Probably a daft electrical, battery/alternator question

[Paul C]

Personally I'd look to fix the cooling circuit, especially if you have that lever to pull (I'd prefer it foolproof/automatic, eg using a second thermostat) but it depends if the engine has other reasons why its ineffective at heating domestic water - ie why you never connected it in the first place.

 

The other option is to actually test your alternator to see if it could cope with 70A continuous.

[magnetman]

Washing less often. Fewer washing events. 

 

Always worth being aware of the grammatical difference between less and fewer.

 

Hot water is over rated. In fact it is a scam very much like electricity and cars and it will rapidly lead to the destruction of humans in very nasty firey armageddons. 

 

When it happens armageddon outa here. 

 

 

 

[Tacet]

1 hour ago, Alan de Enfield said:

 

It'll be a very expensive way of heating a calorifier full of water.

 

To Heat 1 litre of water by 10C = 105Wh (.105Kwh)

 

1 litre of water by 60 degrees = 105Wh x 6 = 630Wh 

 

So with your 600 watt heater it will take ~1 hour for each litre you want heating

 

If your engine uses 1 litre of diesel per hour (£1.50 ?) then it is going to cost you ~£1.50 per litre.

 

Assuming your calorifier is plumbed in to the engine circuit you will of course get heat from that, which will reduce the time you need to use the immersion heater.

 

 

 

18 minutes ago, nicknorman said:

Around a factor of 10 out old chap. Gross error check says that our 2kw electric kettle heats 2 litres of water from 10C to boiling in less than 5 minutes. 1 litre 2.5 mins. 1 litre at 600w about 7.5 mins. 1 litre at 600w by 60 deg about 5 mins.

 

 Being precise, specific heat of water is about 4184 joules per kg k. Or 1.16 Wh/kg k. So 600w is going to raise 1 litre by 60C in 7 mins.

 

We sometimes use our 1kw immersion from the batteries, and so far we haven’t turned into frogs nor been burnt at the stake for heresy. Although plenty have tried!

Yep.  Or it would take 20 minutes to heat 1 lire by 60 degrees using a domestic 3kw immersion heater.  Which would mean a very long wait for a bath full.

[roland elsdon]

just tied up at bottom of erewash. 7.5 hrs boating.

Nice hot tank.

[Paul C]

Its the kind of error an AI bot would make, if it were trying to convince us it WASN'T an AI bot.

[Mike Hurley]

Buy wet wipes, easier.

[magnetman]

Baby wipes. Get them before they are banned. 

 

I have 3.7 years worth of these in the storage areas on the boats.

[Up-Side-Down]

On 09/04/2023 at 16:36, casper ghost said:

Hi. I only have 1 115ah domestic battery, but I'd like to run a small immersion heater, probably a 12 v one. My battery bank won't be up to it, but, if I only ever use it with the engine running, will it run off my alternator, it's a fairly standard alternator, think 70 or 75 amp. I just didn't know if alternator going through the battery would then run the immersion heater, which is probably about 600 watts 12v. It's either that or use a 240v and start a Genny...

Thanks.

I would suggest you start looking into a couple of Solariskit modules – https://www.solariskit.com. I'm just about to start trials work with them on boat installations and will report back in the fullness of time. The plan is to incorporate the heated water feed from the pyramids into the engine/calorifier circuit via a wee 12V pump and a differential controller on an either or basis, initially using simple manual valves. The modules have been very successful in a range of applications from third world countries to first world camp sites.

[magnetman]

The pyramid pool heaters (solariskit) seem a bit tall for the top of a narrow boat. 

 

These pool heater are a bit lower profile.

 

https://www.amazon.co.uk/TANGZON-Thermal-Heating-Inground-Equipment/dp/B0BW89TJ3N/ref=asc_df_B0BW89TJ3N/?tag=googshopuk-21&linkCode=df0&hvadid=651376299312&hvpos=&hvnetw=g&hvrand=16211986942135801218&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=1006886&hvtargid=pla-2004348895648&psc=1

 

 

 

I don't need hot water but if there was a use for it I would be very tempted to try one of two of these. 

 

Also seems more durable. The solariskit modules seem to be flexible rather than a rigid perspex dome. I like the dome as it would be less likely to catch on things.

The solariskit ones seem large but it is difficult to accurately scale them to be fair.

 

Also it might not be rocket science to buy a coil of 'ose and a perspex dome for it to go inside. 

Then arrange a circulation pump with a pwm controller for infinitely variable motor speed. 

