My Lynx Shunt is throwing a low temperature error, with a reported temperature of -430°F. Might have been 460°F, I didn’t get a picture. The reported temperature seems to change to the correct value for a while after I wiggled the wires, then reverts to -430°F. I’m using temperature sensor (ASS000001000).
Such a low reported temperature usually indicates an open circuit, so I’m thinking the sensor is failing. The sensor has been in use for less than a year.
While the sensor isn’t cheap, I don’t know that the replacement cost is so high that just buying a new one is easier/faster than pursuing a warranty claim. I checked the connections and they seem to be OK.
Any other things to check?
As an aside, if the Lynx Shunt is seeing such a low temperature, shouldn’t that prevent the inverter from charging the LiFePO₄ battery. I thought I set the inverter to not charge below 35°F. I know the MPPT have that set.
Test the shunt with a temporary connection of 100 - 800 ohms in place of the sensor.
As for the charging restriction, that depends on the rest of the setup, and the source for the temperature sensing in the Gx device. It’s possible that the battery / BMS has its own temp sensor, so the Lynx Shunt sensor isn’t needed anyway.
I don’t have any resistor that would work for that. I do have a multimeter that could check the resistance in the sensor, but I don’t know what to look for.
I have a total of seven temperature sensors on the battery. One for the Lynx Shunt, one each for the two Cerbo relays (used for activating the warming system) and four for the BMS. I prefer to cutoff charging (by the Quattro and MPPT) at a higher temperature than the BMS cuts off charging. So I need the shunt to have the right temperature.
OK, so if you disconnect the shunt lead from the Lynx, you should be able to probe the cable contacts with the multimeter. This will either give an open circuit reading , or a resistance - typical sensors are 100 ohm@25C, 1kOhm or 10k Ohm, but there are many variants.
The one part number you refer to for me measures about 38k Ohm at 25C.
I had a camping trip this weekend and my wife would not have been happy listening to the alarm, so I replaced the temperature sensor with ASS000001000. No alarms so far.
After pulling out the old sensor, I checked it with my multimeter. I get 40k Ohms, but then it whigs out and throws a random reading, including open circuit. So it looks like the sensor is failing.
The ferrules that came with the new sensor are longer than the old sensor. The old one fit better in the Lynx Shunt. Neither sensor had the yellow tag on the wire like the ASS000100000 for battery monitors does.
I think I had the right sensor, it’s just failing.