Universal Battery Charger

[hisham.i]

It's very intersting, thank you very much flex
but i have a question concerning the charger.
how did you convert the ac voltage to dc voltage? is there any external circuit with transfomer which makes this conversion?

 

[wizpic]

It's very intersting, thank you very much flex
but i have a question concerning the charger.
how did you convert the ac voltage to dc voltage? is there any external circuit with transfomer which makes this conversion?

CAN'T YOU READ :-D
If you looked at his web site there is no drawing for the external circuit. you can use something like this
**broken link removed**
or somthing along these lines
https://www.electro-tech-online.com/attachments/electronic-projects-design-ideas-reviews/1381d1075904841-24v-5-amp-power-supply-circuit-comments-required-ps3schematic.jpg
There are plenty of designs out there

 

[wizpic]

For those who has not got ISIS here is a link to watch it

YouTube - uni charger

 

[Felixls]

You use a DC power supply, this basicly uses a transformer,bridge rectifier and some smotthing caps. an 18-24V 5amps power supply should do it

Wizpic, if you supply with more than 20V will damage the IRF9530 because it exceeds VGS (+/-20V), in my design I put max 24V but is wrong.

Greetings

 

[wizpic]

Thakns for that Felixls I will remember that for the future, My menu system is completed, the next part is the charging routines which is the most challenging part
I have question for you when you charge SLA battery do you use the temp sensor for charing ?

 

[Felixls]

Thakns for that Felixls I will remember that for the future, My menu system is completed, the next part is the charging routines which is the most challenging part
I have question for you when you charge SLA battery do you use the temp sensor for charing ?

"The voltage limit shifts with temperature. A higher temperature requires slightly lower voltages and vice versa. Chargers that are exposed to large temperature fluctuations should be equipped with temperature sensors to to adjust the charge voltage for optimum charge"

source


This means it is not essential, but the temperature sensor may be necessary in certain contexts.

 

[hisham.i]

I read it wizpic, and since i didn't see any external converter i asked the question...any way thanks for reply

 

[wizpic]

Here is the latest hex version of the menu selection, The Nicad,nNimh,SLA are all setup.
Felixls I have some queations for you
Q1. do you control the pwm in the Interrupt routine of within the selected battery type ?
Q2.I persume you have set some variables for the max voltage,charge current,temp and a time limit, then within your routine you keep comparing these against the actual readings ?
Q3.do you use a lookup table for the temp sensor ?

Regards,
Wizpic

 

[Felixls]

Here is the latest hex version of the menu selection, The Nicad,nNimh,SLA are all setup.
Felixls I have some queations for you
Q1. do you control the pwm in the Interrupt routine of within the selected battery type ?
Q2.I persume you have set some variables for the max voltage,charge current,temp and a time limit, then within your routine you keep comparing these against the actual readings ?
Q3.do you use a lookup table for the temp sensor ?

Regards,
Wizpic

Q1. No, I use a while loop, the only thing I do in interrupt is measure time (msec, sec, min).
Q2. Yes
Q3. No, but for a NTC is required. I recommend LM35 instead of NTC.

Regards

 

[wizpic]

Q1. No, I use a while loop, the only thing I do in interrupt is measure time (msec, sec, min).

That makes it easrier

Q2. Yes

I thought so.

Q3. No, but for a NTC is required. I recommend LM35 instead of NTC

I was thinking of using one of those or a DS18B20 or 21, but the 21 does not increment in .5 deg.

So If I understand this correct you set the AH say 2.5AH then set the C say 0.6 = 2.5*.6=1.5 so this gives a charging current of 1.5amps
IS this how you work out the charging current at peak and set the PWM accordingly

thanks

 

[eeye]

Wizpic looks good... There is no problem with all those pesky variables, the AN450 has all the details... Please send me ur source code and I'll add all those charging types including limiting and parameter settings :-D By the way you can use either an LM35 or LM335 for the temperature sensing. The better way to use LM335 would be to use a lookup table with about 5 points and then interpolate the rest. The other way to do it is to break open an old LiIon battery pack, you'll find minimum two thermistors clinging on to the cells. Just use them 8)

 

[wizpic]

eeye the code is wrote in PDS(Proton basic).
The way I was going to work it was get the menu structure up and running then has fotr the charging parts I was going to get them to work on there own first then just integrate the two together. Has I found when I was writing and testing the menu I was getting fed up with waiting selecting everytime I altered some code.

