What about a raspberry pi with python to read the gpio pins and a web=20
server?

Gordon Williams


On 15-02-24 01:30 PM, Dwayne Reid wrote:
> Good day to all.
>
> We've been approached by one of our clients to come up with a
> wireless data logging and reporting system.  This is going to be used
> to monitor Lithium battery packs for failure.
>
> These battery packs are comprised of Lithium primary cells used in
> groups of 6 (3 wide x 2 end-for-end) cells per array, 4 or 5 arrays
> per system.  The cells are size "CC" and look like two "C" cells
> stacked end for end.  They are mounted on the outside of the system
> enclosure but will have another skin added to the system before it is shi=
pped.
>
> The issue is that the customer will very occasionally have one or
> more cells fail while they system is on its' storage cart.  They want
> us to supply a wireless monitoring system that will alert them of a
> temperature rise and then continue to provide live (real-time)
> temperature data should the cell (or cells) proceed to the "vent with
> flame" stage and then through the cool-down phase.
>
> Maximum temperature that has been recorded on a cell undergoing
> failure is about 175C - the temperature sensors should be able to
> withstand that temperature and then continue to report as the
> temperature falls back towards ambient.  The monitoring system will
> be mounted away from those cells and it is unlikely that it will be
> exposed to temperatures much above ambient.
>
> This system needs to have wireless connectivity because the storage
> carts are mobile.  They are happy with us using their internal WiFi
> network but other wireless options are also acceptable.  I'm not sure
> what kind of battery life they want the monitoring system to have but
> I think that we have the freedom to add as much battery as necessary.
>
> Because they evacuate the facility when one of these cells fails, the
> wireless signal must be accessible from outside their building's
> perimeter.  The facility's WiFi network works well in that regard.
>
> The main issue for the customer is that the temperature monitoring
> system must be easily installed and removed from the device without
> being damaged.  We are working on ideas for that right now.
>
> I'd like the monitoring system to have at least 10 inputs but more
> would be nice.  The most ideal would be to have a temperature sensor
> for each cell (30 cells max) but that may not be feasible.  I'm
> planning on using thermistors for many reasons - some models of
> thermistor are good for up to 300C and they are relatively
> inexpensive to replace should a system actually have a cell failure
> that proceeds to the 'vent with flame' stage.
>
> Sample rates: once per minute is fine while the temperature is below
> some threshold.  Sample rate should increase to once per second or so
> after the temperature has increased above that threshold.  I would
> also very much like to have some form of logic output that signals
> when that threshold has been reached.
>
> I'm hoping that someone can suggest a suitable system that is
> available for purchase.  Quantity is going to be only 6 systems or so
> which makes this a project that I don't want to develop internally.
>
> We need both ends of the equation: the wireless monitoring system
> itself as well as the software that makes the data available
> externally.  An ideal system would use a web browser to access and
> display the temperature in real time.
>
> Suggestions gratefully accepted.
>
> dwayne
>

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