I sometimes sit up half the night at my computer falling asleep and somehow double click and buy somethin as I am nodding off and I accidentally buy stuff when checking out ebay on my phone !
Also these "supercaps" are fake ones, check "MH" section of their Gren-Cap datasheet ...managed to buy 16 pieces and all of them are trash. They have maybe 150-200F on good ones and absolutely huge internal leakage. Useless but yeah, they were cheap.
I have a few of those voltage ref boards, the V after the comma are the final two digits of the full voltage... not a separate voltage, mine actually came with batteries, the batteries are marked as 10F2015V, it is about the same size as a 9V battery, just slightly shorter.
18:25 "Time for a new knife" - Well, why don't you order one in a Postbag! - "I can't open the postbag that has the new knife in it because the old one doesn't cut! NOOOOOO!"
The extra pins on the cap are mechanical mounting studs to mount the component more rigidly on the board. It's some protection against shock and vibration for such a heavy component.
Have you ever looked on AliExpress? They do have some very interesting electronics stuff that you can't find on ebay. You do need to do a bit of digging to find it. Made my own post read like spam lol
hm....the only thing i couldnt find on ebay were the mass of IC and COmponent sellers, and maybe baite and the orange pi guys. but i like it more because its cheaper than ebay in 99% of the cases
There are some items on eBay which aren't on AliExpress. I've just ordered a DC/DC module on eBay but I can't read the chip number from the eBay photos. It doesn't appear to be on AliExpress at all.
Julian Ilett Of that specific one as you are looking at on ebay or you can find anything DC to DC on Ali I just like to say I'm not being sponsored in any way, it's just I look on the site all the time and think to my self Julian would like that.
Well I bought this: www.ebay.com/itm/-/172282473702 But I can't see what controller it uses from the rather blurry photos. I was hoping to find the same item on Ali in case their photos were better, or the controller chip was mentioned in the listing.
Julian Ilett Can't find the same, but this meets the spec. www.aliexpress.com/item/Low-Ripple-90W-DC-4-5-60V-to-1-25-30V-Adjustable-Voltage-Step-Down/32701985954.html?spm=2114.01010208.3.1.3NyVO8&ws_ab_test=searchweb201556_8,searchweb201602_2_10057_10056_10055_10037_10049_301_10033_10059_10032_10058_10017_10060_10061_10062,searchweb201603_4&btsid=74ce7815-7a47-47d0-8808-0e2cea147304
Julian, thanks for another great video. Do you have a link to the USB lead "voltage and current detector" that you used on the watch? I have plenty of "charge doctors" that are on the "large " end of the USB cable, but often it could be more convenient if the display was on the "micro" end, like the one you used.
I'd love to see a video testing the accuracy of some of your led voltage meters. I have one with 5 total decimals, but I don't have anything to compare it to.
I have mine connected up to a DC-DC Buck/Boost, with a linear 10 turn potentiometer instead of the multi-turn trim pot that was on there. It is really nice to have all the digits for that, but I have no idea how close it is.
I think that the battery is a 15 volt one, not easily found. I made one up from 5 x 2032 lithium coin cells joined together with 1 mm neodymium magnets, as in your idea, in a cardboard tube . I put a spring in between two of the cells to give spring-loading onto the calibrator's battery terminals.
Thanks for the complement, Julian I do enjoy your offerings and this is the first time that I have bought a featured item before you did! I had done a similar thing with my old analogue Avo multi-meter, loading the original battery case with alkaline button cells. This worked out very cheaply using the card of 30 assorted cells from a pound shop. The lithium cells were from the same source, the resulting battery much cheaper than Maplin's extortionate price. I made the tube from several layers of quality note-paper wrapped round a piece of dowel, soaking the resulting tube in polyurethane varnish for rigidity. Re using magnets as battery contacts, I got some with a countersunk hole through the middle and used countersunk screws and nuts to attach the wire as soldering the magnets will take them beyond their curie point.
Id imagine the extra pins on the super cap are anchoring pins to help secure its large size to the PCB. they are normally just left electrically floating
Actually no, you need ~300°C for soldering and 600+°C to change iron alloys in their crystaline structure to demagnetize it. Not sure if a high neodymium percentage will change it or not though. It's worth a try.
Krisztián Szirtes definitly worth a try, but i remember when i was a kid i thoght i was smart by using a neodynium magnet to fix the flopping baking sheet in the oven to the tray, when making a pizza. I the magnet lost all of its power and was not magnetic at all in the end. The oven was turned to 180°C
The curie temperature for neodymium magnets tops out at 200C for the high temp ones. According to Wikipedia the action of demagnetization is basically the heat overwhelming the natural tendency of the electron alignment, nothing to do with the structure. Though if it doesn't re-magnetize as it cools it should still readily be re-magnetized
surely those extra cap legs are just for mechanical mounting strength. the voltages you were seeing were just stray charge on the DVM leads - didn't you notice when you lifted of the probe the final time the meter continued to show the same small falling voltage? For connecting battery leads to the magnet have you thought about spot welding? in fact super caps could be very handy for making a miniature spot welder!
you can select at top of purchase list select date and click on 2016 and it will bring up everything. pain i know but i too have to do it as i forget what iv purchased. one thing that annoys me is buying resistors and the sellers not marking values on them!
