Simplest 3S or 4S lithium ion protection circuit?

[sam_sam_sam]

Re: Simplest 3S or 4S lithium ion protection circuit?

This will tell you the status of the batteries that you are working with

I found this that you might be interested in

https://banggood.app.link/ediAr9t6v2

[Tarpey]

Re: Simplest 3S or 4S lithium ion protection circuit?

Do you think a setup like that will become cheaper to build anytime soon?

[sam_sam_sam]

Re: Simplest 3S or 4S lithium ion protection circuit?

Well here is some results for the USB charging board that I posted earlier

The one thing that is nice about this board is that it has a LED that lights when you have a load on it

But I think it has a few small problems the first one is that when you charge and have a load on it at the same time the charging current drops down to 350 milliamperes and a load I could not see how many milliamperes it was putting out because my tester was in the way but the board gets warm fast

When you have a one amp load the board gets warm fast but it put out one amp
When you just have the charger on it only it charges at 500 milliamperes and board is some what warm but nothing to worry about

So in the end results are if you keep the load under 750 milliamperes you might be alright
If you do not try to charge and have a very big load on it you might be alright

Is worth the money I paid for maybe depending on how and what I want to use it for

If I use it on non name brand batteries and not put a heavy load and do not care how long it takes to charge and do not want to spend a lot of money on test of concept yeah this fits the bill

[eccerr0r]

Re: Simplest 3S or 4S lithium ion protection circuit?

Yeah, it looks like it charges slower than it can discharge?

[budm]

Re: Simplest 3S or 4S lithium ion protection circuit?

Funny Chinese spec:
input Micro USB rated at 5V 0.62A
USB output rated at 5V 1A

[eccerr0r]

Re: Simplest 3S or 4S lithium ion protection circuit?

500mA doesn't do justice these days... hoping for at least 1A preferably 2 or more...
Then again 500mA is better than 0, I had a box that shuts off charging when itself is being charged...

[sam_sam_sam]

Re: Simplest 3S or 4S lithium ion protection circuit?

Looks like for 1S, and it's limited to 500mA output?

If scroll down to the details of the board it says 1 amp unless you charge and discharge at the same time then it is 500ma


When I test this board I will post the results and let you know what it really is

[eccerr0r]

Re: Simplest 3S or 4S lithium ion protection circuit?

Looks like for 1S, and it's limited to 500mA output?

[sam_sam_sam]

Re: Simplest 3S or 4S lithium ion protection circuit?

You might find this USB charging board interesting

https://www.ebay.com/itm/5V-1A-USB-3...53.m2749.l2649


I bought some to try out

I will post the results after I do some testing

[eccerr0r]

Re: Simplest 3S or 4S lithium ion protection circuit?

Hey, if people can get people to "recycle" their old battery packs for free, why can't I join in the fun? :-p

[sam_sam_sam]

Re: Simplest 3S or 4S lithium ion protection circuit?

Yes you are real cheap but if see something like that I will PM you about it

[eccerr0r]

Re: Simplest 3S or 4S lithium ion protection circuit?

Too expensive

I don't think I'd pay more than a buck or so for dead packs, and less than that prorated for questionable individual cells (on the order of a dime or so.)

So I'm cheap... next?

[sam_sam_sam]

Re: Simplest 3S or 4S lithium ion protection circuit?

I only did it to learn/Proof of Concept. It "does" work, not like it's completely useless, ***** had a host of other problems that I learned greatly from - which was its original intent.

I have done this quite a few times and yes you do learn a lot about a concept weather or it will work or not

Here is a EBAY listening for 18650 batteries for a little less than a dollar a battery

https://www.ebay.com/itm/FAST-Lot-of...8AAOSwHIBd0HsM

[eccerr0r]

Re: Simplest 3S or 4S lithium ion protection circuit?

Nothing special about it at all, it's just another control system. I only did it to learn/Proof of Concept. It "does" work, not like it's completely useless, though it has very poor transient response and had a host of other problems that I learned greatly from - which was its original intent.

In the end I was able to use it as a CC/CV battery charger that I could tell it to shut off after a while. Too bad it wasn't good enough to use as a general purpose bench PSU, which was the initial goal.

[sam_sam_sam]

Re: Simplest 3S or 4S lithium ion protection circuit?

I figure I can use the code I wrote for my failed project, a software SMPS

Could you please explain in little bit more detail about how this was going to work and what you were going to use it for

Too bad, gave up. I think I could work around the problem

I find myself doing a lot of this crap and if it becomes to complicated I run in another direction or table it

[sam_sam_sam]

Re: Simplest 3S or 4S lithium ion protection circuit?

