hybridfree/eevblog-posts huggingface dataset:
"Battery discharger" issue - Page 1
Forum section: electronics / projects

author: bajticzek
author_rank: Newbie
timestamp: March 14, 2020, 04:50:00 pm
content: Hello, for my first post I'd like to introduce myself. I have finished electronics secondary school ~15 years ago, sadly I didn't attend university (girls were more important to me back then) although being accepted to one. I like to tinker a lot and I also work as electrician for all these years + I help my friend in his workshop as an autoelectrician. Right now I am in need of your help. I am working on a small project - battery tester - which basically discharges Li-Ion batteries in a controlled manner. Please have a look at this simplified schematic. All components are 1:1 as I soldered them to a perfboard.I am powering the circuit from Rohde&Schwarz bench power supply which has 4 isolated outputs. One output is used for power, another one works as a tested battery. If I connect the supply output to BAT+ and BAT- terminals and gradually increase the voltage, everything is fine, I can read the voltage from ADC without an issue. Around 4.1 volts the mosfet starts to conduct. I can see there is a noise at opamp output which tends to become stable at 4.3V and is growing steadily. At 5 volts there is ~100mA current flowing through the mosfet although the value from DAC is set to 0 volts. So basically the voltage measurement works fine and no current is flowing up until one point.In another scenario I connect the BAT- pin to common ground. Now there is no current flowing in full tested range, the ADC reads voltage fine from 0 to whatever voltage I try (in safe margin). But another issue arises - if I disconnect the "fake battery" (switch the PSU output off) - the voltage between terminals BAT+ and BAT- immediately jumps to 3.8~4 volts (I guess it depends on the mosfet parameter variations, it is a 4-channel device). If I leave the "battery" disconnected and short BAT+ and BAT- pins, there is of course no voltage across the terminals now and the circuit current consumption increases by 3mA. This wouldn't be an issue, but I need to detect whether the battery is connected or not before starting the discharge cycle. And if I have this 4V reading, then it cannot be done.Any thoughts and any kind of help is very welcome. I can give you more information if needed.

author: bajticzek
author_rank: Newbie
timestamp: March 14, 2020, 05:43:19 pm
content: Whole assembly looks like this:
Battery drain in a split supply configuration - Page 1
Forum section: electronics / projects

author: DrMag
author_rank: Regular Contributor
timestamp: March 06, 2019, 11:43:10 pm
content: I'm puzzling through an idea where I'm not sure what actually happens. Consider a bipolar supply using a two cell battery; Cell A positive terminal is V+, Cell B negative terminal is V-, and the junction between the cells is Gnd. The battery is used to power a circuit that has both analog components (that swing to negative voltages) and digital components (that are strictly positive).In this configuration, since more power is used at positive voltages, does Cell A drain faster than Cell B? If not, how does the digital circuitry get energy from Cell B?I've gone back and forth on what my gut tells me, so now I genuinely don't know what to think.

author: ataradov
author_rank: Super Contributor
timestamp: March 06, 2019, 11:54:09 pm
content: Yes, of course cell A will drain faster. What would be the argument against that?

author: digsys
author_rank: Unknown
timestamp: March 06, 2019, 11:54:27 pm
content: Quote from: DrMagYes. If there is NO active charge equalization, as sometimes found in lithium packs, then A will drain first. PLUS, depending on how you charge them AFTERthey are "flat", you may not get them back to equal status !!Quote from: DrMagDoesn't. Only a complicated DC-Dc charge pump can, and that's not worth it.What is GENERALLY done - You use the cells as a single supply and create a virtual 0V. Depending on how much current you need, it could be a simple op-amp.

author: Audioguru
author_rank: Super Contributor
timestamp: March 07, 2019, 12:17:31 am
content: Please post the schematic that uses a bipolar supply and we will show you how easy it is to use one battery.
Battery for Standard Pneumatic 620 Wire Wrap Gun - Page 1
Forum section: electronics / projects

author: Electro Fan
author_rank: Super Contributor
timestamp: October 15, 2021, 11:41:25 pm
content: Anyone have an idea how to determine what a suitable replacement NiCad rechargeable battery might be for a Standard Pneumatic 620 wire wrap gun based on the info in this spec sheet?http://www.ralphselectronics.com/ProductImages/STPM-62094.PDFAlso, if I have a battery that I think might be a genuine original that still runs the wire wrap gun what would be the best way to test/measure the battery in an attempt to identify a suitable replacement?The original 120V charger is marked 2.9VDC and and 200mA, but when I measure the charger with a DMM at the DC jack I get about 1.9V. The potentially original battery measures 2.9VDC when it's charged up. The battery diameter measures about 26mm and the length (which might be two batteries joined together) is about 96mm or 99mm (maybe 100?mm) including the positive terminal.Thanks

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 16, 2021, 01:32:28 am
content: Just use two NiMH AA in AA to C adapters. Use an external charger to charge them.

author: Electro Fan
author_rank: Super Contributor
timestamp: October 16, 2021, 03:19:04 am
content: Thx NiHaoMike, Other than price any reason to not just use 2 C batteries?