Great vid. I found that if you copper plate a small portion of the magnets the solder and wires stick together very well. I use them to charge batteries. Thanks again for the vids. They are very informative.
The Avo8 multimeter uses a 15V rectangular battery. An option with them is to use your cylindrical battery in a holder to make it rectangular. The cylindrical one is just a stack of common AG10 alkaline button cells and you can make one up very cheaply using sticky tape and cheap cells.
Hey Julian, I know it isn't what you're looking for but I just now remembered that I do know of one LTC3780 with a fully digital front end. It's a power bank by the model QD188-ALT it's from the same guys that made your white 5-13v power bank.
Julian, a man after my own heart. I go on these mad shopping sprees and scratch my head when the packet arrives. Also, on your three meters, remember the old aphorism, "A man with one watch knows what time it is. A man with two watches is never quite sure".
+Julian Ilet I have just got myself one of those voltage references. Now here's a remarkable coincidence: the calibration certificate that came with mine is EXACTLY the same as yours; i.e. with the four voltages to five decimal places being identical to yours. All the more remarkable considering that one of the capacitor leads had not been soldered, causing erratic behaviour...
Me too. Mine just arrived today and I recognized the numbers on the so-called calibration sheet. EXACT COPY, a photocopy I think, of the sheet held by our hero Julian. Luckily we have a Cal Lab at my workplace, so I'll check it out there. Pure comedy...
The extra pins on the supercapacitor can be left floating, usually it's for mechanical purpose and your DMM is probably just being silly from parasitic capacitance with a minuscule charge.
@7:08 get the kkmoon precision reference module instead. it comes with a rechargeable battery and a nice laser cut acrylic case and banana jacks, and a nice user interface. it's a really nice voltage reference for cheap. it's on ebay and also on amazon: www.amazon.com/Precision-Voltage-Reference-AD584kH-4-Channel/dp/B00Z033Y6Y/
I doubt soldering to neodymium magnets wold work, the curie point is fairly low and almost certainly below a reasonable soldering temperature. The nickel coating (so they don't corrode) won't take solder very well either. Welding like for lithium battery tabs might work though.
For those in the US, an ebay-offered $4.50 GC 8271 alignment tool is a less expensive alternative to the Bourns H90 or H91 which are $10 and up including shipping, except for a 10-pack from Hong Kong for $20.
I've got one of those watches. You don't need to use the app if all you want to do is use a few functions...and make and receive calls through your wrist! I haven't downloaded the app for the mentioned security risk, but I have paired the watch with my phone.
Don't believe the 'cal data' piece of paper that comes with the precision voltage reference. I got one and the figures are all identical to yours! What are the chances of that happening? :)
I got the same voltage reference and our sheets are the same numbers I dunno if I believe them as being the true tested numbers. I guess I should test it out on my 6.5 digit bench meter and see what the real numbers are. I bought the reference 3 months ago, but never messed with it.
Here's what I got. 30 min warmup both. 27.1C, input V 15.00437, so here the voltages from calibrated Rigol 6.5 digit Bench DMM with probe master probes.. 10.00334, 7.50373/7.50374, 5.00169, 2.50155
I love your flashlight ,is that something I can buy ,also I bought. That watch at Amazon,for 29.00$ a year ago,everyone sells it 9.00 or less like you got it for ,thanks for the web site too
I had to look it up... looks like those meters are RP4020s, which has the BEST DC accuracy of +/- 0.8%/3 counts. That is within 1 year of calibration and a tight temperature range... These meters are quite in-tolerance. :)
Yes those 500F are similar to the ones I got and are just useless they have about the same or less than the Vina Tech that I sent to you and rated 220F (this are high quality made in Korea) The GreenCaps are completely useless there are huge variation in capacitance between them also internal resistance and they have a huge leakage they can lose 70 to 80% of the initial stored capacity in 24h. To play with just one is fine since even if all are with huge variations between them using just one will not be important. At initial charge it seems they took a lot more energy and they got a bit hot wen if charged at realy low rate. That was a bit strange. And those extra terminals are common for large capacitors just for mechanical support.
Julian, feel the weight of that supercap. Now imagine it flapping about in some product, secured to the PCB with just two solder connections... I'll wager those two extra connectors are purely mechanical, to anchor the cap more tightly to the PCB.
the 2.5 didn't measure 2.499 it measured 2.49967. the comma is simply splitting the number. just like we write 1,000,001 for whole numbers, folk will write 0.100,000,01 with decimal places. The comma is quite normally included in non-English speaking countries.
These 500 F caps look similar to the real "powerstore XV" series but sadly a lot of the "greencaps" are low capacity and have a fairly high leakage, and ESR. The extra connections on the REAL powerstor are open circuit (not used) M.
Neodymium Magnets lose all their magnetism far below soldering temeperatures. You could try spot welding them though, because that wouldnt heat up the entire magnet.
Mine didn't even go over 3A when it started to limiting the current. So it didn't even get hot. Searching on the internet showed some other people had that problem also. Just wondering if yours too.
