Could i have some pointers on refining my diy bike light? - Page 1
Forum section: electronics / projects

author: Ehaze
author_rank: Contributor
timestamp: November 08, 2021, 01:08:29 am
content: I have started a project to make a trail light for my bike .The light pod is a 2000 lumen 20v 2 led pod that is meant to run on 12v car system draws about 1.3 amps .I used a car wiring harness with a 5a fuse and 40a relay .Its powered for now by scavenged 18650s i plan on 6 to 12 connected via battery holders .Its going to go inside bottle in the bottle cage holder .My goals for the build is to get 4 to 6 hours of use and learn about building and powering lights so i can build more . Also to come in well under 100 bucks for the actual finished product !some questions i have have are :1 : I have searched for different batteries from ebike kits to battery water bottles , so im wondering if just getting mid range 18650s at around 4 bucks a cell is the best option , or should i get a pre-made pack.2: Im not looking to have a plug in charger , i have a 4 bay charger and i think that is fine for now ( this will be version 1.0 anyway ) I dont want to spot weld the cells yet and battery holders will work the same ? So im wondering what kind and if i need some sort of BMS or PCB , or any other board to keep the cells safe and balanced .Im pretty new to electrical so i only have bits and pieces of info i get from videos . The light is just on and off for now , no low or high settings but maybe once i learn how i can add that .3: Im wondering about how to combine the cells in series, and I think you need at least 3 cells in series to equal 12-ish volts th light needs to turn on ? If I am using 8 should i make one group of 4 parallel and add 2 parallel groups of 2 in a series . If im using nine its 3 parallel groups of 3 in series ? And what is the best combo for 12.I appreciate the input thanks

author: Ehaze
author_rank: Contributor
timestamp: November 08, 2021, 04:03:15 am
content: this is what i built last weekhttps://imgur.com/a/VaRLBQNthe idea was to mostly scavenge cells , i used my old battery banks this is my first draft , the idea was from a youtube video . Im just wondering if i just buy a board to protect the cells , and what kind of board will work best . Im using a 4 bay wall charger with a full display to charge the cells , and the battery holders so i dont have to hard weld the cells together . It will all go in a water bottle , or maybe the next one will go in a waterproof saddle bag .

author: bob91343
author_rank: Super Contributor
timestamp: November 08, 2021, 04:08:02 am
content: Maybe you are already doing this, although I saw no hint of it. Instead of on/off switching, why not pulse the lamps? You can get a duty cycle of perhaps 30% without sacrificing visibility too much. The increase in battery utilization would be great. The flicker could be a problem but you can play with frequency to change its visual characteristic.

author: AaronD
author_rank: Frequent Contributor
timestamp: November 08, 2021, 04:28:27 am
content: In addition to what @evb149 said, DO NOT BUY THE CHEAPEST BATTERIES YOU CAN FIND!!!They might claim to have built-in protection circuitry, when they don't. So if you naively believe the claim, you could end up making an incendiary bomb by accident. Lithium cells that are directly intended for hobbyists by reputable sources will usually have a protection circuit on each cell, which makes the cell a little bit bigger. Cells that are intended to go into someone else's manufacturing process usually don't, which makes them cheaper, and the manufacturer that buys them is expected to provide that protection. (Dell laptops and Samsung phones, for example) If you take the cells out of a manufactured product, then you'll probably leave the protection circuitry behind...Then we have AliExpress, Wish.com, eBay sellers with inflated ratings, etc., who don't have a clue what they're selling but they can give you an awesome discount on...whatever this glob of matter is.(I gave up on eBay when someone argued with me and insisted that I abort the claims process regarding their advertised 4AWG jumper cables that actually measured 8AWG, or about half the diameter of copper conductor. Their primary argument? The *packaging* said 4AWG! I continued the process all the way through, and eBay sided with me. Nevertheless, I'm hesitant to go there now, because of the products that I'm *not* an expert in, and so I could easily fall victim to something like that.)And there is of course, a motivation to inflate the claimed capacity of a "discount" battery. This is not as much of problem as not being protected, provided that you DO HAVE THAT PROTECTION against overcharge (high voltage) and deep discharge (low voltage), but you're probably going to be annoyed when your "1000Ah" cell only gives you 600mAh. There's a limit to how much chemistry can fit in a given size. Physics still works, regardless of who writes the marketing crap or puts the sticker on.

