hybridfree/eevblog-posts huggingface dataset:
Prof. PAUL CHRISTENSEN Electric Vehicle Battery Fires  - Page 1
Forum section: electronics / general

author: coppice
author_rank: Super Contributor
timestamp: January 18, 2024, 03:24:53 pm
content: Also

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 18, 2024, 08:34:02 pm
content: And unfortunately people are busy bolting this stuff onto the walls of there homes in the guise of PV storage systems

author: nctnico
author_rank: Super Contributor
timestamp: January 18, 2024, 08:55:26 pm
content: Quote from: fourtytwo42 on January 18, 2024, 08:34:02 pmIt makes me wonder whether I want a battery in my home indeed. As part of an ongoing project to have a bigger mains feed to my shed, I'm also going to add an extra pipe through which I can pull control / network wiring so an electricity storage system can sit in the shed if I want.

author: coppice
author_rank: Super Contributor
timestamp: January 18, 2024, 09:40:17 pm
content: Quote from: nctnico on January 18, 2024, 08:55:26 pmThe home battery problem they are talking about is the reuse of old car lithium ion batteries. Custom made home battery systems use LFP batteries, because they aren't concerned about maximum lightness or density. LFP batteries are a lot less susceptible to nasty failure modes, although the lithium batteries which caused fires on the Boeing 787 were reported to be LFP batteries from Yuasa. If those reports were accurate then not al LFP batteries are benign. Its hard to know what to made of the information available.

author: nctnico
author_rank: Super Contributor
timestamp: January 18, 2024, 11:35:46 pm
content: One way or another, any battery is a device which can store a massive amount of energy. This energy can be released without the ability to shut it off. So if you can place such a device in a seperate building instead of inside your home / living space, it will be safer.
Help Please: Inverter Ground Fault solar system. - Page 1
Forum section: electronics / general

author: Solarnewbie
author_rank: Newbie
timestamp: January 12, 2024, 06:16:56 am
content: I'm looking for some help please. I am a newbie to solar and have just installed my first solar system in a shed. However, my problem is the inverter (Renogy 2000W 12V Pure Sine Wave Inverter) says open ground fault.The inverter has a ground terminal and the recommended gauge for grounding is 12gauge. This 12gauge wire goes to a busbar and from the busbar to an earth ground rod. Now, in the manual there is nothing really helpful for in off grid system that's not a vehicle. One paragraph says, at no point should the chassis ground and the neutral conductor of the inverter be bonded. However, this is for a shed so I'm trying to figure out how to get this issue fixed.The inverter has an AC terminal block that I use to plug-in my AC load directly for LED lights and two receptacles (hardwire permanently connected). All of those are connected to a junction box (14gauge wire) and a pigtail to the inverter terminal block (live, neutral, ground). Interesting enough the lights and receptacle actually work but an open ground fault can be dangerous. The inverter has the open ground fault even without the AC terminal block being used. I'm sure I'm doing something wrong here. The system has two 12v batteries in parallel.Any suggestions would be greatly appreciated.Some things I've tried:1. Neutral and inverter ground terminal to ground rod busbar = receptacle comes out correct, inverter turns to hot and neutral reversed.2. Neutral to busbar with inverter ground terminal removed from busbar = AC receptacle correct, inverter hot and negative reverse.3. Nothing connected to the grounding rod busbar = open ground for both the AC receptacle and the inverter AC output plugs.4. Inverter ground to busbar only = inverter corrected, AC receptacle open ground.5. Negative and inverter ground busbar to ground busbar = open ground on both.6. Negative to ground busbar with inverter ground removed from busbar = open ground for both7. Neutral and negative busbar connected to grounding rod busbar = GF gets tripped.

author: fourtytwo42
author_rank: Super Contributor
timestamp: January 13, 2024, 08:01:55 pm
content: PM sent
Thyristor used as "comparator with reference" in short cct protection? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: January 06, 2024, 10:39:26 pm
content: Hi,Our client is using the P102AA thyristor to give short circuit protection in their AC mains circuit.Its a trailing edge phase cutting heater regulator.(The phase cutting is simply done with the switching of the back-to-back NFETs.)As you can imagine, short cct protection involves promptly turning off these NFETs.The thyristor, is simply used as a "comparator", with its VGT voltage (0.8V) as the reference.There is a sense resistor in the mains neutral, and this sense voltage is fed to the thyristor's Gate-cathode terminal.If a short cct current occurs, the thyristor breaks over and pulls current through an opto which results in a comparatorgetting tripped and turning off the back2back NFETs.Advantage is that its obviously an AC power circuit, and the thyristor can trip whether the current is going one way or t'otherin the sense resistor.As can be seen from fig13 of the datasheet, the VT of the thyristor can be anywhere from 0.8V to 1.4V from 25degC to 125degC.Indeed, from batch to batch, this can be different. As such, would you agree, this method of protection issimply unwise?..The poor , back2back SiHG70N60 NFETs will simply not be tripped in a timely fashion when a short cct occurs...and they will explode.Would you agree, what is in fact needed is to use back2back IGBTs instead, and simply use a proper window comparator with +/-supplies to detect overcurrent in the sense resistor. (obviously its AC mains current in the sense resistor, hence the window comparator with +/- supplies.)P102AA thyristor datasheethttps://www.farnell.com/datasheets/2308722.pdfSiHG70N60 FEThttps://www.vishay.com/docs/91598/sihg70n60ef.pdf
Charging EV goes zoom-zoom sputnik - Page 1
Forum section: electronics / general