For the tests of the super capacitor it'll be easier if you get a clamp or two and use melamine (or mdf) to put even pressure on the card holder. Magnets idea looks like to much wasted time. If it works you can tut card holders shallower then use melamine/mdf + 2 metal brackets held with bolts.
That "500F" cap would have an energy density of ~ 36 million Joules / cubic meter! (for dia=33mm & len=60mm). About 600 million J/kg (600Mj/kg). ...typical for supercaps?
a question to the ltc3780 board: would it be possible to replace the potentiometers with with digital potentiometers, add an arduino and some currentsensors to make a step up down mppt solar charger?
I brought the exact same Voltage reference module a few months back. Interestingly, my sino meter same model number as yours is 10 years old and also was only 1 count out, better than my Extech EX330. My UNI-T 210E clamp meter was spot on however. I purchased it to confirm my other voltage reference was accurate, so I now have a AD584K and AD584L. The latter being more accurate. Pretty cool cheap device for testing my multimeters. Oh btw, don't trust that little piece of paper; mine is identical the date, results, etc.
+Julian Ilett yep, I just compared to make sure again. Only difference is the title is indented slightly differently, mine is more centred, yours is a tad to the left of centre. The other unit I have with AD584K has the results handwritten and having tested with a calibrated bench meter does appear to have been tested properly.
Haha, Julian I'm quite enjoy watching you open packages, and I am now realized why many people still think MADE IN CHINA is crap. Yes, I have admit that things sold on eBay ARE crap, and they are made in China. However, they are barely seen on Taobao (where we, Chinese people, usually do online shopping) or they were listed at price around 1/5 of the price on eBay which clearly tells me they are crap. I just ordered some usb-led lights and arduino parts on eBay, looking for ward to open the package. It will take 3-4 weeks shipping form China to Australia, but if I purchase them on Taobao, price+shipping even higher than eBay price :( BTW, I have found an usb-led light that has optical and sound sensor on it, looks awsome
Personally I think you should do a video on alice11011983, who are they? A single individual? a front to a large electronics warehouse? where do they get all their stuff for sale?
if you look at the location, they're in shenzhen, which is a huge area that has tons of marketplaces for electronics and whatnot. i believe you can even find videos on the "shenzhen market" - they have huge sprawling marketplaces with everything you could ever want in electronics. it could very well be just one person or a few people who buy in bulk from other factories. i imagine getting ahold of various electronics in shenzhen is very easy and dirt cheap.
The battery used on those voltage reference modules is a dual 9V battery (2 in series), look here: www.ebay.com/itm/AD584-4-Channel-2-5v-7-5v-5v-10v-High-Precision-Voltage-Reference-Module-/181863456673 -- don't know where to get them though.
Those big solder tabs on super capacitors are a swine to solder, watched someone use two soldering irons on one just to get enough heat in. Still wasn't perfect soldering. Also RIP smart watch. Anyone managed to re-purpose the touch LCD screen ?
Digikey marks their price up significantly. Actual price from the mfg is much lower, within spitting range of that $3 board. However, these are either "recycled" I.e, pulled, or counterfeit. Pulled is obviously much preferable to counterfeit. At best, they might be NOS
Well if it's recycled then it could be real, right? Even then, it might be a real chip but one which was rejected during QA testing in the manufacturing but nod badly enough so it went to the other garbage bin which goes to the other factory. Or it would be a brand new chinese "equivalent" copy. Or in the worst case a recycled chinese copy. Best case scenario? Someone stole a truckload of real chips somewhere and is reselling them for cheap. No way to know really.
some state they are recycled parts, I bought one on a whim and am very impressed, the test data with mine agrees with my calibrated Fluke and Keithley 2002 in work (+/- 5 counts!) needs to be powered up for 15/20 mins to stabilise and was using a lab power supply. ps if buying them you want the K variant chip (high accuracy)
I don't know if it has been mentioned, I apologize it I am repeating someone else's post. Julian, the Ryobi TEK4 instruction manual gives the following information concerning guaranteed accuracy of the meter. DC Voltage: 4 V, 40 V, & 400 V ranges. ±(0.8% of reading +3 least significant digits) For a ten volt input, that means... ±(0.8% X 10 + 0.03) ±(0.08 + 0.03) ±0.11 10.00 - 0.11 = 9.89 volts lower limit. 10.00 + 0.11 = 10.11 volts upper limit. A reading of 9.94 volts is well within tolerance. If you returned it to the factory they might send it right back with a message, "Found within tolerance, no adjustment required." It might be interesting to many of your followers go over how to read the specifications on their measuring and test equipment.
You can increase the voltage rating of your super caps if you place them in series. It will, however decrease the capacitance. You can significantly increase the amount of energy by increasing the voltage (E=CV^2). So with 2 500 farad super caps in series you could get 250 farads of capacitance at 5 volts for a total of 3,125 joules! Now imagine what sort of experiments you can do with that kind of energy.
