Where do I connect the smartshunt external temperture sensor on an 16 cel battery? Just on any cel?
Always on battery plus terminal. That sensor is specifically adapted for use with the BMV Smartshunt and combines the B+ power / voltage sense wire with one of the two temperature sensor wires.
If I recall correctly the sensor is a high resistance (over 100kOhms) NTC wired between B+ and the second input in the BMV.
The temperaturen sensor should measure the battery or cell temperture not the + bolt on the case.. I guess I have connect the sensor on eight (or so) cell to have sufficient voltage for smart shunt power supply need.
Please read the instructions, what you plan to do will not work. Technically speaking I guess you could locate the sensor elsewhere but you’d still need to connect the sensor lug to B+ somehow otherwise the BMV will not be able to read the full battery voltage. That’s just how it is designed, presumably a leftover consequence of the good old lead-acid battery days.
If you need more temperature sensors or at an other location, your best bet would be to get VenusOS on a Cerbo GX or on a rPi in combination with an I/O extension of sorts. Then you can use all kinds of temperature sensors to fit your needs (but not the special BMV sensor though).
PS, we use the BMV temperature sensor to monitor a fuse-solonoid combination on B+ and then use the BMV Smartshunt relay to turn that solonoid off when voltage and/or temperature get out of preset safety ranges.
I want to use the smartshunt as secundary bms if the battery bms fails. (Jk v19)
I do not have any Victron device yet, looking for the multi RS, Cerbo, display, smartmeter and the smartshunt.
For us the key advantage of the Smartshunt, by far, is it’s superior State of Charge (SoC) calculation, especially for lithium batteries. Most consumer grade BMSses, even the latest and greatest JKs, are notoriously incapable of getting (and keeping) track of an accurate SoC%. The rest is pretty much nice to have and yes using it as a secondary safety device to control a relay on the positive battery terminal is nice way to put it’s other capabilities (temperature sensor, programmable relay, alarms and digital interoperability with the VenusOS platform to name a few) to good use.