Adding a 12v DC-AC Inverter

[viper1216]

Hey there,
Boat is a 2001 Maxum 2400SCR. Friend of mine has been telling me to add in an inverter to my boat. I have shore power when at the docks, but nothing when on the water. Genny is not an option. Not looking to power anything crazy. Maybe a small tv, coffee pot, maybe a blender. Trying to figure out what the best method would be here. He has a small portable one he just brings on board, but I would like to look into a more permanent solution. I have space in my engine bay on the Stbd side to add in an additional battery should I choose so I have one dedicated to just the inverter. I currently have 2 batteries now. 1 hybrid deep cell and the other is a starting battery if needed and they are controlled by a switch. Trying to figure out the best way to do this. Looking for idea on how I would charge the inverter battery...can I loop it in so it is charged while the engine is running? Was thinking of putting a single channel marine charger onboard so it gets charged while on shore power. For actually supplying power, can I wire it in so it runs the same 110 outlets I already have on the boat...or would it need it's own dedicated outlets?

 

[demarko210]

Hey there,
Boat is a 2001 Maxum 2400SCR. Friend of mine has been telling me to add in an inverter to my boat. I have shore power when at the docks, but nothing when on the water. Genny is not an option. Not looking to power anything crazy. Maybe a small tv, coffee pot, maybe a blender. Trying to figure out what the best method would be here. He has a small portable one he just brings on board, but I would like to look into a more permanent solution. I have space in my engine bay on the Stbd side to add in an additional battery should I choose so I have one dedicated to just the inverter. I currently have 2 batteries now. 1 hybrid deep cell and the other is a starting battery if needed and they are controlled by a switch. Trying to figure out the best way to do this. Looking for idea on how I would charge the inverter battery...can I loop it in so it is charged while the engine is running? Was thinking of putting a single channel marine charger onboard so it gets charged while on shore power. For actually supplying power, can I wire it in so it runs the same 110 outlets I already have on the boat...or would it need it's own dedicated outlets?

I use a 1500W inverter on my boat. I keep it in the cabin screwed to the wall of the console. It is wired straight to the house battery with a fuse. I use it to power my cabin strip lights mainly and have an open connection for other needs (hot plate etc). Most sensitive electronics (TV, etc) will need a Pure Sine inverter or you may experience some humming in your device. If you are just powering other devices then a regular inverter will do.

 

[sam am I]

Looking for idea on how I would charge the inverter battery...can I loop it in so it is charged while the engine is running?

Yes, having a descent size alternator ( I use a 200A heavy duty after market in my Ford PU) not only helps recharge the battery faster, BUT a BIG alt also can share/run load currents during inverter use if you run the motor at same time....This keeps ya from using up the batt charge thus reducing re-charge time.

Recall Power(watts) in = Power(watts)out and Power = Volts*Current

1000W pure sinewave inverter powering a 1000W toaster example....(I have 3 of these FWIW, so far so good)

1000W/120V = 8.33A

12V*x = 120V*8.33A

Solve for x

x = 83A is required from the battery (and cabling) side, but wait.........

If using a pure sine wave, you'll run about 90% efficient, which means you'll need to provide about 10% more energy in wasted heat to make 1000W on the output, so
1/.9 = 1.11 correction factor for loss

83A * 1.11 = 92 Amps for yummy boat toast


Assuming using your "battery switch" to isolate this house/inverter battery w or w/o engine running....So obviously with engine running and with a 80A alt, during toast time, your alt will be instantly sucked down to the battery voltage (14.4V ----> 12.8V) and will be working like a bad dog.

Hence a 200A alt with a 1000W inverter WHEN/IF RUNNING is a decent de-rating.

Was thinking of putting a single channel marine charger onboard so it gets charged while on shore power.

Sure....have a triple myself that is always connected directly to my 3 batts and is easily just "plugged in" as needed.

For actually supplying power, can I wire it in so it runs the same 110 outlets I already have on the boat..

Yes, BUT you'll need a transfer switch to switch between using the inverter OR shore power as the power source to the 120V outlets

or would it need it's own dedicated outlets?

You could but don't "need" too, so no, see above

 

[KD4UPL]

I would get an inverter/charger that will have a built in transfer switch. This allows it to power all the same 120v outlets in the boat as your shore power. When plugged into shore power it will feed that power thru and charge the battery. When you unplug from shore power it will transfer back to inverter power.
Magnum, Outback, or Victron would be my choice in that order.