Lol and just as I thought, all these people 'calibrating' their B6 chargers so that they won't overcharge their Lithium batts.. 4.20 Volt exactly it must be. Right ... I've also ordered that AD ref board, 2 Flukes show a different voltage and the Uni-T is also different. With that board lets see what is correct. Julian I would definitely check the Voltage on the 18650 batt itself. I've seen some loses on cables, connectors and surely that magnet thing is not something that you want to use to quickly (1 Amp and up) your cells with. So even if the charger says for example 4.08 Volts it might be lower on the batt side.
If you or someone out there could remove the pot's and control the output with an Arduino it would make all sorts of projects pretty straight forward ie MPPT charge controller
I'm always wary of installing "PRC" software, I have an old, wiped, HTC phone I use for the purpose. Just wish I had a network analyzer to see everything PRC firmware does. LOL
I think the smart watch/phone app story is nonsense... encryption doesn't prevent you from seeing where the data goes, so the IP address should be know.
I would also think it should be reasonable to assume that firmware and apps exist for the device that is clean without the risk of security issues. I know some people are toying with the idea of getting it to run other operating systems.
The best bit about these mailbag videos, is Julian trying to remember why he bought things :)
Glad I'm not the only one!
Something to do with making "late night eBay purchases" :) That'll do it! That is probably nearly as bad as my drunk purchases.
+Christmas Eve ffs.. Totally me talking there!
Bought myself a tn36 lately.. But still love it.. Only cost me a dime... FCK alcohol
yeah I do that too wonder why I buy things
I sometimes sit up half the night at my computer falling asleep and somehow double click and buy somethin as I am nodding off and I accidentally buy stuff when checking out ebay on my phone !
"Modern" capacitors with four or more legs like that usually just use the remaining legs for structural support, as the can is so large.
That makes sense - the floating voltage on those pins I now realise is because they're not connected to anything - doh :/
Also these "supercaps" are fake ones, check "MH" section of their Gren-Cap datasheet ...managed to buy 16 pieces and all of them are trash. They have maybe 150-200F on good ones and absolutely huge internal leakage.
Useless but yeah, they were cheap.
tha makes sense. thought it had something to do with the dual thingy
was going to say....
Fake ones!!! Well that sucks. I was going to buy some 500F caps and now I have to question them. Thanks for the heads up...
I like using adhesiver copper tape to solder wires to and then wrap it around a magnet for those type of quick connections.
Nice idea - and they won't stick quite so viciously with a bit of copper in between them.
I have a few of those voltage ref boards, the V after the comma are the final two digits of the full voltage... not a separate voltage, mine actually came with batteries, the batteries are marked as 10F2015V, it is about the same size as a 9V battery, just slightly shorter.
18:25 "Time for a new knife" - Well, why don't you order one in a Postbag! - "I can't open the postbag that has the new knife in it because the old one doesn't cut! NOOOOOO!"
Like those tools for opening blister packs that come in a blister pack.
+webchimp lol 😁
The extra pins on the cap are mechanical mounting studs to mount the component more rigidly on the board. It's some protection against shock and vibration for such a heavy component.
I have a good number of very old Bourns Trimpots which came out of old measuring instrumetns; they are all rated to 1 percent tolerance.
Perhaps conductive glue for attaching wires to magnets?
The figures quoted on the paper are from the 6 digit Agilent, so for 2.5v the Agilent recorded a voltage of 2.49942v and so on.
Everyone who bought that thing got the same numbers on a piece of paper, including the same date.
11:38 the ", " is just a 3-digit group-seperator.
The extra prongs on the super caps are just anchor points because they are so big and heavy! lol
Have you ever looked on AliExpress? They do have some very interesting electronics stuff that you can't find on ebay. You do need to do a bit of digging to find it.
Made my own post read like spam lol
hm....the only thing i couldnt find on ebay were the mass of IC and COmponent sellers, and maybe baite and the orange pi guys.
but i like it more because its cheaper than ebay in 99% of the cases
There are some items on eBay which aren't on AliExpress. I've just ordered a DC/DC module on eBay but I can't read the chip number from the eBay photos. It doesn't appear to be on AliExpress at all.
Julian Ilett
Of that specific one as you are looking at on ebay or you can find anything DC to DC on Ali
I just like to say I'm not being sponsored in any way, it's just I look on the site all the time and think to my self Julian would like that.
Well I bought this: www.ebay.com/itm/-/172282473702
But I can't see what controller it uses from the rather blurry photos. I was hoping to find the same item on Ali in case their photos were better, or the controller chip was mentioned in the listing.
Julian Ilett
Can't find the same, but this meets the spec.
www.aliexpress.com/item/Low-Ripple-90W-DC-4-5-60V-to-1-25-30V-Adjustable-Voltage-Step-Down/32701985954.html?spm=2114.01010208.3.1.3NyVO8&ws_ab_test=searchweb201556_8,searchweb201602_2_10057_10056_10055_10037_10049_301_10033_10059_10032_10058_10017_10060_10061_10062,searchweb201603_4&btsid=74ce7815-7a47-47d0-8808-0e2cea147304
they put 3-4 legs on the big capacitors for better mounting on the pcb
Julian, thanks for another great video. Do you have a link to the USB lead "voltage and current detector" that you used on the watch? I have plenty of "charge doctors" that are on the "large " end of the USB cable, but often it could be more convenient if the display was on the "micro" end, like the one you used.