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 16, 2021, 03:24:13 am
content: That works as well, but NiMH C tends to be more expensive than NiMH AA. Might as well just get a second set of AAs so you can switch between them.You can also 3D print an adapter to use a single 18650, using one of those USB charger/protection boards and possibly a series diode to drop the voltage a bit.
Battery fuel gauge GPOUT pin  - Page 1
Forum section: electronics / projects

author: Nikos A.
author_rank: Regular Contributor
timestamp: June 15, 2020, 04:12:08 pm
content: Hi everyone,I want to include the bq27421 fuel gauge into my project and I need some help with one of its pins. This is the datasheethttps://www.ti.com/lit/ds/symlink/bq27421-g1.pdf?ts=1592237094425&ref_url=https%253A%252F%252Fwww.google.com%252FOne of the pins is called GPOUT and is basically used either to exit the IC from shutdown mode (by toggling the GPOUT), or battery low indication or for SOC interrupt (I do not care about the last one)I found a reference design from TI (sorry for the bad quality)My question is about the GPIO pin of the host.I have to configure a GPIO as input that will continuously monitor the GPOUT for low battery indication right?Then in case I want to exit the fuel gauge from SHUTDOWN state I have to re-configure the GPIO as output and tonggle the GPOUT, right?Is this how it works?Thanks in advanceNick
battery full auto cut off circuit - Page 1
Forum section: electronics / projects

author: Kedar264
author_rank: Regular Contributor
timestamp: February 25, 2015, 01:03:45 pm
content: My design need power cutoff when it detects 13.5 v suggest your designs.

author: Rerouter
author_rank: Super Contributor
timestamp: February 25, 2015, 01:09:49 pm
content: current requirements, way to reset, if auto reset, how large a hysteresis, any time constant needed to prevent false trips from large surges,at the most basic level, a comparator, zener, 4 resistors and a mosfet.

author: Seekonk
author_rank: Super Contributor
timestamp: February 25, 2015, 02:55:33 pm
content: If you really want to cut off, a TL431 and a relay would do it. Use a set of contacts to hold the relay in once it reaches that voltage. See the data sheet. I often hear people saying...... I just want it to do this. That is seldom the case. I wouldn't use less than one of those $3 mini 328 micro boards to create upper and lower limits and time delays.

author: macboy
author_rank: Super Contributor
timestamp: February 25, 2015, 03:28:44 pm
content: If this is a lead acid battery charger, you need to terminate charge when the current drops, not when the voltage reaches a certain level. Otherwise, the battery will never reach full charge.
Battery Li-Ion/Li-Po charger with power-on while charging - Page 1
Forum section: electronics / projects

author: Yaro
author_rank: Contributor
timestamp: October 14, 2016, 12:55:58 pm
content: Hi,I'm looking for a Battery Li-Ion/Li-Po IC charger that have very compact sizes (about 2x2/3x3) that allow me, when charging, to power my circuit from battery or power supply. I know that this can be made with additional circuit, but I want to keep sizes and number of components need very small. I've found for example "MAX1551" and similars but I don't know if, while I'm charging, I can draw current from attached battery.Can someone explain me if it's possible or not (and why)? Also, components raccomandation are welcome.Thank you!

author: klr5205
author_rank: Regular Contributor
timestamp: October 14, 2016, 12:58:58 pm
content: I recently used one of these in a design:http://www.ti.com/product/BQ24266It works well enough."The power path feature allows the bq24266 to power the system from a high efficiency DC to DC converter while simultaneously and independently charging the battery. The power path also permits the battery to supplement the system current requirements when the adapter cannot."
Battery life calculation - Page 1
Forum section: electronics / projects

author: tomshirvo
author_rank: Regular Contributor
timestamp: May 28, 2014, 07:37:09 am
content: Hi All,I have built a project for my work and I have it up and running but I think my calculations were way off.I power these devices with LiPo batteries purchased from Hobby King.They are 3-cell 11.1v batteries with 5000mAhThe devices have 5 volt 90% efficient buck regulators on them.My device uses around 800mA to power the device with everything on.I would calculate it by 5000 / 800 so around six and a half hours.Is this correct or because I'm only using 5v then it will be different?I am finding that with little use the device will last 18 hours.I am interested to know if I could be using a smaller battery. If so what would the correct calculation be for me to find out the best size.Thanks

author: Legit-Design
author_rank: Frequent Contributor
timestamp: May 28, 2014, 07:55:58 am
content: There is a reason in houses power consumption is measured in watt hourshttps://en.wikipedia.org/wiki/Kilowatt_hourfor example your battery has 55.5 W h (watt hours) (5Ah * 11.1v)your device consumes 4 Watts (800mA * 5V) so rough calculation comes to around 13.88 hours. Since your device is not using 800mA all the time but only when everything on, I'd say your 18 hours measurement is about right.With 18 hours of battery life your device consumes around 0.616667 mA of current on average. 55.5/(x×5) = 18, x = 0.616667And you should also never ever use LiPo batteries to 2.5V or whatever their cutoff voltage is. For maximum life safe cutoff voltage would be 3.0-3.3V.

author: tomshirvo
author_rank: Regular Contributor
timestamp: May 28, 2014, 08:15:59 am
content: Thanks for that, I thought that it should work like that but was informed that I was incorrect.Well now I can go to a smaller lighter battery.Thanks again
battery life of this alarm, can we reduce current - Page 1
Forum section: electronics / projects

author: dave_j_fan
author_rank: Regular Contributor
timestamp: October 17, 2022, 02:31:12 pm
content: The circuit uses 4011It does not beep when probes are in water(Npn and buzzer part not shown)Standby current 0.2mA can we reduce further?What will be life of 2AA cells?

