Intelligent battery monitor

[jcsntoll]

I'm looking to build a circuit that will monitor a battery box.  Similar like what laptops use.

I have two 12v 1300Ah batteries in a battery box wired in parallel.  I use them in my car with a 500w inverter ( or cell phone and such )  it has a cord with a cig lighter end for charging, and two cig lighter jacks. ( I plug in an external inverter to run my laptop and such )

I currently have just a basic voltage display now, but I would like to build an intelligent circuit.
One that uses the Pic microcontroller, and a LCD display.
I would like a switch that turns on the display ( to save battery power ) when the display is on
I would like it to show percent charge. also if the batteries are being drained how much longer the charge will last, if the batteries are being charged how much longer till they are at full charge.
I might also like to display the current currently being used ( charging or discharging )
These can either be on one display or scrolled with a push button. I have several 2x16 displays to use.

I'm not sure where to start, but it doesn't seem like it would be that complicated of a project.
I figure the battery stats would be coded in so it can figure out the % charge, and time left.
Perhaps use the ADC to figure out battery voltage and current draw.
I'm not a very good programmer, so I'm not sure where to start.

Any suggestions or does any one of a project like that already? 
Thanks for all your help!
Chris

[Wizpic]

This does exactly what your after and this has been uploaded in the Silicochip topic, 


http://www.siliconchip.com.au/cms/A_111429/article.html

[Ahmad_k]

This is the complete design, it contains all pictures and source code and pcb, plus the article in PDF format

http://rapidshare.com/files/257890816/High_Current__High_Voltage_Battery_Capacity_Meter.rar

[Ahmad_k]

If you want any article from Silicon Chip Magazine just ask for article in this topic :
http://www.sonsivri.com/forum/index.php?topic=19993.0

[pdjh]

If you want any article from Silicon Chip Magazine just ask for article in this topic :
http://www.sonsivri.com/forum/index.php?topic=19993.0

Actually the correct topic for requests is here:

http://www.sonsivri.com/forum/index.php?topic=20780.100

[Jehan]

Linear technology has a dedicated battery monitoring IC LTC6802-1, it can monitor individual voltages even in series stacked battery stacks and has a daisy chainable serial output

[shailesh5]

there are  intelligent battery chargers for different types for batteries at Texas instruments, u even get free sample for evaluation, there are some ics which even have led connected to show u the actual capacity for the battery and the average time left

[MAXPAYNE]

there are  intelligent battery chargers for different types for batteries at Texas instruments, u even get free sample for evaluation, there are some ics which even have led connected to show u the actual capacity for the battery and the average time left

which ics have led connected ?

[shailesh5]

the led are not integrated but have to connect externally , have wrongly express what i meant
 battery fuel guage reference BQ20Z40  
 

Next Generation Patented Impedance Track Technology Accurately Measures Available Charge in Li-Ion and Li-Polymer Batteries
Better Than 1% Error Over the Lifetime of the Battery
Supports the Smart Battery Specification SBS V1.1
Flexible Configuration for 2 to 4 Series Li-Ion and Li-Polymer Cells
Powerful 8-Bit RISC CPU With Ultralow Power Modes
Full Array of Programmable Protection Features
Voltage, Current, and Temperature


BQ20Z40  

Charge Faster than Linear Chargers
High-Accuracy Voltage and Current Regulation
Input Current Regulation Accuracy: ±5% (100 mA and 500 mA)
Charge Voltage Regulation Accuracy: ±0.5% (25°C), ±1% (0°C to 125°C)
Charge Current Regulation Accuracy: ±5%
High-Efficiency Mini-USB/AC Battery Charger for Single-Cell Li-Ion and Li-Polymer Battery Packs
20-V Absolute Maximum Input Voltage Rating
6-V Maximum Operating Input Voltage
Built-In Input Current Sensing and Limiting
Integrated Power FETs for Up To 1.25-A Charge Rate
Programmable Charge Parameters through I2C Interface (up to 3.4 Mbps):
Input Current
Fast-Charge/Termination Current
Charge Voltage (3.5 V to 4.44 V)
Safety Timer with Reset Control
Termination Enable
 hope this can help

 u can try to adapt this to your system togheter with a pic 18 series

[jcsntoll]

Thanks for all your help!
I finally got the parts together to build the Battery Monitor from the Silicon Chip article.

Has anyone else tried to build this?  I have a problem.
The display doesn't work.

I'm using a 16x2 Lcd display with HD44780.  I see the parts list calls for a KS0066 driver.
I was unable to order the one from Altronics, since it would have cost me about $60 USD.
But I've read online these two should be compatible with each other.

I did notice the pin outs were different and corrected for that..
the HD44780 display runs from 1 - 16  ( 15 and 16 being the back light )
Where as the KS0066 display runs 14 - 1 , 16, 15 ( kind of odd but I wired my display to match )
It lights up but only displays the first row of solid blocks.

Does anyone have any suggestions?   is the HD44780 and KS0066 really interchangeable?
Anyone know of a USA distributer of Sunlike Display LCDs??

[shailesh5]

 i think that ure program in the microprocessor is not running or ure missing a wire connection
else try to upload a simple program just to test the lcd
test in is a block i mean just load a program in the pic lets say a led blinking to see the microprocessor activity then load the lcd test program
by the way which microprocessor are u suing , can u send the sillicon file to me see if i can help u
 
keep trying thats the solution jst take a break n start again never stik to it continously u wont find the solution thats the way i work normally well it my personal view

[jcsntoll]

Thank you for your response shallesh5.
The project I built is the Battery Monitor from the Silicon Chip June/July 09 issue.

The processor is running, because it turns on and the 5v adj regulator ( normally about 3v in sleep mode )
it also turns on the back light of the LCD, ( and infact does a nice slow transistion from on to off after a moment not
pushing any buttons )

The LCD it self works, I have another small project that tests them. Personally I think it's an init issue.
either that or I understand the KS0066 has some built in memory, perhaps they are loading something special
that the HD44780 can not use.

I've emailed the magazine to ask for either the source code, or a recompiled version of the hex built for the HD44780.
No reply from them yet.

[pickit2]

all the code for this project in here. see link  if you know C then you can recompile it.
the pins 1 to 14 and 15,16 for the back light are down to the maker or customer of the display.
I use two types and both look the same but when pluged in to the circuit one dispays data upside down.
Looking at the code, I see that the programmer uses a load of special grafics that are sent to the display,(ie double sizeds caractors)  is this your problem? your display can't have these in memory.

why not build it in proteus

http://www.sonsivri.com/forum/index.php?topic=23705.msg81105#msg81105

[jcsntoll]

Thanks Pickit2, I didn't notice the source was there.
I do not know much about C, but I'm sure the special grafics is the issue.  I don't believe the HD44780
can do that many special characters.

What controller are you using for the displays you are testing with?   Do you have the datasheets for them?
I'd like to compare to what I have here.  I have tried a couple myself, both look the same.
All I get is row one is a full row of blocks, and row two is blank.

Is someone willing to remove the special characters and replace them with standard ones and compile a Hex?
That should work with the HD4780.