Polymer electolytic capacitors like those on that buck-boost converter board generally have very low leakage current.
I'd love to see a video testing the accuracy of some of your led voltage meters. I have one with 5 total decimals, but I don't have anything to compare it to.
I'd like to check that too. I bought two and they were very closely matched - that gave me confidence that they are accurate. But best to check.
I have mine connected up to a DC-DC Buck/Boost, with a linear 10 turn potentiometer instead of the multi-turn trim pot that was on there. It is really nice to have all the digits for that, but I have no idea how close it is.
This is actually pretty awesome.
Cheaper than doing it myself, almost the same curiosity scratch.
For the voltage standard, the recommended battery when I bought it was a 10F20 15V. It fits and works.
I have had one of the "smart" watches for a few years. It works great connecting to my mobile phone but the battery is crap.
I think that the battery is a 15 volt one, not easily found. I made one up from 5 x 2032 lithium coin cells joined together with 1 mm neodymium magnets, as in your idea, in a cardboard tube . I put a spring in between two of the cells to give spring-loading onto the calibrator's battery terminals.
Nice bit of improvisation!
Thanks for the complement, Julian I do enjoy your offerings and this is the first time that I have bought a featured item before you did!
I had done a similar thing with my old analogue Avo multi-meter, loading the original battery case with alkaline button cells. This worked out very cheaply using the card of 30 assorted cells from a pound shop.
The lithium cells were from the same source, the resulting battery much cheaper than Maplin's extortionate price. I made the tube from several layers of quality note-paper wrapped round a piece of dowel, soaking the resulting tube in polyurethane varnish for rigidity.
Re using magnets as battery contacts, I got some with a countersunk hole through the middle and used countersunk screws and nuts to attach the wire as soldering the magnets will take them beyond their curie point.
I have one of those somewhere, not exactly sure where right off. The battery life was less then one day, so I never really used it at all.
20:20 that's the sony ericsson you've got a message tone
Id imagine the extra pins on the super cap are anchoring pins to help secure its large size to the PCB. they are normally just left electrically floating
Maybe the extra pins on the cap are for PCB mounting...?
you can't solder to these, they completely lose their magneticity (?) at solderung temps :)
Actually no, you need ~300°C for soldering and 600+°C to change iron alloys in their crystaline structure to demagnetize it. Not sure if a high neodymium percentage will change it or not though. It's worth a try.
Krisztián Szirtes definitly worth a try, but i remember when i was a kid i thoght i was smart by using a neodynium magnet to fix the flopping baking sheet in the oven to the tray, when making a pizza. I the magnet lost all of its power and was not magnetic at all in the end. The oven was turned to 180°C
I soldered two Cables to two Magnets for doing exactly what Julian does. I sanded the Magnets a bit on one side and soldering was realy easy.
The curie temperature for neodymium magnets tops out at 200C for the high temp ones.
According to Wikipedia the action of demagnetization is basically the heat overwhelming the natural tendency of the electron alignment, nothing to do with the structure.
Though if it doesn't re-magnetize as it cools it should still readily be re-magnetized
+muh1h1 Well I didn't say it doesn't happen at lower temp, but soldering won't take 90 minutes which a pizza does :D
surely those extra cap legs are just for mechanical mounting strength. the voltages you were seeing were just stray charge on the DVM leads - didn't you notice when you lifted of the probe the final time the meter continued to show the same small falling voltage?
For connecting battery leads to the magnet have you thought about spot welding? in fact super caps could be very handy for making a miniature spot welder!
you can select at top of purchase list select date and click on 2016 and it will bring up everything. pain i know but i too have to do it as i forget what iv purchased. one thing that annoys me is buying resistors and the sellers not marking values on them!
Great vid. I found that if you copper plate a small portion of the magnets the solder and wires stick together very well. I use them to charge batteries. Thanks again for the vids. They are very informative.
+Arthur Schroeder Brilliant idea 💡
Thanks Julian, Just be real quick on the heat or it will ruin the magnet properties.
I soldered to magnets it just has to be super quick,those leads are for mounting on pcb
the 2.5 measured 2.49942V. the comma is just a 1/1000 separator
The Avo8 multimeter uses a 15V rectangular battery. An option with them is to use your cylindrical battery in a holder to make it rectangular. The cylindrical one is just a stack of common AG10 alkaline button cells and you can make one up very cheaply using sticky tape and cheap cells.
Hey Julian, I know it isn't what you're looking for but I just now remembered that I do know of one LTC3780 with a fully digital front end.
It's a power bank by the model QD188-ALT it's from the same guys that made your white 5-13v power bank.
Julian, a man after my own heart. I go on these mad shopping sprees and scratch my head when the packet arrives. Also, on your three meters, remember the old aphorism, "A man with one watch knows what time it is. A man with two watches is never quite sure".
I would say that those extra capacitor pins are just for structural stability.
I think the commas on the cal certificate are just thousand separators, so the meaning of the numbers after them should now be clear.
The magnets won't affect the workings of the super cap?
+Julian Ilet I have just got myself one of those voltage references. Now here's a remarkable coincidence: the calibration certificate that came with mine is EXACTLY the same as yours; i.e. with the four voltages to five decimal places being identical to yours. All the more remarkable considering that one of the capacitor leads had not been soldered, causing erratic behaviour...