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: January 05, 2024, 05:48:21 pm
content: OK I found this in my youtube feed. This thread might degenerate into politics, but I thought the EEV blog crowd might be amused to see a Chinese BEV launch into space.On second viewing the initial car explosion may have been staged/fake. Can't tell. Some folks around the corner appear to anticipate and are filming with their phones, Or it could be car battery pack was giving warning signs like hissing evolved gas. It doesn't look like a conventional movie set.
LTC7803?  No connect Vin pin? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: January 02, 2024, 07:25:48 am
content: Hi,We wish to use LTC7803 buck controllerWe will feed it 12v into EXTVCC.Does this mean we can No-connect Vin?Datasheet doesnt sayDuring test, tech may hot plug and with LC filter, vin may go above 35V, which is >ABS MAX....so we'd rather just not connect it...or just put a 1k/100n there to slug any ringing.LTC7803https://www.analog.com/media/en/technical-documentation/data-sheets/ltc7803.pdf

author: tggzzz
author_rank: Super Contributor
timestamp: January 02, 2024, 12:50:05 pm
content: Before bothering to respond, be aware of the OP's reputation. Have a look at his other first posts, and see the responses.These are typical:https://www.eevblog.com/forum/chat/a-new-type-of-electronics-degree-course/msg5250390/#msg5250390https://www.eevblog.com/forum/manufacture/prototype-board-with-16msop/msg5238015/#msg5238015https://www.eevblog.com/forum/renewable-energy/sync-buck-driver-has-problem/msg5238129/#msg5238129https://www.eevblog.com/forum/manufacture/test-enamel-insulation-on-torroid-inductor/msg5232909/#msg5232909
AD2700UD Output Voltage Error - Page 1
Forum section: electronics / general

author: squizzel
author_rank: Newbie
timestamp: January 10, 2024, 04:36:38 pm
content: Hi All,Long time lurker here with a question that is currently stumping me and my team. We're a component test house that was tasked to test output voltage error across a specified temperature range. The datasheet that we have is either crystal clear and we're just special, or it's a bit vague.Device: AD2700UDTemperature Drift: 3ppm/°CTmin - Tmax: -55°C - 125°CTest Temperature Range: -30° - 70°CWe decided to calculate the limits at -30°C and 70°C based on the 3ppm/°C and nominal voltage (10V). We then added the error at 25°C: +/- 2.5mV. Does this make sense?https://www.analog.com/media/en/technical-documentation/data-sheets/AD2700_2701_2702.pdf
Charging protected 18650 cells - Page 1
Forum section: electronics / general

author: mojoe
author_rank: Frequent Contributor
timestamp: December 29, 2023, 07:28:18 am
content: Perhaps a dumb question, but if I have three protected 18650 cells in series, is it OK to charge them all together with one of these:https://www.amazon.com/dp/B0C5GQYNL1/Since each cell already has a protection/BMS circuit internally, I would think that this should be OK. I know that if I had unprotected cells, I should use a separate BMS module that is wired to each cell.I already have the protected cells that I bought for another project, but didn't use.

author: Siwastaja
author_rank: Super Contributor
timestamp: December 29, 2023, 10:19:38 am
content: Quote from: mojoe on December 29, 2023, 07:28:18 amI would not trust that. The high voltage cutoff limit is larger than normally, because these "protected" cells are meant to be charged using a voltage-limiting charger. The primary function of the protection is the low-voltage cutoff. High-voltage cutoff is just an extra safety feature. You'd end up overcharging the cells.

author: Peabody
author_rank: Super Contributor
timestamp: December 29, 2023, 03:48:27 pm
content: I don't see anything on those modules that provides any charging intelligence. One chip appears to be a boost converter, and the other a mosfet. What provides the CC/CV algorithm, and what terminates charging?Anyway, what you clearly don't get is any balancing. I guess opinions differ on whether balancing is important.I think if each cell is protected, you don't need anything more. But of course you will shut down when any cell experiences any protection event. If you were doing 3P, I think you would definitely want to use unprotected cells, with protection provided on the board

author: mojoe
author_rank: Frequent Contributor
timestamp: January 01, 2024, 02:26:40 am
content: How about some suggestions for charging three series connected, protected cells? I have a nice external charger, but I don't want to remove the cells for charging. Something that I can buy online is preferred.
Sync Buck driver has problem? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: December 23, 2023, 11:17:59 pm
content: Hi,Was just about to use the MIC4102 sync buck driver when i read on page 18 that it shouldnt be used when a series gate resistor is used with the low side fet.But thats very bad, because that resistor is needed to slow up the gate.Why do they say this?I mean, i know its because of the adaptive ST protection...but there's no point in using the chip with thisMIC4102 page 18https://ww1.microchip.com/downloads/en/DeviceDoc/20005575A.pdfThen found the LM5106...this has nice dead time setting resistor...however, when the sync fets are re-enabled, one would have to drive the down pulse with the EN pin for a while, so that the output wasnt discharged through the lo side sync fet...since as you know, the first pulse of a restart, should always be from the hi side...but the LM5106 has no "automatic" way of ensuring this, meaning that the above described jiggery pokery is needed...and all the auxiliary cctry that goes with it.I dont think a realistically designed sync buck driver IC actually exists.Also, page 11 of the LM5106 datasheet says that any undervoltage on the bootstrap capacitor will disable only the hi side drive....this is deffo NOT wanted for a sync Buck driver....which this chip proclaims to be.

