Ran out of 12 DC @ 3 AM 1st night.
Our first boon dock night in our new to us MH and the 12V DC went dead. When I bought the coach they told me the batteries were fairly new I need to see if they have dates on them. Now for the use may...
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First, let me say, you can throw a lot of money at this issue especially if you want someone else to do all of the work. The diagnosis is not that hard, so it is time to learn a bit about 12VDC electric power.
You need 2 tools, and old fashioned non-LED 12V test light and a multi-meter, preferably one with a built in "amp clamp" like this one.
A good quality pure sine wave inverter easy between 80-90% efficient.
LESSON #1 - Watts is watts, whether it is AC or DC, 120V or 12V (well, close enough anyway) and voltage time current equals watts or V x I = W (I don't know why they use I for current). If your CPAP machine draws 1A @ 120VAC (120W) it is going to need about 10A @ 12VDC (120W). Then you have to add the loss of the inverter so you need an extra 20% or 12A.
Probably, but it does depend on how good a job your charger does topping off the batteries.
LESSON #2 - Monitor your battery voltage. There are many different volt meters you can mount inside the coach at a convenient location.
Concur on both !
You need 2 tools, and old fashioned non-LED 12V test light and a multi-meter, preferably one with a built in "amp clamp" like this one.
Gundog wrote:
Do the inverters draw a lot of power if they don't have a large load on them?
A good quality pure sine wave inverter easy between 80-90% efficient.
LESSON #1 - Watts is watts, whether it is AC or DC, 120V or 12V (well, close enough anyway) and voltage time current equals watts or V x I = W (I don't know why they use I for current). If your CPAP machine draws 1A @ 120VAC (120W) it is going to need about 10A @ 12VDC (120W). Then you have to add the loss of the inverter so you need an extra 20% or 12A.
Gundog wrote:
Had I run the generator before going to bed we would have probably been OK but it seems it should have lasted longer than it did.
Probably, but it does depend on how good a job your charger does topping off the batteries.
LESSON #2 - Monitor your battery voltage. There are many different volt meters you can mount inside the coach at a convenient location.
Gundog wrote:
My battery bank for the house is 4 - 6 volt golf cart type batteries.
camperdave wrote:
With 4 6 volt batteries you should have no issues getting through the night even with the heater. Checking the dates and condition of the batteries would be step one.
Trackrig wrote:
Also - check your battery water level and clean your battery cables.
Concur on both !
