The CR800 has his supply voltage specified at 9.6-16 volts dc. Now I've seen that a CR800 has been running for over 2 years on a supply voltage between 13.0 and 17.2 volts. (Recorded by the logger itself using the BATTERY instruction.) The logger runs fine and the readings are prooven to be precise. So I asking me what is really the maximum supply voltage whitout damaging the logger?
The upper limit is really limited by a surge protection device on the wiring panel which is a 1.5KE20CA. You can look up the spec yourself but the key limit is for constant DC voltages, it starts to become leaky as the voltage is increased into the range of its nominal surge clamp voltage of 20 V. It is possible to damage that component if you hold the voltage continuously near its clamp voltage causing it to dissipate a lot of power.
There are also other issues of internal heat generation, which could increase measurement errors at high temperatures especially if powering sensors or peripherals from the logger.
This is why we quote a limit of 16V which is within the normal operational voltage of lead acid batteries. If the voltage crept a little above this, especially when cold, it should not cause a problem.
Thanks for answering. That helps a lot. Fortunately this logger is permanently at low temperature (0 to 10°C). Nevertheless we will occasionally install a power supply with less peak voltage.