I have also got one with exactly the same calibration values... Seems as if the just print out a note, without making any actual measurements
Me too. Mine just arrived today and I recognized the numbers on the so-called calibration sheet. EXACT COPY, a photocopy I think, of the sheet held by our hero Julian. Luckily we have a Cal Lab at my workplace, so I'll check it out there. Pure comedy...
The extra pins on the supercapacitor can be left floating, usually it's for mechanical purpose and your DMM is probably just being silly from parasitic capacitance with a minuscule charge.
I wondered if they were just for mech stabilization, given the size of the cap.
@7:08 get the kkmoon precision reference module instead. it comes with a rechargeable battery and a nice laser cut acrylic case and banana jacks, and a nice user interface. it's a really nice voltage reference for cheap.
it's on ebay and also on amazon: www.amazon.com/Precision-Voltage-Reference-AD584kH-4-Channel/dp/B00Z033Y6Y/
I doubt soldering to neodymium magnets wold work, the curie point is fairly low and almost certainly below a reasonable soldering temperature. The nickel coating (so they don't corrode) won't take solder very well either.
Welding like for lithium battery tabs might work though.
For those in the US, an ebay-offered $4.50 GC 8271 alignment tool is a less expensive alternative to the Bourns H90 or H91 which are $10 and up including shipping, except for a 10-pack from Hong Kong for $20.
smart watch look nice, think u, its good to buy it? how long battery?
I've got one of those watches. You don't need to use the app if all you want to do is use a few functions...and make and receive calls through your wrist! I haven't downloaded the app for the mentioned security risk, but I have paired the watch with my phone.
Julian,
The LTC3780 10A units, could two be used in parallel to up the current capability to about 16A? I would add more heatsink area to be safe.
I'm sure I've seen that exact watch available at petrol stations here in the UK.
Julian, Where is you GREAT swiss army knife?
Don't believe the 'cal data' piece of paper that comes with the precision voltage reference. I got one and the figures are all identical to yours! What are the chances of that happening? :)
Give the magnets a recommendation if they last will you?
I got the same voltage reference and our sheets are the same numbers I dunno if I believe them as being the true tested numbers. I guess I should test it out on my 6.5 digit bench meter and see what the real numbers are. I bought the reference 3 months ago, but never messed with it.
Here's what I got. 30 min warmup both. 27.1C, input V 15.00437, so here the voltages from calibrated Rigol 6.5 digit Bench DMM with probe master probes.. 10.00334, 7.50373/7.50374, 5.00169, 2.50155
What about digital pots and an Arduino sketch for that DC-DC converter?
I nearly bought a digital pot module just recently.
What stopped you? ;)
The thought of running up the Arduino IDE which is becoming a bit of a bloaty mess.
Julian Ilett Haha, yeah that would be quite frustrating...
Atom + PlatformIO or just PlatformIO IDE
Do you have a good meter? you might want to try a fluke.
i didnt find anything for that screwdriver for the pots on ebay. can you please provide a link or a different keyword? thank you!
I love your flashlight ,is that something I can buy ,also I bought. That watch at Amazon,for 29.00$ a year ago,everyone sells it 9.00 or less like you got it for ,thanks for the web site too
out of curiosity.. why do you have three of the same multimeters?
They were cheap - couldn't resist :)
Hah. Nice :D suppose its a good reason. And quality is ok? Except the numbers seem to throw a bit
So you must have a low resistance? Use one of your DVM's to check it!!
I never have the patience to wait to open parcells :p
I had to look it up... looks like those meters are RP4020s, which has the BEST DC accuracy of +/- 0.8%/3 counts. That is within 1 year of calibration and a tight temperature range... These meters are quite in-tolerance. :)
The joy of living vicariously, new knife? Get a bowie like Dave Jones... Good video.
Yes those 500F are similar to the ones I got and are just useless they have about the same or less than the Vina Tech that I sent to you and rated 220F (this are high quality made in Korea)
The GreenCaps are completely useless there are huge variation in capacitance between them also internal resistance and they have a huge leakage they can lose 70 to 80% of the initial stored capacity in 24h.
To play with just one is fine since even if all are with huge variations between them using just one will not be important.
At initial charge it seems they took a lot more energy and they got a bit hot wen if charged at realy low rate. That was a bit strange.
And those extra terminals are common for large capacitors just for mechanical support.
can you make a video testing the capacitor's capacity?
I want that charging icon to be my friend and go on adventures with it.
Julian, feel the weight of that supercap. Now imagine it flapping about in some product, secured to the PCB with just two solder connections... I'll wager those two extra connectors are purely mechanical, to anchor the cap more tightly to the PCB.
the 2.5 didn't measure 2.499 it measured 2.49967.
the comma is simply splitting the number.
just like we write 1,000,001 for whole numbers, folk will write 0.100,000,01 with decimal places.
The comma is quite normally included in non-English speaking countries.
