Are the 2600f 2.5v capacitors dangerous - Page 1
Forum section: electronics / beginners

author: Horryhop
author_rank: Contributor
timestamp: March 06, 2016, 09:58:45 pm
content: By dangerous mean if I touched both terminals when it is fully charged. Also is there any project ideas with these capacitors you can think of. Thanks rich

author: Simon
author_rank: Unknown
timestamp: March 06, 2016, 10:01:13 pm
content: You have answered your own question. The capacitor is 2.5 V, can 2.5 V harm you? If it can I suggest you put down all the batteries you've ever touched very carefully. It is the voltage stored in a device which is lethal as it will drive the lethal amount of current that can harm you. No idea what to do with them though put them in series I news mother battery someone did that for his car.

author: wblock
author_rank: Regular Contributor
timestamp: March 06, 2016, 10:13:14 pm
content: Please show pictures. A 2600 Farad capacitor is going to be pretty big.

author: MK14
author_rank: Super Contributor
timestamp: March 06, 2016, 10:18:17 pm
content: Quote from: Horryhop on March 06, 2016, 09:58:45 pmBe careful, because if they get short circuited (e.g. accidentally), by say metal. It can very rapidly reach potentially dangerous temperatures.Quote from: wblock on March 06, 2016, 10:13:14 pmIt depends what you mean by big. If by big, you mean somewhat small, then yes. (Joke).Ultracapacitors.I guess they are fairly big and chunky:

author: wraper
author_rank: Unknown
timestamp: March 06, 2016, 10:20:19 pm
content: Quote from: Simon on March 06, 2016, 10:01:13 pmYes it can be dangerous. Take a piece of wire, and short it while holding the wire in your fingers, wire will melt and insulation will burn into your your fingers.

author: Cliff Matthews
author_rank: Unknown
timestamp: March 06, 2016, 10:25:02 pm
content: Quote from: wblock on March 06, 2016, 10:13:14 pmHere's all you need.. Maybe you meant ultra cap? (there is a difference, the type mentioned is likely a supercap for micro power backup).http://www.farnell.com/datasheets/1640983.pdf

author: wraper
author_rank: Unknown
timestamp: March 07, 2016, 01:09:30 am
content: Quote from: Cliff Matthews on March 06, 2016, 10:25:02 pmHave you ever seen 2600F backup supercap??? Max capacitance in that datasheet is 26 times smaller.

author: vk6zgo
author_rank: Super Contributor
timestamp: March 07, 2016, 01:38:58 am
content: Quote from: Horryhop on March 06, 2016, 09:58:45 pmUnless you are a metallic robot--NO!Please Google for Ohm's Law!

author: Shadetreeprops
author_rank: Regular Contributor
timestamp: March 07, 2016, 01:53:42 am
content: Quote from: Horryhop on March 06, 2016, 09:58:45 pmThere was a test on youtube done on this, anything below 40v DC was okay, above that to 50v was painful, and anything past that dangerous. that was a constant current too. so a 2.5v might be like a static pop but nothing that will hurt you.now i have a 600V cap 500uf, that will probally stop a heart. but not that i am willing to ever try that. also have several 400v caps that i rescued from a dumpster, i gave them a lovely home on my parts shelf, they are comfy, and well taken care of, those poor caps were just left out in the cold..poor poor stray caps.

author: uncle_bob
author_rank: Unknown
timestamp: March 07, 2016, 02:06:31 am
content: HiOne of the most basic questions:If you short out your 2600F cap does it self destruct?A lot of these parts are long on hype and quite short on actual specs. The Maxwell web site lists zillions of "applications" and very few things that show the real performance of their latest parts.You don't have to have the TV on for long before somebody will have pictures of exploding lithium cells burning down major cities and significant fractions of continentsThe energy density in some caps is also quite high ...Bob

author: tautech
author_rank: Super Contributor
timestamp: March 07, 2016, 02:13:09 am
content: Quote from: Simon on March 06, 2016, 10:01:13 pmSimon, did you mean member Psi?https://www.eevblog.com/forum/chat/i-didn't-realise-supercaps-worked-this-well/msg440964/#msg440964

author: Cliff Matthews
author_rank: Unknown
timestamp: March 07, 2016, 02:14:11 am
content: Quote from: wraper on March 07, 2016, 01:09:30 amNow I have.. I hadn't looked into that stuff in a while. He used a lower-case f so it sent me off thinking about stuff like this

author: vk6zgo
author_rank: Super Contributor
timestamp: March 07, 2016, 02:48:17 am
content: Quote from: Shadetreeprops on March 07, 2016, 01:53:42 amNo,2.5 volts will feel like nothing at all!Thecurrent capacityof a device or circuit has no effect upon the currentthrough youit can cause,if the voltage is insufficient to produce a dangerous,or sometimes,even a perceptible,current.----Ohm's Law again!Voltage is the determining factor.*Touch both terminals of a fully charged 12v car battery (a device with a massive current capacity) on a cool,dry day,& it will feel exactly like afully dischargedcar battery on a cool,dry day.If it is hot,& you are sweating,12v will give you a very slight stinging sensation,if you contact both terminals with a sweaty part of your body--most commonly your forearm.*Sort of,but not quite an exception!In some circumstances a high voltage supply designed to operate with an extremely low current draw,may have such poor voltage regulation that you will get an initial "zap" falling off rapidly to nothing.It is always best to assume that WON'T happen!

