Inverter

[scarlet]

first let me preface this by saying that I am completely ignorant about electrical systems. My husband and I already have signed up for 2 courses in Marine electrical in the spring.. so we already have a plan to rectify that situation.

We are in the middle of what is going to end up being a legal suit against an electrition who took our inverter... bought us an expensive new one, and fried it... won't get it back to us...yadda yadda yadda…

Since he took our old 220 inverter, and our new one as well... I have no idea what kind of 220 inverter I'm going to need to get. I do know that the original one was a cristec… the new one he had us buy was 8000 watt power 230volt Power Inverter. (that seems like a lot of watts... )

I've tried googling and found tons of inverters.. they all look very similar to our other ones, and they are priced anywhere form $75 (12v- to 220.. 2000W) up to $4000... f

Can someone offer me a suggestion of what to look for, and perhaps why there is such a discrepancy when the V and watts are so similar? What is a good price to pay?

Our boat is a Lagoon 450 fly.

[BobHorn]

The differences are due to:
Power, for $75 I can't imagine more than a few 100 watt.
Waveshape, true sine wave or not.
Does it have the ability to pass through shore power when available, in other words, automatically switch from pass through to inverter power?
Does it include charging capability?

[Adelie]

$75 will get you a 500w more or less inverter.

[scarlet]

ok.. so here is one... will this work?
https://www.ebay.com/itm/3000-Watt-P...AAAOSw1Zpa6OWn

[scarlet]

Originally Posted by BobHorn

The differences are due to:
Power, for $75 I can't imagine more than a few 100 watt.
Waveshape, true sine wave or not.
Does it have the ability to pass through shore power when available, in other words, automatically switch from pass through to inverter power?
Does it include charging capability?

I don't really know the answer to any of your questions.... I do know that I want to be able to run my air conditioner when plugged in on shore... we weren't able to do that before.. only on generator.

[Ded reckoner]

I think 8kW is compatible with 50A usage. 4.5-5kW works for 30A systems that can run AC units, but a soft start capacitor could be necessary to help with voltage droop at compressor startup. 220/230V will protect American electrical components and systems (as compared to 208V or such). If you're getting another inverter, ensure you get one that has pure sine wave inversion capability (again, to protect components).

[Pizzazz]

The inverter converts 12V to AC. If you have an 8000W inverter, it will draw 700A at max power. This is a very large current draw, requiring massive batteries. Most of the time the inverter will run at lower wattage which will be inefficient. The best way to size the inverter is according to the outlet. In the US, most outlets are 1,800W, so you would not need a bigger inverter than that. There would be no appliances other than AIrcon that will use more power. If you need to use a few appliances simultaneously, say a heater and a vacuum, it is better for the batteries to stage them. In summary, I see no need for an inverter bigger than 1,800-2,000W.

[evm1024]

Take a look at Peter Kennedy - lots of information and references to get you thinking


https://shop.pkys.com/

[stormalong]

Originally Posted by scarlet

ok.. so here is one... will this work?
https://www.ebay.com/itm/3000-Watt-P...AAAOSw1Zpa6OWn

Don't go cheap on an inverter. Inverters draw a huge amount of power from your batteries. A short circuit from cheap components and poor overload protection could cause a fire. Stick with a name brand with a good reputation.

BTW, any inverter advertising specifically directed towards the PV market is directed at people that do not know what they are buying. The source of the power is irrelevant.

[skipmac]

Hi Scarlet,

Sorry to hear about your problems. Unfortunately your question is pretty open ended and not easy to come back with a detailed answer without more information.

First, about running your air conditioners on shore power. In a cat your size I'm guessing you have three units: one for each hull and one for the main cabin. An air conditioner when it first starts up draws a LOT of power but just for a second. Depending on the size of your units, if you try to start them all at once you could be pulling far more amps than the shore power can supply. First thing I would try is start one unit, let it run a few minutes, then the next and the next. If the first two start but not the last then you are exceeding the shore power even after the big start load it over.

If that is the case then as pointed out, an inverter will help you get them started and running but could run your batteries down to nothing pretty quickly.

If you can get all three to run on short power by starting them sequentially then adding a device called Easy Start could help but again you don't want to run the air conditioners on the inverter unless you're prepared to deal with a very large battery bank and keeping it charged.

[Pete7]

Originally Posted by scarlet

ok.. so here is one... will this work?
https://www.ebay.com/itm/3000-Watt-P...AAAOSw1Zpa6OWn

No, its 50Hz and designed for places like Europe. You will likely need 60Hz for the US.

Rather than spend any money at the moment, do those two courses first which will then give you the information you need to make the right decisions.

Pete

[GoneDiving]

Originally Posted by Pete7

Rather than spend any money at the moment, do those two courses first which will then give you the information you need to make the right decisions.

Pete

Scarlet,

+1. And you will be able to ask meaningful questions of any licensed electrician. I'd consider consulting another electrician essential if design changes are going to be made to enable shore power to aircon(s).

A like for like swap of a dead inverter is easy. Changing the system to allow for 8000w loads and converting aircon(s) from generator to shore power is not a trivial DIY job. The loads you are talking about, if not handled correctly could easily do do major damage to your boat or somebody's health.

I wish you well

[skipmac]

Originally Posted by scarlet

ok.. so here is one... will this work?
https://www.ebay.com/itm/3000-Watt-P...AAAOSw1Zpa6OWn

As noted, this inverter is designed to make European style AC electricity.

With inverters, to a great degree you do get what you pay for. The cheap ones make square waver or modified since wave power. Avoiding the high tech definition you can just call it dirty power. Some things won't work on it at all.

[smac999]

An 8000w inverter is rediculus. No 40’ boat is going to run that.

Running air con off shore power has nothing to do with an inverter.

Find another electrician and get them to figure out what you need.

[ranger58sb]

I think Scarlet's cat was/is originally set up for European power throughout?

So some of the inverter goal is maybe to deal with 230V/50Hz versus 240/60Hz or 2x 110/60Hz issues?

-Chris