author: f4eru
author_rank: Super Contributor
timestamp: December 24, 2023, 07:49:37 am
content: Quote from: Faringdon on December 23, 2023, 11:17:59 pmAsk Santa to bring you a DC/DC driver chip.

author: georges80
author_rank: Frequent Contributor
timestamp: December 24, 2023, 11:49:00 pm
content: Clearly the folk that design IC's must be complete idiots - maybe they need treez/blah to set them straightLooking forward to 2024 and the gems that will be posted by our esteemed block of wood.cheers,george.

author: langwadt
author_rank: Super Contributor
timestamp: December 27, 2023, 12:58:29 am
content: Quote from: georges80 on December 24, 2023, 11:49:00 pmyeh, young players like Microchip and TI are clearly no match for his wealth of knowledge and experience
Looking for bidirectional AC 230V/DC 48v inverter for battery storage  - Page 1
Forum section: electronics / general

author: Miyuki
author_rank: Frequent Contributor
timestamp: December 13, 2023, 12:27:06 pm
content: Hi folks, not sure if this is the right forum.I'm looking for a bidirectional inverter/charger for a 48V battery system with a desired power of about 5kWIt should be able to charge and discharge at this rate.Charge rate is important to be able to buy electricity at low prices.I was thinking about the Victron Multiplus series but they have charging mode at about 70% of the power delivered and are somewhat on the expensive side.Another interesting alternative is the Mean Well BIC-2200 series, it has a little more power in charging mode than in inverter mode and costs similar to the Victron but seems to me to be easier to control over can busIs there any cheaper alternative to do such in a controlled way?If the inverters alone will be really cheap but allow full power control I can have a separate charger as this is the cheap and simple part, where I can live with easy ON/OFF control.

author: dmills
author_rank: Super Contributor
timestamp: December 23, 2023, 02:46:38 am
content: I have been eyeballing the Victron stuff, for I suspect, much the same sort of application (Familiar with them from the marine scene).Not that the Multiplus II is 5kVA but only 4kW in inverter mode, so it might be that the real power in both directions is broadly similar (3.3kW on charge as I make it).Not sure how much luck you will have with much cheaper things of decent reliability especially if compliance with G98 or such matters to your intended use (Even if you are not planning to export anything, if it is sourcing current in parallel to the grid it probably needs to be.

author: dmills
author_rank: Super Contributor
timestamp: December 23, 2023, 02:44:00 pm
content: Just to note that the Meanwell needs external hardware to really make the anti islanding thing work, and that that will be safety critical (and certifiable) doings.I would be very tempted to get an old 48V server rack/telecom supply maybe some Flatpack II or similar for beefing up the charging side, loads of current and widely available on the surplus market, and leave the inverter/grid bit to something designed and certified for the purpose.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 25, 2023, 12:50:40 am
content: If you only want to supply the load and not export to the grid, consider a used UPS that uses a 48V battery (some rackmount units do) and figuring out how to get it to switch to batteries on command, could be as simple as software.

author: johansen
author_rank: Super Contributor
timestamp: December 25, 2023, 01:01:10 am
content: Build your own.An 8010 board off eBay and the biggest toroidal transformer you can afford, wound for a low copper loss balanced against your needs.Numerous threads on fieldlines and thebackshed.
Electronics setup for wind turbine - Page 1
Forum section: electronics / general

author: fish654321789
author_rank: Newbie
timestamp: December 19, 2023, 05:10:48 am
content: Hello, I have a wind turbine project but I have a problem.I will use a 24v AC generator rated at around 5kw max output.I want to use the electricity in my home or put it back into the grid and for that i need 220/230v AC power.I can't find any 24v AC to 220/230v AC transformers.The current option I'm looking at is converting 24v AC to 24v DC and then convert 24v DC to 220/230v AC.The problem with this is that I firstly can't find any 24v AC to 24v DC converters and secondly this solution is presenting a lot of energy loss.What would your solution be?

author: Halcyon
author_rank: Unknown
timestamp: December 19, 2023, 06:30:02 am
content: Duplication of two other threads.
LED driver flashes when on Trailing edge dimmer - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: January 09, 2024, 08:10:39 pm
content: Hi,Have you ever seen one of these type of LED drivers (CL8800) turning on/off at period of some 1 second when on trailing edge dimming and only slightly dimmed.....ie, just the last little bit of the mains cycle "chipped off".They are OK when on non dimmed mains, and they are ok when trailing edge dimmed up to some 70% of max, and they are ok when leading edge dimmed.CL8800https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/UserGuides/CL8800-230-VAC-Offline-LED-Driver-Evaluation-Board-User-Guide-DS50002764A.pdf

author: jonpaul
author_rank: Super Contributor
timestamp: January 10, 2024, 12:58:32 am
content: typical triac phase control dimmer "kerosene lamp wick" effect.j
AFDD - Arc Fault for dc Solar MGs - Page 1
Forum section: electronics / general

