Forum - Recent Threads

Lithium Battery Charger Board With Confusing Connections

rictrajano — Fri, 01 Nov 2024 20:43:49 GMT

Hello Smart people,

my objective is very simple, to connect 3x 14500 3.7v lithium batteries in parallel and charge them with this module:

https://www.aliexpress.com/item/1005004957459719.html?spm=a2g0o.order_list.order_list_main.38.44211802hKnngk#nav-specification

I have two questions:

1 - Would I need a BMS?

2 - In the product's description they reference two pads that should be shorted if your batteries don't have discharge protection (or is the other way around?) I can't really understand the english. Would someone be able to understand what should be done in which situation?

Here's the description

Instructions for use

Output voltage adjustment potentiometer

VO+VO. IN-IN+

output input

LX-LCBST

VO+ Vo B+ B- T point

battery output battery

The module supports type-c interface input and solder joint input of back annotation input. You can choose one, the recommended voltage is about 5V. The module is marked with two outputs. The two outputs are the same, and the lines are connected in parallel. You can choose one of them. The following focuses on connecting the battery.

If your battery comes with its own protection board, you can choose our package without discharge protection. After the battery is connected to B+ and B-, you must short the T point to charge and discharge.

If your battery does not have a protection board, choose a package with discharge protection. This is very important, because over-discharge of the battery is likely to cause the battery to be scrapped. Most of similar competitive products do not have discharge protection. After -, the T point cannot be shorted, otherwise the discharge protection will be invalid.

After connecting the wires, you can use a screwdriver to adjust the output voltage you want.

The battery chooses 3.7V lithium battery, and the full voltage is 42V. The battery type can be 18650 polymer and other batteries.

Thanks for your help

Does any one know what this (automotive thing) is ?

michaelkellett — Tue, 07 May 2024 14:07:09 GMT

A friend (who mends agricultural machinery) has asked me.

MKI

PTC Thermistor

Alexis_992 — Thu, 23 Feb 2023 07:27:59 GMT

Hello all,

Recently I have a problem with PTC pill.

So, the problem is that the surface of the PTC pill is “burned”.

This problem occurs on the AC with 115 V.

My questions would be:

1) Why is this happening?

2) Why is this happening only on one side of the PTC pill?

I would be very grateful if you can help me or provide some advice to me.

Question about fuses

Art_Cole — Tue, 14 Feb 2023 20:25:40 GMT

I’m looking for protection devices (presumably fuses) that I can use in some underwater equipment. This equipment is at the end of an underwater cable and its two main components are in parallel, sharing the two power conductors in the cable. Because they are in parallel, if one floods and starts drawing too much current, the other component will stop working. What I would like to do is to fuse each one separately so that if it shorts, its fuse will burn out, allowing the other to function. The problem is, these devices may draw up to 2 A when functioning properly and only go up to 5-7.5 A when shorted (the shore power supply maxes out at 7.5 A so that’s as high as the current can go). That’s not a great separation between operational and shorted current levels. I need the devices to be very trustable, as an unwanted blowout means that the equipment needs to be recovered, which requires a vessel and can cost hundreds of thousands of dollars.

I’ve looked at slow-blow fuses, but it’s hard to know how they will perform here, as the time/current curves in their product sheets are almost vertical. They are also temperature derated, making things a bit confusing. Any advice? Thanks in advance.

Numbers:

400 VDC

Nominal I: up to 2 A

Faulty I: 5-7.5 A

Operating temperature: 0 to 5 deg C

Roast My Circuit: LiPo Battery Protection for Raspberry Pi

Sean_Miller — Thu, 28 Jan 2021 02:10:58 GMT

I dreamed up a circuit that would prevent my Raspberry Pi project from damaging its LiPo battery. A 3 cell LiPo should not go below around 10V or it will balloon and become unusable - if not a fire hazard.

The Pi and circuit work together to shutdown cleanly and disconnect the LiPo entirely.

