It the problem still exists after vacuuming the detector, it may be your batteries gassing off during charging. This is not usually a problem if you only have the WFCO converter since it rarely gets above 13.6V. If you have solar
, it may produce enough voltage as it finishes off the charge or goes into equalization, to cause the batteries to produce a bit of hydrogen gas, which will set off the detector.
A number of attempts to better seal the top of the battery
box have been tried with mixed results, but switching to AGM or lithium batteries definitely solves the problem.
The detectors do fail early. The propane
detector in my 2017 21 failed in under a year. The replacement did OK, other than 2-3 times per month going off due to the solar