BIG YES to pressure monitoring. ?
??
Minimum of one pressure sensor is decided for my first 280Ah 4S build. It's a "no-brainer" to me after seeing so much tragedy and loss when things go "puff pastry".
As for how to integrate it, and what sensor to use, I personally am still in evaluation phase.
- Load cell + amplifier
- Barometer
- Force sensitive resistor
These three are the ones I am seriously considering. Force sensitive resistor, as you mentioned, is extremely easy to integrate. For that reason alone I might end up using it as well.
However, the force sensitive resistor is not known to me for its linearity, so I would want to verify its performance myself before installing it, out of an abundance of caution. Nonlinear resistance based measurements are one of those things I keep my eye on in that way.
Barometer.
Like having a heavy duty inflatable whoopee cushion instead of the springs. Rigid outer walls, two heavy duty air bladders, and the pack in between. Fill the bladders to specified PSI at specified SOC and cap them and monitor pressure. Patch holes if leak form, with epoxy or other appropriate sealant.
This sensor seen above supports up to 25PSI and reads out 24-bit values which is A LOT OF NUANCE! Alas, haven't found a satisfactory airtight heavy duty whoopee cushion to do this yet. But it would work. I've used that sensor in other remote sensing projects. Good stuff.
Load cell + amplifier.
load cell
https://www.sparkfun.com/products/13331
load cell amplifier 24 bit
https://www.sparkfun.com/products/13879
These are what I'm planning on using, because simply do not feel that confident in force sensitive resistor linearity long term for my own needs. However, integrating them is a little bit more annoying than FSR.
It'll be expensive to include 8 load cell sensors and amplifiers, but it's my first pack and I need raw data to get away from all the anecdotes.
View attachment 67141View attachment 67142
Four load cell sensors mounted on an exterior plate which is ridigly fixed. (Black plus knobs) Then a rigid separator (Gray line) and the battery (blue box with nub on top).
Like this, on each side of the pack. Intending to monitor all 8 in realtime and log time averaged values. Very open to other ideas. Feel good about this template design one for my own use.
Hope this helps. Pressure monitoring is a big yes from me.
if anyone sees flaws in these assessments, please let me know!