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Continual cruising - hot water & Generators


ScrimpyJack

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looking for advice before i set sail and leave my marina and try continual cruising this year, I have a 3kw inverter with 570w of solar panels and been spoilt with mains supply and ever ready tank of hot water. When Ive been out cruising I've always struggled after a few weeks to keep my batteries topped up, and have to run the engine now and then. Presumably our continual cruisers run their engines or use a generator to get hot water...

 

do you recommend an affordable generator to do this and how long do you need to run it to top the battieries up and get a tank of hot water from the calorifier.

 

Im not technical when it comes to solar charge or plumbing so any advice would be helpful. 

 

apologies if this has been asked before.

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A reliable and quiet portable generator is useful for re-charging the batteries and providing 230v electricity when away from mains electricity.

We use a Honda suitcase generator with all the usual safety precautions when handling petrol powered generators. It works out cheaper and quieter than running the main engine.

Another reason is that, although when continually cruising, a boat is likely to be moving under power most days, the main engine may not be running fast enough to keep the battery bank fully charged - especially these days when continually passing moored boats at tickover . . .

For hot water we use a Morco gas fired water heater. This is the most economical way of providing on-demand hot water whenever needed.

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How often you need to run your engine for your batteries and hot water all depends on how much you're planning on moving the boat, your alternator output, but most of all how much electricity and hot water you're consuming.

 

For hot water, most people are going to have used a 60litre calorifier up in 1 or 2 days. For electricity it's much more complicated and the first thing you need to do is a power audit. You say you're not technical but for this to work I'm afraid you're going to have to try to get your head around it. Don't go out buying a generator until you've understood what you're already generating, your storage capacity and what you're consuming. The other thing is that carrying a suitcase generator means carrying petrol. Where are you going to store both? 

 

Suggest you do some searching on the forum as there are a lot of threads on your questions. I'd also suggest you go out for a few weeks in the boat before giving up your mooring and bear in mind that CCing is a lot easier when the weather is good.

Edited by blackrose
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Have a read of this thread on the basics of battery charging.

 

Battery charging primer

 

Your regime for cruising where you struggle after a few weeks is a sign that you are under charging your batteries and this is the main reason for killing batteries, if you operate like this continuously your batteries will not last very long. They need to get a good recharge at least once per week.

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There is no one answer, it depends on your electricity usage, particularly things like fridge and TV, and also the size of the engine domestic alternator. You don’t say how you are measuring the state of charge of the batteries?

 

With the solar you have, in anything approaching summer you would like to think that would recharge your batteries on the days that you do not move.  For hot water, running the engine for an hour is the simple way, and that will also do a chunk of the bulk charging of the batteries, so the solar is more likely to get there.

 

I would not jump into buying a generator until you know that one is really for you, for example where are you going to store it and the petrol.

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13 minutes ago, PeterF said:

Have a read of this thread on the basics of battery charging.

 

Battery charging primer

 

Your regime for cruising where you struggle after a few weeks is a sign that you are under charging your batteries and this is the main reason for killing batteries, if you operate like this continuously your batteries will not last very long. They need to get a good recharge at least once per week.

 

And that means charging for into two numbers for hours unless you have some form of battery monitoring. From what you say I guess you may not and only rely upon a voltmeter or the lies solar controllers tend to tell. It's perfectly possible to infer the batteries state of charge from rested voltage but for much of the year solar will make that less easy and it involves you gaining technical knowledge. Be aware that the common battery monitors all have  shortcomings and the more popular ones that give percentage of charge tell lies unless you understand even more technical  stuff. However, they provide an accurate ammeter and voltmeter so you can use the ammeter to tell you when to stop charging (1 to 2% of battery capacity and not dropping for  a while) and the voltmeter (after you understand how to do it) can be used to infer state of charge.

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9 hours ago, ScrimpyJack said:

so any advice would be helpful. 

 

As has been already said, it is quite a complex situation that you do need ' to get your head around' or it will get expensive with you needing to buy a new battery bank every couple of months (or sooner).

 

Basically if you are crusing every day for (say) 6 hours you will have suffcient hot water and fully charged batteries

If you are simply 'playing the game' and moving a couple of miles every 14 days you will have no hot water and destroyed batteries.

 

Your 'personal sweet spot' may well lie somewhere between the two but only you can work out where it is by doing a full electrical audit of usage vs generation.

 

The average consumption seems to be around 100Ah per day so you need to put back in around 120Ah per day which (as a simple guide) could take 3 or 4 hours of engine running (PER DAY) if you do not have solar.