Ah! That would make sense!! Cheers!
the clue was in the item description, "each board tested with a 6-digit Agilent meter"
not much point in that if you only write down 4 of them
These 500 F caps look similar to the real "powerstore XV" series but sadly a lot of the "greencaps" are low capacity and have a fairly high leakage, and ESR. The extra connections on the REAL powerstor are open circuit (not used)
M.
the meter kept changing when you took it off the cap terminals, they are structural and probably not even connected to each other :p
Neodymium Magnets lose all their magnetism far below soldering temeperatures. You could try spot welding them though, because that wouldnt heat up the entire magnet.
Voltages on your reference are 6 digit, so 2.49942v, 5.00037v and so on
your meter is 0.02v out, 20mV, probably well in specs of the meter
The 500F cap on ebay has only two pins.
Julian, could you check if your LTC3780 module goes to 10 A? Mine didn't, I was hoping to use it for bench power supply.
Most of the listings suggest 'strengthening the heat dissipation' if you're going to use it at the maximum rated current.
Mine didn't even go over 3A when it started to limiting the current. So it didn't even get hot. Searching on the internet showed some other people had that problem also. Just wondering if yours too.
It's probably just a rip-off copy chip which has a much lower current capability anyways.
Probably yeah. Still haven't found a module for my bench supply.
I have a trimpot twiddler that once was my uncle's. It says "Adobe - Here's a REAL tool for your network." It's one of the most useful tools I have.
For the tests of the super capacitor it'll be easier if you get a clamp or two and use melamine (or mdf) to put even pressure on the card holder. Magnets idea looks like to much wasted time. If it works you can tut card holders shallower then use melamine/mdf + 2 metal brackets held with bolts.
Nice work as usual Julian thanks for another great video. :)
Remove the commas from the voltages listed on the calibration sheet, it'll make more sense.
Oh yeah, I get it now :)
hi! i love your vids, but how does a crystal actually work? and what is the difference between the different chips on an aduino
That "500F" cap would have an energy density of ~ 36 million Joules / cubic meter! (for dia=33mm & len=60mm). About 600 million J/kg (600Mj/kg). ...typical for supercaps?
I soldered wire to a neodymium magnet once and not longer had magnets
a question to the ltc3780 board: would it be possible to replace the potentiometers with with digital potentiometers, add an arduino and some currentsensors to make a step up down mppt solar charger?
Yeah - it sounds so easy ;). But how do you control the input voltage - the panel voltage. That's the bit I don't get.
if the 3780 is in CC mode and the max.constant Currrent get reduced, that would reduce the drain and increase the panel voltage or am i wrong?
So Ryobi sponsored you with some DMMs? This video exactly shows what kind of quality they are...
No, I bought them when the TEK4 series was being discontinued in the UK.
They're pretty good for what they are, certainly better than my $20 Equus multimeter.
I brought the exact same Voltage reference module a few months back. Interestingly, my sino meter same model number as yours is 10 years old and also was only 1 count out, better than my Extech EX330. My UNI-T 210E clamp meter was spot on however.
I purchased it to confirm my other voltage reference was accurate, so I now have a AD584K and AD584L. The latter being more accurate. Pretty cool cheap device for testing my multimeters.
Oh btw, don't trust that little piece of paper; mine is identical the date, results, etc.
That's cheeky, sending the same test results out with every unit!
+Julian Ilett yep, I just compared to make sure again. Only difference is the title is indented slightly differently, mine is more centred, yours is a tad to the left of centre.
The other unit I have with AD584K has the results handwritten and having tested with a calibrated bench meter does appear to have been tested properly.
Haha, Julian I'm quite enjoy watching you open packages, and I am now realized why many people still think MADE IN CHINA is crap. Yes, I have admit that things sold on eBay ARE crap, and they are made in China. However, they are barely seen on Taobao (where we, Chinese people, usually do online shopping) or they were listed at price around 1/5 of the price on eBay which clearly tells me they are crap.
I just ordered some usb-led lights and arduino parts on eBay, looking for ward to open the package. It will take 3-4 weeks shipping form China to Australia, but if I purchase them on Taobao, price+shipping even higher than eBay price :(
BTW, I have found an usb-led light that has optical and sound sensor on it, looks awsome
I never expected smartwatches to become so cheap so rapidly. Maybe if the app can be restricted communication it might actually be a fun thing to try.
Probably not even close to 500F... Maybe it's time to build a nice Farad-meter???
hey sir
can you please make a video where you show us how to use super capacitors
how to charge them and how to use them in projects
My supercapacitor powered bluetooth speaker project will cover most of that :)
before even watching: YAY a new Postbag
AND..... it was enjoyable :)
Personally I think you should do a video on alice11011983, who are they?
A single individual? a front to a large electronics warehouse? where do they get all their stuff for sale?
+jeales895 Who pays for my trip to China?
+Julian Ilett pitch it to the bbc. Call it "99p with free shipping"
if you look at the location, they're in shenzhen, which is a huge area that has tons of marketplaces for electronics and whatnot. i believe you can even find videos on the "shenzhen market" - they have huge sprawling marketplaces with everything you could ever want in electronics. it could very well be just one person or a few people who buy in bulk from other factories. i imagine getting ahold of various electronics in shenzhen is very easy and dirt cheap.