author: Kleinstein
author_rank: Super Contributor
timestamp: October 17, 2022, 02:53:22 pm
content: The 4011 logic gate uses quite some current when in the in beteen range and used as a more linear function. One may reduce the current a little with lower supply voltage, but 3 V is already quite low and 2 near empty cells would be only 2.4 V and thus lower than specs. One could get lower current with a low power comparator, like MCP6541 or similar. A low power OP-amp is also possible.If the transition is reasonable sharp, one may also get away with some schmidt trigger chip (74HC14), that may be a little lower in power than the 4011 and work down to 2 V.Alkaline AA cells are around 2000 mAh . So 0.2 mA would be 10000 hours or a bit over 1 year. This may be acceptable, but the circuit as shown may fail before 2.4 V and use less of the capacitance.
Battery Management / Charging / Discharging Solutions - Page 1
Forum section: electronics / projects

author: ChristopherN
author_rank: Unknown
timestamp: February 01, 2017, 08:48:59 am
content: Hi,I'm building some test hardware that will be used on the go and in vehicles. So I'm looking for a matching battery pack with BMS and charger. This is low volume stuff, so I'm searching for of the shelf solutions.Most of my systems run off one 5VDC supply. I'm are drawing up to 4A peak, idle current 0.5A. I need something like 60Wh to get a useful life out of the system. I would like to have a single power input for the device that should charge the battery pack but will also act as a pass-thru if the battery is charging or full and the system is still connected to external power. Input voltage should be something like 9-32VDC.I like to have some information about the battery status, like a fuel gauge, voltage, number of cycles and so on. It would be great if the solution could support an external power button as well as shutdown thru software.Can anyone suggest a decent solution?ThanksChristopher

author: Rerouter
author_rank: Super Contributor
timestamp: February 01, 2017, 09:47:41 am
content: As you already have some processing power, the cheaper options actually tend to just be interfaces for the host,texas instruments have a great bunch of options depending on how many cells your going formAs your running off of 5V, with a lower spec of 9V, it sounds like 2-3S would suit you, so that the 5V system only needs a single buck converter rather than a sepic,you can split this problem into 2 parts, 1 is a BMS / balancing charger, the other part is a battery changeover switch, the switches are dirt cheap, the BMS for 2-3S are generally under $2 for an IC with balancing,
Battery management choice for 12V, 500mA battery from 18650 cells - Page 1
Forum section: electronics / projects

author: Richard Crowley
author_rank: Super Contributor
timestamp: September 17, 2018, 06:32:24 pm
content: I would like to make a battery gadget to power a 12V load (a Moog Theremini) It wants 12VDC @ 300mA rated.I would like to make it rechargable using a conventional micro-USB 5V source.I have lots of 18650 cells of varying measured capacity. I can select perhaps a dozen of very similar capacity.Would it be better to connect them all in parallel to make a 3.7V battery of whatever capacity of the parallel cells and then boost-convert to 12V?Or would it be better to connect the cells in series to make something >12V and then buck-convert to 12V?Or is there some commercial product that would do this better than I could and probably for less $$?There is a great variety of battery management/converter/charger boards to choose from. Anybody have a favorite 12V board?I rather like these power bank cases where they just parallel 8 cells. But they only put out 5V. I would like an equivalent for 12Vhttps://www.amazon.com/gp/product/B01EY9YMSI

author: IanB
author_rank: Super Contributor
timestamp: September 17, 2018, 06:38:56 pm
content: I see you would like to re-use your existing cells, but could a possible alternative be a 12 V lead acid replacement LiFePO4 battery (such as for motorcycles)? It would be off the shelf and would have a standard charging solution.

author: Richard Crowley
author_rank: Super Contributor
timestamp: September 17, 2018, 06:53:32 pm
content: While I would like to recycle my 18650 cells, a 12V SLA battery would be an option.Anybody have a favorite mains-powered 12V SLA charger board?I would like to make something self-contained with an IEC mains power inlet and built-in charger.

author: m3vuv
author_rank: Super Contributor
timestamp: September 17, 2018, 08:44:38 pm
content: search ebay for 3s bms,should be near enough.

author: sokoloff
author_rank: Super Contributor
timestamp: September 17, 2018, 10:08:08 pm
content: Quote from: Richard Crowley on September 17, 2018, 06:32:24 pmHow tolerant is the load? You're extremely close to the voltage where a 3S LiPo pack (11.1 V nominal, but 12.6 V or so peak) will cover the load without any conversion at all. As the pack drops below 10.5V, hopefully the device will shutdown/malfunction prior to the pack dropping below 10 V or so. If that's the case, you have the perfect load for a 3-series pack.If you get relatively closely matched 18650s and periodically check the balance, you might just run a straight pack without any smart management.
Battery management system(BMS) balance current rating - Page 1
Forum section: electronics / projects

author: santoshgurral
author_rank: Contributor
timestamp: March 24, 2020, 08:37:26 am
content: Hi GuysI am working on a 18650 Li-ion battery pack system. So I was scouting for a BMS for my battery pack. I see a specification called "balance current" for BMS what does this mean?There are BMS boards with different balance current ratings like 40mA balance current 70mA, 100mA and so on...What does this balance current rating on a BMS board signify? Which one should I choose? I want to understand what is this 40mA/70mA/100mA signify, is it like the BMS keep discharging a full charged battery(4.2v) with 40mA until the other cells in the system reach its full capacity(ie 4.2v)?

author: abyrvalg
author_rank: Frequent Contributor
timestamp: March 24, 2020, 09:50:23 am
content: Yes, mostly correct, the BMS on your picture will discharge overcharged (above some "balancing threshold voltage") cells with that current until these cells go below threshold. But this process doesn’t care about other (not overcharged) cells.

