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Time to replace batteries?


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1 minute ago, IanD said:

 

I'd be very surprised if 30 mins or so engine running will heat the hot water enough, in my experience on various boats it takes a lot longer than that. Dave Jesse measured that his generator puts just over 1kW into the calorifier coil, which isn't much -- depends on the size of the calorifier, a big one (55l) will heat up by about 15C per hour (8C in 30mins), the same as using a 1kW immersion heater -- a smaller one will obviously be faster.

 

Ironically, heating the hot water with the engine works better with lead-acid batteries where you need to run for hours to fully charge them, with lithiums the engine running time is much lower so less good for hot water...

 

I must admit I've never actually timed it, but I also dont wait until the water is very hot. Hot enough to wash or shower is probably about 40-42 degrees, and that's hot enough for me. 

I'll time it next time I get washed (I think its January 2022), and get back to you.

 

 

 

 

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7 minutes ago, Tony1 said:

 

I must admit I've never actually timed it, but I also dont wait until the water is very hot. Hot enough to wash or shower is probably about 40-42 degrees, and that's hot enough for me. 

I'll time it next time I get washed (I think its January 2022), and get back to you.

 

 

How big is your calorifier?

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14 minutes ago, TheBiscuits said:

 

I switch on the immersion heater if running the engine just for hot water which gets there faster.

I use the immersion as well when I need a quick hit of hot water, 55L calorifier, however the immersion only heats the top part of the calorifier so only about 25L enough for a couple of showers.

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6 minutes ago, IanD said:

 

How big is your calorifier?

 

I must be brutally frank- I have no idea- its under the bed, with screwed down bed boards on top, and since it hasn't caused me any headaches I've left it alone. 

 

I dont know if I'm getting an unfairly positive impression because the baseline/ambient temperature has been a bit warmer over the summer, so the water takes less heating. I also have the CH on for the odd hour in the mornings, just to take the coolness out of the air, and things like that might have given me a false impression of the water heating times.

 

Yesterday there was plenty of hot water anyway because I was cruising, so I'll try and remember to stick to 30 mins of engine tomorrow, and see if it really does get warm enough to wash.  

 

 

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We have the TravelPower so if we need to run the engine just to heat water /charge the batteries, I turn the immersion heater on. No impact on battery charging rate since the 100A Mastervolt Combi charger takes about 1.5kw, another 1kw for the immersion heater is still well within the 3.5kw capability of the Travelpower. Plus of course the 175A alternator is unaffected, and can put out about 120A continuous without getting too hot, ie 220A into the batteries. That is a fair mechanical load on the engine which I’m sure makes it coolant heat up quicker & thus heat the calorifier quicker.

 

And course the Mikuni can always be used to heat the water if no engine running is needed.

Edited by nicknorman
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8 minutes ago, nicknorman said:

We have the TravelPower so if we need to run the engine just to heat water /charge the batteries, I turn the immersion heater on. No impact on battery charging rate since the 100A Mastervolt Combi charger takes about 1.5kw, another 1kw for the immersion heater is still well within the 3.5kw capability of the Travelpower. Plus of course the 175A alternator is unaffected, and can put out about 120A continuous without getting too hot, ie 220A into the batteries. That is a fair mechanical load on the engine which I’m sure makes it coolant heat up quicker & thus heat the calorifier quicker.

 

Even if the engine is hot the calorifier coils are quite small and have limited heat transfer capacity -- in Dave's case the generator was dumping something like 19kW into the skin tank (nice hot generator!) and 1.1kW into the calorifier. If the engine isn't hot it will heat up even more slowly -- but for sure more loading on the engine (Travelpower, alternator) is a good thing because it makes use of more of the energy, so the overall CHP efficiency goes up and you have to burn less fuel 😉

28 minutes ago, TheBiscuits said:

 

I switch on the immersion heater if running the engine just for hot water which gets there faster.

 

It doesn't really help charge the batteries though :D

 

 

For sure if you're running the engine for hot water then turning the immersion heater on is the right idea, it'll heat the calorifier up twice as quickly so halves the engine running time.

