Re: Propane/CO2 Alarms
We have a propane detector that came in a pop-up camper. The unit must be mounted near the floor. I would suspect CO2 is heavy and sinks, also, but CO detectors are usually mounted up high. Our CO detector is on the ceiling.
edit: I see the device in the link detects CO, not CO2. Nevermind.
The draw is minimal when boondocking. I haven't measured it, but I am sure it is less than leaving a light on. Now an RV furnace is quite another story . . . If you get a third night out of a single battery , you are doing well.
By the way, A Kill-A-Watt is for measuring plug-in AC devices, not 12 volts DC. If you put a Kill-A-Watt on your shoreline and measured the bus with everything but the detector switched off, you would be adding converter losses and battery charging current to the measurement, giving an improperly high reading.
There are two proper ways to measure DC current. High current draws, like an engine starter motor or a high-wattage inverter input, can be tested with a portable ammeter whose jaws clamp around the wire and sense the magnetic field the current is creating. Normal current draws, like lights, radios, and propane detectors are done by disconnecting one wire and inserting an ammeter in series so current to the device flows through it.
The easiest way is insert a meter is to remove a fuse, and put the leads of the (fused) ammeter across the contacts of the fuse holder. All the current in the circuit flows through a "shunt" inside the ammeter, allowing the meter to take a sample of the flow to measure.
Permanently installed battery monitors for off-grid or boondocking power systems, like the Bogart Tri-metric, use an external high-current shunt at the battery, and low-current wiring takes samples to the meter from the external shunt.
Someone said "Making good decisions comes from experience, experience comes from bad decisions." I say there are three kinds of people: those who learn from their mistakes, those who learn from the mistakes of others, and those who never learn.