3000w inverter

[Leigh marshall]

How much does it cost to fit a 3000w inverter in a narrow boat 

[Mike Hurley]

A quality unit like Victron is over 1k, ebay has cheap ones, Chinese, from 200 quid, Do you have an inverter already? If not then installing will be extra, new cables, fuses, circuit breakers etc.

[Tony Brooks]

And one may ask why 3kW and if you need one that large have you sorted out how you will replace (recharge) the electricity it takes from the batteries. This is very important for the optimum life of lead acid batteries. This will not be a problem if you are using a shoreline and have a decent charger. It is likely to be a problem if relying on an engine alternator and solar for about half a year.

[blackrose]

Avoid the cheap inverters on Amazon, eBay, etc. Many/most are not neutral-earth bonded and may not be compatible with the safety circuit breakers in your boat's AC system. 

[hider]

1 hour ago, blackrose said:

Avoid the cheap inverters on Amazon, eBay, etc. Many/most are not neutral-earth bonded and may not be compatible with the safety circuit breakers in your boat's AC system. 

I think that the ac type rcds are fine on inverters, no need to go to type b or f rcds as there should be no DC component in the 240v AC.

[Alan de Enfield]

11 hours ago, Leigh marshall said:

How much does it cost to fit a 3000w inverter in a narrow boat 

 

Just remember that a 3000w inverter (if using full power) will be drawing about 300amps from your batteries, so, for example a 100Ah battery will be 'flat' (50% SoC) in 10 minutes.

You will need a very large battery bank, and means of recharging them in addition to the cost of the inverter.

 

Bear in mind that your electrical system is a combination of many components and you cannot change one with having an effect on the others.

 

A bit like putting a 1000hp engine in a Mini and expecting the clutch, gear box and brakes to be able to handle the power.

Edited July 26 by Alan de Enfield

[MtB]

Fitting the 3000W inverter is only the start of it.

 

As Tony and Alan point out, the truly massive drain on the batteries means you'll probably need to add another four, and then run your engine 25 hours a day to keep replace all the energy 3kW of power will be using. 

 

On the other hand maybe you only want a big inverter to supply the start-up surge on something with a motor. So out of curiousity, why do you need such a large inverter? 

[IanD]

1 hour ago, Alan de Enfield said:

 

Just remember that a 3000w inverter (if using full power) will be drawing about 300amps from your batteries, so, for example a 100Ah battery will be 'flat' (50% SoC) in 10 minutes.

You will need a very large battery bank, and means of recharging them in addition to the cost of the inverter.

 

Bear in mind that your electrical system is a combination of many components and you cannot change one with having an effect on the others.

 

A bit like putting a 1000hp engine in a Mini and expecting the clutch, gear box and brakes to be able to handle the power.

 

Actually much worse than that since battery capacity -- lead-acid in particular, usually specified at the 10h or 20h rate -- drops rapidly at high discharge rates, you'd be doing well if it lasted 5 minutes at a 1C rate, maybe only 2 minutes at 3C... 😞 

Edited July 26 by IanD

[Leigh marshall]

4 hours ago, Alan de Enfield said:

 

Just remember that a 3000w inverter (if using full power) will be drawing about 300amps from your batteries, so, for example a 100Ah battery will be 'flat' (50% SoC) in 10 minutes.

You will need a very large battery bank, and means of recharging them in addition to the cost of the inverter.

 

Bear in mind that your electrical system is a combination of many components and you cannot change one with having an effect on the others.

 

A bit like putting a 1000hp engine in a Mini and expecting the clutch, gear box and brakes to be able to handle the power.

Well I have 820ws 

Well I have 820ws off solar panels and I only be using the inverter for tv charging phones and a microwave 

[Alan de Enfield]

12 minutes ago, Leigh marshall said:

Well I have 820ws 

Well I have 820ws off solar panels and I only be using the inverter for tv charging phones and a microwave 

 

Thats fine when the sun shines, but November until about March you'll be getting nothing from the Solar.

 

If you only want to run a microwave why buy a 3kw inverter ?

My 1800w inverter runs my microwave.

 

Surely you charge your phones directly from yout boat batteries - it is stupidity to 'make' 12v DC, then convert it to 230v AC, then convert it to 5v DC (with all the losses involved)

 

NB - you'll probably find you TV is actually 12v (even tho it may have a 230v plug on it)

Edited July 26 by Alan de Enfield

[Leigh marshall]

I have a1800 inverter and it sturgalls run a 620w gigsaw I have had this inverter for 20 years and not knowing much about electric’s we were probably talked into buying it  

[Alan de Enfield]

11 minutes ago, Leigh marshall said:

I have a1800 inverter and it sturgalls run a 620w gigsaw I have had this inverter for 20 years and not knowing much about electric’s we were probably talked into buying it  

 

I run drills, jigsaw, (700w) microwave, (900w) toaster, (900w) kettle & (1500w) toastie maker (not all at the same time) from my 1800w Inverter.

I have a 6x 230Ah battery bank.

[bizzard]

16 minutes ago, Alan de Enfield said:

 

I run drills, jigsaw, (700w) microwave, (900w) toaster, (900w) kettle & (1500w) toastie maker (not all at the same time) from my 1800w Inverter.

I have a 6x 230Ah battery bank.

Good old George Foreman.

