Inverter or Generator - that is the question

[Steph H]

I have at least one question in this post. The background is, I bought my boat (to be a liveaboard) earlier this year and have just finished doing the first part of the move of it to the Midlands, Rugeley to be exact. It is an ex hire boat so whilst I can move straight on board, it doesn't have all the bells and whistles.  Such as no inverter, everything is 12volt, which is fine for now, however I am going to need to get an inverter for a washing machine (not needed straight away) and the occasional use of a hair dryer (definitely not needed straight away) and power tools etc. I am doing a minor reworking of the internals and some exterior work over the next couple of weeks and so will need access to to 230v power. It currently has two, old leisure batteries, that will be replaced shortly, and added to as needs/funds be. Solar panels will be added at a later date, as funds are available.

 

My question is as follows, do I get a generator to do the work I need to do? Or do I spend the money on an inverter? I realise that the inverter will use power and I will more than likely need to have the engine running for certain tasks, (vacuuming, orbital sander etc). But I'm not sure on wether I can just get an inverter, wire it in and work from there? Or do I need other bits and bobs to get it all to work? I have a battery monitor that needs fitting. Is it just easier to go with a generator for now and then sort out an inverter at a later date? 

 

Budget is a little limited, I have the funds for one or the other (generator or inverter) but not both.

 

Hope that isn't too confusing and please don't lambast me for being a twit, I'm still learning.

 

 

[Alan de Enfield]

A quality (Victron or Mastevolt) inverter big enough to power a washing machine will probably cost 2x the price of a generator, and you will not 'get away' with just 2 batteries powering an inverter big enough for a washing machine.

You will be drawing about 200 amps from the batteries for the time when the heater is on so ideally you would need 4 x 110Ah batteries in good condition.

Running the engine will assist and provide 50 amps (?) but you will also need to run it for a fail period once you have finished with the washing machine to replace that taken from the batteries.

 

Initially I'd go for the 'quick-fix and lowest price option of a Generator of around 2.2Kw but make sure you are fully aware of the safety regulations re storing petrol and a generator on board, and the health risks of running one (Carbon Monoxide) - the generator should always be lifted off and run on the bankside.

Edited August 9, 2020 by Alan de Enfield

[nicknorman]

Since an inverter only converts electricity from one type to another, you would still have to generate the electricity some how. 2 leisure batteries won’t last long at all, even with a modest load. Therefore if it is one or the other I think it has to be a generator first. Try to get a suitcase inverter type generator, not one of those horrendous frame generators that run at the same speed regardless of load and are VERY noisy and antisocial!

[zenataomm]

From a very untechnical viewpoint.

If your batteries are too low to start your engine, an inverter is useless.

 

Generator first.

 

ps cross posted with nicknorman

[Chewbacka]

Before I vote for gennie I would pose the following -

1). What is the output of the engine alternator?

2). What is the peak 240v load - remember that motors have a peak load a lot higher than the rating plate, and that needs to be considered when sizing a generator or inverter.

3). How often and for how long will you want 240v appliances running?  And the average power required?

 

So if the engine alternator can provide enough power to cover your inverter needs,  and you don’t need 240v for hours at a time then an inverter could be the way to go, but if the engine alternator is less than your requirement and you want power for more than a few mins at a time, just 2 batteries will not last long before needing replacement, in which case a gennie is better - also useful in winter for battery charging when there is no solar.

[redwing]

3 hours ago, Steph H said:

 Or do I need other bits and bobs to get it all to work? 

Cable, a decent switch and a fuse,  Some inverters come with suitable cable, some come with unsuitable cable.

You might need to replace your batteries depending on their capacity and what you're hoping to run

 

You can hire a genny or could you borrow one?

[Sea Dog]

I have yet to hear of a generator, even the class leading (and expensive) Honda ones, that your neighbours will enjoy. Also, do heed earlier advice about storing and using petrol and make sure you understand where the fuel vapour might end up.

 

There are solutions which do not involve the power demands of a modern washing machine - perhaps start there whilst you build up your knowledge and experience. Battery tools mean you can spread a lower charging load across several hours, rather than have high instantaneous power demand as you work. 

 

The conclusions you draw will depend on whether you intend to cruise or stay put.

[Alan de Enfield]

27 minutes ago, Sea Dog said:

There are solutions which do not involve the power demands of a modern washing machine

 

Indeed - we use a twin tub - less that 1/10th of the 'leccy' needed, does a more than adequate job, and, gets them drier than the automatic does.