author: robint
author_rank: Regular Contributor
timestamp: December 10, 2023, 05:46:16 pm
content: hi GuysThe latest Amd 2 of the 18th IET Regs has the hots for AFDDs. Sure we all know how these work dont we? A little Arduino Nano filters the the ac current for signs of high freq arc noise (naturally the Big Corps want to keep it all secret - but we can know all about RCD workings and their problems with dc levels saturation and spike damage - which is why they have a test button)Draw you own conclusions on this expensive addon £60-80 for your rack.But I am here to address the Solar dc needs. We can maybe assume that the AFDD doesnt work on dc (indeed to work at all it needs ca 180mA load obviously?). The ever helpful Trade Press noted it cant protect on faulty ring circuits so leccies are in no fear of being replaced by this AFDD AIPay attention at the back- It seems to me that Solar panels are prone to arc faults from wiring, connectors, heavy bird impact, cellular shorts et al. So this might show it self as noise current. If one used one of those small current transformers and listened via an amp to the circuit might on hear the characteristic squishing noise of an incipient arc? Would the Inverter input noise drown it out?Just a thought guys, I havent got the means to look myself, perhaps someone else might.Who knows this might be a useful audible warning . Im not suggesting this becomes an automatic disconnect device - thats another level of potential nuisance.Anyone care to help?Robin
LM5021: Soft start pin - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: December 07, 2023, 06:50:06 am
content: If i have LM5021 fed by a startup resistor...which obviously cant sustain it...but i also diode-in a 12V bias.....to sustain it...then if i switch off the 12v bias, then does the soft start capacitor get discharged, and stay discharged?https://www.ti.com/lit/ds/symlink/lm5021.pdfdatasheet doesnt say.

author: Gyro
author_rank: Super Contributor
timestamp: December 07, 2023, 09:19:39 am
content: Quote from: Faringdon on December 07, 2023, 06:50:06 amI'm not surprised it doesn't say!

author: Kean
author_rank: Unknown
timestamp: December 07, 2023, 03:20:13 pm
content: The functional block diagram in the datasheet shows an internal discharge FET on SS pin driven by VCC_UVLO, so it will depend on whether VCC reliably drops below the threshold after you switch off the 12V bias. Mind you, if the startup resistor is still there, even if VCC initially drops and triggers UVLO, surely VIN and VCC will rise again enough to try restart.If this is important to your design, rather than asking here you really should be asking an actual TI FAE. And/or maybe test it for yourself.

author: floobydust
author_rank: Super Contributor
timestamp: December 07, 2023, 09:16:39 pm
content: Pulling power to the IC is not a good idea for your unknown extra feature you are trying to create.The SS discharge mosfet needs power... so the VCC fall time is expected to be reasonable and give it a chance to do the job. I would expect the gate-drive mosfet needs the same... or it will blow the main mosfet...OP cross-posted here:https://www.edaboard.com/threads/shutdown-and-then-soft-start-for-lm5021.409223
150A Art No.:FT08 high-precision watt meter and power analyzer ? - Page 1
Forum section: electronics / general

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: November 30, 2023, 05:48:06 pm
content: I bought a couple of these a couple - ? yrs. ago and used for checking mostly solar , battery etc.Just wanted to see ohters question the limited claims --- and then the lack of info .The 1st one [ seems to me the most likely failure ] the claim to test 150 amp - maybe 10ga wires , do not want to test what seems like it would kill these units , maybe some else - just wanted to play with " magic smoke "With what is labled on the box & user sheet in box - no mention of AC volts - maybe newbes do not read more into Chinese maunals - or the lack of ?There are mentions of batteries in the user sheet - implying DC --- but no direct mention I would expect from english manuals ?

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: November 30, 2023, 07:05:53 pm
content: Should have provided a link the 1st time , I do not like to do a search on a item being talked about - harder to reply when guessing what the item is ;(https://www.ebay.com/itm/363879107542
RUBIDIUM PSCILLATOR or SCHEMATICS WANTED - Page 1
Forum section: electronics / general

author: Magman
author_rank: Newbie
timestamp: November 30, 2023, 03:20:32 am
content: I am looking for a Varian model 49-538A RUBIDIUM OSCILLATOR (WORKING or NOT for parts) AND/OR A SCHEMATIC of it. What is unique about this one IT IS NOT DISCIPLINED.Don (Magman)

author: Magman
author_rank: Newbie
timestamp: November 30, 2023, 03:27:40 am
content: My first post and I screwed it UP...OSCILLATOR not P whateverDon

author: KE5FX
author_rank: Super Contributor
timestamp: November 30, 2023, 04:50:16 am
content: Interesting piece of hardware! Some Googling suggests that one was used in aquantum magnetometer(an experimental one, at that) back in the mid-1960s. That might explain why it doesn't have a traditional lock-in loop.I don't see any references to the model number inBill Riley'sbook, but he does cite anearly-60s Varian patentfor a device that looks a lot like it. This patent does describe a complete Rb frequency standard. No schematics, unfortunately.

author: Magman
author_rank: Newbie
timestamp: November 30, 2023, 05:32:51 am
content: Thanks KE5FX.These were used by Varian to make an Automatic Standard Magnetic Observatory(ASMO).
Where to buy a few new Panasonic 18650 batteries? - Page 1
Forum section: electronics / general

author: duckduck
author_rank: Frequent Contributor
timestamp: November 16, 2023, 01:29:49 am
content: Digikey doesn't sell them, neither does Mouser. I don't trust Amazon, ebay, or Aliexpress based on what they've got for sale. Anybody got a place (or a known good seller on Amazon/ebay/Aliexpress) they order from to get legit Japanese 18650s? Thank you.

author: PeteH
author_rank: Unknown
timestamp: November 16, 2023, 02:35:21 am
content: How many do you need to buy? Cost sensitive?New?

