Overwintering, heating control.

[MtB]

14 minutes ago, MartynG said:

I have only had that happen one occasion and it was eventually traced  to a faulty appliance on one boat . 

 

 

Ah yes, that too. 

 

So using the lectric for frost protection has you reliant on the quality of the installations in every other boat on the supply, as well as your own boat. 

 

 

[Momac]

45 minutes ago, ditchcrawler said:

By which time all those boats that left their inverters on have flat batteries trying to power their heaters 

My boat doesn't have an inverter . So that's not a problem for me.

But in any case  I would have thought frost protection heaters are best powered without batteries being involved. 

 

47 minutes ago, MtB said:

 

Ah yes, that too. 

 

So using the lectric for frost protection has you reliant on the quality of the installations in every other boat on the supply, as well as your own boat. 

 

 

That's true. But most of the time not an issue .

[rusty69]

1 minute ago, MartynG said:

My boat doesn't have an inverter . So that's not a problem for me.

But in any case  I would have thought frost protection heaters are best powered without batteries being involved. 

 

The problem being that some inverter/chargers will automatically switch to inverter powered electrics in the absence of a shoreline connection. Of course, this could be prevented in the majority of cases, but often isn't,in my experience.

[ditchcrawler]

2 minutes ago, MartynG said:

But in any case  I would have thought frost protection heaters are best powered without batteries being involved. 

 

 

I suspect most people will plug them into a 13A outlet permanently wired into their boat electrical system which when on shore power gets is energy from there but when cruising gets it from the inverter, If they don't switch their combies to charge only then in a power cut the batteries would power the heaters.

[IanD]

19 minutes ago, ditchcrawler said:

I suspect most people will plug them into a 13A outlet permanently wired into their boat electrical system which when on shore power gets is energy from there but when cruising gets it from the inverter, If they don't switch their combies to charge only then in a power cut the batteries would power the heaters.

...until the batteries run out... 😞

 

Unless you have a genny set to come on when the batteries get low. In which case this would power the heaters until you run out of diesel... 😞

 

Or the shore power comes back on, which is much more likely 🙂

[cuthound]

1 hour ago, Peugeot 106 said:

Beware the sink drain freezing 

 

I've not experienced that in the 10 years I've been using the dehumidifier on the boat, even when the temperature has remained below freezing for several days.

 

When the weather is at or below freezing point the relative humidity will also be low, so the dehumidifier doesn't take any moisture out of the air, and when it is above freezing the amount of water from the dehumidifier is small and my drain goes straight down to a skin fitting, so no U bend to hold water and freeze.

Edited November 25, 2023 by cuthound
To remove a duplicate post.

[Peugeot 106]

40 minutes ago, cuthound said:

 

I've not experienced that in the 10 years I've been using the dehumidifier on the boat, even when the temperature has remained below freezing for several days.

 

When the weather is at or below freezing point the relative humidity will also be low, so the dehumidifier doesn't take any moisture out of the air, and when it is above freezing the amount of water from the dehumidifier is small and my drain goes straight down to a skin fitting, so no U bend to hold water and freeze.

I guess that’s good real world experience. As I understand it the compressor types don’t work at low temperatures even if there is a lot of damp around and you have to raise the temperature to get them to work at all. I have one in my shed and 

that doesn’t freeze ( it drains outside) but I don’t heat the shed so it’s self regulating! The desiccant types work much better at low temperatures and I suspect the dribble drain overboard may freeze. All i’m Saying is that the possibility of the drain freezing could be taken into account and don’t assume it won’t happen under all circumstances ie type of dehumidifier or internal boat heating

[Momac]

I once did a survey on an unoccupied house during a long cold snap. The kitchen was like a winter wonderland of ice . Upstairs the bath was solid ice. The bath waste had frozen so the bath had filled from a defective tap and overflowed the the whole lot had frozen over. 

That must have been in the late 1980's when we had proper winters. Possibly less of a risk in more recent years .

So do be aware of the damage ice and water can cause .