 

I looked at all this for the hybrid boat I'm having built (9kW diesel genny + Eberspacher) and concluded that it was better to use a twin-coil calorifier with both coils connected to the Eberspacher for hot water -- this can throttle down to <2kW so no short-cycling even with radiators off, and is better than having one coil for the generator which will do very little given short lithium running times. So hot water/heating is Eberspacher only, generator (plus solar) is only for battery charging -- but any spare power from solar can power the immersion heater. If more hot water is needed it's much better to run the Eberspacher than the generator.

Edited by IanD
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1 minute ago, nicknorman said:

We have the TravelPower so if we need to run the engine just to heat water /charge the batteries, I turn the immersion heater on. No impact on battery charging rate since the 100A Mastervolt Combi charger takes about 1.5kw, another 1kw for the immersion heater is still well within the 3.5kw capability of the Travelpower. Plus of course the 175A alternator is unaffected, and can put out about 120A continuous without getting too hot, ie 220A into the batteries. That is a fair mechanical load on the engine which I’m sure makes it coolant heat up quicker & thus heat the calorifier quicker.

 

And course the Mikuni can always be used to heat the water if no engine running is needed.

 

I've been pondering asking Ed to install some wiring so that the water can be heated from the batteries. During the summer with loads of excess solar, there are a few months where I'll effectively get hot water with no engine running. 

But Ian has previously pointed out that more energy draw from the batteries will shorten their lives to an extent, and I'll have to accept that asking the batteries to provide enough energy to power say a 1kw immersion will add a significant usage onto their normal cycle. 

But on the plus side, it will save a good few engine hours during between say June- Aug

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7 minutes ago, Tony1 said:

 

I've been pondering asking Ed to install some wiring so that the water can be heated from the batteries. During the summer with loads of excess solar, there are a few months where I'll effectively get hot water with no engine running. 

But Ian has previously pointed out that more energy draw from the batteries will shorten their lives to an extent, and I'll have to accept that asking the batteries to provide enough energy to power say a 1kw immersion will add a significant usage onto their normal cycle. 

But on the plus side, it will save a good few engine hours during between say June- Aug

 

Fit a thyristor, basically a volume control for the immersion heater.  You can choose how much voltage to feed the immersion heater using a square law.

 

A 1kW immersion heater at 240V is a 58 ohm resistor, so if you feed it 120V it's only a 250W immersion heater, which gives you free silent water heating.  It's not very efficient, but it uses the waste sunshine that your batteries can't store.

 

 

 

Edited by TheBiscuits
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14 minutes ago, Tony1 said:

 

I've been pondering asking Ed to install some wiring so that the water can be heated from the batteries. During the summer with loads of excess solar, there are a few months where I'll effectively get hot water with no engine running. 

But Ian has previously pointed out that more energy draw from the batteries will shorten their lives to an extent, and I'll have to accept that asking the batteries to provide enough energy to power say a 1kw immersion will add a significant usage onto their normal cycle. 

But on the plus side, it will save a good few engine hours during between say June- Aug

If they're lithium batteries you really don't need to worry about lifetime, if they're properly managed they'll last longer than you will 😉

 

You should be able to use excess solar power to heat water "for free" -- the solar charges the batteries (current in), the inverter powers the immersion (current out). If the two balance the batteries never see any current... 😉

 

(yes I know this won't happen hour-by-hour even if it works on average...)

Edited by IanD
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3 minutes ago, TheBiscuits said:

 

Fit a thyristor, basically a volume control for the immersion heater.  You can choose how much voltage to feed the immersion heater using a square law.

 

A 1kW immersion heater at 240V is a 58 ohm resistor, so if you feed it 120V it's only a 250W immersion heater, which gives you free silent water heating.  It's not very efficient, but it uses the waste sunshine that your batteries can't store.

 

 

 

 

Yes, and thanks for this suggestion. Once the basic wiring is in place I'll put one those things in for more control. 

