nate7358
05-20-2005, 10:05 PM
My EB40 has been giving me less and less run time lately, so I sought out a solution. Amoon went the versatile charging route, but I wanted to maximize time in between charging. I tried to keep it simple and as cheap as possible.
My old USB mod to the EB40
http://i5.photobucket.com/albums/y190/nate7358/EB2.jpg
EB40 modded to accept external power source and bypass EB40 battery pack when plugged in. Just as some of you had suspected, the EB40 contains 2 UX batteries inside wired in parallel.
http://i5.photobucket.com/albums/y190/nate7358/EB3.jpg
New power connector, I should probably sand it down more but I’ve opened my EB40 way too many times already
http://i5.photobucket.com/albums/y190/nate7358/EB4.jpg
My new extended extended battery pack comprised of four 850 mah lithium-ion cell phone batteries assembled with a liberal use of electrical tape. If I can find a better enclosure, I could even add one more battery.
http://i5.photobucket.com/albums/y190/nate7358/extendedbattery.jpg
And just for the heck of it, I put together an extended battery extender with a Radio Shack battery box and a female USB connector from a USB>PS/2 adapter. To be on the safe side, I also put a schottky diode for a forward voltage drop. OFF=Schottky diode, ON=straight through to USB connector.
http://i5.photobucket.com/albums/y190/nate7358/bbox1.jpg http://i5.photobucket.com/albums/y190/nate7358/bbox2.jpg
End result:
http://i5.photobucket.com/albums/y190/nate7358/charging.jpg
Purchased items:
Schottky diode
Radio Shack 4 AA battery box
1.3mm male and female DC power connectors
Case Logic leather memory card case
USB mini-B female connector (for old EB40 mod)
Everything else was lying around the house
Before I put everything together and made it look pretty, I did a test discharge and charge. The new battery pack alone, put up with 7 hours of Bejeweled and Village Sim running with full brightness, Wi-Fi on (I never used it), and mp3s running from my 2GB memory stick continuously in the background via Media Launcher. It was a good 1-1.5 hour before it even dropped below 100%.
Cons:
- I wired it so that only one battery pack is charged/discharged at a time. Keeping the packs separate was a safety precaution to prevent overcharging and overdischarging.
- Charging took well over 10 hours before the led on the EB40 turned off, and even then I’m pretty sure it’s not fully charged. At the moment, I can only charge the new pack through the EB40. When I get back from vacation, I’ll build my own lithium charger that should cut the time down to less than half.
- The EB40 won’t charge the UX to 100%. I wish I could somehow gain control of the EB40’s circuitry and choose whether I want to charge the UX, or just be a plain extended battery.
- When plugging/unplugging the new battery, I need to remove the EB40 momentarily to reestablish the connection to the UX. Though, this doesn’t happen while charging.
- I feel the need to be careful with this whole setup. The first few days after I finished everything, I lived in constant fear of the battery exploding on me. There are a lot of horror stories on the internet about people’s cars and houses burning down involving lithium batteries. But I made sure all soldered connections were solid, and put glue in areas that might be prone to shorting. I’ll get over it.
So was it worth it all? Yes and no. It’s still a battle between convenience and battery life. I can’t use the extra battery without the EB40 and I’m not going to directly mod my UX anytime soon. I might ultimately end up using the battery extender instead because it's slightly smaller and batteries would charge faster. We'll see.
My old USB mod to the EB40
http://i5.photobucket.com/albums/y190/nate7358/EB2.jpg
EB40 modded to accept external power source and bypass EB40 battery pack when plugged in. Just as some of you had suspected, the EB40 contains 2 UX batteries inside wired in parallel.
http://i5.photobucket.com/albums/y190/nate7358/EB3.jpg
New power connector, I should probably sand it down more but I’ve opened my EB40 way too many times already
http://i5.photobucket.com/albums/y190/nate7358/EB4.jpg
My new extended extended battery pack comprised of four 850 mah lithium-ion cell phone batteries assembled with a liberal use of electrical tape. If I can find a better enclosure, I could even add one more battery.
http://i5.photobucket.com/albums/y190/nate7358/extendedbattery.jpg
And just for the heck of it, I put together an extended battery extender with a Radio Shack battery box and a female USB connector from a USB>PS/2 adapter. To be on the safe side, I also put a schottky diode for a forward voltage drop. OFF=Schottky diode, ON=straight through to USB connector.
http://i5.photobucket.com/albums/y190/nate7358/bbox1.jpg http://i5.photobucket.com/albums/y190/nate7358/bbox2.jpg
End result:
http://i5.photobucket.com/albums/y190/nate7358/charging.jpg
Purchased items:
Schottky diode
Radio Shack 4 AA battery box
1.3mm male and female DC power connectors
Case Logic leather memory card case
USB mini-B female connector (for old EB40 mod)
Everything else was lying around the house
Before I put everything together and made it look pretty, I did a test discharge and charge. The new battery pack alone, put up with 7 hours of Bejeweled and Village Sim running with full brightness, Wi-Fi on (I never used it), and mp3s running from my 2GB memory stick continuously in the background via Media Launcher. It was a good 1-1.5 hour before it even dropped below 100%.
Cons:
- I wired it so that only one battery pack is charged/discharged at a time. Keeping the packs separate was a safety precaution to prevent overcharging and overdischarging.
- Charging took well over 10 hours before the led on the EB40 turned off, and even then I’m pretty sure it’s not fully charged. At the moment, I can only charge the new pack through the EB40. When I get back from vacation, I’ll build my own lithium charger that should cut the time down to less than half.
- The EB40 won’t charge the UX to 100%. I wish I could somehow gain control of the EB40’s circuitry and choose whether I want to charge the UX, or just be a plain extended battery.
- When plugging/unplugging the new battery, I need to remove the EB40 momentarily to reestablish the connection to the UX. Though, this doesn’t happen while charging.
- I feel the need to be careful with this whole setup. The first few days after I finished everything, I lived in constant fear of the battery exploding on me. There are a lot of horror stories on the internet about people’s cars and houses burning down involving lithium batteries. But I made sure all soldered connections were solid, and put glue in areas that might be prone to shorting. I’ll get over it.
So was it worth it all? Yes and no. It’s still a battle between convenience and battery life. I can’t use the extra battery without the EB40 and I’m not going to directly mod my UX anytime soon. I might ultimately end up using the battery extender instead because it's slightly smaller and batteries would charge faster. We'll see.