So the way I was going to do it is set the values manually create the Interrupt (well copy the one I already use) for the counting the time then work it out from there, so if you want you could have ago at creating the charging part with all the limiting and parameter settings then we could integrate the two together. :-D

 

[MikeOhio]

I was thinking of using one of those or a DS18B20 or 21, but the 21 does not increment in .5 deg.

Steve,
I think if you check Dallas AN 105 you'll find the DS1821 is capable of hi-resolution. If you want some to play with, I can mail you a handful
Mike

 

[wizpic]

Thanks for the offer Mike, I have a few of these lying around. I have looked at the AN105 notes, I will have to see about converting it to PDS.

I'm just making a few amendments for the final version of the menu structure.

eeye any joy yet with the charging types including limiting and parameter settings code yet ?

 

[RenatoBR]

Can anyone confirm some conection between LCD and PIC?
Pic pins 39 and 40, where to conect on LCD?
R/W from LCD, where to conect?

Renato

 

[wizpic]

Renato
Looking at the schematic pins 39 and 40 connect to the LCD DB6 and DB7 which are knwon has ISCP_PGD&ISCP_PGC
looking at the RW pin on the LCD that goes to ground but not shwn on the schematic
Hope that help you any more questions and I will try my best to answer them for you

wizpic

 

[wizpic]

This is my latest version of the code, The menu system is working all batteries have now been added, I've changed the the capacity from say 2.5AH to 2500MA has this is what shows on most batteries, I've aslo step in 50ma (but this can be changed if need be). I've also added the Interrupts for the timing.
You select battery type then charge/discharge set the capacity then the charge current then the number of cells then once you press enter this then displays the counting time and if I have worked it out correct is shows what the charging current will be limited to.

eeye any joy yet with your codings ?

 

[eeye]

Wizpic you seem to have made some great strides in your attempts. Great work man. I have been fighting with this C code for now about a week and still no joy :sad: Seems like this code conversion from the AN450 is a pain and not any useful even after many attempts Your path of making a whole new code seems to be the best way. It would be great if you could share your code instead of just the hex file, so that we poor souls can also contribute to the progress :-D

 

[wizpic]

I have been fighting with this C code for now about a week and still no joy :sad: Seems like this code conversion from the AN450 is a pain and not any useful even after many attempts Your path of making a whole new code seems to be the best way. It would be great if you could share your code instead of just the hex file, so that we poor souls can also contribute to the progress :-D

I knew it would not be an easy task to do, The best way would be to read the code and get a good understanding then from that write your own. I don't need to share any code at the moment it is only the menu system. If anyone wants to contribute you can, Like I said just write some code (the charger routine) and I can add them into main code.
With out been funny eeye it sounds like to me that your just after the source code, anybody can say I've been at it all week with no joy other than I can't see no evidence you've tried to or it just seems to be me doing all the work and only you interested in it. If you start from scratch with just one charging routine and come back we can progress from there
It would be good if Felixls share just bits of his code so we all can gain from his way of writing code.

 

[eeye]

I don't need to share any code at the moment it is only the menu system."

See you don't want to share a simple menu and you expected Felixls to share all his hard work 8O.

If anyone wants to contribute you can, Like I said just write some code (the charger routine) and I can add them into main code.

Where is the main code and what is it all about? My understanding is that the charging is the main code.:roll: The menu is just icing on the cake.

With out been funny eeye it sounds like to me that your just after the source code, ...

Dude, don't make such comments. Look back in the posts even Felixls had the same opinion about your writing. I had given you my website address, where I have shared most of my code under GPL. Its all my hard work written in C. I don't know what you do for a living, but I have a job to do and a family of 4 to feed. Given the bad state of our economy in the US, this battery charger project is not my Top priority. I don't care if it is not done, I'll pay $50 and get something from Radioshack that just does the job of charging batteries. I do these projects in my free time. I hope you got it.

By the way here is some ADC code Freeware (useful to read battery voltage and current), if you want to integrate it into the "Main Code". It is all in C and easy to digest.