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Saftey issues Answered

Hello,
I have been thinking about a project for a long long time, using 2 huge super capacitors with usb devices, such as an ipod. I am currently thinking of using 2 these: Link to 350 maxwell ultra capsLink to 350 maxwell ultra caps

But my real concern is safety. These capacitors can produce loads of amps at 5v, and that alarms me. Are my concerns real, if so, is there any safety precautions that one could take?

Discussions

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penguins

10 years ago

Wow thanks for the help all, I will post an instructable, once I get it done. It may not that fast though :p.

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NachoMahma

10 years ago

. Yes, a large capacitor can be dangerous; possibly lethal. But, at 5V, your setup will not be very dangerous to you. Skin resistance will keep the current down. You might get a burn, but your chances of getting electrocuted with 5V are very, very low. . If there is enough current capacity, a dead short can cause a small explosion. . . Insulating the cap terminals and wiring should keep you reasonably safe. Insulation material and thickness are determined by the working voltage and environmental conditions, not amps. . If you're still nervous, keep one hand in your pocket when the caps are charged. This will prevent forming a current path through your heart. . . BTW, to safely discharge your caps, place a 1-5MΩ resistor across the cap terminal for a few seconds.

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11010010110NachoMahma

Reply 10 years ago

low internal resistance of the cap does not make it more dangerous for electrocution. your resistance is way more than enough to protect you at 5 V

a 9 V battery will let more current thru you than the capacitor

its just 5 volts

i begin to feel current when i touch about 30 - 35 V. you may be more or less sensitivwe than me but i really dont believe you can feel anything or get harmed on 5 V

the real danger of this thing is fire

for example if you short it with 0.1 ohm resistor it'll generate heat at 250 W power. less resistance = more power. its way more than enough to get things white hot

the thing is 5 V 350 F. i dont think few seconds 1 M resistor are gonna affect the charge on it. to discharge connect 5 - 24 V lightbulb (less volt and more watt = better) to it

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Sandisk1duo

10 years ago

Safe, but will tingle if you lick it the neat thing about capacitors is that you can charge them really fast, and they put out a lot of current, and you can charge them 100s of thousands of times while you are at it, post an instructable on how to build it! oh, your iPod might not like so much current, you CAN ruin the battery/blow a fuse in the ipod, what i recommend you do is, get a 0.5A voltage regulator, and wire it to the capacitor, so that the capacitor cannot dump ALL of its power into the iPod within a couple seconds (unless the capacitor has very high internal resistance)

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Sandisk1duoSandisk1duo

Reply 10 years ago

ok, i checked the datasheet, the capacitor has super low internal resistance, so you DO need a voltage regulator

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11010010110

10 years ago

if ipod is 5 V and the capacitor gives 5 V i think it should be ok (the ipod should take its normal current and not more) if you want you can add a circuit breaker in series. it protects the cap and wires and not the ipod a series tiny resistor reduces alot the short circuit current but is a fire hazard unless properly protected (0.5 ohm resistor conected to 5 V converts 50 W of electricity to heat). i'd go without resistor