 

https://www.ebay.co.uk/itm/NEW-TWIN-TUB-PORTABLE-230V-WASHING-MACHINE-OUTDOOR-GARDEN-CAMPING-SPIN-DRYER-3-6/361505902858?

[OldGoat]

1 hour ago, Alan de Enfield said:

 

Indeed - we use a twin tub - less that 1/10th of the 'leccy' needed, does a more than adequate job, and, gets them drier than the automatic does.

 

https://www.ebay.co.uk/itm/NEW-TWIN-TUB-PORTABLE-230V-WASHING-MACHINE-OUTDOOR-GARDEN-CAMPING-SPIN-DRYER-3-6/361505902858?

That's what we have and use it when we go on longer cruises. Fine for small stuff even a pair of heavy jeans on occasion.

It even runs off a small 300w inverter - which powers the TV and like kit.

If you keep your simultaneous power requirements low then you can get a high frequency inverter from around £150 from Bimble.

[Jen-in-Wellies]

There are two things that need considering. Minimising both these are good, but overall energy consumption is a higher priority.

• Overall energy consumption, which determines how many batteries you need and how long you'll need to run generators, engines, or solar to keep them charged. 
• Peak mains power requirement, which determines how big an inverter, or generator you need and is based on the most electric thirsty gadget. This could be a fridge, a hair dryer, or an automatic washing machine.

The last few posts show there are ways of minimising energy consumption and peak power draw. All of these will mean that a smaller inverter is required. If you have a 12V fridge, then you don't need the minimum 1kW inverter size needed to start up a mains fridge. Having a battery powered vacuum cleaner means that you need a much smaller inverter for the battery charger than the 1.5kW plus inverter typically needed for a mains vac. An automatic washing machine will likely need 2 to 3kW inverter, compared with 300W for the twin tubs mentioned above. The auto washers use a lot of mains to heat the water. There are ways round this, like rare hot fill machines, or tricking one in to being mains fill. Some brands and models don't like the wave form from some inverters, or generators and throw a hissy fit.  The twin tubs get their hot water from the calorifier, via a stove back boiler, or the engine heating. Much cheaper and easier.

A generator is restricted to 8am to 8pm running, so if you are away from the boat a lot during the day it is very limiting, especially in winter. Lower power and efficient battery powered gadgets will make recharging the batteries a lot easier. A smaller inverter from a good manufacturer will be a lot cheaper and waste a lot less power when idle, or inverting than a large inverter from a good manufacturer and save even more power wastage than a big inverter from a bad manufacturer.

Going this route with a 12V fridge, then a 500W inverter would be perfectly adequate and the generator, or engine running can be used for less time to keep the batteries topped up in winter. Get solar panels for summer, if your boat doesn't already have them. Hair driers and straighteners are a problem. No easy way round the huge power draw they take. Power tools are available battery powered. If you stick with the same range, I have Makita, then the expensive batteries can be used on a variety of tools. More expensive than mains power tools, but very good quality. 

 

Jen

[Laurie Booth]

Good laundrette in Rugeley.

[The Gravy Boater]

32 minutes ago, Laurie Booth said:

Good laundrette in Rugeley.

Seconded.  Call ahead for a service wash, was cheap as chips.

[Steph H]

Thank you all for your replies, really appreciate the thought and effort gone into them.

 

Just to address a couple of things that have been mentioned.

 

I will be getting Solar at some point, but that will be when funds become available.

 

I had already thought a twin tub would be the way to go and sufficient for my needs, so thanks for the link, will put it on my watch list.

 

I've already got a 12v fridge freezer which I'm very pleased with so am keeping that.

 

I'll definitely be replacing the batteries in the next 4-6 weeks-ish. 

 

I will be wanting to use some tools for longer periods, I am very aware of the noise factor with this so am going to try and find somewhere out of the way to do noisy work. ? and will definitely be keeping it well within the noise hour requirements.

 

I think for now I'm going to go with a genny, that will get me through my short term requirements and give me an alternative power "source" for the time being.  And give me some time to do yet more research on inverters and just what my needs are. It may be that solar becomes a bigger priority than an inverter as I've got friends who have said I can do washing whilst at theirs. Fine for the short/medium term but I'm sure they'll get sick of it after a while.

 

As far as storing the genny, I understand about storing it outside etc, but can someone give me a plain and simple explanation of where I can store it exactly? The same with the petrol? I've read the regulations but they make my eyes glaze over. So can I store the genny on the stern? I have a cruiser stern, with gas locker at the back. Or on the roof? Be bloody heavy to lift up there. Or on the bow? Not massive but doable. The same questions with the petrol? Obviously DO NOT have either in the cabin, or near vents into the cabin, but what else do I need to be aware of? If its stored in the stern will the vapours go into the engine bay and explode when the engine is started? Or point me in the direction of a clear and plain explanation?

