how to build a simple 3.7 volt cellphone battery charger that i can connect to the battery only?

my sharp 550sh cell phone battery charger socket has pulled out of the phone body,i cant charge the battery,the phone works fine apart from that,can n e one help with ideas on how to make a battery charger that will charge my phone battery outsice the phone?this place rocks,you guys and girls are way cool,thanks chris bennett

klee27x8 years ago
You really shouldn't do it the way kelseymh says. The wallwart puts out 5V. This goes to the circuitry in the phone, and the phone charges the battery at 4.2V. Hooking the wallwart directly to the battery will fry it. Not to mention, it's impossible to put alligator clips onto a cellphone battery. If you could find the connections that originally went to the socket, you could connect the wallwart there. But those connections are soooo tiny that it might be impossible for the average joe. I gave up on that idea after seeing how small the connector is on my particular phone! If you make your own charger, you can bypass the charging circuitry and charge the battery directly. You can charge the battery outside the phone or inside the phone. It is actually easier to charge it inside the phone, because you don't have to make a battery holder (I've made those, too, and it's not that hard. I should really make an instructable for that.) If you aren't up to making your own charger, you can buy a lithium ion single cell charger from places like Deal Extreme for less than 10.00. To make a connection to the battery, you need to remove the battery cover. Remove the battery. Solder a fine wire to the + and - connectors which are inside the phone, itself, but do it in such a way that the battery can still fit back inside. Now there's probably zero space in there for any extra wiring. So drill a hole in the battery cover about where the wires are. Thread the wires through the hole. Try to leave just enough excess wire where you can still open and change the battery if needed. Now solder the wires onto a small connector, like a piece of header. Use epoxy putty to adhere the connector to the back of the battery cover and to cover the hole and any exposed wires. Now you can connect your battery charger whenever you need to charge it, without opening the phone. As I said, you can also make an external battery holder for charging. It depends on the shape of your particular battery how hard it would be to do.
chad10 klee27x4 years ago
I tried this but my battery icon does not blink like it did when i charged it before and the light does not come on either and I had it set so the screen did not time out and it does when I hook it up like Mypillow said help help
sam D5 years ago
Charging isn't hard, but never connect them direct to a DC voltage without knowing what you're doing.

LiPo batteries have a very specific program - you take them up slowly to 4.2volts per cell, then you hold them there until the current drops right back.

This is hard to do manually, so that's why microprocessor units are usually needed.

I've done quite a bit of soldering mobile battery packs from old LiPo cells and recharging. You can read about it on my blog:
kelseymh8 years ago
If you have the wall wart and the socket it fits, you can hack something together. It won't be electrically "safe" or pretty, but it can do the job. Attach a couple of alligator clips to the positive (red) and negative (black) wires on the socket. On you battery, clip the postiive alligator to the positive battery terminal, and negative to negative. If your battery has multiple contacts, you'll probably need either to look up the battery spec on Google or use a multimeter to find the power contacts.