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RNC725 02-04-2011 03:59 PM

Okay, a 700 watt West Marine Inverter
does not come with mounting hardware and the instructions state to :

1. to avoid discharging the battery power source always turn off the power inverter and disconnect the inverter form the power supply when not in use.

2. disconnect the inverter from a vehicle when starting the engine

So, I should only "hook her up" when I'm planning on using the inverter?
If hooked up and using, do not start the engine?

Actually it was purchased for the blender this summer and perhaps a laptop to watch a movie or two.

My kayak surely didn't have these system issues -- of course the kayak wasn't propelled by the wind, didn't have a head, bunks, icebox, etc etc.

thanks guys, be as candid as you like, I'm a newbie and the curve is steep!

sailingdog 02-04-2011 04:30 PM


So, I should only "hook her up" when I'm planning on using the inverter?
If hooked up and using, do not start the engine?
Yes, and yes.

Sabreman 02-04-2011 04:39 PM

This is a pretty light inverter. Using the rule p =i*e (power = voltage * current), the 700W / 120 VAC = 5.3 Amps. Depending on what you plug in, you may trip the overload protection.

1. I assume that this is a cigarette lighter setup, that your boat has a master OFF switch, and that the cigarette lighter plug is wired through the switch panel and not direct connected to the battery (dear God I hope so). If so, then simply switching the master power to OFF will keep your battery from draining.

2. I would keep it off or unplug it (if there is no power switch) due to the surge when starting.

3. In general, on the boat I leave electronics off unless I need them. We leave our inverter off until we use it, which is rarely. Of note is that we originally purchased our inverter to power the laptop, but the power loss from an inverter is about 0.5A. So I bought a DC laptop charger and draw 25% less power while the laptop is plugged in. This matters a lot when operating all day and all night without charging the boat's batteries. Invest $20 in a DC laptop charger.

Don't apologize for asking questions. When we question common assumptions, we find how little we really know.

RNC725 02-04-2011 05:04 PM

it has 2 plug in ports and 2 USB ports
it's hard wired to the battery
still, its interesting to me that you can't mount it somewhere
it's easy enough to "unplug" from the battery

J36ZT 02-04-2011 05:31 PM

Yep, turn off the inverter when not in use. Even at "idle" they suck power.

Yep, unplug the inverter when not in use if possible. Could be the inverter is not totally "marine grade" and may cause you to discharge electricity into the water.

Yep, do not have the inverter on when you start the engine. Likely, inverter is not ignition protected. If you have a battery switch (and you should), it should have ingnition protection built in. However, I'd play it safe (not tempt fate) and disconnect the inverter when starting the engine.

Sounds very much like WM took an off-the-shelf inverter, put their name on it, called it "for marine use" without changing or adding anything to it, and doubled (or more) the price. But, it should work fine as long as you take the necessary precautions.

J/36 "Zero Tolerance"

RealityCheck 02-04-2011 05:38 PM

It is a light duty unit.... had two which only lasted half a year or less each. Got a 1200 unit which has been in service for more than 17 months.

They do have a significant loss so when not in use, unplug them. Never leave them on just to charge something like a phone all the time... it will kill a battery.

sailingdog 02-04-2011 05:53 PM

You really should have that run through a circuit breaker or a switch on your panel to make your life a lot easier. You should definitely have a fuse or circuit breaker somewhere in the line for it too, or you risk a fire.

Originally Posted by RNC725 (Post 694599)
it's hard wired to the battery
still, its interesting to me that you can't mount it somewhere
it's easy enough to "unplug" from the battery

LakeSuperiorGeezer 02-04-2011 06:58 PM

On an automobile when you turn the key to start the engine, the accessory connection on the switch will interrupt power to the sensitive electronics in the car. That is why the radio drops out while you are cranking the engine. Not sure how many boats have the same setup, but a relay could be hooked to the accessory connection and drop out all the electronics. What happens is the starter draws a lot of current through coils that are wrapped around metal that becomes temporarily magnetized because of the current. When the current is interrupted because the engine catches and you let go of the key, this magnetic field had stored electrical energy and releases it back into the battery as a large voltage spike. Transistors in the electronics may not have high enough of a voltage rating to handle that spike. Ideally all of the electronics on the boat should be disconnected when cranking the engine.

newhaul 02-04-2011 07:26 PM

the one i got from hf is a 750 watt unit i use it in the truck and on the boat in the truck the unit is hard wired to power(with resettable breaker) and it auto shuts off when i start the truck and then resets itself after truck is running. on the boat its hooked up to the battery the same way however i dont have an inboard engine on my boat just wind and solar. (the hf unit is on sale for 39.95 this month) my current one has lasted over 2 years and many thousands of miles hauling freight charging puter and running coffee pot.

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