Edited April 11, 2023 by magnetman
odd double post

[Paul C]

49 minutes ago, Up-Side-Down said:

I would suggest you start looking into a couple of Solariskit modules – https://www.solariskit.com. I'm just about to start trials work with them on boat installations and will report back in the fullness of time. The plan is to incorporate the heated water feed from the pyramids into the engine/calorifier circuit via a wee 12V pump and a differential controller on an either or basis, initially using simple manual valves. The modules have been very successful in a range of applications from third world countries to first world camp sites.

 

What do they do on a day like today? 

 

Opening it up wider - I suspect solar water heating is basically rubbish except on the handful of hot summer days, and I don't think we need to wait for a trial of another kit. But happy to be proven wrong.

[Tony Brooks]

2 minutes ago, Paul C said:

 

What do they do on a day like today? 

 

Opening it up wider - I suspect solar water heating is basically rubbish except on the handful of hot summer days, and I don't think we need to wait for a trial of another kit. But happy to be proven wrong.

 

I think that we have at least one member who is using solar water heating. Possibly Jen, or Buccaneer, but it seems to be a proper system, not some plastic fantastic, no easy to find performance data job.

[Bee]

The economics of heating water are not great but it doesn't take long to heat a kettle to 100 deg C and that will give you 2 kettles full of water at hair washing/shaving etc. temp (Which is probably what you do) and if you run the engine whilst you are doing it you will probably get a tank full of fairly warm water (which again is probably what you do) So you might be stuck with doing that. It's what we do on Bee. However, if you get some cheap black hose and fill it with water and lay it in a coil on the roof it will get surprisingly warm surprisingly quickly. Take one end through the bathroom window and take the plug out and voila! a shower! Doesn't work too well in winter but nobody sweats in the winter so it doesn't matter.

[ditchcrawler]

57 minutes ago, Tony Brooks said:

 

I think that we have at least one member who is using solar water heating. Possibly Jen, or Buccaneer, but it seems to be a proper system, not some plastic fantastic, no easy to find performance data job.

I have seen one or two around with the proper vacuum tubes as used on houses

[GUMPY]

17 hours ago, Paul C said:

 

What do they do on a day like today? 

 

Opening it up wider - I suspect solar water heating is basically rubbish except on the handful of hot summer days, and I don't think we need to wait for a trial of another kit. But happy to be proven wrong.

I've had solar water heating on the roof of the house for just under two years. From April to October we use no other water heating. In the winter it only requires a sunny day not even a warm day and the water is hot, where it scores is that even on a dull day it will raise the stored water temperature to about 25 degrees thus meaning you only have to raise the water temperature by 25 rather than 40 degrees to get useful hot water. The secret is having a 300litre well insulated storage tank meaning once the water is hot it stays that way.

 

ETA on a sunny summer's day I have seen the temperature at the panels reach 130degrees and have 300L of 60deg water in the tank.

Edited April 12, 2023 by Loddon

[magnetman]

It seems to me that taking more and more of the sun's energy in this way is going to mean the sun has to get hotter to deal with the demand and eventually we'll all fry.

 

[Alan de Enfield]

28 minutes ago, magnetman said:

It seems to me that taking more and more of the sun's energy in this way is going to mean the sun has to get hotter to deal with the demand and eventually we'll all fry.

 

 

Or, It'll 'run out' and we will all freeze and die.

[Peanut]

No worries, our sun will become a Red Giant, and the world will fry, but there will be none left by then.

[magnetman]

Tom Lehrer put it so well

 

 

[Mad Harold]

Am a missing something here?

Loads of gobbledegook about batteries, alternators etc.

Wouldn't the simplest answer to having hot water without running the engine, is to fit an instant hot water gas heater.

[Alan de Enfield]

16 minutes ago, Mad Harold said:

Wouldn't the simplest answer to having hot water without running the engine, is to fit an instant hot water gas heater.

 

It would be, but many people do not like gas and there are an ever increasing number of 'gas-free' boats, and, the other reason is that the Sun is 'free' - gas is getting more and more expensive.

Edited April 12, 2023 by Alan de Enfield

[casper ghost]

On 12/04/2023 at 11:34, Mad Harold said:

Am a missing something here?

Loads of gobbledegook about batteries, alternators etc.

Wouldn't the simplest answer to having hot water without running the engine, is to fit an instant hot water gas heater.

I'm not against the idea of a gas water heater, but I was trying to think of an easier idea with less work for me.. Unfortunately, there doesn't seem to be one. For now i'll have to stick to boiling pots of water and put the engine cooling back into the calorifier. 

[Phoenix_V]

6 hours ago, casper ghost said:

, but I was trying to think of an easier idea with less work for me.. Unfortunately, there doesn't seem to be one.

 

This simple enough? https://www.ebay.co.uk/itm/20L-Solar-Power-Water-Shower-Camping-Portable-Seaside-Sun-Compact-Heated-Outdoor-/175217173656?_trksid=p2349526.m4383.l4275.c10