Yes these coding projects took sometime months to finish because I would work on them when I had time to work on it

I am not very fast with writing code so it takes me some time to figure out how to write the code the way I want it to function and then I test the hell out of it to make it fail if I can make it fail

[sam_sam_sam]

Re: Simplest 3S or 4S lithium ion protection circuit?

The Basic Stamp was very easy for me to learn I find that the Atmel was hard for me to understand but

I guess because I started with the Basic Stamp and because there are so many example to be found on Parallax website and there was a Nut and Bolts magazine they had a contributor that had example code every month ( now this person writes a monthly code for the Parallax Propeller micro controller chip ) and can still be found on the internet

I have a Basic Stamp code for the DS1302 time chip where I could cause the time chip to start and stop it count and could also save the time count in the time chip

I learned how to do this because I had a project for a company that I used to work for that has a silo that held product for a sand blaster machine and they need a way to know how much product they had in the silo so poor soul would not have to climb to the top of the silo and look inside

If you are interested in the post what the finished product look like you can see it in this post

https://forums.parallax.com/discussi...t-in-the-works

If you want to look at the code written for this project you can look at it here

https://forums.parallax.com/discussi...ReSet_Demo.bs2 ( just hit the view button)

The way this code went is as follows

If the air gun trigger was pushed the time chip would start counting

There was some math that would take the time count seconds and the amount of used product ( 50 pounds of product how long it took to use this amount of product to be use up and how many seconds)

When the trigger was released the time chip would stop counting

Then I would save the count results in the time chip

I going to take this code and modified it so that I use it for battery testing in the way that I show in the example I gave earlier

But I going to modify the charger / discharge controller that I gave a link to as the load controller so I do make it more complicated than it needs to be

If I do this project it would make testing batteries a lot easier your post got me to think about this problem I was having testing batteries

One note I have not use a Basic Stamp in about two years so there is going to be a little bit of refreshing my coding skills again

Here is the code for the pool timer project

https://forums.parallax.com/discussi...ool-pump-timer

https://forums.parallax.com/discussi...Pump_Timer.bs2. ( just hit the view button )

[eccerr0r]

Re: Simplest 3S or 4S lithium ion protection circuit?

I've never used Parallax's offerings before, but I knew I did not like Microchip's PIC that I used for another project... Yuck Yuck Yuck. It wasn't the fact that I had to program in PIC-assembler versus C for the AVR (I programmed assembler for the AVR as well), but the nuances of the PIC...EEIIEEW.

It broke my heart that Microchip ended up buying out Atmel, it should have been the other way around and that braindead General Instruments/PIC blown to smithereens, though there's too big of a PIC following as well.

[sam_sam_sam]

Re: Simplest 3S or 4S lithium ion protection circuit?

Well if a few seconds off and hour is not so bad for what you would be do with it as long as it is conscience on each battery tested which would be the more important thing

I would be using a Basic Stamp 2 only because I have work with them before

[eccerr0r]

Re: Simplest 3S or 4S lithium ion protection circuit?

I figure I can use the code I wrote for my failed project, a software SMPS using an AVR.

I think it was using pretty much all the goodies on the AVR, using the ADC channels to monitor voltage and current, using the PWM to control voltage, LCD status and UI with pushbutton menus, and even had a software clock and remote RS232 CLI control, though I was cutting the CLI out as it was using a lot of memory.

Alas the system was too slow, even with doing my best to not have an interrupt storm from the software clock as it was a tradeoff from interrupts or ease of computation. Main interrupt that must be done is the PID controller based on ADC samples, and the timer had to be second priority. I figured that I could execute a few more instructions to correct accuracy issues for not getting a more frequent clock pulse, though I recall that I ended up with some strange fractional interrupt frequency like 28.125 Hz due to the dividers.

Took a few iterations but got the 1Hz needed to update a clock, both to enable a timed shutdown and to help out with key debouncing/repeat so I don't have to pound the up/down button 100 times to change the setpoint a few volts - just need to hold down the up/down button.

I guess the exact frequency for the clock pulse wasn't that critical, but it was good to finally get it working to within a few seconds per day, probably due to crystal tolerance versus the software problems I had initially (I had it losing several seconds per hour initially!). Might have been easier to get the frequency right if I had chose a crystal for the clock but rather I chose the crystal to ensure I get RS232 baud rate generator, though ended gutting most of the CLI anyway.

The LCD driver ended up being second fiddle. It was a busyloop and updated whenever it had free cycles, turned out there was enough free cycles to update smoothly. I just needed to make sure that the PID recompute interrupt doesn't take too long and crash into the next PID interrupt...

Too bad, gave up. I think I could work around the problem with a larger inductor and filter cap, but oh well.