author: santoshgurral
author_rank: Contributor
timestamp: March 24, 2020, 07:30:11 pm
content: so I better choose a BMS with a relatively high balance current so that my battery pack balancing process is fast. is this correct?ThanksSantosh

author: santoshgurral
author_rank: Contributor
timestamp: March 25, 2020, 11:19:56 am
content: HiPlease see attached imageIn 1S5P arrangement 5 cells in parallel for total 8514mA, Will each cell be charged to its full capacity or each cell charge is limited by the cell with the smallest charge capacity?I mean, since c3 is the cell with the lowest charge capacity of 1166mA each among all other cells in the pack will this make the TP4056 module to charge all cells c1,c2,c3,c4,c5 only up to 1166mA irrespective of their full capacity and stop charging the pack after 1166*5=5830mA instead of 8514mA?ThanksSantosh

author: Siwastaja
author_rank: Super Contributor
timestamp: March 25, 2020, 12:39:44 pm
content: Use the lowest possible balancing current so there is a smaller risk for thermal shit hitting the fan if something goes wrong and the balancer gets stuck on.40mA is likely enough unless this is a massive (tens of kWh) battery pack, or a pack built from a nearly-dead (poor quality, or abused and reused) cells.
Battery Manager - can it withstand battery polarity reversal? MAX77751CEFG+ - Page 1
Forum section: electronics / projects

author: dostr63
author_rank: Newbie
timestamp: November 04, 2023, 02:04:21 pm
content: Obviously this is a question that should be in the data sheet (either it isn't - or I missed it!)MAX77751CEFG+ is lithium battery and charge manager, for single-cell lithiums.Simply - does anyone know, either from tech data or experience, if this particular chip is damaged (or allows a damaging reversed voltage onto the rest of the PCB) - if a battery (in this case an 18650) is inserted incorrectly into the battery holder?AFAIK - the manufacturer hasn't published data, and the technical query (I put in some time ago) has not been answered.https://www.analog.com/media/en/technical-documentation/data-sheets/max77751.pdfMany thanks for any insights, about this particular chip - or perhaps if you know the behaviour of similar chips, that might be an indication of likely behaviour!(If all else fails - then I'll have to sacrifice a prototype PCB to an 'experiment'!)

author: mmame
author_rank: Newbie
timestamp: November 06, 2023, 08:06:50 am
content: Although I can't help on that specific part: as long as there is no explicitly mentioned reverse voltage protection in the datasheet, I would never assume it could whitstand reverse connections. Why not just adding a simple protection by using a Diode and a Polyfuse?

author: Daixiwen
author_rank: Frequent Contributor
timestamp: November 07, 2023, 01:19:05 pm
content: It says in the Absolute Maximum Ratings part of the datasheet that the limits for the BATT pin are -0.3V to +6.0V. So this means there is no reverse polarity protection
Battery module design for uSupply or other small project - Page 1
Forum section: electronics / projects

author: Jon_Paul_Clarke
author_rank: Contributor
timestamp: September 20, 2015, 11:49:25 am
content: Hey guys and gals.Just a few quick questions regarding the uSupply design and its optional battery feature.I realise everyone is sick to death of hearing about the uSupply. Mostly because it's a bit like waiting for Microsoft to end spam- It's taking forever(No offence Dave. I know you've got David2 working on it).But here is the question: If one was to add a battery function to this or any other small powered project, how can you go about it? I know that I am asking in effect, "how many ways are there to skin a cat", but if Dave had the idea of using a set of Li-Ion batteries and looking at Rev C, possible MCU(s), then what would be the best approach to use that is in keeping with the low power nature of a portable project?There are a thousand CCT's if you google it, but what is not clear is the basic design parameters.So I understand that the CCT should have:1. A way to detect and control regulation between mains/plug pack and battery2. It should be able to charge the batteries when the mains is on3. It should cut off voltage when the batteries have reached 100% charge4.That's as far as I've got. Any help would be appreciated. And no, this is not for a Uni assignment. I am actually thinking of making Rev A uSupply (Less coding, more hardware).Thanks Heaps.

author: Rerouter
author_rank: Super Contributor
timestamp: September 20, 2015, 12:29:44 pm
content: ... In most cases you never plan the battery charger to connect straight to mains, you generally have it built to cope with either what ever your input can cope with, or you tie it off and already regulated rail, You then use a charge controller chip, and some power Oring chips to switch to the battery when mains is lost, again both the charge controller and the oring chips would generally be hooked up to your controller, e.g. the input power has been on for 15 seconds, Its stable, lets start charging, and for the or'ing chips, you can use the enable pin to allow the device to switch itself off, rather than running the batteries flat, you then have the wake up / power on button toggle these enable pins to there other state,

author: Jon_Paul_Clarke
author_rank: Contributor
timestamp: September 22, 2015, 08:54:05 am
content: Hey Rerouter.Thanks for the reply. What you said makes a lot of sense regarding Mains/Battery isolation and timing. I hadn't considered the idea of using a sense input to detect voltage and therefore begin/stop charging. I saw some cct's last night and I can now see those methods implemented.Personally, I like the idea of using a plug pack and having a fixed voltage source to muck around with; the mains cctry is external to the project and you don't have to worry about having to design a step-down transformer and rectifier.Thanks againJon
Battery NTC calibration formula help - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: November 17, 2015, 08:19:51 pm
content: Hi,Is anyone able to help me rearrange these two formula to work the other way. I want to figure out what the Rcold and Rhot values will be for any given Rlo and Rh.I've tried a few times with wolfgram alpha but don't seem to be getting consistent results.Vcold is 1.99Vhot is 0.75Vin is 5