I bread boarded the basics and it appears to work fine. Being that I scribbled it out of my noggin versus copying from a trusted source, it probably has all kinds of theoretical holes.

Here is the gist:

14.8V LiPo is switched with a momentary switch.
When switched, power gets to a voltage regulator which powers the Raspberry Pi. (The user knows to keep holding the switch until they hear the click of the relay.)
The Raspberry Pi outputs a pin high when it starts to boot which switches a NPN transistor.
The transistor takes the relay to ground latching in power to the regulator/Pi. It's latched in as long as the Pi keeps that pin high.
The user can let go of the momentary switch once they hear the click as the relay is now latched in.
There is circuit block that monitors the main battery voltage and takes a pin low once it decreases to ~10V.
The Pi detects this and takes action to alert the user and shutdown safely.
A 1000uF capacitor is on the signal line so that the circuit will remain latched for 20 Seconds more to give the Pi time to finish the shutdown process after it takes the signal pin low.

So, please roast my circuit - what could be better (not the crappy schematic - but the design/components)?

Thanks,

Sean

Can I have multiple powersources Powering one device if I use diodes?

Sean_Miller — Fri, 15 Jan 2021 19:47:21 GMT

I have a lithium ion battery powered device that I would like to allow plugging in a wall wart to power it as well.

If I put a diode on the lithium ion battery, would this prevent causing an issue to the battery when I connect the device to the wall wart supply?

Thanks,

Sean

Modern electronics. Do we still need to be careful about ESD?

macnewton — Wed, 15 Jul 2020 21:44:22 GMT

Years ago, when I got started in electronic repair and design, we were trained in all areas of ESD protocols. As a bench tech I felt naked if I didn't have my grounding strap attached to my left hand.

35 years later I'm still paying close attention and making sure that I'm well-grounded whenever I'm handling any kind of electronic circuit boards.

I'm now retired from business, and I'm now a full-time maker. Whenever I get a new visitor to my shop I always provide a short overview of ESD rules and regulations. It now appears that most younger makers haven't been trained to protect their electronics and in fact I get ridiculed whenever I bring the subject up. So my question today is this, are modern electronics designed to be handled without having to be grounded?

Let's look at one piece of electronics that I use in the number of my Raspberry Pi projects.

It's the element14 Raspberry Pi V2 Camera. Can this camera module be handled on the bench without having to worry about EST protection?

Attachments:

HELP!!!.... Blown Electric Mistress pedal

Andy Betts — Sat, 23 May 2020 15:59:41 GMT

I have made a huge school boy error... i was looking at running my original Electric Mistress pedal for a recording I'm doing and needed to run it off an external power supply. I had a 18v supply to hand which I just needed to connect up to a DC plug so that I could power the pedal. In my haste, I accidentally connected the negative and voltage wires the wrong way round...... connected the pedal, switched on the power and I immediately heard a small pop and the smell of burning. I have blown an original 1977 Electro Harmonix Electric Mistress effects pedal worth around $500!!! however, i'm sure it's not dead yet, and it can be brought back to life... Hence this post.

For your reference I have attached the schematic.

can anyone advise the best place to start troubleshooting, I'm assuming anything on the ground side of things could have been the first thing to blow, and I'm thinking a transistor.... bearing in mind the 18v supply was connected to the ground, and the ground was connected to the voltage in. Anything can be replaced, the only issue is if the culprit ends up being the SAD1024 chip that's it... the pedal is a gonner. However I very much doubt the voltage got that far in the circuit to be honest (hopefully)

Attachments:

community.element14.com/.../Mistress_5F00_v2_5F00_schematic.pdf

Mistress_v2_schematic.pdf

Powering a Rane SM82 Rack Mixer

Andy Betts — Wed, 25 Mar 2020 10:04:57 GMT

I've just bought an SM82 from the US, and got it for good money ($50 inc shipping) Obviously the PSU it came with is for 110v power so i've gathered together all the bits to make my own 230v PSU. they do sell reproduction PSU's on EBay but they go for around £50 and I can make one for around £20. i do have quite a bit of experience with soldering and electronics, but NOT with PSU's, never made one. But it's one of those things i want to have a go at to tick off the bucket list of things to do.

