Few, if any, of these cameras at this price are hermetically sealed. The only way you can prevent this type of moisture intrusion in an outdoor device where there is even indirect exposure to humidity and moderate heat followed by cooling off is by using O-rings, gaskets and sealant on the case, all fittings and pigtail cable then slightly pressurizing the case with inert gas. That would make our $120 cams cost probably 5 to 10 times more. Cams I swapped out back in the 80's on the building for offloading and counting the fares from municipal transit buses were of that type. The technology of that era used Vidicon and Trinicon tubes, not CMOS sensors, and cost several hundred 1980's dollars.
Today's cameras are assembled tightly with perhaps gaskets and sealant rings, not filled with inert gas and are rated generally
IP66 or IP67 but until you reach IP68, I think the following occurs under the right ambient conditions.
Cameras generally acquire and collect moisture inside them due to a process I call
Thermal Differential Cycling.*
After being warmed up from the sun during the day, the camera case cools off as dusk approaches and it begins to draw in the moist, outside air. Where the pigtail enters the camera can be a definite point of ingress for this moisture. As the night progresses and the temp of the camera's case drops, that moisture condenses on the inside of the case, most noticeably on the inside of the lens. Then the sun comes up and begins to heat the case of the camera, the air inside begins to expand, pushing some air but little of the moisture out of the case...and the cycle starts all over again.
Opening the camera, drying it out and replacing the desiccant bags periodically is only a temporary fix and a more lasting solution is desirable. I suggest the following procedure to fix a chronically affected camera and help prevent future moisture intrusion is as follows:
Wait until the ambient relative humidity is at its lowest point. Chose the driest environment you can for this procedure; in other words, the bathroom after someone took a hot, steamy shower or the kitchen after or during the stove has cooked or boiled anything is NOT a good place. This will be the biggest challenge but is likely the best way to not trap moisture-laden air inside the cam before re-assembly. Late afternoon, outdoors, sunny, no rain for 24 hours and out of direct sun may be your best bet.
Open up the camera, noting how it is assembled and what gaskets and sealant rings are in place then dry it out. Soak up excess moisture with lint-free cotton rag, handkerchief, etc. Use a small hair dryer on low to assist with the drying out of the cam's interior but don't overheat any of the components.
Allow the camera to cool down to room temperature.
Replace the
bag(s) of desiccant with new or dry. If you have no new bags, take the existing ones, dry with hair dryer then bury in a cup of uncooked, instant rice for several hours to absorb moisture from the bag.
Reassemble the camera (DON'T FORGET THE BAG(S) OF DESICCANT), insuring gaskets and sealant rings are in place. VERY important: Insure that the pigtail cable entrance is sealed with
non-gassing, outdoor-rated silicone sealant. If any gaskets or sealant rings are missing or damaged or the cable entrance is not sealed, you'll be wasting your time and moisture will be back in sooner than later. You should use clear, non-gassing outdoor-rated silicone sealant to caulk the mating surfaces before AND after re-assembly, including the pigtail cable entrance. Allow to dry overnight before placing back into service.
* Thermal Differential Cycling : the device heats up during day, air inside expands, cools off at night and contracts, drawing in damp outside air, condenses, travels to low point, is trapped and won't escape during warm up cycle, just continues to collect inside at low points.
-TonyR 2020
EDIT: 11/11/23 0706 CT ; updated product links
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. I will check it out again when stops raining to check silicone is still intact etc and then hope was one of due to very hot temps in uk with sudden heavy rain. Thank you for sll your comments everyone.