author: Kasper
author_rank: Frequent Contributor
timestamp: November 08, 2021, 05:07:09 am
content: Quote from: Ehaze on November 08, 2021, 04:03:15 amWhy not get 5V LEDs and use the battery banks without taking them apart?Either way, another thing to be careful with is heat, particularly when you put it in an enclosure.

author: Ehaze
author_rank: Contributor
timestamp: November 09, 2021, 01:45:02 am
content: im trying to use scavenged cells for now .

author: Ehaze
author_rank: Contributor
timestamp: November 09, 2021, 01:46:12 am
content: my light is 2000 lumens 12v draws 1 amp!

author: Ehaze
author_rank: Contributor
timestamp: November 10, 2021, 08:00:29 am
content: Do i need a voltage display and some kinds of protection board , if im running 18650 cells in battery holders , and i plan to charge them on a wall charger? Can i just run the cells raw to the light with on a 5a fuse and a 1.5 a switch , and just run them to they loose power and be safe . I have read i might need some sort of protection board that cuts power before the cells run too low , I got about an hour on 4 cells wired in series , so i plan on 3 sets parallel then in series .The only other thing is they will be scavenged from electronics not being used ?

author: Kasper
author_rank: Frequent Contributor
timestamp: November 10, 2021, 04:24:46 pm
content: You should be measuring temperature and voltage when they are being used, even if you're not charging them.Many chargers will not charge if the voltage is too low.Are you putting batteries and light in the same enclosure? Have you measured the temperature in the enclosure? What is the max temperature of your batteries?If you aren't familiar with them, look up videos of e-cig explosions.

author: AaronD
author_rank: Frequent Contributor
timestamp: November 10, 2021, 04:33:45 pm
content: DO NOT EVER DEEPLY DISCHARGE A LITHIUM CELL!!!!!!!!Not even by accident.Below a certain voltage, it starts forming "whiskers" or "stalactites" inside that can short the cell. The worst case is when the first one almost gets to that point but isn't quite there yet. It's possible then, to charge it up to a decent voltage, which then arcs through that almost-connection. Once the arc starts, it becomes a dead short, and now you're dumping the entire stored energy of the cell at once. Instant fire that cannot be put out because the chemistry contains its own oxidizer.Thus, every useful battery management circuit includes a low-voltage cutoff, and every good charger will refuse to add energy to an extinct cell. Of course, you can make your own stuff to circumvent those safety policies, but if you do, it's only a matter of time until it spontaneously sprays burning liquid all over everything.Older chemistries that you might be used to, specifically Nickel-Cadmium (NiCd) or Nickel-Metal-Hydride (NiMH, which is only a minor change from NiCd and so behaves similarly while solving some of the problems), don't self-destruct when they run out, and in fact, NiCd has a "memory effect" that requires a deep discharge to reset. (that's one of the primary problems that NiMH was made to solve) So you might be confusing multiple different chemistries that each have different requirements.

author: Zero999
author_rank: Super Contributor
timestamp: November 12, 2021, 09:59:43 pm
content: The electronics for a bike light are easy. A simple battery charger IC, connected to a decent lithium ion battery. A cheap 8-bit MCU for functions such as flashing, dimming, low battery indication etc. The LEDs could be driven by a linear (op-amp, voltage reference and MOSFET), or a switched mode power supply (IC & suitable inductor). I'd rather use the latter, because it gives extra battery life, without increasing the size weight so much, even though it's a bit more complicated and expensive.What's more difficult is developing a design which is resistant to vibration, water ingress and doesn't fall off, even when riding over a big pothole. This also affects the design of the electronics: pay attention to flexing of the PCB, which can destroy ceramic capacitors and provide plenty of strain relief for the internal wiring, which also needs to be well-secured to prevent it from working loose.