 

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9 minutes ago, TheBiscuits said:

 

Fit a thyristor, basically a volume control for the immersion heater.  You can choose how much voltage to feed the immersion heater using a square law.

 

A 1kW immersion heater at 240V is a 58 ohm resistor, so if you feed it 120V it's only a 250W immersion heater, which gives you free silent water heating.  It's not very efficient, but it uses the waste sunshine that your batteries can't store.

 

 

Don't need to do that, just turn the immersion on until the water is heated up, then the solar will top the batteries back up -- solar is unlikely to provide more power than the immersion uses.

 

The batteries act as an energy buffer, there's no need to match the immersion and solar power at any instant in time.

Edited by IanD
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5 minutes ago, IanD said:

If they're lithium batteries you really don't need to worry about lifetime, if they're properly managed they'll last longer than you will 😉

 

You should be able to use excess solar power to heat water "for free" -- the solar charges the batteries (current in), the inverter powers the immersion (current out). If the two balance the batteries never see any current... 😉

 

(yes I know this won't happen hour-by-hour even if it works on average...)

 

So the opposite of a double whammy- not only is the energy free (in a way), but it also doesnt add to the cycling which ages the batteries? Champion. 

 

Of course my other nefarious plan was to get a compact air conditioning unit and use the excess solar power to stay cool. Something has to be done- on the days I couldnt find shade, the boat interior went above 30 degrees, which creates a H+S issue.

I can handle walking around sweating and shirtless, of course, but there is a significant risk that passing ladies will be be distracted by my godlike physique, and fall into the canal.

Sometimes you have to put the punters first.

 

 

 

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1 minute ago, Tony1 said:

Of course my other nefarious plan was to get a compact air conditioning unit and use the excess solar power to stay cool. Something has to be done- on the days I couldnt find shade, the boat interior went above 30 degrees, which creates a H+S issue.

 

When it was crazy hot a couple of months ago, I hid under some trees.  I was laughing at myself having to run the engine to charge batteries in the shade when two boat lengths away it was 30+ degree temperatures and blazing sunshine.

 

Kept the boat pleasant inside though, so it was worth it.  My inner cheapskate was wondering about making an extension lead for the solar panels and putting them in the sunshine ...

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12 minutes ago, Tony1 said:

 

So the opposite of a double whammy- not only is the energy free (in a way), but it also doesnt add to the cycling which ages the batteries? Champion. 

 

Of course my other nefarious plan was to get a compact air conditioning unit and use the excess solar power to stay cool. Something has to be done- on the days I couldnt find shade, the boat interior went above 30 degrees, which creates a H+S issue.

I can handle walking around sweating and shirtless, of course, but there is a significant risk that passing ladies will be be distracted by my godlike physique, and fall into the canal.

Sometimes you have to put the punters first.

 

 

I've also looked at built-in aircon -- for heating as well as cooling -- but apart from the cost it's a real pain to fit into a narrowboat (air ducting, noise, freshwater cooling, condensate drain...), and can't be guaranteed to work in winter so you need another heating system (e.g. Eberspacher). Which makes it a *very* expensive way of staying cool 😞

 

For the few days when this is a real problem, a portable air-conditioner plugged into the onboard 230Vac mains is a lot easier and cheaper 😉

 

https://www.expertreviews.co.uk/home-appliances/1406249/best-portable-air-conditioner

Edited by IanD
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4 minutes ago, TheBiscuits said:

 

When it was crazy hot a couple of months ago, I hid under some trees.  I was laughing at myself having to run the engine to charge batteries in the shade when two boat lengths away it was 30+ degree temperatures and blazing sunshine.

 

Kept the boat pleasant inside though, so it was worth it.  My inner cheapskate was wondering about making an extension lead for the solar panels and putting them in the sunshine ...

 

I was doing exactly the same thing on the Llan- my new thing was to look for tree cover around the prospective moorings in my 'target' area, so I was looking at google terrain view, and aiming for the overshadowed locations. It worked pretty well to be fair. 