A guy previously made one and posted his build on another site (I've also posted on that site to try and gain more information) his build is here https://www.thegearpage.net/board/index.php?threads/diy-rane-rs1-power-supply-for-sm26-and-sm82.1838728/

he built his with no thermistors in series, which i don't want to do, I want to play safe.

I've purchased a transformer from Rapid Electronics (Vigortronix VTX-120-5412-209 PCB Transformer 230V 12VA 9V+9V) which should do the trick, but my question is around the thermistors. The PCT Thermistors are there to prevent inrush current into the transformer so i'm a little loath to build this without thermistors in place.

The schematic for the original PSU is not available, however there is a schematic for a Rap 10. The Rap 10 is the same as the single PSU, just multiplied 10 times, so please ignore the other 9 outputs on the schematic.... Here is the schematic https://www.ranecommercial.com/legacy/pdf/old/rap10sch.pdf

As the thermistor is variable resistance how do i know what one to buy?? Is there a way of calculating the zero power resistance? Rapid have the following on their site

https://www.rapidonline.com/Catalogue/Search?Query=thermistors&Tier=PTC

Any ideas??

Are these fuses

Sean_Miller — Thu, 20 Jun 2019 23:06:14 GMT

Are the components I’m pointing at with the screwdriver fuses?

This is a video card that suddenly stopped working.

There are no signs of a component that overheated.

This is right at the power connector. When I tested with an ohmmeter it shows that both of them are open.

Thanks,

Sean

Anyone recognize this fuseholder?

highstream — Fri, 01 Jun 2018 18:01:00 GMT

I've got a couple of fuseholders that screw into the back of ATC powered speakers that have acted up, that is, they won't screw in all the way. It's not about fuses blowing, but probably because the aftermarket (audio oriented) fuses I was screwing in were a fraction of an mm too long, and the ATC fuse holding tolerance is not great (these aftermarket fuses go easily into everything else in my system). Now, no fuses will screw in. I've attached a couple of photos. The holder is slotted screwdriver cartridge type, 5x20mm, slow-blow,, presumably 10A (fuse is 5A). I'm not sure exactly how it screws in internally - the holder has no threads - but there is a metal sleeve inside the speaker fuse channel with a slot where the holder flange presumably grabs. Anyone recognize the part or manufacturer? I am in contact with ATC for replacements, but would like to find out where these holders come from, so maybe I won't be dependent on them and their U.S. distributor if it happens again. I didn't find the holder on the U.S. element14 site (Newark), but thought maybe because ATC is a British company, someone might have seen it before (of course it could be sourced from anywhere). Thanks,

Attachments:

How is the H11AA1 ic working with AC mains voltage?

rishi2628 — Sat, 04 Feb 2017 20:59:14 GMT

I am making an arduino controlled fan speed controller that would digitally control the speed of my ceiling fan working on 230 VAC and 50 Hz. I am using the following circuit which is designed for 110VAC and 60Hz. I took this circuit from this website:- http://playground.arduino.cc/Main/ACPhaseControl

Working:-

When the AC voltage goes from zero to peak, the optocoupler is active and activates the output side. The arduino pin connected to the output of the optocoupler senses a HIGH voltage. When the pin reads a low it means we are approaching at a zero crossing of the AC mains voltage and depending upon the timing, the arduino will activate the TRIAC driver that is optocoupler MOC3052 that will further activate the TRIAC providing the power to the ceiling fan.