[jonathanA]

19 hours ago, Leigh marshall said:

I have a1800 inverter and it sturgalls run a 620w gigsaw I have had this inverter for 20 years and not knowing much about electric’s we were probably talked into buying it  

If its 20 yrs old its probably not a pure sine wave inverter. Like Alan I have an 1800 w inverter, which runs pretty much everything I need it to. However mine isn't a pure sine wave so some things don't like the lumpy lectric it produces. Electric toothbrush charger being one and an angle grinder being another.  My other angle grinder works fine..... 

[Alan de Enfield]

24 minutes ago, jonathanA said:

If its 20 yrs old its probably not a pure sine wave inverter. Like Alan I have an 1800 w inverter, which runs pretty much everything I need it to. However mine isn't a pure sine wave so some things don't like the lumpy lectric it produces. Electric toothbrush charger being one and an angle grinder being another.  My other angle grinder works fine..... 

 

As is mine - it's a "Sterling Modified Sine Wave" (ie a square wave)

[Leigh marshall]

23 hours ago, Alan de Enfield said:

 

I run drills, jigsaw, (700w) microwave, (900w) toaster, (900w) kettle & (1500w) toastie maker (not all at the same time) from my 1800w Inverter.

I have a 6x 230Ah battery bank.

The thing is I got a 20 year old inverter and it won’t run a 600w jigsaw so for a 1200w more I got a 3000w inverter 

[Alan de Enfield]

1 hour ago, Leigh marshall said:

so for a £1000 more I got a 3000w inverter 

 

Amended for you.

 

My Inverter was fitted in the boat when it was built in 2003

[Peanut]

Battery ► Inverter ► Jigsaw, any one of which could cause your problem.  I would expect an 1,800W inverter to run a 620W jigsaw.  If the inverter powers everything else you use, then in might be that the jigsaw, just doesn't like your inverter, and may not be liked by a new one either.

Edited July 27 by Peanut
liked

[ditchcrawler]

If the jigsaw has electronic speed controller it could well have a hissy fit connected to a square wave power source 

[Tony Brooks]

19 minutes ago, Peanut said:

Battery ► Inverter ► Jigsaw, any one of which could cause your problem.  I would expect an 1,800W inverter to run a 620W jigsaw.  If the inverter powers everything else you use, then in might be that the jigsaw, just doesn't like your inverter, and may not be liked by a new one either.

 

Especially  if it has electronic speed control and the inverter was not a quality pure sine one.  I suspect a basic jig saw with just an on-off trigger would work OK, be it a bit noisier than usual and possibly getting a bit hotter.

[cheesegas]

On 26/07/2024 at 09:27, hider said:

I think that the ac type rcds are fine on inverters, no need to go to type b or f rcds as there should be no DC component in the 240v AC.

All RCD types rely on neutral and earth being bonded at source, which can't be done if the inverter has a floating live/neutral output. The whole system must be designed to float if so, and not rely on RCDs.

 

Better inverters bond the neutral and earth - ones with a built in transfer switch have a relay to do it automatically.

[jim mitchell]

A new 18v makita jigsaw would set OP  back < £250 with batteries  and thats an expensive unit so why not invest in a good new battery jigsaw  and use the existing inverter for all else plus free yourself from trailing cords power points etc.

 

Then no installation costs , no mods to boat wiring etc and potentially an extra £800  in your pocket .

 

 

Unless you intend using it full time as 'professional' joiner might do ?

[blackrose]

On 26/07/2024 at 14:33, Alan de Enfield said:

Surely you charge your phones directly from yout boat batteries - it is stupidity to 'make' 12v DC, then convert it to 230v AC, then convert it to 5v DC (with all the losses involved)

 

It's it really stupidity? A phone draws so little current I think the losses must be tiny and hardly worth worrying about. 

 

I don't worry about it anyway. It doesn't have any significant impact on my batteries.

22 hours ago, Alan de Enfield said:

 

As is mine - it's a "Sterling Modified Sine Wave" (ie a square wave)

 

I had the same inverter for many years, but I got rid of it and installed a 2kW pure sine wave inverter when I installed solar panels a couple of years ago and went off-grid. My thinking was that if I'm going to be using it all the time I need something a bit better quality.

 

Also couple of people told me that that chopped sinewaves can have a detrimental effect on some appliances, even if they appear to run them ok. I don't know how true that is?

[cheesegas]

8 minutes ago, blackrose said:

It's it really stupidity? A phone draws so little current I think the losses must be tiny and hardly worth worrying about. 

I don't worry about it anyway. It doesn't have any significant impact on my batteries.

 

I had the same inverter for many years, but I got rid of it and installed a 2kW pure sine wave inverter when I installed solar panels a couple of years ago and went off-grid. My thinking was that if I'm going to be using it all the time I need something a bit better quality.

 

Also couple of people told me that that chopped sinewaves can have a detrimental effect on some appliances, even if they appear to run them ok. I don't know how true that is?

Your first statement depends on the setup. If you are off grid in winter, it most definitely has an effect as the phone draws so little; a good quality 3kva inverter might draw 1-2a @ 12v, or around 20w with nothing connected to the output. This is more power is takes to charge a phone. You're using more energy to power the inverter than you are to charge the phone. Not a problem in summer when there's lots of free power or if you're in a comfy marina with shore power, but in winter off grid every watt counts.

 

Modified sine wave inverters are basically a square wave. It can cause the filters in switchmode power supplies (phone chargers, laptop chargers etc) to run hot as they're working harder to take out the transients, which probably won't affect a well designed power supply but a cheap one will probably fail prematurely.