author: AaronD
author_rank: Frequent Contributor
timestamp: November 12, 2021, 11:12:51 pm
content: Quote from: Zero999 on November 12, 2021, 09:59:43 pmThat looks to me like a very good start. Make absolutely sure that the charger IC will not break the battery (FIRE HAZARD!), including both overcharge and extinction. (and balancing for a multi-cell pack*) And then make sure that you also include a low-voltage cutoff. (would you rather be in the dark now or on fire later?)(*Lithium doesn't self-balance like other chemistries do, so you could eventually end up with one cell almost full and another almost empty at the same time, and a correspondingly small safe-capacity that might not be evident depending on how you measure it, thus making it easy to violate and cause a fire.)Possibly include both the low-voltage and a thermal cutoff in the MCU code if you go that route. It might seem odd to do such a safety-critical thing in software, but it's really pretty reliable. Just be careful that you ALWAYS scan the safety-critical logic regardless of what else is going on. Some programming styles do that automatically, so it'd be good to learn one of those if you haven't already, and use it.If you're concerned with random errors, that certainly is possible, but a *huge* saving grace in a continuous real-time system like this, is that you're *constantly* scanning this logic, over and over and over again. So each reading and its answer are only valid for one scan time, and a single error hardly means anything. Also, get an MCU that has a watchdog timer in it, and use it. That'll reset it automatically if the "clear watchdog" instruction hasn't been executed recently, which can be used to enforce a "non-blocking" code style (that instruction should only appear once, at the top of the main loop) in addition to being a safety net in case the chip goes completely nuts.If you did it in the MCU, it would take 2 ADC channels, a P-channel mosfet to power the *entire* circuit (the P-FET goes right next to the battery connector, before any regulation even), an NPN transistor so that the MCU can "reach" the mosfet's voltage to control it, and a handful of resistors.Essentially, one resistor is used to pull the P-FET's gate close to the source, which turns it off (source to the battery +, drain to the rest of the circuit +), then the NPN pulls the gate to ground to turn it on. Another resistor connects the NPN's base to the MCU for control. A momentary button bypasses the P-FET to get things going, and the MCU turns on the FET "quickly enough" once it gets to the normal logic part of the program. No special "quick-start", and in fact the initialization code should have it turned OFF so that the ONLY thing that turns it on is the normal test of everything being okay.Maybe even include a capacitor in series with the button, so that it's only capable of momentary operation. That is, you can't defeat the MCU's cutoff code by holding the button down. (again, would you rather be in the dark now or on fire later?)Or instead of the P-FET, you could use a relay, with the usual caveats that those come with (flyback diode, etc.), but it would require a bit more power to keep the coil energized than to keep a FET turned on.---Once you have the protection sorted out, THEN you can think about what it should actually do. Lithium batteries are nasty in raw form (if you don't know for sure, then you need to assume that what you're working with *is* raw), butonce you have all the protection present and working, it practically becomes one of the *safest* chemistries to work with.PWM'ing the LED's is essentially a switching power supply already, so that's that problem solved (inductor optional), and most MCU's have built-in PWM generators. A dedicated switcher just for the MCU probably isn't worth the effort nor would it be all that efficient anyway, compared to a linear regulator.Then just think of what functions you want to have, what software in the MCU would be required to create those functions, what inputs (probably additional buttons) you need to trigger that software, etc.---Quote from: Zero999 on November 12, 2021, 09:59:43 pmYES!! All this talk about electronics, butdon't forget the mechanics as well!The best circuit in the world doesn't work so well when a capacitor breaks off, or a wire pulls loose, or it gets mud on the circuit board, etc.Also consider physical damage to the battery! That can make it blow up regardless of any protection circuitry or logic, as the problem is entirely within the battery itself.

author: Ehaze
author_rank: Contributor
timestamp: November 12, 2021, 11:14:17 pm
content: The light pod is mounted to the front of my bike and the batter and switch are in a water bottlehttps://imgur.com/a/FxkIZPA

author: Ehaze
author_rank: Contributor
timestamp: November 12, 2021, 11:19:48 pm
content: thats a good reply , right bow i just plan on removing the cells and charging them on an external wall charger to bypass the more complicated stuff, i think the simple on off will do for now , but along the way i can reference this post and work out what to buy . I plan on adding in a low voltage protection board , and padding the packs and internals with old amazon packaging .this is what i have so farhttps://imgur.com/a/FxkIZPA

author: Ehaze
author_rank: Contributor
timestamp: November 12, 2021, 11:26:39 pm
content: I understand , i plan on charging the cells on an external charger for now , so I think i wont have to worry about forcing charge into a damaged cells ?The wall charger has a display that tells me voltage and capacity of each cell , its one of those 4 bay slow chargers . So i think that will keep me safe , but let me know if its not enough .I also ordered some 12v low voltage boards to wire in .https://www.amazon.com/gp/product/B07QNXM4LS/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1From what i have been reading that should be enough until i want to make a more traditional pack thats spot welded and relies on a plug in charger ?

