Always Using Inverter for 110vac

[hummingway]

I've 30a on the boat but at my current slip shore power only provides 15a. This got me thinking. Is it possible and advisable to wire things so shore power only runs the battery charger and all the 110v on the boat runs off of an inverter? This way if I was drawing more then the 15a from shore power the batteries would draw down to cover the extra and then recharge when less power was being used. This would mean less juggling on power consumers.

[senormechanico]

It should work ok. If I were you, I'd use a sinewave inverter so the microwave would work properly.
Also, you will need a decent sized battery bank.

[delmarrey]

When they built the marina did they put gaps between the dock boards and use pvc piping for the waterlines too.

Unless you have been popping the braker I wouldn't recommended it.
1) It puts undue wear and tear on the inverter.

2) it actually consumes more power draw from the dock per amp of use. But would not pop the braker.

3) if I were not on the boat I'd be more concerned about a fire if 110v stuff were running. One would want an oversized inverter for safety.

4) I'd make sure the invert is properly placed. Inverters create heat.

[johnar]

My first thought is are you a live aboard?

what is eating up the power over 15 amps?

The more you pull off the Battery's the longer they take to charge anf life drops off.

I do use my inverter when I am on the hook but I watch what I draw while I run it, they pull a bank down fast.

If you are a live aboard try to not use a/c and think about wind/solar, I know homedepot has 400watt wind gens for $585 and now days you can get solar $.68 to $4.00 per watt.

I just do not see how 15 amp charger could keep up with your needs if you use more than that already, even with your statement "charge when you are not using as much"


Dutch

[hummingway]

Thanks for the replies. I am a live aboard and in a cooler climate. I'm installing a new furnace this week which will help with the problem. Currently to run the water heater (110) I turn the electric heater off first. I have a 110 freezer and am not using it yet since I do have a 12v fridge but would like to. Most of the time 15 amps is adequate and may be all the time when the furnace is installed (Nordic 40D). I'm not too concerned about a little inefficiency but don't want to do anything dangerous. I do plan on adding solar, wasn't convinced about wind yet and thought a Honda 1000 as backup would be nice. I guess I need to try and determine the draw of the freezer and hw so I can see just what is needed. I'm off the dock at least twice a week and expect to spend quite a bit of time at anchoring out once the weather warms.

[tomperanteau]

Running off of an inverter will work fine, but there is a bit of inefficiency in the set up. You will loose some power in the inversion process and therefore need a higher amp charger to offset not only what you already use, but to make up for the loss. You will actually need more power from the marina and will pop your breaker more frequently. As for wear and tear; as long as you use quality equipment, there will not be a wear and tear aspect with the exception of the fans that cool the inverter.

I engineered communications systems for many years. They were all run off of inverters that were powered by batteries that were constantly being charged. There were rarely any failures, but we used industrial grade inverters, hence my advice to use quality equipment. Had there been issues with doing it this way we and all the other companies would never have set things up this way. This system was, and still is, used on many thousands of communications towers. Your backup in the event of a failure would be to simply go back to shore power until you can fix what is broken.

I do second senormechanico on his suggestion to use a sinewave inverter. Modified sinewave or cheaper inverters can burn out electronics and motors in appliances.

[btrayfors]

Victron MultiPlus inverter/chargers have an automatic power-assist function. When there's not enough shorepower available, they supplement it using battery power to the inverter. Seamless. Works well; might not be ABYC approved, though.

These units also have the ability to dial in the total amount of shorepower to be used. And, the correct way to wire them in is for full-time use. They have a built-in transfer switches -- 30A or 50A (newer ones) .

See the Victron website: Victron Energy - Inverter/chargers - Inverters - Battery Chargers - and more

Agree with others that you'd have to keep pretty close tabs on your power use, though, so as not to deplete the batteries/cause their early demise.

Bill

[senormechanico]

btrayfors said it in a nutshell.

[hummingway]

Thanks everyone. The Vectron Quattro looks likes a good place to work a design from.

[CharlieJ]

You can use either the Victron Multi Plus or the Quattro as they both have this unique power assist feature. Victron and MasterVolt designed their inverter/chargers so that, even when charging, the unit is being kept synchronized with the incoming shore power (mains) frequency. This feature is the key to being able to parallel.

Currently, ABYC E-11 prohibits paralleling power sources to supply a load center. A new standard (A-32 Power Conversion Equipment and Standards) is being developed that will probably recognize this feature.

[hummingway]

Originally Posted by CharlieJ

Currently, ABYC E-11 prohibits paralleling power sources to supply a load center. A new standard (A-32 Power Conversion Equipment and Standards) is being developed that will probably recognize this feature.

Does it matter to me? I'm in Canada although undoubtly will sail in USA waters at some time. Are there waters where ABYC standards are regulatory?

[CharlieJ]

ABYC Standards are becoming accepted worldwide.

[delmarrey]

Originally Posted by hummingway

Does it matter to me? I'm in Canada although undoubtly will sail in USA waters at some time. Are there waters where ABYC standards are regulatory?

It's only monitored if a boat is being built, going into public service or used commercially.

If you were to get boarded it wouldn't even come up on a VSC inspection.
National Department of Vessel Safety Checks

[Masoncruiser]

I have a xantrec ( may have misspelled that) and it has the PowerShare mode which works great. We are always on the move and at different marinas with different power options and have found it invaluable. I have the boat wired so all AC power to the outlets and microwave is from the inverter. The refers, aircon and hot water heater run straight off shore power. I do agree you do need a good size battery bank though. I have 6 8d's to take up the slack.

[CharlieJ]

To clarify, there is a vast difference between passing through qualified shore power while using a portion of it for charging (like the Xantrex mentioned in #14 and most other marine inverter/chargers) and the Power Assist function provided by the Victron and Mastervolt units. With these units, if the load exceeds the supply from shore power or the genset, the difference (up to finite limit) is made up by the inverter/charger automatically going into invert mode and paralleling with the source of power.