size of the wires on the cap connector are a concerns as well. More experimenting to come. I'll check the links out later when I have a chance.

And definitely a DIY project, recommended only for those comfortable with electronics.


Offline mcparsons

Re: Power Supply on the road
« Reply #8 on: July 22, 2011, 08:05:47 pm »
I built this using RadioShack parts (cost $13).  Worked great.  Charged my Droid X from empty to full and recharged an older ipod. Charging from empty, the batteries and 12V plug were warm but not more than I would expect.

I can see going through a  lot of AAs with this so rechargables and a small charger might make sense.

I'll be road testing on RAGBRAI this week and will report.
 Next step is to build an enclosure.

Offline bud16415

Re: Power Supply on the road
« Reply #9 on: July 24, 2011, 06:52:51 pm »

Great report!

Sounds like your results are the same as what I saw last year using mine. Slightly warm batteries and charger and being able to full charge if needed. Most of the time I don’t let my device get completely discharged and had been doing more of a maintenance charging when riding using apps that are battery drainers.

We could use a fuse in line if someone was worried about a runaway discharge I guess, but I really think a quality car charger should have that protection built in along with voltage regulation and current draw. If you plug any of these into your car there is potential for huge current draw and the device has to maintain the charging level. True the voltage in the car normally is maintained between 12 and 14 volts with a well working car. But they still need to take into account in the charger design a low voltage condition. That seems to be the case as around 9 volts my iPhone and charger combination gives a message and just wont allow it to charge. Nothing is heated or damaged, it’s just time to replace the batteries.

You mentioned using rechargeable. A single cell in a old style battery makes 1.5 volts x 8 = 12 volts as I designed this. Rechargeable single cells only make 1.2 volts thus the reason radio shack puts the 9v snap on the battery holder. So that might not work out to well. I didn’t see any reason to consider rechargeable because if I had access to 120vac I just use my wall charger much lighter than 8 batteries.

I thought about using a small Tupperware box or something to hold all this but ended up just using a rubber band around the batteries to hold them. The pouch on my bar bag works well to hold the two units and car charger. When I hit bad weather the phone stores in there also.

I’m very interested to see how you make out after your RAGBRAI ride. I hope you are surprised as I was at how many charges I got out of a fresh setup.

Joe B

  • Guest
Re: Power Supply on the road
« Reply #10 on: August 06, 2011, 07:31:25 pm »
the 3G vs 4G charging capability and issues are explained in detail well here . I use this system for charging a iPod touch , combined with a 30 pin extender cable and a pass through 30 pin with a mini USB power injector it allows me to have external power to the iPod as well as have the ANT+ receiver plugged in as well to pickup my heartrate strap and the bike cadence/speed sensors. All in all very similar to the original posters setup on the DC current part. You can see that I use a external batterypack to power the charger, this allows me to use a small 2-AA set when 1 or 2 recharges are needed or  the 3-D cell setup or a massive 6-cell (2 banks of 3 cells) That I have not found the charging limit on, after 2 weeks I gave up and lost count .

« Last Edit: August 08, 2011, 01:43:12 pm by Joe B »

Offline SilasTarr

Re: Power Supply on the road
« Reply #11 on: August 07, 2011, 07:46:41 pm »
This is a very interesting thread that I'll be sure to follow!  Like bud16415 (OP), I also like the idea of using my iPhone to track my progress and statistics.  I've been experimenting with this during my training for my upcoming first tour.  I've tried out a couple of applications and had decent success, although I certainly noticed a drain on my batteries (from 100% to 50% in about 3 hours) and all the apps I'd tried had their downsides.

However, I look forward trying out the iPhone app you recommended, "Cyclemeter GPS."  I've downloaded it and will be giving it a try over the next week!

Offline bud16415

Re: Power Supply on the road
« Reply #12 on: August 29, 2011, 02:50:43 pm »
I built this using RadioShack parts (cost $13).  Worked great.  Charged my Droid X from empty to full and recharged an older ipod. Charging from empty, the batteries and 12V plug were warm but not more than I would expect.

I can see going through a  lot of AAs with this so rechargables and a small charger might make sense.

I'll be road testing on RAGBRAI this week and will report.
 Next step is to build an enclosure.

Just wondering how you made out with the charger?