I would have had no issue using a UL-listed home CO detector had it not been for the simple fact that it didn't work
for us after multiple purchases if different brands had multiple failures all with false alarms, usually in the middle of the night.
I suspect our flooded lead-acid batteries
at certain spots of the charging
cycle were just too much for them. Had they worked, we would still be using them today. It could be that other boats with other battery
chemistries have fewer problems.
The Xintex marine direct-wire unit was indeed expensive at $100. But it does not false alarm
It does only blink dimly for a fraction of a milisecond every three or four minutes. If you blink you will miss it after staring at it all that time and have to wait patiently for yet another few minutes of staring at it. This is a bit ridiculous IMHO.
Also, the test button does work
very well but I have yet to figure out exactly what the exact procedure is to cancel the test and shut the darn super-loud and annoying test mode off again.
It is a Steve Jobs "one-button" design and pushing it again seems to have no effect, nor does pushing it and holding, or any combinations of pushing and holding. The manual is a joke and really is not much help here. It says simply to push it again to cancel the test. That is demonstrably pure & unadulterated BS.
Every time we test the unit it is a few hellish minutes of trying everything I can think of to shut it up again including swearing, jumping up and down, and pulling my hair out until I chance upon whatever input it is looking for many minutes later. I am beginning to suspect that nothing turns off this brutal test mode and it is just a matter of time elapsing before it finally stops torturing you with loud annoying chirps that come and go before it is silent again. It is so annoying that I put off testing it as much as I should. I just hope it is still working which is a bit of a stretch since the little up-status blinking light is so shy I almost never see it.
But what so you expect for only $100?