 

Solar can go along way to contributing to battery health for around 5-6 months of the year but will only do a 'bit' for a couple of months & do virtually nothing for 4-5 months of the year, if you plan to CC from October / November to March then you will definitely need some form of battery charging, either engine running or generator.

 

You will also need to set up some form of battery monitioring system to tell you when you need to charge your batteries and just as importantly when to stop charging them.

 

 

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Lots of variables. Our Beta 43 heats up a tank of hot water in about 1 hour, it will also give a useful charge to the batts in that hour too, it has not got lots of alternators either. If that sounds like magic it is because we only have a small hot water tank, only two 110 ah batts for domestic use, one small (rationed) telly ,with a tiny e bay inverter for phones and cordless stuff, led lights and the fridge is only used sparingly. Oh, one solar panel too. We also usually travel daily.  We reckon that that works well but to increase the electric or hot water demand would need a lot of money spent on batts, diesel, big alternators and electrical gizmos, as soon as you want the comforts of a house the cost goes up like a very big rocket. As for generators, A small, fixed diesel generator in the engine room is better than a portable petrol thing. A friend had a single cyl. Lister permanently mounted in the engine hole and with clever rubber mounts and silenced air and exhaust it was incredibly quiet.

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45 minutes ago, Alan de Enfield said:

You will also need to set up some form of battery monitioring system to tell you when you need to charge your batteries and just as importantly when to stop charging them.

 

The red bit - for lead acid batteries you are unlikely to do an ydamage by continuing charging after they are fully charged so I think Alan is talking about minimising wear on the charging device (engine), minimising fuel burned, and minimising potential annoyance of close by boats.

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Just now, Tony Brooks said:

 

The red bit - for lead acid batteries you are unlikely to do an ydamage by continuing charging after they are fully charged so I think Alan is talking about minimising wear on the charging device (engine), minimising fuel burned, and minimising potential annoyance of close by boats.

 

Indeed,

Sorry, I could have ended up 'writing war and peace' trying to get everything covered.

 

Once the batteries are charged (and that is ascetained by the charging current being ~1% of the battery bank capacity, and holding at 14.4-14.6v for at least an hour) you can stop to save cost of fuel, wear & tear on the engine and 'noise'.

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3 minutes ago, Alan de Enfield said:

 

Indeed,

Sorry, I could have ended up 'writing war and peace' trying to get everything covered.

 

Once the batteries are charged (and that is ascetained by the charging current being ~1% of the battery bank capacity, and holding at 14.4-14.6v for at least an hour) you can stop to save cost of fuel, wear & tear on the engine and 'noise'.

 

Could not many of us - I know the feeling very well.

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Are you planning to heat your hot water with an immersion heater from your generator? If so assuming (bad move) its a 1KW Immersion heater you are going to need at least a 2Kw generator to charge your batteries as well as heat the water

 

 

13 hours ago, ScrimpyJack said:

 

do you recommend an affordable generator to do this and how long do you need to run it to top the batteries up and get a tank of hot water from the calorifier.

 

 

 

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12 minutes ago, ditchcrawler said:

Are you planning to heat your hot water with an immersion heater from your generator? If so assuming (bad move) its a 1KW Immersion heater you are going to need at least a 2Kw generator to charge your batteries as well as heat the water

 

 

That is a good question because the OP was not clear in what he was on about. I read it as asking about a built-in generator that would also heat the calorifer but I suppose the word "affordable" in the original question. probably rules that out.

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I'm supposed to be a continuous cruiser: only twelve months out on the cut. I have a solid fuel stove and Webasto, there is hot water all the time. I think the Webasto can heat the calorifier tank in about  30 mins if I want a shower, or I can put the fire on for a few hours overnight, water is warm. There are shower facilities at most sanitary stations. I have solar panels which are esentially there to feed the fridge. The fridge is OFF in winter.

I have to adjust my lifestyle because I no longer live in a house. This means monitoring water, fuel, electricity, laundry, but I think that a boat for living off grid requires the boat to be set up for that purpose. 

To me , buying a petrol generator is a no no.

Edited by LadyG
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20 minutes ago, ditchcrawler said:

Are you planning to heat your hot water with an immersion heater from your generator? If so assuming (bad move) its a 1KW Immersion heater you are going to need at least a 2Kw generator to charge your batteries as well as heat the water

 

 

 

 

 

Just for the benefit of the OP that doesn't mean you need a 2Kw generator it means that you need a geberator with a continuous rating of at least 2Kw.

 

Most '2Kw' generators are rated at around 1600w (1.6Kw)  continuous rating, but, a lot of sales details have that fact hidden away in the small print.