author: eneuro
author_rank: Super Contributor
timestamp: November 17, 2015, 09:09:18 pm
content: I've used 1% NTC with 1% 10k in this configuration and by using manufacturer given 3380K for this partNTCM-HP-10K-1% -55÷125°C; 50mWI;ve made look up table for MPU, so If I wanted I could read directly MPU ADC value and hadrcode in MPU to create desired logic and now I can forget about opamps, but using calculator shown above where I've checked experimantal data by making measurement of NTC resistance at known room temperature using another termometer, voltages thesholds could be estimated, to be able use comparator instead of MPU with ADCMore about this look up table method and link to this quite nice NTC calculator starting from here:NTC Thermistor resistance (Li-Ion Charging) ...
Battery Operated Light Box - Photographing Electronics Projects - Page 1
Forum section: electronics / projects

author: prenato
author_rank: Regular Contributor
timestamp: August 18, 2012, 01:27:38 am
content: I often photograph my electronics projects in the lab so I can post them on my site. If you ever done this before, you know that having some sort of controlled light-box is very helpful. Inspired by watching Dave's video tutorial on the MC34063, I decided to build a boost-converter current source to drive the LEDs in this project.You can check the whole project at my site:http://paulorenato.com/joomla/index.php?option=com_content&view=article&id=89&Itemid=2Here are some photos:Paulo

author: prenato
author_rank: Regular Contributor
timestamp: August 18, 2012, 01:29:30 am
content: Hmm, the photos didn't come through... let's try again.
Battery pack absolute beginner! - Page 1
Forum section: electronics / projects

author: Joe.destinct
author_rank: Newbie
timestamp: November 30, 2014, 11:54:16 pm
content: Hi, I understand I may not get an answer here but would at least appreciate a shove in the right direction!I want to buy some heated insoles for my girlfriend but the battery packs are over £70 each, they just contain a small circuit board and 4 nimh batteries. The circuit board adjusts the power of the insoles.After some research I read I could use a 555 timer with some better batteries to achieve the same result.I would need a battery housing with a way of switching the power/potentially 2 switches?! 1 for heat and one to turn on a pulse. A 555 timer, resistors and a cap?I am stuck from here as to what exactly I need, where to source it from and how to do this.
Battery Pack Protection Question - Page 1
Forum section: electronics / projects

author: DDCE88
author_rank: Newbie
timestamp: August 26, 2021, 11:38:32 pm
content: What exactly is the difference between the protection of the Lithium Ion/Polymer battery pack and Lithium Iron Phosphate battery pack. I'm currently stuck with using Lithium Iron Phosphate batteries (Long story don't ask). And I'm trying to design a protection circuit for it for a custom enclosure. What I'm ultimately wondering is what is the difference in protecting Lithium Ion and Lithium Iron Phosphate. I've tried looking up protection IC's for specifically LiFePO and they are all either really expensive (IE >$6) or require a separate Microcontroller (the second part is not a deal breaker but seems unnecessary especially when I'm trying to keep cost down). When I just do a general search for battery protection IC's I find several reasonably priced and simple IC's but they are for Lithium Ion.Now I know that Lithium Ion runs at a higher voltage than Lithium Iron. Lithium Ion @ 3.6 nom and Lithium Iron at 3.2-3.3 nom. Also I know that the charge and discharge rates are different between the two. I was just wondering if anyone has any experience dealing with these types of protection circuits.
Battery pack & Short circuit protection - Page 1
Forum section: electronics / projects

author: Nikos A.
author_rank: Regular Contributor
timestamp: November 07, 2019, 05:42:27 pm
content: Hi everyone, I am designing a circuit and I need to place two batteries in parallel. I purchased this battery holder from Banggoodhttps://www.banggood.com/2-x-3_7V-18650-Battery-Holder-Box-Container-With-Wire-Leads-p-1448993.html?rmmds=myorder&cur_warehouse=CNMy problem is that if someone accidentally connects the batteries in series everything will blow up (the batteries will be shorted out). I am looking for a solution to protect against short circuits the batteries. I want to avoid the fuse solution.I found this battery holder that seems to have an embedded PCB that prevents from shorting the batteries but I am cautious..https://www.batteryspace.com/Battery-holder-Li-Ion-18650-Battery-Holder-1S2P-With-2.6-long-20AWG.aspxThanks in advance

author: Nikos A.
author_rank: Regular Contributor
timestamp: November 07, 2019, 05:57:41 pm
content: Also, I want to avoid the diodes solution due to the unavoidable voltage drop.

author: Gallardo
author_rank: Newbie
timestamp: November 09, 2019, 04:15:22 pm
content: In the absence of a more suitable battery holder, we can enhance the marking and try to start with the battery, such as the 18650 battery with protection.https://de.aliexpress.com/item/32805302685.html?spm=a2g0x.12010612.8148356.7.25273fd89sX4hc

author: Nikos A.
author_rank: Regular Contributor
timestamp: November 09, 2019, 04:34:34 pm
content: In general I am looking for a protection circuit that I could integrade in my pcb design.I am thinking to use a mosfet to protect the bateries from shorting. What do you think?