+kekejojo1212 thanks for your reply. Really interesting stuff
The battery used on those voltage reference modules is a dual 9V battery (2 in series), look here: www.ebay.com/itm/AD584-4-Channel-2-5v-7-5v-5v-10v-High-Precision-Voltage-Reference-Module-/181863456673 -- don't know where to get them though.
If you heat magnets up, like soldering to them they will loose their magnetic "charge" (don't know the word in english)
Why 3 multimeters?
They are Ryobi. If he had a Fluke, you would only need 1.
Maybe he needs to measure two different voltages and a current at the same time... you are new here?
I have dozens of those yellow sinometers. When I forget where I put my multimeter, I'll just grab a new one from the box.
I meant why 3 same multimeters, I also have 3 or 4 multimeters, but why 3 same ones, Julian?
Those big solder tabs on super capacitors are a swine to solder, watched someone use two soldering irons on one just to get enough heat in. Still wasn't perfect soldering.
Also RIP smart watch. Anyone managed to re-purpose the touch LCD screen ?
why 3 of the same meters?
They were being sold off cheap. I thought they'd be useful for my solar power videos.
Fair enough, deals have got to be had
On digikey 5000 qty of AD584 are selling for $10.49 USD. How can they sell this module for $5.62 USD? Is this a real AD584 or is it recycled?
Digikey marks their price up significantly. Actual price from the mfg is much lower, within spitting range of that $3 board.
However, these are either "recycled" I.e, pulled, or counterfeit. Pulled is obviously much preferable to counterfeit. At best, they might be NOS
Well if it's recycled then it could be real, right? Even then, it might be a real chip but one which was rejected during QA testing in the manufacturing but nod badly enough so it went to the other garbage bin which goes to the other factory. Or it would be a brand new chinese "equivalent" copy. Or in the worst case a recycled chinese copy. Best case scenario? Someone stole a truckload of real chips somewhere and is reselling them for cheap. No way to know really.
some state they are recycled parts, I bought one on a whim and am very impressed, the test data with mine agrees with my calibrated Fluke and Keithley 2002 in work (+/- 5 counts!) needs to be powered up for 15/20 mins to stabilise and was using a lab power supply. ps if buying them you want the K variant chip (high accuracy)
It's obviously a Chinese knock-off of the AD584. They do copy chips and usually they are way out of (AD) spec.
I don't know if it has been mentioned, I apologize it I am repeating someone else's post.
Julian, the Ryobi TEK4 instruction manual gives the following information concerning guaranteed accuracy of the meter.
DC Voltage: 4 V, 40 V, & 400 V ranges.
±(0.8% of reading +3 least significant digits)
For a ten volt input, that means...
±(0.8% X 10 + 0.03)
±(0.08 + 0.03)
±0.11
10.00 - 0.11 = 9.89 volts lower limit.
10.00 + 0.11 = 10.11 volts upper limit.
A reading of 9.94 volts is well within tolerance.
If you returned it to the factory they might send it right back with a message, "Found within tolerance, no adjustment required."
It might be interesting to many of your followers go over how to read the specifications on their measuring and test equipment.
Julian with one multimeter knows what voltage it is.... Julian with 3 multimeters is never quite sure :)
You can increase the voltage rating of your super caps if you place them in series. It will, however decrease the capacitance. You can significantly increase the amount of energy by increasing the voltage (E=CV^2). So with 2 500 farad super caps in series you could get 250 farads of capacitance at 5 volts for a total of 3,125 joules! Now imagine what sort of experiments you can do with that kind of energy.
Lol and just as I thought, all these people 'calibrating' their B6 chargers so that they won't overcharge their Lithium batts.. 4.20 Volt exactly it must be. Right ...
I've also ordered that AD ref board, 2 Flukes show a different voltage and the Uni-T is also different. With that board lets see what is correct.
Julian I would definitely check the Voltage on the 18650 batt itself. I've seen some loses on cables, connectors and surely that magnet thing is not something that you want to use to quickly (1 Amp and up) your cells with. So even if the charger says for example 4.08 Volts it might be lower on the batt side.
If you or someone out there could remove the pot's and control the output with an Arduino it would make all sorts of projects pretty straight forward ie MPPT charge controller
You should be able to access eBay purchase history going back 3 years by clicking on "Purchase History" header on the MyeBay page.
I can access the history, but in many instances the seller is no longer selling the item.
I'm always wary of installing "PRC" software, I have an old, wiped, HTC phone I use for the purpose. Just wish I had a network analyzer to see everything PRC firmware does. LOL
Julian Thank You
Install the mediatek app, instead of the one with the qr code
I threw caution to the wind, and installed the Mediatek app on my tablet - but I can't make the two devices connect.
+Julian Ilett what problem are you having? any errors popping up?
I think the smart watch/phone app story is nonsense... encryption doesn't prevent you from seeing where the data goes, so the IP address should be know.
The story is also here: www.theregister.co.uk/2016/03/02/chinese_backdoor_found_in_ebays_popular_cheap_smart_watch/
I would also think it should be reasonable to assume that firmware and apps exist for the device that is clean without the risk of security issues. I know some people are toying with the idea of getting it to run other operating systems.