author: duckduck
author_rank: Frequent Contributor
timestamp: November 16, 2023, 05:42:08 pm
content: Under a dozen. Not cost sensitive. New.EDIT:Someone on my ham radio group recommendedhttps://www.imrbatteries.com/panasonic-18650-batteries/I'll give that a shot. Thanks.

author: Magman
author_rank: Newbie
timestamp: November 30, 2023, 02:38:21 am
content: WISH.COM has quite a selection. Don't know how good they are???
Parallel path resistor contamination for large value resistors (~1MEG and up)  - Page 1
Forum section: electronics / general

author: Jim from Chicago
author_rank: Regular Contributor
timestamp: November 28, 2023, 08:21:53 pm
content: Some colleagues of mine were saying to avoid using large value resistors whenever possible (~1MEG and up) because contaminants (e.g. dust in a humid environment) over years can create a parallel path resistance that is low enough to significantly lower the total resistance. My question is, is it possible to have a rule of thumb for what the value of this parallel "R_contaminant" is worst-case? For example, if I have an 0603 resistor is it reasonable that contaminants could form a parallel 10MEG path across it? Or is that way too low a value that would ever be seen?I realize it's a difficult question to answer because it depends on the environment and application. Nonetheless if you've dealt with this issue before I'd be interested in any thoughts.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 28, 2023, 08:59:06 pm
content: So far the parasitic leakage on the board I encountered was more in the 10-500 Gohm range - at leat with a reasonable clean board. It may get a lot worse with mold growing and than high humitity.With modern PCBs the solder mask helps quite a bit by keeping the contamination away, though appications that want super low leakage (e.g. Tohm target) may not want the solder mask.Another really bad case was with some of the old style glue (AFAIK some neoprene type) that over time changes from white / yellow to brown and becomes conductive. There I once got some 100 K.Resistor of more than 1 Meg usually have a relatively large TC and often not so great stabilty on there own. So it is not just dirt and board leakage. The better / thin film types often max out at 1 M.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: November 29, 2023, 02:39:18 pm
content: Use a conformal coating to protect the board from leakage.

author: tszaboo
author_rank: Super Contributor
timestamp: November 29, 2023, 03:01:48 pm
content: Quote from: Kleinstein on November 28, 2023, 08:59:06 pmI've found "no clean flux" together with a small amount of water, due to condensation, completely wreck my measurements, in the tens of KOhm range. The sensible solution is to keep the electronics away from condensation of course, and say no to "no clean flux".

author: Kleinstein
author_rank: Super Contributor
timestamp: November 29, 2023, 04:45:15 pm
content: No clean flux is mainly a problem when not fully heated. It than can be a little hygroscopic and even corrosive. This can be an issue especially for small parts flowing off to the sides when using a iron.
Where does this symbol come from - Page 1
Forum section: electronics / general

author: robint
author_rank: Regular Contributor
timestamp: November 25, 2023, 03:06:01 am
content: Hi guys, I have been rooting around for an hour or more trying to find the authentication of this commonly observed symbol for what I guess we would take to bedc supplywithout the text of courseI havent found it in IEC standards or CAD symbol library etcBear with me here as IMHO it has important implications - particularly in the field of electrical protective devices. You find this symbol slipped into the markings on fuses and switchgear often from the PRC. This crops up in device offered for sale for use with Solar systems and associated batteries, inverters, switchgear, fuse protection.Without text this symbol on a drg might imply a screened cable - for example.Anyone know of an official source for this symbol used for dc supplies? BTW the official IEC symbol is=BTW as a corollary to the above, you are surely aware of the widespread use of a fake CE markinghttps://www.pat-testing-training.net/articles/ce-mark.phpThis has shown to be a particular problem in electrical gear from the PRC eg mobile chargers and dangerous outdoor lighting fixtures (metal case 3 wire, but earth not connected, not IP65) a fatality occurred in a pub beer garden.) and so on.The EU CE mark in a self certified joke dont trust itFake CE means "China Export"

author: IanB
author_rank: Super Contributor
timestamp: November 25, 2023, 03:34:50 am
content: You don't need to authenticate it. It is the symbol used everywhere and universally for DC, on all devices, from all sources, since the beginning of time.

author: ejeffrey
author_rank: Super Contributor
timestamp: November 25, 2023, 03:46:21 am
content: https://www.iso.org/obp/ui#iec:grs:60417:5031

author: robint
author_rank: Regular Contributor
timestamp: November 25, 2023, 04:08:38 am
content: Now that is the spirit and supports the ethics of a competent designer - the devil is in the detail.Standard :IEC 60417 — Graphical Symbols for Use on EquipmentThanx 10^6For a reward here is a source of amusement. What do you make of thishttps://vi.aliexpress.com/item/1005006186701661.html?spm=a2g0o.productlist.main.9.74b65fb1xuLjAm&algo_pvid=7dec7003-85fd-4ef7-856f-8f7a02e34fa3&aem_p4p_detail=202311240551391041740414718370008757971&algo_exp_id=7dec7003-85fd-4ef7-856f-8f7a02e34fa3-4&pdp_npi=4%40dis%21GBP%2134.68%2134.68%21%21%2142.19%21%21%4021038e8317008338988114753e3bae%2112000036184949658%21sea%21UK%21929926363%21&curPageLogUid=z2Pg4YDEidSI&search_p4p_id=202311240551391041740414718370008757971_1
Wolfspeed Speedval Firmware and GUI - Page 1
Forum section: electronics / general