author: Horryhop
author_rank: Contributor
timestamp: March 07, 2016, 05:21:33 am
content: Well thanks very much for all of the reponses, although i will rephrase my second question, being 'is there any projects i can do that have a variable that can be changed'. Thanks for the replies so far rich

author: Richard Crowley
author_rank: Super Contributor
timestamp: March 07, 2016, 05:29:10 am
content: A 2600F capacitor (or array of capacitors) would be as big as a bread-box.I seriously doubt that anybody makes a 2600F capacitor.It might easily be mistaken for a battery.I don't understand what you mean by..."projects i can do that have a variable that can be changed"Essentially ANY project has variables that can be changed.You want to narrow that down to something practical?

author: Brumby
author_rank: Unknown
timestamp: March 07, 2016, 06:00:01 am
content: Quote from: Richard Crowley on March 07, 2016, 05:29:10 amYou should check out the capacitor labelling in this video - as well as the maths occuring at around the 35 second mark....Quote from: wraper on March 06, 2016, 10:20:19 pm

author: Dago
author_rank: Frequent Contributor
timestamp: March 07, 2016, 06:05:34 am
content: http://www.maxwell.com/products/ultracapacitors/k2-2-85-series

author: tszaboo
author_rank: Super Contributor
timestamp: March 07, 2016, 08:35:09 am
content: Quote from: Richard Crowley on March 07, 2016, 05:29:10 amThey sell it on Digikey...It is used for regen braking and such. China wants to run buses with them (not serial, the big thing on the street). You can probably build a coilgun with a lot of those, and get arrested. Anything where thousands of amps is required for a short time.These have less than 1mOhm ESR, so 5000A from it is very possible.

author: Zero999
author_rank: Super Contributor
timestamp: March 07, 2016, 08:43:56 am
content: Quote from: Shadetreeprops on March 07, 2016, 01:53:42 amPeople have different sensitivities to electric shock. There's a 75VDC PSU where I work and I can touch it without feeling a thing. If I'm very sweaty I may get the odd tingle but nothing really bad.It also depends on the path of current. Touching a 1000uF capacitor charged to 600V with one hand won't kill you but it will give you a nasty shock and a severe burn, but touching the cathode with one hand and the anode with the other could kill.The capacitance is also a factor. A 100pF capacitor charged to 10kV may give you a shock but it will be only as bad as a static shock received when touching a metal door knob, after walking on a wool carpet wearing rubber shoes.

author: Richard Crowley
author_rank: Super Contributor
timestamp: March 07, 2016, 12:14:24 pm
content: It would be virtually impossible to get anything that could be described as a "shock" from such a very low voltage.That is because of the rather high resistance of your outer skin layer (of dead cells).Even if you had soaked your hands in salt-water (to make them more conductive) is it unlikely that you could even perceive 2.5VIt takes considerably higher voltage to make it into your body.However, if you had electrodes implanted into your heart or your brain, 2.5V could be very significant. That is much higher than the normal "signal levels" that our nervous system operates at.OTOH, if you had something metal/conductive in your hand and you touched against the terminals of something with a lot of power behind it (such as a battery or a very large capacitor) then there would be danger from thermal burns as the metal conducts and turns into a heating element. There are many stories of wrenches and screwdrivers, etc. being thrown across the room from accidental contact to a large capacity battery (even like the ones used in automobiles). For THIS reason a very large value capacitor is just as dangerous as a battery as a source of accidental heat/spark source around flammable materials.These kinds of capacitors are typically used in applications where you need high current power, but only for a short period of time. For example for short-term backup to a critical circuit while the main power source is changed (like while changing the battery). Or even perhaps weight-sensitive applications like quad-copters which use high-current but can't handle power sources that weigh very much.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 07, 2016, 12:39:40 pm
content: The only hazard is burns.fire if shorted.I had a play with a 3kF one :https://youtu.be/mY2X-ZQpnvY?t=1687

author: tszaboo
author_rank: Super Contributor
timestamp: March 07, 2016, 12:55:31 pm
content: Quote from: Richard Crowley on March 07, 2016, 05:29:10 amfew hours later...Quote from: Richard Crowley on March 07, 2016, 12:14:24 pmSeriously?Are multiple people using your login?

author: Richard Crowley
author_rank: Super Contributor
timestamp: March 07, 2016, 12:58:45 pm
content: Quote from: NANDBlog on March 07, 2016, 12:55:31 pmRecommend avoiding posting while seriously sleep-deprived from travelling for 24 hours.

author: tszaboo
author_rank: Super Contributor
timestamp: March 07, 2016, 01:04:16 pm
content: Quote from: Richard Crowley on March 07, 2016, 12:58:45 pmHappens to the best of usAnd that is why we have version control!

