Energy solutions onboard a live aboard

[lawrence_craig]

Hi all,

Please excuse my novice question. I am relatively confident I think I know the answer to my own question but thought I would answer anyway.

I am about to buy a boat with both 12V sockets and 230V. It also has a 4kW generator installed.

I think I understand that in order to use the 230V sockets, I will either have to connect to shore power or use the generator.

However is it possible to use my 230V appliances without the generator? For example, if I wanted to charge my laptop without starting the generator. Or if I wanted to use a handheld blender. I am guessing I will need an inverter for this? Will this not play havoc on my rechargeable laptop batteries for example.

Many thanks for your help.

[ontherocks83]

you can use an inverter but they are incredibly inefficient and use up your house bank faster. ok for occasional things but not efficient to use as a frequent thing

[john61ct]

And laptop is DC native anyway, just get a 12V "car adapter" or DC converter for that.

[billknny]

Yes, an inverter can do what you are asking.

And, no, inverters are not "incredibly inefficient." They actually do a rather good job at converting 12 volt power to 230V. The issue is that MOST things that use 230 volt power on a boat tend to use a LOT of it. Batteries have an intrinsically limited supply of power to deliver between charges. If you over use the inverter (and how much that is depends on a lot of things...) you can drain your batteries dead.

We run our small 220V appliances using our inverter every day, charge our electronic toys, etc. All off our battery bank which is mostly charged with solar. Every two or three days we run the genset to run the watermaker, do laundry, and top off the batteries.

If you have a reasonably sized battery bank, then you can most certainly run a blender for 2 minutes, grind you morning coffee, or charge your laptop--every day. You can not run an air conditioner for hours.

MOST quality inverters you get these days produce "true sine wave" power and you can run anything with those.

[john61ct]

Many people using inverters are wasting a very large percentage of the total energy consumed.

Yes it can be done relatively efficiently, but doing so is a challenge.

Some people run a mains charger powered by an inverter into large batteries, just silly to me.

Avoiding inverter usage when possible is a sound strategy.

DC to DC conversion is much more efficient.

[a64pilot]

Inverters can be over 90% efficient.
However there is an overhead if you will with them, so if your powering up a 3 KW inverter to charge your laptop, it’s very inefficient, reason is that a 3 KW or so inverter eats about 20 W (1.5 AH) or so just sitting there turned on, delivering no power.
I bought the smallest pure sine inverter I could find to power my TV / Satellite receiver, and save the big one for big jobs, like running the vacuum cleaner etc.
https://www.solar-facts.com/inverter...efficiency.php

[hellosailor]

A car adapter for a laptop is indeed an inverter. The marketing folks just try not to use three-syllable words because it confuses and scares the buyers. You will need one that has enough power for your laptop (watts) and while more is pointless, you might want one that offers more watts and has different adapter tips, if you plan to replace the laptop in the not-too-distant future.

And then you'd get a bigger inverter for any appliances you were planning on, like a microwave or blender. It is not entirely mad to buy two inverters, one just a little bigger than most of what you will need, and a second much larger one, to be used only for the large loads. That way you gain efficiency AND you get some redundancy, because anything electronic can break down, and many of the inverters on the market have been "built to a price".

[newhaul]

If your dead set on charging your little toys on an inverter .
https://www.sportsmanswarehouse.com/...saAsn2EALw_wcB

[sailorboy1]

I installed a USB charging strip to use for my cell phone and tablets. For the TV and laptop I installed a small 400W inverter. These have been very efficient overall with the draw from the small inverter while watching the TV and charging the laptop being the same as the draw of my main inverter just being turned on with no load at all.

[RaymondR]

Originally Posted by a64pilot

Inverters can be over 90% efficient.
However there is an overhead if you will with them, so if your powering up a 3 KW inverter to charge your laptop, it’s very inefficient, reason is that a 3 KW or so inverter eats about 20 W (1.5 AH) or so just sitting there turned on, delivering no power.
I bought the smallest pure sine inverter I could find to power my TV / Satellite receiver, and save the big one for big jobs, like running the vacuum cleaner etc.
https://www.solar-facts.com/inverter...efficiency.php

Yep, 1500 watt for the big AC power users such as the vacuum cleaner and microwave and 300 watt for the computers, TV and food processor. Three switched sockets for the shore power, 1500 watt and 300 watt inverters and a plug on the AC distribution panel feed.

[Simi 60]

Originally Posted by ontherocks83

you can use an inverter but they are incredibly inefficient and use up your house bank faster. ok for occasional things but not efficient to use as a frequent thing

We have no problems.

We live aboard at anchor using 240v appliances including 3 fridge freezers totaling 750 litres , full size washing machine and a 240v hot water system
Lights are 12v pumps are 24v
Genset rarely used but do have large solar array.

Appropriate sized gear makes it a non issue.

[StuM]

[QUOTE=a64pilot;2728701]Inverters can be over 90% efficient.
However there is an overhead if you will with them, so if your powering up a 3 KW inverter to charge your laptop, it’s very inefficient, reason is that a 3 KW or so inverter eats about 20 W (1.5 AH A) or so just sitting there turned on, delivering no power.
/QUOTE]


Just sayin'

[Nicholson58]

We have a 3.5 KW inverter for big stuff and a 300 watt full sine Samlax inverter in the 97%+ efficiency range. Great for electronic device charging. Losses on these things are rated as a percentage of full scale. SO, small inverter amounts to small losses. In this case, 3% of 300 Watts = who cares. Your electronics like full sine.

[john61ct]

Originally Posted by hellosailor

A car adapter for a laptop is indeed an inverter.

No. Inverter is from DC to AC.

DC to DC is a converter.

[john61ct]

If you get an AH counter between your inverter and battery, and compare to a Killawatt reading on the other side,

you will find the actual inefficiency losses to be much greater IRL than the best-case "optimistic" specs claimed by the vendors.

If you have plenty of surplus power of course who cares, but for a mostly-solar setup often every AH counts.