author: BNElecEng
author_rank: Regular Contributor
timestamp: December 01, 2023, 12:54:43 pm
content: Afternoon all. I'm having a little trouble getting a response out of Wolfspeed after buying their Speedval evaluation kit.They advertise that firmware for the TI and NXP controllers is available, along with a GUI. Unfortunately when you make the request on their website, they aren't interested in requests that come from public email domains such as Gmail. I tried their official forums as well and had no response.Has anyone else had a similar experience? Even better yet, does anyone have a copy of the firmware and GUI they'd be willing to share?Cheers
Way to search for synchronous FETs with low trr? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: November 21, 2023, 02:00:59 pm
content: Hi,Doing Synchronous Flyback for 48V to 24V, 48W, at 150kHz. Transformer is 1:1.Need to find synchronous FET with low trr, however, digikey etc don’t sort FETs on their diode’s trr.Do you know how to get round this?…..ive found that DFN style SMD FETs seem to have lower trr than DPAK or TO220 etc, but is there any other giveaway forlow trr?I mean, Infineon seem to be the kings of sync fets, btu they are v expensive, eg IPT044N15N5 is £6https://www.mouser.co.uk/datasheet/2/196/Infineon_IPT044N15N5_DataSheet_v02_02_EN-3362749.pdfFDD120AN15A0 i cheaper at £0.71 but you only get to these after 30mins of searching or so for each fet.FDD120AN15A0https://www.digikey.co.uk/en/products/detail/onsemi/FDD120AN15A0/978480(Also, its best if CGD is low, and CGD/CISS <0.02 preferably)One way round it is to put a UF diode in parallel...it will likely have higher vf than the internal diode, but will still pinch some of the current, so that the internal diode carrys less, and thus has a lower trr effectively....but woudl rather be able to seek the low trr fets directly if poss.
Tesla open-sources Roadster - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 22, 2023, 11:06:53 pm
content: https://x.com/elonmusk/status/1727392569238159491?s=20https://service.tesla.com/roadsterEven includes some component-level schematics & PCB files!
Two tran forward SMPS..Synch rects cross conduction - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: November 21, 2023, 07:54:17 am
content: Hi,As we know, when a Two Tran Forward uses synch rects, during heavy load, they actually feature significant time when both sec side synch rect FETs are on simultaneously...this is OK because the leakage inductance prevents shoot through currents...of course, its a disaster if this happens in light load.......so why are no synch rect controllers out there offering a shutdown pin so the user can sense load current and shut off the synch rects in light load?
Bi-Directional DC Relay Contactor and Auxilkiary contact failure - Page 1
Forum section: electronics / general

author: wjmuss10
author_rank: Newbie
timestamp: November 08, 2023, 02:19:46 am
content: Looking for help figuring out why my Normally Open Aux contact will randomly not close even when my DC coil is energized and the contactor closes.Checking continuity with my volt meter and the Aux seems to not work. I can verify with the actual studs that the contractor is closed. Sometimes I can power down the battery BMS system and reset and the Aux contract starts working correctly.Coil input voltage is 24VDC,Using Altran AES500

author: uer166
author_rank: Super Contributor
timestamp: November 08, 2023, 03:35:15 am
content: Wetting current issue maybe? How much current does your meter inject when you test it?

author: uer166
author_rank: Super Contributor
timestamp: November 08, 2023, 03:36:47 am
content: "Aux contact current min.: 100mA at 8V". Well there it is!

author: f4eru
author_rank: Super Contributor
timestamp: November 08, 2023, 09:26:09 pm
content: Yep. Clearly the contacts have a very thin oxide layer, appear to make contact, but in fact do not until you break down the tarnish layer with the 8V.
Replacement Enphase Microinverter firware 25% more efficient? How ?  - Page 1
Forum section: electronics / general

author: DougSpindler
author_rank: Super Contributor
timestamp: December 29, 2023, 05:15:59 pm
content: My solar system was installed about 4 years ago. I began noticing one of the Enphase micro-inverters every 10-20 days was producing 95% less than the day before and the others in the array. Called Enphase, (excellent customer service), and they sent out a replacement. Installed the replacement and noticed it's now outputting 25% more? HOW CAN THAT BE?Called Enphase and was told it is fairly common for replacement micro-inverters to have newer experimental firmware that will produce more. When asked if I could get the firmware in all of the other micro-inverters upgraded I was told now.Details of the install.I'm in NA where it's winter and less sun hours right now.All panels in the array are same make/model/wattage and installed at the same time.Replacement microinverter is same make/model but this one has newer firmware. IQ-7+How is it this microinverter's firmware produces 25% more?Why wouldn't Enphase roll this firmware out to everyone?Heck, that would be like increasing the size of my solar system by 25%.What's going on?