author: station240
author_rank: Unknown
timestamp: March 07, 2016, 07:59:46 pm
content: Quote from: NANDBlog on March 07, 2016, 08:35:09 amThey actually built buses, granted they get recharged along the route.https://en.wikipedia.org/wiki/Capa_vehicleChina are using their own brand of ultra capacitor in these buses, I can't seem to find the reference to what brand it is today.Of course being chinese build quality on the entire bus, you get things like this.http://www.greencarreports.com/news/1063473_chinese-electric-bus-catches-fire-on-road-not-the-first-oneThat blackened box that's been ripped open is one of the 4 super capacitor banks.

author: Horryhop
author_rank: Contributor
timestamp: March 07, 2016, 09:29:35 pm
content: Hmmm, thanks for the info, but I guess the sort of project I would like to build needs to be practical to build in a small workshop. Thanks for all of the help so far, rich

author: Seekonk
author_rank: Super Contributor
timestamp: March 07, 2016, 09:35:38 pm
content: Someone on another board just replaced his aging 48V battery bank in a solar application with super capacitors. Says he has just under 1KWH of storage. I'm waiting to see how that turns out long term.

author: MK14
author_rank: Super Contributor
timestamp: March 07, 2016, 10:11:41 pm
content: Quote from: Horryhop on March 07, 2016, 09:29:35 pmAssuming you are talking about a maximum of one, of them.You only would have 2.5V available (max), to play with. (Assuming you are not going to mess with shorting it out, to make mini firework (like) displays on youtube). Your options would be one of the following 3 options.(1)...Find stuff like small motors (low voltage ones) and some colours of leds (e.g. Red & Green) which work at around 2V. Then play with them, WITHOUT needing either battery power or a mains adapter. I.e. Super/Ultra Capacitor powered (it is NOT clear which type you have, you have not provided details or pictures. Apparently such a high value is available in both varieties).(2)...Make/design or buy a voltage converter, such as a voltage doubler, or probably better still a small switched mode power supply. Choose the DC to DC converter (if you can get any at such a low voltage), to produce a level which will power your projects. E.g. 5V for USB, or 12V for some bigger projects. Or whatever you want.E.g. To power Torches/Nightsticks, mini computers, big arrays of flashing LEDs, music making equipment, robotics, motors etc etc.(3)...Make a serious, big project. By buying enough of these to make a bank of them (best to NOT do this, if you are not competent enough with electronics). People make things like car battery replacements, and all sorts of other things. Such as massively powerful, youtube video entertainment, electronics under huge stress, of wild over current/voltage via these massive capacitor banks.

author: Horryhop
author_rank: Contributor
timestamp: March 08, 2016, 12:02:26 am
content: Where is the best/cheapest place to buy 2600F capacitors. Thanks rich

author: MK14
author_rank: Super Contributor
timestamp: March 08, 2016, 12:15:35 am
content: Quote from: Horryhop on March 08, 2016, 12:02:26 amI have no idea what you want them for, or why you want to buy them in the first place.Ebay seems to have many available, usually from China, at lower prices than proper, quality suppliers.But I am very worried that the quality of them is bad, and that they are fakes and/or NOT at the ratings/values that they claim.tl;drPersonally I'd avoid them altogether and buy from a proper supplier. But then they are VERY expensive.I've wanted to buy some myself, but my options were ebay/China/suspect quality, so I ruled that out.Proper quality supplier ones (e.g. Farnell/UK), are very expensive. SO I ended up buying NONE.I would strongly advise you to try and buy something completely different, within electronics. How about an electronics starter kit, or Raspberry PI or something ?You don't come off as someone who knows enough about them, to use them safely. My opinion is that complete beginners (who seem to think that 2.5V can electrocute), should avoid stuff like that. Learn/begin on something completely different and inherently safe.Capacitors can get VERY nasty if you don't know what you are doing, and over charge (volt) them.Potentially cheap Chinese capacitors may have cheaped out on the safety features, combined with your apparent inexperience, could lead to them exploding and causing injury. (If the safety device(s) are missing).

author: Richard Crowley
author_rank: Super Contributor
timestamp: March 08, 2016, 12:20:32 am
content: That's not exactly the kind of component one goes out looking for a bargain for.Or casts about looking for a project unless you already had one in-hand.Did you just pick 2600F capacitors at random?Both Mouser and DigiKey show 2600F capacitors, but neither of them stock such exotic parts.So you will have to wait weeks to months to get one. And of course you will pay well over USD400 each.This seems like an extraordinarily odd question.

author: Mr.B
author_rank: Unknown
timestamp: March 08, 2016, 12:38:35 am
content: Just out of curiosity I went and had a look...Mouser are showing plenty of stock of 3000F 2.7vNot a bad price considering what they are - between NZD97 and NZD140

author: uncle_bob
author_rank: Unknown
timestamp: March 08, 2016, 12:47:37 am
content: Quote from: Horryhop on March 08, 2016, 12:02:26 amHiHow many hundred are you planning on buying? The real use for these is in fairly large stacks ....Bob