My camera shut down from low battery just when I needed to take some pictures. Here's how to charge any battery enough to keep
doing the important stuff. Fact 1: All past and future rechargeable batteries can be safely trickle charged if you don't overcharge them. Trickle means low current, like half an amp for an average camera or phone battery. This is the battery to my Canon S30. It's got three terminals, labeled "+", "-", and "T". Warning! Wear eye protection and if anything weird happens don't breathe the fumes! What was that other terminal marked "T" for? TIMMY of course, just like in the nursery rhyme! "Digital sensor, huh?" would be a running joke back when Americans knew Greek and knew that digits are fingers. But then numbers got so much use we forgot about counting on fingers, and now people barely know how to do anything with their hands. Anyway, here's a finger used as a digital thermometer. Which reminds me of the joke about the doctor... Step 2: Charge From Car Battery With Lightbulb RegulatorsSAFETY WARNING: scroll to the bottom if you want to read safety warnings. Here I am charging my camera's battery from my car battery. I'm using three christmas lightbulbs at once as a current regulator to get half an amp to flow into the camera battery.
For example, here's my test of one of these mini christmas lightbulbs hooked up to a bench DC supply: Volts Amperes I tested two bulbs and the data was the same. Since
my car battery is at ~13 volts and the camera battery is at ~7 volts, there will be 6 volts across the bulb. So I put three bulbs in parallel to get about 0.5 amperes to flow into the battery. Now just stand there for fifteen minutes or so until your battery is charged enough to take pictures again, you can make calls on your phone or whatever. SAFETY WARNINGS: Step 3: Charging From Any DC Source and ResistorHopefully you own an electrical meter. As seen in the previous step, the best improvised current regulator is usually a small lightbulb. The bulb is great because the resistance goes way up when the filament gets hot and limits the current. And you can only put an amp or so through one without burning it out, so it acts as its own fuse. And they're free gifts from garbage Santa. Here I'm using two bulbs in series to limit the current going into a gelcell. Use your multimeter to measure what current goes through your bulb at different voltages. Or you can just cowboy it and use one tiny bulb for a few minutes, while feeling to see if the battery gets hot or not. Wear eye protection and don't breathe the fumes! Step 4: Current and Voltage From a Bench SupplyThis step uses a bench power supply to charge a battery. A lot of us have those sitting around even if we can't find our cell charger. Or we know where to find an electronics guy who has one. Now what? Want to be totally mystified? Look up "lithium battery charge control". But we just want to take pictures or talk on the phone. So
here's what we do: Turn up the voltage and current limit knobs until 500 milliamps (0.5 amps) is flowing into your battery. If you feel like being careful look up how much current the experts use. My electronics guy told me to set my voltage limit to 8 volts for my 7.2v li-ion battery. Usually facts like that are luxuries. The point of this method is to trickle charge anything without being able to know much about the properties of the battery. Step 5: Time LimitIf 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. 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. That's it! Enjoy cautiously! 1 Person Made This Project!RecommendationsHow do you manually charge a battery?Hooking up the Battery Charger. Make sure the charger is off.. Hook-up the positive cable on the charger to the positive terminal on the battery.. Hook up the negative cable on the charger to the negative terminal on the battery.. Set the charger to the slowest charge rate.. Turn on the charger and set the timer.. Can you charge a 20V battery with a 18V charger?So yes, 18V and 20V MAX systems operate with the same amount of voltage. Let me say it again: 18V batteries and 20V MAX batteries produce EXACTLY the same voltage.
Can I charge a lithium battery with a normal charger?You can use a lead acid charger on a lithium battery if you want, HOWEVER, you must NOT use a lead-acid charger if it has an automatic “equalisation mode” which cannot be permanently turned off.
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