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 30, 2023, 01:25:56 pm
content: Better MPPT algorithm.

author: bdunham7
author_rank: Super Contributor
timestamp: December 30, 2023, 04:33:33 pm
content: If those are full-day numbers for your panels, then you have low total insolation at this time, as do many installations in the winter. What they've likely done is somehow improved the MPPT and/or efficiency at very low power levels, trying to glean a few more watts from the twilight. 25% does seem like a lot, but these changes likely won't affect performance at higher insolation levels and thus won't change the overall (annual) output very much. Still, something is better than nothing.

author: ejeffrey
author_rank: Super Contributor
timestamp: January 01, 2024, 03:04:19 am
content: The MPPT algorithm seems likely, but is there a chance you cleaned the panel either before or after the replacement?

author: DougSpindler
author_rank: Super Contributor
timestamp: January 01, 2024, 07:52:57 am
content: Nope no cleaning. No way I could clean on panel in the middle of an array without cleaning the others.
My monitor's power supply creates spikes on the outlet, will it burn my house? - Page 1
Forum section: electronics / general

author: sblantipodi
author_rank: Newbie
timestamp: November 22, 2023, 09:13:47 am
content: Guys I'm a little worried about my monitor's power supply.I have an Acer X32FP, before I got one that met my accuracy requirements I tried several units and they all had the same problemWhat you see in this screenshot is my home automation system recording the loads on the electrical outlet.On that electrical outlet there is only the monitor's power supply now and nothing else.The power supply is also disconnected from the monitor.How is it possible that several times in an hour it has an absorption of around 80W if it has no peripherals connected?This happens even if the monitor is connected but turned off.Do you think I should worry?

author: jonpaul
author_rank: Super Contributor
timestamp: November 23, 2023, 09:57:29 pm
content: normal as monitor periodically checks for video activity and SMPS kicks on for a fraction of a second.Your UPS power monitor is not accurate enough.j

author: sblantipodi
author_rank: Newbie
timestamp: November 23, 2023, 10:42:34 pm
content: The problem I described happen alsoWhen the monitor is disconnected from the power supply.So no, it's not the monitor that causes it...

author: jonpaul
author_rank: Super Contributor
timestamp: November 24, 2023, 07:59:47 am
content: PSU has wake up periodically to check if any load is connected.SearchPower Supply Monitor Watchdog Timersj
bms with Li-ion - Page 1
Forum section: electronics / general

author: LLee
author_rank: Newbie
timestamp: October 29, 2023, 10:56:24 am
content: Hello I got 2 Li-ion batteries, I want to use them but someone told me to have a bms. So I got a bms (picture below). Now I don't understand how this will work 100%.So my plan is to connect my batteries with this bms like the picture below but also at the same time connect it with my circuit (for leds). Is this possible, and are my batteries protected against charging eachother while they provide power to my circuit?I just want to be safe and its the first time working with bms...Thanks in advance!

author: Faringdon
author_rank: Super Contributor
timestamp: October 29, 2023, 12:24:43 pm
content: Proper BMS seems overkill for low power LED...why not just sense voltage of each cell, and stop the charging when either cell goes overvoltage?AND...stop the discharging when either cell goes undervoltage.That is a kind of BMS though, i suppose.You could put in active cell voltage balancing, so you can squeeze the most power in and out of the cells...but it seems overkill for your application.

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 29, 2023, 01:09:31 pm
content: That's a charger board, not a BMS. The most basic of BMS boards are quite cheap and will monitor each cell individually.Probably the most sensible option would be a 1S configuration with the two cells in parallel. You can find combined charger/BMS boards for those, you can identify them as they'll have separate connections for the battery and load.
Reasonable resistance values between LFP cells - Page 1
Forum section: electronics / general

author: rteodor
author_rank: Frequent Contributor
timestamp: October 17, 2023, 07:05:07 pm
content: Asking because I have measuredbetween 1 and 3 mOhmin between 280Ah cells. With 16 cells and possibly > 100A it may be too high.A while ago I found some forum post stating 0.5 to 0.6 mOhm but I am not sure if it included the cell internal resistance or not.The connectors are some Aluminium of some sort, thin and wide.This is what I tried: scrub the connector on both sides and that lowered the resistance to0.8mOhm.Applied NoAlox on the upper side where there is an inox (A2 marked material) o-ring and the resistance dropped further to0.45mOhm.I did not want to damage the cells terminals by scrubbing them or by applying NoAlox on the bottom so I stopped at this point.Now I am asking more experienced people if I should continue and scrub the cell terminal too (also Aluminium) and/or apply NoAlox on the bottom side too ? I do not want to repeat this process every few years.And what are your measured/typical/reasonable resistance values?
NEDAP PR50SB-BS SolarRouter power inverter problem - Page 1
Forum section: electronics / general

author: Mikaelin
author_rank: Contributor
timestamp: October 16, 2023, 10:39:37 am
content: Hello,I have a 5KW solar router power inverter NEDAP PR50SB-BS that works only under low loads. For example, in a normal sunny day, I can watch TV powered by this power router with no problem. The power from the solar pannels converted to AC by this power router is feeding my TV (local out) and the over production power is fed in the public grid line. But if I try to start a microwave owen or 1KW heater, the power router is clicking (the relay is switching house power from solar to the grid, that is normal) butthe problem is- it never switches back to local out power when I unplug all energy consumers, it stays every time grid connected. It is trying to switch to local out power without succes in a loop, endless clicking. The only way to make it work again from solar is to perform a reboot from the built-in control panel.I don't understand why it behaves like that. Nothing changed in the configuration. Before all was OK, if the sum of consumed power is greater than the solar production power, then the router is taking current from the grid and switching back to the solar power when the consumed energy is less than solar production power (this is normal operation).On the front panel there is a LED error that never triggers. So is no error reported. When it tries to switch back to solar energy, the LED Operational is steady ON and the Grid LED is blincking.The power router is without battery and was configured by a certified technician a few years ago and all worked fine in this mode. I was happy.I can't contact the manufacturer because NEDAP is closed since 2016 and the 5 years warranty is expired.Please help with an advice if you have an idea what the problem could be.The link to the manual ishere.Thank you
Cheap 3 phase 115VAC generator - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: October 14, 2023, 10:00:30 am
content: Hi,We need a cheap, quick, rough and ready, pure sine, 3 phase, 115VAC generator for just 10W or so, do you know the quickest way?

