Lost Your Charger? How to Charge any Battery Survival-Style

Step 5 Time Limit

If you really have to do something else while charging your battery, you better hook up something to disconnect it after a few minutes.

The whole point of this instructable is that we're not going to fully charge the battery because we don't know how, and we're in a hurry.
We're just going to charge it enough to go back to our regular jobs. The phone or camera will tell us roughly how charged the battery is after we start using it.

So we're only going to charge it for ten minutes or so.

My camera battery has 1200 milliamp/hours of capacity. So if it's fully discharged and we charge it at 500 milliamps, it would take more than two hours to fully charge it.

Some types of batteries can be badly damaged by overcharging. Some are just damaged a little.
This picture shows how my golf cart avoids overcharging. There's a built in appliance timer that turns off the charger automatically. It won't let you charge for more than 24 hours.

That's it! Enjoy cautiously!
To make your own external battery pack, check out AT's splefty booster pack.

Comments

[dpark76]

I think these instructions were pretty well thought out, and would be rather useful for mechanically or electrically inclined people, and NOT for the average Joe.  These instructions help the "initiated" to think outside the box. Just like everything else in life...it's a calculated risk.

Heaven forbid if I'm driving through the mountains and get stranded without my phone charger, and my phone dies, at least now I know i can hack together a few wires, and light bulbs to charge my phone to send out that brief but urgent SOS. That's empowering to know.

[averagejoe1999]

I guess I cant do this...

[jay886]

Start keeping christmas lights in your car haha :]

[lukeyj15]

Or your headlights. I hope you keep them in your car.

[jay886]

Or possibly cutting a USB extension cable and using the black and red wires in the same fashion on the contacts of the battery, but keep your eye on it.

[omgitzstegman]

You would be so much better off diverting power at an appropriate level into the built-in BCC (battery charge controller) with the battery in the equipment. For instance, I was given a bluetooth earpiece that could be charged with AAA batteries, or a very rare type of USB cable via a small adapter the earpiece fit into. After going thru about 10x AAA batteries (expensive and wasteful), I just decided to hook up the battery contacts to my adjustable DC power supply at 1.5V fixed Voltage and floating current. After an hour the bluetooth would be charged. I did this for months until finally misplacing that one, as well. I would trust doing this on any equipment, especially when the OEM DC charger's voltage and current is known. Most equipment is easy, and gives the voltage where the charger plugs into the device. Good luck.

[davegriff]

Thats a pretty dangerous way to charge a lithium battery. Ever seen one burst (explode!!) into flames. Any way, if it doesn't self destruct it certainly won't have a very long life using this method of charging. DONT ATTEMPT THIS

[KahlZun]

Unless you really have to.

[mikeeg555]

Thanks Tim! I had to do this today...my charger was left 1000 miles away. I used a 5 volt AC/DC wall adapter and some wires with my multimeter in between to watch the current. I was giving it 1.7 amps, which was the maximum the adapter could pump out, and maybe a bit high, so I charged for one minute, rested for a few minutes then charged another couple minutes. This was enough to take another hundred photos! DO ATTEMPT THIS (if you're without recourse)

[legless]

I'm pretty sure that if I am away from where my chargers are located, I probably won't have access to a bench supply or a multimeter. If it's that important to be able charge stuff, one should have a home charger, a work charger and a car charger.

[bikerbob2005]

never leave home with out your dig multimeter.or pocket protector ,multi-tool. yes the TSA people realy like me we have long conversations and i get free coffee

[technogumbo]

I think Tim does a decent job of explaining the risks involved. I think I would give it a shot if I were in a jam. I would only use a very low amp source to do this though. Doing it with a car battery is too shaky for me.

[icebox]

Li-Ion batteries require a complicated charging curve - the temperature sensor also controls the charging curve. Direct charging like this will probably terminate its life, or at least seriously reduce it. Only do this kind of charging if you are really desperate, watch your fingers, incorrect charging on li-ion tend to make them catch fire, and be prepared to buy a new battery in a short time. In other words DON'T.