author: Siwastaja
author_rank: Super Contributor
timestamp: November 09, 2019, 04:50:43 pm
content: Note that the batteries will be equally "shorted" and destroyed (possibly resulting in a fire) if the user connects them in parallel, as you intended. Unless they are so lucky that the cell voltages happen to match.You need the diodes, or active diode-like circuit, for the bare minimum. The protection PCBs usually won't properly protect from excessive charging currents.

author: Gallardo
author_rank: Newbie
timestamp: November 09, 2019, 04:52:36 pm
content: I think it is a good idea in the case of small currents!

author: Nikos A.
author_rank: Regular Contributor
timestamp: November 09, 2019, 05:05:29 pm
content: I am thinking of using two Mosfet, one at each cell.If the user connects on of the batteries on the wrong polarity then they wont shorted out isn't it?

author: Nikos A.
author_rank: Regular Contributor
timestamp: November 11, 2019, 09:15:25 am
content: Anyone?
Battery pack thermal management/protection circuit - Page 1
Forum section: electronics / projects

author: davegravy
author_rank: Regular Contributor
timestamp: August 26, 2023, 07:52:52 pm
content: I'm trying to design a circuit to be used with some 12V LiFePO4 battery packs which don't have an integrated heater, so I can add thermal management/protection.The circuit would sit between a65W solar charge controllerand the battery's existing BMS.It would sense temperature with an MCU and during detected freezing conditions it would:disable charging using an n-channel MOSFETenable a heating pad when charge current is availableprevent the battery from discharging into the heating padnot prevent the battery from discharging into the loadI won't have access to the load terminals so my circuit sees the charger and load together. The load is about 2W.A rough calculation to size the heating pad is: assuming 50W heat dissipation and if the charger supplies up to 14.5V the pad should be (14.5^2)/50 = 4.2ohms.Now I understand this charger like most most will operate in constant-current and top off the battery in constant-voltage. I'm unclear if there's a problem with stopping the flow of charge current to the battery and switching on the heater pad load if the charger is pushing 5 amps in CC (from the datasheet). 5amps through 4.2ohms is 21V which I'm guessing would trigger the charger's control system to conclude the battery is charged and to shut off.Also the datasheet mentions there must be a minimum of 7.2V voltage from the battery for normal operation. I think since I'm using a mosfet to control direction of current (not completely disconnecting the battery) that voltage will still be visible to the charger, unless the battery is truly dead.Does a typical charger control system do anything like periodically stopping charge current to measure float voltage? I was planning on disconnecting the heater if I detect the condition that the battery is discharging into it, which I suspect would happen every time a charger pauses charging- if this happens frequently it could be messy.Is there some circuitry I should put around the heating pad so it's not disruptive to a typical charger? Or is it just a matter of sizing the heating pad resistance so that at max charge current the voltage doesn't exceed a full battery's voltage ~14.5V?Does anyone know if there are any freely available simulation models (e.g. LTSpice) that would predict how a charger would work in my scenario? Or how I could model this myself?
Battery PCM when should be used and when can be avoided - Page 1
Forum section: electronics / projects

author: Yaro
author_rank: Contributor
timestamp: July 04, 2015, 10:37:27 am
content: Hi all!I'm looking to find more informations about batterys PCM.Each battery should have a PCM? and where/when I can omit it? I see that battery charger ICs have already charge voltage protection and charge current protections and sice almost always batteries pack are builded for a specific device and are not interchangeable, I design my circuit to not go in over voltage or over current consumption of battery.If it's possibile to avoid them, there is specifics regulamentations in Europe/Asia/America that explicitly say that every battery in products should have PCM or some kind of protection?
Battery pogo connector temperature rating - Page 1
Forum section: electronics / projects

author: hcglitte
author_rank: Regular Contributor
timestamp: May 27, 2020, 02:25:54 pm
content: Hi,I'm going to use a pogo connector, originally intended as a battery connector, for connectivity between 2 boards.The specs state it works down to -20 C.In my design it must work down to -40 C.I'm curious if the specs only says -20 C because batteries normally only operate down to this temperature. And that they don't care to test it below this level because its expensive to test, and not needed.It's a rather simple part consisting of plastic and metal. I guess the plastic could crack at low temperatures perhaps?Any experience here, anyone?

author: Syntax Error
author_rank: Frequent Contributor
timestamp: May 27, 2020, 02:46:28 pm
content: Maybe the pogo springs stop flexing at -21c ?

author: hcglitte
author_rank: Regular Contributor
timestamp: May 27, 2020, 03:08:44 pm
content: It's Bc‐11‐4pd in attached file.So it's spring contacts. Not sure about the flex properties.But a freeze spray may find this out.
Battery powered 4-20mA/0-10V analog input module for low power battery module - Page 1
Forum section: electronics / projects

author: virtapp
author_rank: Contributor
timestamp: July 07, 2021, 11:45:44 am
content: Hi guys,I've actually done some experiments for my low power battery-operated arduino pro mini sensorboard following this guide (https://learn.sparkfun.com/tutorials/reducing-arduino-power-consumption/all) i've reached 5uA of current draw from arduino in deep sleep.Now, i need to design something that can allow me to acquire two type of signals: 4-20mA and 0/10V, i know that this can be done in a bunch of ways, but i need to use low-power designs in order to keep my sensor run on battery for at least 2 year.I'm planning to use standard AA batteries like these old-fashioned Duracell Plus Powerhttps://docs.rs-online.com/1623/A700000007325672.pdf, they are claims to be able to deliver 3Ah per single cell and i want to use two of them in series, so i can reach 3V.My maximum target consumption during sleep can be around 20-25uA during deep sleep.My thoughts drive me to this schematic: using a low power NCS20062DR2G (https://www.onsemi.com/pdf/datasheet/ncs2006-d.pdf) in this configuration i can read 4-20mA, 0-10V...and in addition a dry contact from external sensors/systems.In order to put everything on battery and keep it "zero" on consumption during sleep, i'm thinking to attach the VCC pins to a Arduino digital pin output and then do a digital write high (putting it to 3V).Anyway, i have some doubts about this design:How it works when the battery discharges...say at 2.3V?It can be a good solution for this specific purpose?I'm completely opened to alternative solutions, please note that this is only my initial idea...and i'm not sure about that.About the given schematic, this was seen on Iono Arduino board, you can find more informations here:https://www.sferalabs.cc/files/ionoard/doc/ionoard-user-guide.pdf(at page.And for completeness, here it's the complete schematic of the Iono Arduino Board:https://www.sferalabs.cc/files/ionoard/doc/ionoard-sch.pdf