author: AaronD
author_rank: Frequent Contributor
timestamp: November 12, 2021, 11:51:17 pm
content: If the external charger *shows* you the condition of each cell, then I would hope that it also *uses* that information. Which means that it would also balance them. And presumably, it's also good enough to not add energy to an extinct cell. If all of that is indeed true (You're betting a fire on your answer to that, so how sure are you really?), then you only have the discharge side left to worry about.---Those low-voltage-cutoff boards claim to do what you need, but again, it comes down to how well you trust them to not start a fire. Amazon isn't exactly known to be a guaranteed-reputable supplier, with reviews for lots of different products ranging from "It's perfect!" to "They quietly swapped parts for one that doesn't work! I ordered two of the same thing at different times and they were different. The pictures still show the first one that worked." The worst case is one that appears correct, works in testing, and then fails later. Again, you're betting a fire on your answer to that, so how sure are you really?(Also, with the present shortage of silicon electronics in general, the pressure to counterfeit has gone up. It may look perfect on the outside, and may even function superficially, but it can't take the stress of its intended use. Budget and "general public" suppliers and module-builders are generally more susceptible to using and/or selling counterfeit parts, as their quality control tends to be a bit lax...)---And there's still thermal and mechanical protection too. You're at least thinking about mechanical, with the old Amazon packing; that's good. But I haven't seen anything about thermal yet. Above a certain temperature, a Lithium battery will "run away" on its own, effectively shorting itself internally with the obvious result. How do you know, continuously, that that isn't about to happen?

author: Ehaze
author_rank: Contributor
timestamp: November 13, 2021, 12:12:15 am
content: Im really trying to harvest old stuff from around my house , would you have any suggestions on where to harvest a reliable protection board .Also your saying i need to add a thermal cutoff and or look for a board of some kind that can do low voltage protection and or discharge protection , as well as thermal cut off protection ?And maybe switch my charger to one that has a better balancing feature ?

author: AaronD
author_rank: Frequent Contributor
timestamp: November 13, 2021, 02:31:40 am
content: Quote from: Ehaze on November 13, 2021, 12:12:15 amIf you really want to harvest stuff for cheap, I'd advise against using lithium. Nickel- and lead-based batteries don't have the energy or power density that lithium does, but they're SO much better behaved that you don't need any protection at all except for catastrophic discharge. (short circuit)You still want to take care of them, like to not discharge lead-acid all the way to zero, as you can still kill the cell, but at least they don't try to return the favor!Quote from: Ehaze on November 13, 2021, 12:12:15 amYes, or make one. Either way, YOU need to ensure that it works like it's supposed to. Both now, *and* later when it's needed. Anyone can fake a compliance logo...Quote from: Ehaze on November 13, 2021, 12:12:15 amBalancing is really not that complicated. Some might be smarter than others and thus do it more quickly, but if yours does at all, then I would expect the balancing to also be done, with equal results to anything else, when the front panel indicator says "charged".The discharge curve for lithium drops quickly from the charge voltage into a long flat region (so you can't use voltage to measure how much is left - there are "charge counter" IC's specifically for that purpose), and eventually drops off a cliff at the end. The goal of balancing is to end up with each individual cell at the same voltage above the flat region. How that happens is up to the designer, provided that the cells are not overstressed in the process.(Bleed some off if it's getting there too quickly, or use an independent charging circuit for each cell, or just slap a resistor ladder on it and charge slowly, for the more obvious solutions. Like most things, there are at least as many ways to fill the requirements as there are engineers.)

author: Ehaze
author_rank: Contributor
timestamp: November 13, 2021, 05:41:32 am
content: Maybe not cheap , but from salvage stuff , I have a board from a drill battery , and a few boards from single cell battery chargers ? LMK where to buy the thermal boards , or should i program an MCU . On the next pack I plan on it being for road so sooth roads in the summer , and ill come back and build up a more traditional system:)THANKS

