How do i track the voltage level of a battery?

I am an intern at a solar power company and am working an a project that tracks deep cycle batteries voltage level.

I need help with putting together a circuitry that would enable me get a hold of the voltage level of a battery at a time interval of 5 minutes, it then store this value at a memory location on a chip (am not sure which one). voltage level calibration should be in the range of 0-12 volts.

I don't understand the problem. What's keeping you from simply measuring the battery voltage with a microcontroller and storing the value in EEPROM? What exactly are you stuck on?

The issue is am new at this.
I want a guild in building the circuitry to do the measurement as well as how i can do the storage on an EEPROM.
If you could work up a schematic, i would be grateful. a specification of chipset names for the MC and the EEPROM would be ok too.

The essence of the storage is to enable me get a hold of voltage level values and send them to modify a remote database file.

How do you plan to communicate between the microcontroller and the remote database file?

ooh i get the part on 'simply measuring the battery voltage with a microcontroller' but am in a fix as to how i can do the storage.

based on suggestions i got from an IRC session, i am trying to see if i could use RF Link Transmitter.
this was the one suggested to me http://www.sparkfun.com/products/8945

what do you think?

If you plan to communicate via RF you need to answer a few questions:

* How much data do you need to transmit and how often? This will be based up on your spec of how often you need to measure the voltage.
* How far away do you need to transmit the data?

Other questions come to mind:

* What is the power requirements of your measurement and communication circuit?
* Is this a battery powered circuit?
* Can you use the power from the battery that you are measuring to power the device?

Victor,

If your microcontroller doesn't have non-volatile memory on chip or otherwise insufficient amount on chip you will need, as Olin mentioned, an external memory IC such as a EEPROM to store the values.

You will need to choose a memory device large enough for your data that uses a communication bus your microcontoller can act as the master for (SPI, I2C, etc.).

You would have to read the datasheets for the microcontroller and memory chip to determine how to set up the communication protocol between them (whatever it may be).

i can't say the amount of data, except that it wouldn't be something more than can be held in a memory location on my storage chip.

I intend to measure and transmit at a 5 minutes interval.

For i would use a range of a little over 50 meters, since the batteries i would be using are in battery boxes on solar streetlight poles at my companies premises.
the circuit would be powered by battery.

With regards the consideration on using the batteries i am monitoring to power my circuit, i can't yet.

I would be dealing with deep cycle batteries(over 100Ah) and am not sure how a small circuit could cop with supply from such.

Until i find a way of making supply from the batteries harmless to my circuit, i might have to stick with batteries that have low amperage.

Thanks Alec, you've just taken me over one hurdle.

But am not really clear on how to make the microcntroller act as the master in communication process.

If you plan on having several in the same area to make it easy by having the ADC, microcontroller, and RF transceiver all in one, take a look at the following module.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=602-1096-ND

Better yet, here is one with 32k of Flash memory on it.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=602-1181-ND

Victor:

Take a look at the www.synapse-wireless.com. I don't know how cost sensitive your solution has to be, but these guys make a really nice solution for what you are doing. Better yet, you MAY be able to use the micro inside their module to ALSO sample your battery voltage (through an appropriate resistor divider) and then send it onto the PC based system host. ALL of the wireless protocall management has already been done with their "SNAP" system: it is amazingly slick. Worst case here is that you would take a small PIC microcontroller and use it to sample voltage and communicate with the Synapse module. Still, you should try to get the Synapse part to do the entire job. That way, you will be up and running in no time! (Their system would require you to write simple little PYTHON scrips inside their development enviroment which is very easy to get up the curve on.)

Best Regards,

Just use a micro controller with an A/D converter, use can calculate a 5 minute interval from the CPU's Clock cycle or use a RTC.

Hi Victor,

I wasn't sure if you also read the comments on the same question you posted on Digi-Key's TechXchange below.

http://www.digikey.com/techxchange/message/3404#3404

Did you get all the basic explanations you needed so that you at least know what topics you need to do some research in to get yourself started?

Thanks David.

Thanks Dennis.
I was thinking they should be a way of simulating the timer in the microcontroller by adding a timing functionality to my codes for the conroller?

My deduction at this point is that i would be needing a microcontroller with an ADC and that has peripheral connections for a RTC (Real time clock), an EEPROM and that i would need to set up a communication bus between the the MC and the EEPROM based on specifications on their datasheets, keeping in mind that the MC would be the master.
Am i correct?

I would check the SNAP system.

I think that you should be able to find a microcontroller with an ADC and enough memory for your application. You might even get one with a built in RF transceiver. Take a look at this "microcontroller":http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en010384

* 10-bit Analog-to-Digital (A/D) converter
* ASK/FSK RF transmitter
* 128 bytes of EEPROM

This is the first device I came across. There are other devices with different options.

I would certainly check it out.
Thanks Cody.