author: esepecesito
author_rank: Regular Contributor
timestamp: July 08, 2021, 02:49:03 pm
content: I would not use any op-amp. just couple of resistors and direct to A/D input.Good question about the voltage: the "Ah" rating of the batteries is total capacity, including the discharge well below the nominal 3V. Typically you should have a dc/dc converter which warranties the 3V.

author: Benta
author_rank: Super Contributor
timestamp: July 08, 2021, 04:29:48 pm
content: Are your external sensors self-powered?

author: virtapp
author_rank: Contributor
timestamp: July 12, 2021, 10:10:46 am
content: Yes, the sensors are already powered up with typical +24VDC DIN power supply.And yes, i've changed my initial approach and i've chosen to keep it simple: i'm planning to use a simple ADS1115 in this configuration:About the batteries i'm planning to use, i'm considering these Energizer Lithium Iron Disulfide AA Batteries 1.5Vhttps://uk.rs-online.com/web/p/aa-batteries/1966692/with this typical discharge curve:You think that will be a good choice?Thanks.
Battery powered boombox: battery charging - Page 1
Forum section: electronics / projects

author: Waff0l
author_rank: Newbie
timestamp: May 24, 2015, 06:08:53 pm
content: As a hobby project, I'm turning a set of old Philips 22RH427's into a pretty hefty boombox, which obviously needs to be able to run on batteries.As a starting point I have a mains transformer laying around (33V-0V-33V @2.25A (75VA)). I'd like to prevent having to design a mains-operating power supply for my own safety.At the end I want dual rails, capable of delivering at a maximum 50W to the amplifiers (continuous power will be less as in most audio applications), as well as some batteries for storage.I already made a design using a BQ24450(datasheet), charging two AGM(wiki)batteries.I'd really like some feedback

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 24, 2015, 06:14:57 pm
content: You don't need active balancing with lead acid.

author: Zero999
author_rank: Super Contributor
timestamp: May 24, 2015, 06:22:59 pm
content: The part number for Q2 is for an NPN transistor. Did you mean the TIP32?

author: Waff0l
author_rank: Newbie
timestamp: May 24, 2015, 06:29:21 pm
content: Quote from: Hero999 on May 24, 2015, 06:22:59 pmYes, my bad

author: Zero999
author_rank: Super Contributor
timestamp: May 25, 2015, 05:49:27 pm
content: Quote from: blueskull on May 25, 2015, 09:56:13 amYes, booster transistors need to be added.The uA741 may also be unstable with those massive capacitors on the output.
Battery powered lab power supply - Page 1
Forum section: electronics / projects

author: ptricks
author_rank: Frequent Contributor
timestamp: July 15, 2013, 01:21:38 pm
content: Has anyone seen a lab supply that can use either AC or DC for the power source ?I have quite a few 18650 cells and was considering building a supply around them as both something that is portable and something that is guaranteed to be isolated from the work. I'm thinking I will put all the cells internally and put a jack on the back for charging the cells. I am thinking it could do a range of -12V to +12V at several amps easily.Anyone done something like this before ?

author: Asim
author_rank: Regular Contributor
timestamp: July 15, 2013, 02:15:24 pm
content: I think it can be done, but the capacity of a 18650 is (2200–3400) mAh so if you are going to use it for several amps the battery will go flat very fast. if the power supply will be used to power small projects for example, it will be a great power supply to build.

author: Nermash
author_rank: Frequent Contributor
timestamp: July 15, 2013, 02:16:05 pm
content: Take a look at Dave's power supply series:)

author: Mr Smiley
author_rank: Frequent Contributor
timestamp: July 15, 2013, 03:00:42 pm
content: Quote from: Nermash on July 15, 2013, 02:16:05 pm
ungrounded/battery powered oscilloscope - Page 1
Forum section: electronics / projects

author: king129
author_rank: Contributor
timestamp: April 27, 2019, 11:19:08 pm
content: Hello i was watching Eevblogs video on how not to blow up your oscilloscope and was thinking what if I got a car battery put and converted its DC to 110 volts ac with the right amount of current and powred my oscilloscope useing that. Would I be able to put my oscilloscope anywhere in my house without worrying about it blowing up? If this would work would I be able to put my any number of my oscilloscope probes in a grounded circuit without anything bad happening? If I'm wrong please tell me why so I get this idea out of my head so I can think of something else. Thank you in advance.note the battery is not plugged in while im powering the oscilloscope.this is a repost of something i put on the beginners form mistakenly.Sent from my LGMP260 using Tapatalk