author: AaronD
author_rank: Frequent Contributor
timestamp: November 13, 2021, 01:31:56 pm
content: Quote from: Ehaze on November 13, 2021, 05:41:32 amIf you use the drill battery *unchanged*, except for the connector, then you *might* be okay. Be careful though, that there isn't anything important hiding in the connector. Likewise if you disassemble it more to make it fit somewhere. Look carefully to make sure that you keep everything that was hiding in weird places. A thermal probe, for example, might not be on the board, but next to the cells. Or it might be on the board with the assumption that everything's in close enough thermal contact for that to work. If you provide a way for the cells to heat up without heating the board, then that assumption doesn't work anymore.Programming an MCU is a quick and easy way to ensure that all the required logic is indeed present. Of course, it does not guarantee that its inputs are correct or that the outputs have the required effect, or that your logic is even correct! It's not magic.---One tip about measuring temperature: it can be tricky to calibrate in raw form because of the small, non-linear response that most things have, but there are specialty ADC chips just for that purpose. They handle the non-linearity and scaling for you, and give you a number with real units over SPI or I2C. Usually as a fixed-point number with a few fractional bits. Think of it like an integer representation of 1/16th degrees C or something like that, so that room temperature might be reported as ~400, which is 25*16. Read the datasheet to see what it actually does, and make sure you give it the type of probe that it's designed for. (and that the probe is designed for the temperature that you need to watch for)---Then you only need 1 ADC channel in the MCU to read the battery voltage. If you regulate the MCU, then that'll provide a fixed reference for the ADC to use. It then gives you a fraction of that reference as a fixed-point number with all-fractional bits. (a 10-bit ADC gives you 1/1024-ths of full-scale, for example) Then use a resistor divider from the battery to the ADC input. Do the math from there, to figure out what ADC reading corresponds to the correct cutoff voltage.Do some smoothing in software, which effectively converts the noise in the lower bits to more resolution (more fractional bits, so now you're probably working with 1/65536-ths of full scale in a 16-bit "integer" variable) as well as removing weird spikes, then run that through some hysteresis so that the threshold to turn on is higher than the threshold to cut off. The init code then starts the reading at 0, so that it takes some time to climb up to the higher "okay" threshold. Only at that time does it turn the FET on to power itself.For a quick-and-easy smoother:Code:#define SHIFT 2 //adjust this to suitoutput -= (output >> SHIFT);output += ( input >> SHIFT);That's an arithmetically-rearranged version of an exponential average, or a 1st-order IIR lowpass. Exactly the same response as an analog R-C filter. (chain 2 together if you really need 2nd order, etc.) SHIFT determines the cutoff frequency as a fraction of the sample rate. The equation for it is weird; you can derive it if you want, or you can just give yourself a debugging output and tweak it until you like it. Also, you might be able to use the ADC's justification setting to save yourself some shifts. (left-justified is (input >> 0); right-justified for a 10-bit ADC is (input >> 6) for free) The idea here is to run the ADC as fast as it will go at its full resolution, run this code for every sample, and then the code that actually uses it just picks off what it needs when it gets around to it.---If you use a capacitor to limit the time that the "turn-on" button is effective for, it needs to last long enough for the above to happen, and not much longer. More math to figure that out, based on current draw, allowable voltage, and the capacitor equation. Also include a bleeder resistor across the cap so that it has the full capacity the next time it's used. (It starts at 0 voltage across the cap, and the cap charges while powering the circuit. When the cap is fully charged, the circuit is back to 0 volts, so the end point in your calculations needs to be some time before then.)

author: Ehaze
author_rank: Contributor
timestamp: November 16, 2021, 02:28:41 am
content: do you know of any all in one product i could buy , or a web site that sell legit stuff ?

author: Kasper
author_rank: Frequent Contributor
timestamp: November 16, 2021, 02:54:27 am
content: If you want an all in one product, consider battery banks. They usually output 5V but you could convert to 12V with a boost SMPS.

author: Ehaze
author_rank: Contributor
timestamp: November 18, 2021, 12:26:26 am
content: i have a board from a drill battery , and a couple BMS board from battery chargers . I just got an OPTUNE battery pack it should have a nice BMS in it . Im thining of switching the system to just use a 2ah drill battery in a frame bag or custom case , might just be easier and safer .

author: Ehaze
author_rank: Contributor
timestamp: November 20, 2021, 01:08:35 pm
content: I dont know how i would make a usb battery bank work , it would cost more than just buying a pre made battery pack , I would just use the drill battery adapter and carry 3 or 4 2ah packs , down side would having to swap them up and keep track of the drained ones , but maybe much safer than a custom pack . But once i figure out a protection system it should be easy

author: Renate
author_rank: Super Contributor
timestamp: November 22, 2021, 01:24:45 pm
content: You should be sure to implement a "classic compatibility mode". Since for decades we've relied on tiny screw-in bulbs running on little DC generators running off rubber wheels pushing along a bent wheel. This means there should be a limit of 1/2 candlepower and the light should go out entirely every wheel rotation.

author: Ehaze
author_rank: Contributor
timestamp: November 25, 2021, 08:53:18 am
content: not sure what that means but im not using any dyno or generator , just 3p3s lipo cells in holders connected to a 20w 12v led light..