author: jonpaul
author_rank: Super Contributor
timestamp: October 14, 2023, 02:25:43 pm
content: https://en.wikipedia.org/wiki/Motor%E2%80%93generatorInput as desired>>motor>>shaft>>small 3 phase synchronous genj

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 16, 2023, 02:21:02 am
content: Audio amplifier and a pair of transformers wired in "open delta" configuration.
Is lasting damage to Li-ion coin cells poss w/ short exposure to freezing temp? - Page 1
Forum section: electronics / general

author: yrmzzi
author_rank: Newbie
timestamp: October 31, 2023, 09:44:01 pm
content: I have many lithium coin cell batteries like Sony CR2450, Energizer CR2430, Duracell CR2, Saft LS14250 in my stock.I sell battery kits for various scuba diving computers and this fall I will be going on a road trip to Pennsylvania and will be camping some nights where the night time temps will dip below 0 Degrees Celsius (32°F) during the night and back up to 10 Degrees Celsius (50°F) during the day.I understand its best practice to store lithium coin cell batteries at around room temperature but will exposing these batteries over several days to -4°C to 0°C (25°F to 32°F) night time temps for a few hours each day cause any lasting damage for when they are eventually used??The batteries will not be used during the time that they are in this cold environment. I will be storing these batteries in an air tight insulated container but this only retains so much heat.All the spec sheets for these batteries show -30°C to 60°C ( -22°F to 140°F) as the Recommended Operating Temperature.Will being exposed for a short time over a few days to below freezing temps cause lasting damage, or am I being paranoid?Thanks,Jon

author: Siwastaja
author_rank: Super Contributor
timestamp: November 01, 2023, 08:05:35 am
content: Note, your title says li-ion cells but images show primary lithium (metal) non-rechargeable cells. Totally different thing.Anyway, as far as I know, there is no damage mechanism on lithium (or lithium-ion, or NiMH, or NiCd, or alkaline, or nearly any other battery chemistry) cells even at temperatures as low as -30degC (counterexample: lead acid (car battery) can freeze already at -20degC if not fully charged; but it would be destroyed by sulfation anyway if left uncharged).Quite the opposite, the colder it is, the slower self-degradation gets, increasing shelf life. Although lithium metal cells have very low degradation rate to begin with so there is not much to gain.Of course, in extreme cases (think about -50degC where the batteries are not tested at) there might be some weird non-chemistry related stuff like differences in thermal expansion of different materials used in the cell, brittleness of some seals or something like that, I don't know.
Full bridge gate drive transformer - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: October 11, 2023, 06:48:19 am
content: Hi,The attached LTspice and jpeg, is the best way to drive full bridge fets....there is no spurious oncoming, since the top and bottom fets are fed with opposite polarity gate outputs...it doesnt even produce spurious oncoming when "suddenly OFF'd", as you can see in the LTspice.Why do not more people and App Notes recommend this way?.the problem is trying to find gate drive transformers for this. We need 1:1:1 and Lpri >200uH, and Lleak <400nH. And 500vrms isolation.....and >40V.us.Nothing exists offtheshelf like this.And the small formers and core sets to wind one ourselves are not available either....Do you know where we can source?

author: Simon
author_rank: Unknown
timestamp: October 13, 2023, 02:54:11 pm
content: Perhaps you should formulate the actual question, this makes no sense.
RVing - 24v - 12v ? - Page 1
Forum section: electronics / general

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: October 11, 2023, 03:39:25 pm
content: Because of RVing [ many items are 12v ] I like the idea of 24v [ even 48v ] solar / battery system .The issue is that most RV's [ mine is an 1985 ] are equipped for 12v .So looking to see what is happening on converting higher voltage to lower ?The " Have Your Cake & eat it too "Concerned with loss's - keeping to a min. ?I am saving up to upgrade my battery , inverter system , I have a mix of Uni-Solar 24v [ these are high quality flexable ] - maybe 700 watts & about 200 watts in 12v .Can not afford to replace solar panels --- even though I would like to use glass / aluminum frame panels [ to elevate off roof a few inches for cooling / side affect of shade ] .
Best way to operate LTC3901 synchronous rectifier driver? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: October 08, 2023, 06:43:44 pm
content: Hi,Do you agree, the modification shown attached, (in dotted line) by way of the output current monitor, which disables the synchronous rectifiers in light load, is the best way to operate the LTC3901 synchronous rectifier driver. Otherwise, there are high overvoltages on the synch FETs in light load.LTspice and jpeg attached.LTC3901https://www.analog.com/en/products/ltc3901.htmlLTC3723https://www.analog.com/en/products/ltc3723.html
QLD Megapack battery fire and link to a power statistics website - Page 1
Forum section: electronics / general

author: chrisb741
author_rank: Regular Contributor
timestamp: September 28, 2023, 10:36:05 am
content: Hi,Dave just posted a YT video about the fire at the qld megapack battery siteHe said something about statistical data and has anyone got access to stuffYoutube keeps removing my comments trying to post the link to a good site about Australia's power supply and demand along with a bunch of other stuff and statisticshttps://opennem.org.au/You can even view the facility in questionhttps://opennem.org.au/facility/au/NEM/BBATTERY/?range=3d&interval=30m