author: Ian.M
author_rank: Super Contributor
timestamp: April 27, 2019, 11:33:42 pm
content: Don't repost. You (the O..P) can move a topic, then ask a moderator to delete this one.Original:https://www.eevblog.com/forum/beginners/battery-powred-oscilloscope/

author: king129
author_rank: Contributor
timestamp: April 28, 2019, 12:17:26 am
content: how do i ask a moderator to delete somethingSent from my LGMP260 using Tapatalk

author: Ian.M
author_rank: Super Contributor
timestamp: April 28, 2019, 12:43:36 am
content: Normally, you can delete your own posts, but IIRC that isn't possible for the first post of a topic with replies because the SMF forum software doesn't like orphaned posts.There's a 'Report to moderator' link at the bottom of every post you see. Its usually used for reporting SPAM and gross violations of nettiquette, but in this case you can use it to report the first post in this 'reposted' topic and request deletion of the whole topic.@moderators: I am happy for you to delete this topic including all my posts in it.
Battery Powered Passive Listening Wireless Solution? - Page 1
Forum section: electronics / projects

author: Blue_Alien
author_rank: Contributor
timestamp: November 11, 2015, 11:54:03 pm
content: Hello, I would like to design a battery powered product that has a microcontroller in deep sleep for long periods of time, wakes up when a wireless transmission is received, does a task, then goes back to deep sleep.From my research, I can find many solutions for having a sensor transmit infrequently, then sleep. But not the other way around where the device is waiting to receive a wireless transmission.In this case, it almost seems like there does not exist a battery powered solution for a passive listening RF device with low power consumption. Maybe it's an oxymoron?
Battery powered Raspberry Pi Zero with Picaxe charger - Page 1
Forum section: electronics / projects

author: Reider
author_rank: Contributor
timestamp: January 17, 2017, 10:41:37 pm
content: HelloI'm designing a battery powered project around a14.4V NI-MHbattery aRaspberry Pi Zeroand aPicaxechip to control battery voltage and charging.The man logic will be running on the Pi Zero that will control motors and use WiFi to communicate. The Picaxe chip will be responsible for theNI-MHcharging and battery protection with low voltage cutoff when settingP/ONtoLOW.I'm usingNI-MHbecause I already have the device (a robot vacuum cleaner) that I want to control by recreating the electronics and motor control circuits.Pulse charging will start by setting theCHARGEline toHIGHand adjusting the digital pot to C/4 charge current from the CC module.Also I would implement dT/dt and -dV/dt sensing and a timeout to stop C/4 charge. After that switch to tickle charge by adjusting the digital pot.VSENCEwould also be used to check for low battery voltage, signal to the PI to shut down gracefully, and after turning it off withP/ON(not designed yet)The14V4line would be used to power the motors and large load devices. (not designed yet)I would like to get some feedback if I did something wrong.Thank You
Battery Protection Circuit - Page 1
Forum section: electronics / projects

author: jram
author_rank: Contributor
timestamp: May 01, 2018, 03:22:56 am
content: Hi folks, Not my first posting but anyone that read my first will realise I'm pretty new to this. I thought I'd share my 2nd revision of a battery protection system for my LiFePO4 batteries - I live off grid for a good part of the year.The original circuit and board worked well during last solar season and now I'd like to refine the design and seal it up in a box. (The attached photos will show why I need a new board)This is a battery protection system. The it drives 2 Bistable relays that provide battery protection in case of over-voltage, under-voltage or cell differential by disconnecting the chargers or the loads attached to the batteries.The board is designed mainly to drive 2 bistable high-current relays. (Blue Sea 7700http://assets.bluesea.com/files/resources/instructions/990180170.pdf) requiring an 'on' and 'off' signal on separate lines. The IXDN604shttp://www.ixysic.com/home/pdfs.nsf/www/IXD_604.pdf/$file/IXD_604.pdfprovide a simple solution for driving all kinds of relays - oh, and MOSfets and I had some so I used them.The LED channels are used to monitor the voltage on the LED output from the relays which allows the status of the relays to be known.The relay driver channels are driven from an ESP32.I'd welcome input on any changes or enhancements that might make this a more robust solution.I previously used an I2C ADC to monitor cell voltages and I'm in 2 minds as to whether just to use the ADC channels on the ESP32 instead so if anyone has any fors or againsts in that department - it would be good to hear as well.P.S. Please ignore the pinout allocations for the ESP - they are purely placeholders in this schematic.Many thanks in advance - This forum is fascinating reading.
Battery protection/charge board, could use another set of peepers on it? - Page 1
Forum section: electronics / projects

author: Automobilie
author_rank: Newbie
timestamp: December 09, 2016, 02:36:35 am
content: Designed and assembled a single cell liion battery charge/pcb that fits a single 18650. I used the recommended circuit diagrams from the chips datasheets and even the recommended NMOS fets for the protection circuit. There's three of them, but two of them are not working properly.Normally, if you plug in a 5v USB, or just 5v, the batteries should start charging up until BAT hits 4.2v and the charger drops into standby. If the battery voltage exceeds 4.3v and below 2.8v, the protection circuit should shut off the battery output. It is also suppose to include over-current protection, so I used the FET's the datasheet preferred.-One has problems not resetting the protection circuitry when 5v is applied, regardless of battery voltage.-On the other, the STC4054 charge IC will drop about a volt between BAT and Vcc and put about +2v on Vcc with nothing else connected.It may very well be the case that I've got some dead IC's, but I want to make sure it something stupid I did rather than a bad circuit design or missing protections. I can't find any bad solder joints though.