author: Ehaze
author_rank: Contributor
timestamp: November 25, 2021, 08:55:11 am
content: one thing that might be of concern is it is getting cold and my 2 hour trail rides will be in 40 f of below , wondering how dangerous that can be to the system , i know most of the time my phone or garmin will just die , but they use tiny batteries connected to some protection , all i have is a 5amp fuse and and an led light ?

author: Renate
author_rank: Super Contributor
timestamp: November 25, 2021, 10:43:25 am
content: Quote from: Ehaze on November 25, 2021, 08:53:18 amThat was humor. Historically, bike lights have been horrible.

author: Ehaze
author_rank: Contributor
timestamp: November 28, 2021, 04:15:15 pm
content: When i was young we didnt even have lights , just used our eyes , now i can make a light so powerful i have to worry about blowing up ;p

author: Kasper
author_rank: Frequent Contributor
timestamp: November 30, 2021, 05:06:00 pm
content: I found this company on alibaba:General Electronics Battery Cohttp://www.gebattery.com.cn/I've probably made about 5 orders from them, LiPo pouches and packs of 18650s, all of which came with PCM (protection modules). They've been easy to deal with, answered technical questions quickly, and haven't said 'no' yet. They have fulfilled requests for specific LiPo pouch sizes, 18650 pack layout, specific model of higher temperature 18650s and they got UN38.3 certification when requested.I tested the PCM for the 18650s in the hot sun, using a spare car battery and it passed.If you want custom packs, you could try them. If you just want PCM, they might do that too.Could also checkhttps://www.batteryspace.com/,I haven't dealt with them much but their ad sounds nice:"Total solution for Portable Power since 1995.Products are designed , assembled & Quality Controlled in USA. All products are shipped from California"

author: AaronD
author_rank: Frequent Contributor
timestamp: November 30, 2021, 05:36:10 pm
content: Quote from: Kasper on November 30, 2021, 05:06:00 pmAlibaba (or was it Aliexpress? I can never keep them straight) has enough naively-designed-to-a-price chinesium time bombs on it to stay well away from. So anything associated with them carries the same reputation by default. That doesn't mean thateveryonewith that association is necessarily evil, but they do have some extra work to do to make themselves credible.Some more "devil's advocate" points:"Never saying no" could mean that they don't know what they're talking about, or they assume that you don't, or both. You're probably not actually getting what you think you're getting, if they ALWAYS say yes to everything. (ask for the physically impossible, get a "yes" answer, and "something" arrives soon after...)"Getting a certification when asked" could also be fake. Just scan an official logo, slap it on your thing, and claim that it's certified. Easy! If you want paperwork, then that's similarly easy to forge."Testing the one unit that you got" isn't proof that the next one will perform similarly. One data point is never proof of anything. It could be that the entire production run is good, or that could be theoneunit that worked by accident, or anything in between.So, what assurance do they give that their stuff is actually good, and how well-set are they to follow through on that, or to suddenly and conveniently disappear or hide behind international boundaries?International law requires a huge political mess to enforce, straining relations on a global scale, and carries a remote but real possibility of war. Most countries will let a lot slide before they go that far, and so it's practically the wild west for individual consumers buying from overseas, and most sellers know it.

author: Kasper
author_rank: Frequent Contributor
timestamp: November 30, 2021, 06:00:42 pm
content: Quote from: AaronD on November 30, 2021, 05:36:10 pmGood points. While we are on the subject, do you know any good options in North America? I wouldn't trust any company from anywhere but I have a little more faith in local sources. A few examples why it is foolish to trust anyone would be volkswagen emissions scandal, theranos and flint city water.Working with locals makes it a little easier to enforce some kind of penalty for wrong-doing but that doesn't mean it'll undo the problem it caused.Just for the record, I haven't requested anything impossible, just specific sizes, layouts, connectors, cells and thermistor. I've tested at least 1 from each batch. The high temp cells had the model I requested printed on them, not sure who printed it but it's better than having the wrong model printed on it.

author: Renate
author_rank: Super Contributor
timestamp: November 30, 2021, 07:52:59 pm
content: Visual is one thing, but you ought to check screen grabs to see if the actual data written is fuzzy.(Of course) I recommend by AdbGrab.exe (in the sig).If you see something that looks like JPEG artefacts (but it's not, because it's PNG) that could be the "High Contrast text".