 

Again I apologise for sounding like a moron, but I clearly still have a lot I need to learn ?

[Alan de Enfield]

52 minutes ago, Steph H said:

As far as storing the genny, I understand about storing it outside etc, but can someone give me a plain and simple explanation of where I can store it exactly? The same with the petrol? I've read the regulations but they make my eyes glaze over. So can I store the genny on the stern? I have a cruiser stern, with gas locker at the back. Or on the roof? Be bloody heavy to lift up there. Or on the bow? Not massive but doable. The same questions with the petrol? Obviously DO NOT have either in the cabin, or near vents into the cabin, but what else do I need to be aware of? If its stored in the stern will the vapours go into the engine bay and explode when the engine is started? Or point me in the direction of a clear and plain explanation?

1) Store the generator on the stern, BUT, when using it, only run it on the bank-side and let it run until it runs out of petrol. That will ensure there is not much in the way of 'fumes' to leak into your boat when you store it on the stern.

 

2) Petrol should be stored in a locker to the same build specification as the gas locker, if you have room you could store the petrol cans (if plastic) in the gas locker.

 

3)  By law you can only have / store 30 litres of petrol on a boat, so its going to be a case of filling a couple of 5 litre cans every couple of days (depending how much you use the Generator.

 

4) Getting hold of petrol is a problem as it is not sold 'canal side' so you have to walk to the nearest petrol station to fill your cans.

[WotEver]

Have a read of Section 5:

https://www.boatsafetyscheme.org/media/268789/ecp-private-boats-ed3_rev2_apr2015_public_final.pdf

[Chewbacka]

Just a word of warning, if you get a good genny (eg Honda) you will need a good chain and padlock (and something to fix it to) when storing it otherwise it WILL be stolen.   I have even heard of bank side running generators being stolen.......

[Paul Gwilliams]

12 minutes ago, Chewbacka said:

Just a word of warning, if you get a good genny (eg Honda) you will need a good chain and padlock (and something to fix it to) when storing it otherwise it WILL be stolen.   I have even heard of bank side running generators being stolen.......

Is that why that chap on another thread runs two at a time as most opportunistic thieves won't know which one to take!

[peterboat]

8 hours ago, Jen-in-Wellies said:

There are two things that need considering. Minimising both these are good, but overall energy consumption is a higher priority.

• Overall energy consumption, which determines how many batteries you need and how long you'll need to run generators, engines, or solar to keep them charged. 
• Peak mains power requirement, which determines how big an inverter, or generator you need and is based on the most electric thirsty gadget. This could be a fridge, a hair dryer, or an automatic washing machine.

The last few posts show there are ways of minimising energy consumption and peak power draw. All of these will mean that a smaller inverter is required. If you have a 12V fridge, then you don't need the minimum 1kW inverter size needed to start up a mains fridge. Having a battery powered vacuum cleaner means that you need a much smaller inverter for the battery charger than the 1.5kW plus inverter typically needed for a mains vac. An automatic washing machine will likely need 2 to 3kW inverter, compared with 300W for the twin tubs mentioned above. The auto washers use a lot of mains to heat the water. There are ways round this, like rare hot fill machines, or tricking one in to being mains fill. Some brands and models don't like the wave form from some inverters, or generators and throw a hissy fit.  The twin tubs get their hot water from the calorifier, via a stove back boiler, or the engine heating. Much cheaper and easier.

A generator is restricted to 8am to 8pm running, so if you are away from the boat a lot during the day it is very limiting, especially in winter. Lower power and efficient battery powered gadgets will make recharging the batteries a lot easier. A smaller inverter from a good manufacturer will be a lot cheaper and waste a lot less power when idle, or inverting than a large inverter from a good manufacturer and save even more power wastage than a big inverter from a bad manufacturer.

Going this route with a 12V fridge, then a 500W inverter would be perfectly adequate and the generator, or engine running can be used for less time to keep the batteries topped up in winter. Get solar panels for summer, if your boat doesn't already have them. Hair driers and straighteners are a problem. No easy way round the huge power draw they take. Power tools are available battery powered. If you stick with the same range, I have Makita, then the expensive batteries can be used on a variety of tools. More expensive than mains power tools, but very good quality. 

 

Jen

^^^^^^^This