How to log voltages of a lithium battery 16S6P?

[jumpjack]

I have this battery:
16S6P, 64V, 24Ah, Li-Ion
Which one of ther very interesting Texas Instruments ICs is more suitable to be used together with Arduino board to log voltage on each cell during my electric-bike travels?

 

[davec]

the cellog 8 is a good solution
not only can it store/the data - you can also upload it to a computer later on to chart graphs
there are 2 versions so you have to make sure you get the right one

 

[jumpjack]

the cellog 8 is a good solution
not only can it store/the data - you can also upload it to a computer later on to chart graphs
there are 2 versions so you have to make sure you get the right one

I like DIY, so I'd like something I could connect to my Arduino board.

 

[ambroseliao]

You'll need two and be sure it's the Cell-log 8S which is the logging version. The 8M is the non-logging version.

 

[jumpjack]

Has 8M any output I could connect to Arduino board for logging?

 

[megacycle]

With 16 arduino analogue I/O's can you run a program to sample the individual cells and display volts i'm not sure how many bit the basic Arduino are 24? would you need much to interface the cells to the Arduino, resistor divider not sure?
Is there already a volt logger Arduino, how's that done.

I'd be very interested in this reckon Arduino could provide a cost effective complete ebike monitoring solution.
Not just volts all parameters, alarms, temps, gps, bluetooth, android to smart phone used as interface/display.
Man its almost limitless.

 

[jumpjack]

If you think better about how to design the circuit, you'll figure out it is not possible (due to common GND).
But I found several very cheap ICs suitable for this task.
For example a Maxim MAX11068; I just received some sample, together with many others from others manufacturers, I'll spend summer experimenting... :lol:

 

[dak664]

Atmel introduced a couple of chips several years ago. The 6 cell monitor-only went obsolete pretty quickly
http://media.digikey.com/pdf/PCNs/Atmel/HE121704_ATA6871_Obs.pdf

The device for 6 cell monitoring and equalizing seems available in quantity. The evaluation kit is pricey, but samples are a possibility
http://www.atmel.com/devices/ata6870.aspx

All those potentially high current landings a half millimeter apart scare me, I think a <$1 attiny on each cell would be a safer and even cheaper solution. They could send the readings through optoisolators, or to completely eliminate intracell wiring through infrared leds, or a high frequency carrier riding on the DC output.

 

[megacycle]

Sorry i gave up electronics in the eighties for electrical so not to flash on latest stuff, so please forgive my ignorance.
What chip does cellog use, any good for this.

 

[jumpjack]

All those potentially high current landings a half millimeter apart scare me, I think a <$1 attiny on each cell would be a safer and even cheaper solution. They could send the readings through optoisolators, or to completely eliminate intracell wiring through infrared leds, or a high frequency carrier riding on the DC output.

These chips already do this: they "cycle" through the cells, electrically connecting to only one at a time and sending data to an external micro.

 

[themotorman]

If you think better about how to design the circuit, you'll figure out it is not possible (due to common GND).
But I found several very cheap ICs suitable for this task.
For example a Maxim MAX11068; I just received some sample, together with many others from others manufacturers, I'll spend summer experimenting... :lol:

The max11068 and the eval board they provide does work to provide detailed monitoring of the pack. However I have been using these for a large pack of 7 x 16 cells ( 400 volt ) and found a failure mode possibilty due to an open cell or open wiring to one of the monitoring inputs to the 11068. If this occurs you get the full pack volts across the open cell location with bad results. I am talking to maxim about this and hope to post a solution as otherwise the chip is really great.

 

[jumpjack]

Can you please give more details?

 

[themotorman]

If you think better about how to design the circuit, you'll figure out it is not possible (due to common GND).
But I found several very cheap ICs suitable for this task.
For example a Maxim MAX11068; I just received some sample, together with many others from others manufacturers, I'll spend summer experimenting... :lol:

The max11068 and the eval board they provide does work to provide detailed monitoring of the pack. However I have been using these for a large pack of 7 x 16 cells ( 400 volt ) and found a failure mode possibilty due to an open cell or open wiring to one of the monitoring inputs to the 11068. If this occurs you get the full pack volts across the open cell location with bad results. I am talking to maxim about this and hope to post a solution as otherwise the chip is really great.

Solved ( I hope!! ) you put 5 volt zeners across all the cell inputs to the chip, thisa makes sure that even with an open cell or cells oyu cannot get more than 5 volts across the chip inputs, that is a safe voltage. I haven;t tried to test this by deliberatley opening a cell connection as it is too messy to replace SM parts that might blow and almost imppossible for me to check if the 11068 chip is damaged but not blown..it has low current zeners for static protection that could blow and you wouldn't know. I am getting very close to testing a 112 cells array using 5 MAX11068 eval systems. I'll post results if and when it is working..
I am open to direct contact via email if your questions are outside this topic.