charging your G1/future android phone with double AAs!

**ddee8** · 10-09-2008, 02:12 AM

We all know battery technology just isn't keeping up with the advancement of smartphones these days, so lets just assume the battery life on the upcoming G1 and future android phones will keep us wanting more (especially for those power users).

I'm currently sporting a t-mobile dash which barely lasts me a day and I'm sure with my upcoming g1 and having 3g capabilities at my fingertips, it'll be even worse! So to prepare myself I've been looking into portable battery adapters. I'm usually moving from point A to B during the day, so AC wall chargers aren't going to cut it for me. And for buying an extra G1 battery? It just seems like to me, a hassle having to turn the phone off, popping the cover, switching the battery, cover on, power on.

So I came across this DIY (do it yourself) website and just thought I'd share it with everyone. Haven't seen anyone else post it up yet.

http://www.instructables.com/id/Mint...LDEST#comments

Further searching found an more updated device (version 2.0). If you scroll down, several HTC devices are listed as compatible with the device.
http://www.ladyada.net/make/mintyboost/index.html

Seems like a fun little project to do while theres still 2 weeks left of waiting. Anyone want to try it with me?

**yosho** · 10-09-2008, 03:41 AM

ddee8, I too am using a Dash. While I like the idea of the external battery chargers (I have a commercial device, a cellboost.com IPR3 for ipod, but does just fine on my dash), I think you should also evaluate exactly why your Dash is soaking up so much juice. I regularly go 2-3 days between charges, and that is with Activesync running over Edge, and using the wifi while in my office (about 6 hours) per day.

I should note that I am using a Windows Mobile 6.1 rom from http://forum.xda-developers.com/forumdisplay.php?f=309 , and once I installed the custom firmware, all my stability / usability issues went away. It is not perfect (hence my order of a G1!), but it makes the device much more usable. After unplugging my dash from charge about 16 hours ago, my battery is reading at 85%, after a full day at work, including listening to some music for about 2 hours over A2DP.

Just thought to mention... HTC makes great hardware, just a shame that the various wireless companies feel the need to trample all over their great work with shoddy firmwares that are inefficient or cluttered.

2 more weeks is too long....

**remister** · 10-09-2008, 04:30 AM

This looks like virtually a good project to do. Thanks for the heads up!

**CJ Chitwood** · 10-09-2008, 05:19 AM

Yeah, saw that minty charge thing before once and plan to do it someday.

All you really need is 5 volts at roughly half an amp [edit: you don't need half an amp -- it's just that USB spec provides for up to half an amp, so the phone will draw less than that if it can be charged by computer] on the right pins of a USB connector and the phone will charge. That device simply steps up from 3 from the AA to 5 at the USB, which is why you need the circuitry in there in the first place. Truth be told, if you use the lithium photo batteries, you might just have enough juice pushing out of them to make close enough to 5 volts without circuitry to make the phone charge (if it's like the Blackberry, it's probably running only about 3.7 volts at the battery, and anything more than that, the phone should be able to use to charge with).

However, all that talk about efficiency, wouldn't the most efficient be -- if you had to do it this way -- 6 volts with a voltage dropping diode or resistor? It would be bulkier, but this would be a lantern battery or simply a 4-AA, 4-C, or 4-D charger then...

Even 3 cells would be close at 4.5 volts... If the unit would charge off of that, just put a 3-cell battery holder directly to a USB port.

**ddee8** · 10-10-2008, 01:29 PM

Originally Posted by yosho

I regularly go 2-3 days between charges, and that is with Activesync running over Edge, and using the wifi while in my office (about 6 hours) per day.

I should note that I am using a Windows Mobile 6.1 rom from http://forum.xda-developers.com/forumdisplay.php?f=309 , and once I installed the custom firmware, all my stability / usability issues went away. It is not perfect (hence my order of a G1!), but it makes the device much more usable. After unplugging my dash from charge about 16 hours ago, my battery is reading at 85%, after a full day at work, including listening to some music for about 2 hours over A2DP.

Wow I find it amazing that you're able to go that long between charges. I really don't know why my battery life is so low. When I first got this 3rd party battery, I prime it by fully charging it just as the manufacturer recommends. Maybe because its a 3rd party battery? but its still your standard 960mah. Even with the first OEM battery that came with the dash, I don't remember going 2-3 days between charges lol. I'm mostly streaming podcasts through my bluetooth headset throughout the day (2-3 hrs), 2 email accounts that automatically check for emails every 2 hrs, and some web browsing here and there. As for the WM 6.1 rom, I am also running the same.

Originally Posted by CJ Chitwood

However, all that talk about efficiency, wouldn't the most efficient be -- if you had to do it this way -- 6 volts with a voltage dropping diode or resistor? It would be bulkier, but this would be a lantern battery or simply a 4-AA, 4-C, or 4-D charger then...

Even 3 cells would be close at 4.5 volts... If the unit would charge off of that, just put a 3-cell battery holder directly to a USB port.

Yeah, it'd be a lot more simpler without all the circuitry. Also, four AA rechargeable batteries have the right amount of voltage if your usual rechargeable is at 1.25V each (total of 5V). I have so many NiMH rechargeables lying around the house that I think I'll just get a 4-battery holder from my local radio shack today and solder it to a female USB port. I'm going to try this out first, before I give the mintyboost charger a try. I'll give it a test run on my dash and get back to you guys.

**Habitat** · 10-10-2008, 09:29 PM

I turn off my backlight at night and during the day when I don't need it on my wing. My battery last a lot longer if I do so...But nice idea..I'll have to see how it works out. DEFINATELY buying a car charger unless it comes with..If I have a car charger I should be good.