My doubt is that in the datasheet of H11AA1H11AA1 optocoupler ic the absolute max forward voltage of the optocoupler is not mentioned How is this ic working directly with AC I understand that the current is low since there are two 15k Ohms resistors but the voltage is still around 55VAC at the pins 1 and 2 of H11AA1H11AA1 How is this IC not destroyed?? Also will the circuit work for 230VAC 50Hz??

Datasheet of H11AA1H11AA1 http://www.vishay.com/doc?83608

whole house surge protector

stmkts — Sun, 30 Oct 2016 18:35:01 GMT

I'm looking for a whole house surge protector (ie 2 x 120vac). The units avail use MOVs and are good for only one substantial surge. Is there anything better on the market?

Tks

Marty

Montreal Canada

How to decide the Temperature range of an IC??

rishi2628 — Thu, 30 Jun 2016 05:54:42 GMT

I am using a MAX3241E ic in a device that has to run 24x7 out in the open. I am facing a problem deciding the temperature range of the the IC. Since it is out in the open, the ic has to withstand the heat from the sun plus the heating effect due to losses and resistances, etc. I am living in Delhi, India and here the temperature easily reaches 35 degrees. This ic that I have choosen can bear a max temp of 70 degrees. Should I use this ic or should I go for a higher temperature one? Also please tell how should one decide the max temperature of any ic?

Datasheet of the IC: - http://www.mouser.com/ds/2/256/MAX3222E-MAX3246E-99333.pdf

Which circuit is more stable?

rishi2628 — Mon, 20 Jun 2016 05:09:24 GMT

The circuits in the picture are basically opto-couplers connected to a relay circuit. The input pin of the opto coupler is connected to a MCU and the output of the opto coupler is connected to the relay. Initially I was using circuit 1 but then I modified it to circuit 2. Both the circuits are working perfectly. My question is that is circuit 2 more prone to spikes and could the MCU get damaged or short due to any abnormality in circuit 2. I am using the circuit for long term continuous use. Which circuit, out of circuit 1 and circuit 2 is more reliable for long term continuous use?

If you cannot see the image then use this link:- https://drive.google.com/open?id=0B2HbfYZlVykfcEx0QWNkQjVJSlU

Attachments:

Why is this transistor required

rishi2628 — Tue, 14 Jun 2016 06:59:29 GMT

Why is the transistor Q3 required in this circuit of a optocoupler and a relay. Can't I directly attach the power pin of the relay to the opto coupler pin 3 and ground the other pin of the relay. I tried it and it works. Just want to know why is it not implemented and why is the transistor required.

Attachments:

Solar panel Raloss delivered with inverter?

compositessensing — Mon, 23 Feb 2015 15:32:52 GMT

Hi,

I am interested in purchasing the 20W- 12VDC solar panel (SR20-36 - RALOSS).

Is the inverter included (or any electronics)?

Or do I need to purchase this seperately?

If so, which inverter do I need to purchase/ is compatible with this panel?

Thank you in advance!

Eli

how to pulse a signal

Former Member — Mon, 09 Feb 2015 23:34:36 GMT

I want to build a hack that closes a switch using an optocoupler every 1-100 times a second. I was wondering what module/circuit/ic that could pulse an adjustable signal using a pot. Could someone direct me in what could do that?

How do I resolder a ripped off wire to circuit board?

Former Member — Sun, 04 May 2014 13:48:04 GMT

Hi, this is a small circuit board from inside a Pioneer S-Z460 speaker. As you can see in the picture, one of the wires has been ripped off. How can I resolder it without the copper solder area in place? I've tested the two other points at the red marking with the small copper sticking out from underneath the green paint, and it's a connection. Do you think those three are just the same? I'm new at this so please explain simple, thanks!

My power supply has a fault varistor with following no's SL 22, 10008, 4213. Can anyone recommend an equivalent. Thanks.

Former Member — Fri, 28 Mar 2014 10:02:49 GMT

The power supply Cotek AK-3000-48 has gone faulty. The varistor is faulty. The numbers are on the varistor are

SL 22, 10008, and 4213.