 

 

 

2 minutes ago, LadyG said:

There are shower facilities at most sanitary stations.

 

 

I would suggest that that is far from true (in my limited experience)

Edited by Alan de Enfield
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3 hours ago, Bee said:

Lots of variables. Our Beta 43 heats up a tank of hot water in about 1 hour, it will also give a useful charge to the batts in that hour too, it has not got lots of alternators either. If that sounds like magic it is because we only have a small hot water tank, only two 110 ah batts for domestic use, one small (rationed) telly ,with a tiny e bay inverter for phones and cordless stuff, led lights and the fridge is only used sparingly. Oh, one solar panel too. We also usually travel daily.  We reckon that that works well but to increase the electric or hot water demand would need a lot of money spent on batts, diesel, big alternators and electrical gizmos, as soon as you want the comforts of a house the cost goes up like a very big rocket. As for generators, A small, fixed diesel generator in the engine room is better than a portable petrol thing. A friend had a single cyl. Lister permanently mounted in the engine hole and with clever rubber mounts and silenced air and exhaust it was incredibly quiet.

 

There's no doubt that marine diesel generators are safer and better than portable suitcase petrol generators. The trouble is that unless it's a self build diy job, most proper marine diesel generators are incredibly expensive. You're looking at least 5 x the price. 

Edited by blackrose
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14 minutes ago, Alan de Enfield said:

 

I would suggest that that is far from true (in my limited experience)

 

In my experience too. I'm not sure how many sanitary stations Lady G has visited but I think those with showers are pretty few and far between.

17 minutes ago, LadyG said:

 

To me , buying a petrol generator is a no no.

 

Yes, those who don't know what they're doing shouldn't buy petrol generators. Unfortunately lots do and accidents happen.

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Just now, blackrose said:

 

In my experience too. I'm not sure how many sanitary stations Lady G has visited but I think those with showers are pretty few and far between.

 

 

I seem to think that since she left the marina about a year ago she has been moored up outside a sanni station (the same one all of the time due to covid, and then when restrictions were lifted she developed gearbox problems, then, by the time it was fixed lockdown was back again) this sanni station happens to have a shower, so extrapolate that, and you have 'most of them have showers'

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8 minutes ago, Tony Brooks said:

But let's not dilute the good sense in the rest of the good lady's post about adjusting your lifestyle to onboard living by concentrating on that rather poor comment.

 

There is some good advice, much of which was added subesquently to my post picking up the point about the showers.

 

She does post some useful stuff, but has a habit of posting facts which could affect choices made by a newbie (remember this was the OPs 1st post and he does not know who has experience and who doesn't). If such posts are taken at face value (and not corrected) he may think that he could pass a sanni station every day and have a shower and not have to worry about having hot water on the boat.

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59 minutes ago, LadyG said:

I'm supposed to be a continuous cruiser: only twelve months out on the cut. I have a solid fuel stove and Webasto, there is hot water all the time. I think the Webasto can heat the calorifier tank in about  30 mins if I want a shower, or I can put the fire on for a few hours overnight, water is warm.

Absolutely. Heating water electrically is a non-starter if you are away from the shoreline. That's why most boaters rely on some combination of calorifier heated by the main propulsion engine, or a webasto/mikuni/eberspacher type diesel heater or the Alde gas equivalent, a solid fuel stove with back boiler or an instantaneous gas water heater.

Solar water heating is possible (@Jen-in-Welliesdescribed her system a year or two back), but solar electric water heating is impractical.

Edited by David Mack
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1 hour ago, Alan de Enfield said:

 

 

Just for the benefit of the OP that doesn't mean you need a 2Kw generator it means that you need a geberator with a continuous rating of at least 2Kw.

 

Most '2Kw' generators are rated at around 1600w (1.6Kw)  continuous rating, but, a lot of sales details have that fact hidden away in the small print.

 

 

And a good one is about £1000 which could also run on gas as well as petrol

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2 hours ago, Tony Brooks said:

But let's not dilute the good sense in the rest of the good lady's post about adjusting your lifestyle to onboard living by concentrating on that rather poor comment.

Don't worry Tony, I have those trolls on ignore for good reason. They always have some gripe on every single post I make.  They give the impression of being very unpleasant people. 

 

 

 

 

 

Edited by LadyG
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32 minutes ago, LadyG said:

They absolutely hate my posts, so why do they feel obliged to read them and comment

 

Because you are writing rubbish, which I , and others , have suggested is misleading. You write as if your speculation is fact when it is not.

If you stuck to posting about what you know, and have experience of (which is patently not the canal system) you may well get less adverse  comments.

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