I found that if I couldnt find full shade, it was better to be shaded in the afternoon and evening, when the sun was hottest- but even half a day of sun was never great. 

 

When it was at its worst, I wondered about the wisdom of painting the boat white...

 

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22 minutes ago, IanD said:

 

I've also looked at built-in aircon -- for heating as well as cooling -- but apart from the cost it's a real pain to fit into a narrowboat (air ducting, noise, freshwater cooling, condensate drain...), and can't be guaranteed to work in winter so you need another heating system (e.g. Eberspacher). Which makes it a *very* expensive way of staying cool 😞

 

For the few days when this is a real problem, a portable air-conditioner plugged into the onboard 230Vac mains is a lot easier and cheaper 😉

 

https://www.independent.co.uk/extras/indybest/house-garden/household-appliances/best-portable-air-conditioners-units-summer-b1890512.html

 

Yes, I did think about something like this as well.... I reckon the solar could pretty much power it, but the real challenge for me is lack of space on a 50ft liveaboard.

 

Finding storage space for a unit like this, to use for just a few weeks per year, would mean something else having to go, and I dont know what that would be. 

I've had several Great Purges, possibly more ruthless than those of Stalin, but I always seem to struggle for storage...

 

 

Edited by Tony1
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3 minutes ago, Tony1 said:

 

Yes, I did think about something like this as well.... I reckon the solar could pretty much power it, but the real challenge for me is lack of space on a 50ft liveaboard.

 

Finding storage space for a unit like this, to use for just a few weeks per year, would mean something else having to go, and I dont know what that would be. 

 

Is 35x35x70cm so difficult to find space for, if it keeps you cool for those few sweaty weeks per year? 😉

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15 minutes ago, Tony1 said:

 

I was doing exactly the same thing on the Llan- my new thing was to look for tree cover around the prospective moorings in my 'target' area, so I was looking at google terrain view, and aiming for the overshadowed locations. It worked pretty well to be fair. 

I found that if I couldnt find full shade, it was better to be shaded in the afternoon and evening, when the sun was hottest- but even half a day of sun was never great. 

 

When it was at its worst, I wondered about the wisdom of painting the boat white...

 

I have noticed in the hottest days that my chrome plated tiller tube stays remarkably cool, so my next boat is going to be blinged up with a mirror chrome finish like one of those footballers Range Rovers.

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2 minutes ago, IanD said:

Is 35x35x70cm so difficult to find space for, if it keeps you cool for those few sweaty weeks per year? 😉

 

During the Great Sweltering of July, I would have thrown the ship's dog overboard to make space, such was my desperation. 

Fortunately for the ship's dog, he is entirely fictional, so he escaped this fate. 

But you do have a point here. 

Something has to give; something must be expendable....

 

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4 minutes ago, PeterF said:

I have noticed in the hottest days that my chrome plated tiller tube stays remarkably cool, so my next boat is going to be blinged up with a mirror chrome finish like one of those footballers Range Rovers.

 

Absolutely inspirational thinking Sir.

Forget your Spitfires and your bouncing bombs. This is the kind of innovative thinking that made Blighty great, by Jove.

The question of cost does of course rear its ever-ugly head.

 

Perhaps I could find a dodgy back-street painter or tradesman willing to chrome up my boat....

It might cost a bit, but on the plus side I could play rap music with no embarrassment whatsoever.

Silver linings, methinks. 

 

 

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23 minutes ago, Alan de Enfield said:

 

 

Just remember "every silver lining has a cloud around it"

 

Dash it all man, our chaps would never have beaten the Hun with that kind of negative attitude. 

Chrome boats has to be way forward. Cooler boats, and even cooler boaters.

  

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On 24/09/2021 at 20:30, Tony1 said:

 

Dash it all man, our chaps would never have beaten the Hun with that kind of negative attitude. 

Chrome boats has to be way forward. Cooler boats, and even cooler boaters.

  

 

And a tinfoil hat, which not only keeps you cool but stops 5G radiation from frying your brain... 😉

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