Can anyone recommend equivalent.

Thanks

GFCI PCB Wiring Diagram/Schematic

Former Member — Tue, 04 Mar 2014 21:37:32 GMT

I would be grateful to any one who could point me to a GFCI PCB Wiring Diagram/Schematic for 110v and 208v AC power

Panasonic 1W/2W ESD protection diode in small packages

Former Member — Thu, 17 Oct 2013 18:28:01 GMT

Panasonic is now offering 1 W and 2 W power rating ESD protection diodes in its 2-lead Small packages SOD123W and SOD128

- industry-top-class small pacakges.

These series are new developed small surface mount package ESD protection diode series which power dissipation are

1W (DZ2W series) or 2W (DZ24 series), mainly used for surge absorption.

Features

45% mounting area comparing with conventional 1W type (DZ2W series)
Zener voltage tolerance : ±5%
Zener voltage : 2.4V to 51V (DZ2W series)
4.7V to 51V (DZ24 series)
Halogen Free Package

Applications

Surge absorption circuit
Clipper circuit
Constant voltage circuit

For further information, please contact me or visit our website.

http://www.semicon.panasonic.co.jp/en/products/discrete/diodes/zenerdiodes/

Attachments:

community.element14.com/.../Panasonic-1W-1W-ESD-protection-diode.pdf

Panasonic 1W 1W ESD protection diode.pdf

Are Magnetic Components Producing Trannies Well?

Former Member — Fri, 17 May 2013 01:12:46 GMT

Hi all,

If you read through magnetic components official site and their description of how they make these trannies,

they make it sound like theres is better than say Mercury or Heyboer or even Marstran.

They say that they dont hammer their transformers that they do some other process,

where they use a press machine. I'm pretty sure these guys make awesome trannies for everything, but guitar tube amps are a whole other monster.

What do you guys think?

Have any of you compared these with the originals or with Heyboers?

Thanks.

Simple FET question

billabott — Thu, 03 Jan 2013 12:48:09 GMT

I will be double checking any opinion with a Multimeter. I ordered a less expensive part for this project "by mistake" from Newark. The N-Channel FET equivalent of Q2 (ZVN2106A) was ordered and was 33% of the cost of the P-Channel FET. The gate of Q1 is controlled by a signal coming over the Parallel port of a desktop PC. It seems to me that Q1 and R5 can be swapped and everybody will be happy. Am I correct?

How to protect a flyback SMPS's output for misconnection of 230VAC mains

Former Member — Wed, 28 Nov 2012 09:50:52 GMT

I had have written this title to power managment but here i can find something better maybe?

You can see previous title from here,

http://www.element14.com/community/message/64903#64903/l/re-how-to-protect-a-flyback-smpss-output-for-misconnection-of-230vac-mains

Any help is welcome.

It is easy and clear to understand from the title,

I have a SMPS for an device, it works good but traders say in usage people allways misconnect such things without reading our asking anything even they are educated for that kind of jobs. So we need to protect our SMPS's output from misconnection of 230VA or anything?

SMPS is made with PI's TNY275GN, there is a MUR115 Diode looking to output and a parallal 150uF Al. electrolic Capacitor as usual. After that we have a DC/DC converter made with LM25011MY/NOPBLM25011MY/NOPB to limit current on a specifik value (we put that to control output's rise times and fall times in normal mode and current limit mode). After this LM25011MY/NOPBLM25011MY/NOPB converter circuit we connect our devices but we need to protect this output for 220/230VAC 50/60Hz mains with large tolerances. LM25011 circuit is the circuit when you write TI's main page 23-25V input and 17,5V/0,22 output select LM25011 with adjustable current limit from selections then you can see the circuit which needs to be protected from mains connection.

Is there any easy way anyone already know basicly?

Best Regards,

Tolga,