Small gauge wire from battery

[TitanMike]

Originally Posted by Outsider

Anyone have any idea if the new 24VDC units actually draw less current over time than the previous 12VDC units. This is out first CPAP so I have nothing to compare to.


If we have to keep this 24VDC unit what setup would use the least amount of battery in the long run when dry camping? (12V to 24V adapter straight from the battery perhaps?) As I mentioned earlier we do about 50% boon docking/dry camping. I already plan to add 2 GC2 batteries and will probably have to boost my solar panel as well (have 100W on top from the factory and may add about a 200W portable with charge/controller to the side mount solar port).



Thanks.

It all boils down to wattage. 120 watt appliance (just to use this as an example) will draw 240 watts on 12 volts which converts to 20 amps plus whatever overhead of the inverter. If your inverter is powered by 24 volts then it only will draw 10 amps plus inverter overhead. Still the same wattage output with the difference being the input voltage/current to the inverter.

Rather than look at the voltage of the CPAP unit, look at the wattage then divide it by 12.5 to see how many amps it will draw whether through direct connection if 12 volt or through an inverter if a 24 volt unit.

Once again, think watts as they will be the same at 12, 24, or 120 volts.

As said earlier, connecting directly without adapters or Inverters is the most efficient.

[Bobduck]

I ran a 14 awg speaker wire from a fuse block I put near the battery, to a 12v accessory jack I installed under the bed. I actually put one on each side of the bed in case I sleep there. Each has their own fuse (15 amp).

[Outsider]

Bobduck or anyone,


Where can pick up the 12V adapter port that you mounted in your camper? Any local stores likely to have them heavy enough for this application? I like to buy local when I can. Lowes? Home Depot?



Thanks.

[llamb]

Maybe an auto parts start or marine or RV dealer. Big box hardware, maybe, but much like auto parts, they might be auto specific and designed to be surface mount. You're wanting a panel mount version.

[Bobduck]

I went back to my RV dealer. It is a family owned business and they bend over backwards to provide service after the sale.

[2WheelJon]

Originally Posted by Bobduck

I ran a 14 awg speaker wire from a fuse block I put near the battery, to a 12v accessory jack I installed under the bed. I actually put one on each side of the bed in case I sleep there. Each has their own fuse (15 amp).Attachment 251751

If fused at 15 amps then you're figuring 14 gauge wire can handle 15 amps. It can, but only up to 6 feet. Longer than that you need to go to 12 gauge. Or lower the load on the wire to 10 amps, fuse it at 10 amps and the you can go 9 feet.

[Bobduck]

My cpap only draws 6.7 amps with heater in use and I never use the heater so I feel that the wire size and length are more than adequate. I probably should use a 10 amp fuse.

[2WheelJon]

Originally Posted by Bobduck

My cpap only draws 6.7 amps with heater in use and I never use the heater so I feel that the wire size and length are more than adequate. I probably should use a 10 amp fuse.

Given that load the 14 gauge wire will do fine. However, the fuse, which protects the wiring and device attached, should be sized for the load and wire size. So yes, you should reduce the fuse to 10 amps and then all will we fine.