[ditchcrawler]

When I was a kid often you couldn't use the bathroom basin or bath because the waste was frozen solid

[IanD]

To give some numbers on how much heat/power is needed for frost protection, in the last week the diesel boiler on my boat (set to come on at 4.5C) has run for a total of 6 hours (it comes on in bursts about 20mins long each); working back from the amount of fuel used, the average electrical heater power needed would have been something like 500W (12kWh/day). But that's the average over a week, the coldest day it ran for 1 3/4 hours which was about double that (1kW average=24kWh/day). This suggests that if you want to put electric heaters in for frost protection, you need at least 1kW, probably more if you want to protect against exceptionally cold weather. The dual 750W heaters used by @cuthound look about right... 🙂

 

And needless to say this only works on shore power, if this is cut any batteries would be flattened pretty damn fast... 😞

Edited December 2, 2023 by IanD

[IanD]

How anti-frost heat use varies from day to day. Spot the cold days...

Edited December 3, 2023 by IanD
Added picture

[Bugsworth Tippler]

On 21/11/2023 at 14:16, Phlea said:

I use one of these to very good effect, temp can be remotely monitored and alerted, as can power availability, and the heater can be switched manually or automatically. You do need a mobile signal within the boat, I hang mine in a window on an extension lead to be sure. 

 

https://www.tekview-solutions.com/powertxt.php

 

I used an Envirotxt device from this company (no longer produced) for many years to find out the temperature on my boat and recently purchased a Powertxt to control two 750watt electric heaters. It didn't initially work but I had wonderful assistance from tekview-solutions via e-mail and phone calls and am now pleased to say it does what I wanted. It keeps me informed of power cuts, temperatures and switches power to the heaters on and off. I am sure the reason it didn't work was down to a failure on my part, perhaps over confidence and failure to read instructions properly. You do need a 2G sim and I ended up buying one from tekview which was very reasonably priced. My other SMS devices work well on GiffGaff sims which are also quite cheap to use.

[Richard10002]

1 hour ago, Bugsworth Tippler said:

 

I used an Envirotxt device from this company (no longer produced) for many years to find out the temperature on my boat and recently purchased a Powertxt to control two 750watt electric heaters.

I am off grid, so wonder if there are 12v or 5v gizmos that do similar things?

[Phlea]

2 minutes ago, Richard10002 said:

I am off grid, so wonder if there are 12v or 5v gizmos that do similar things?

I’m looking into this at the moment for my new boat so I can leave it Bankside with the inverter off. 
 

I’m putting a 12v 5G router in place, and looking at home automation kit which is battery/12v powered and which will connect to the WiFi.

 

Currently looking at this for monitoring…

 

https://shellystore.co.uk/product/shelly-ht-white/

 

And this for potentially switching the diesel boiler…

 

https://shellystore.co.uk/product/shelly-uni/

[Phlea]

1 hour ago, Phlea said:

I’m looking into this at the moment for my new boat so I can leave it Bankside with the inverter off. 
 

I’m putting a 12v 5G router in place, and looking at home automation kit which is battery/12v powered and which will connect to the WiFi.

 

Currently looking at this for monitoring…

 

https://shellystore.co.uk/product/shelly-ht-white/

 

And this for potentially switching the diesel boiler…

 

https://shellystore.co.uk/product/shelly-uni/

 

They also do flood sensors 

 

https://shellystore.co.uk/product/shelly-flood/

 

[Bugsworth Tippler]

On 02/12/2023 at 12:41, IanD said:

To give some numbers on how much heat/power is needed for frost protection, in the last week the diesel boiler on my boat (set to come on at 4.5C) has run for a total of 6 hours (it comes on in bursts about 20mins long each); working back from the amount of fuel used, the average electrical heater power needed would have been something like 500W (12kWh/day). But that's the average over a week, the coldest day it ran for 1 3/4 hours which was about double that (1kW average=24kWh/day). This suggests that if you want to put electric heaters in for frost protection, you need at least 1kW, probably more if you want to protect against exceptionally cold weather. The dual 750W heaters used by @cuthound look about right... 🙂

 

And needless to say this only works on shore power, if this is cut any batteries would be flattened pretty damn fast... 😞

This is very useful. I have two 750w electric heaters (the marina supply won't cope with more than 2kW) which I can control remotely. They haven't been on in the recent cold spell as I think my Webasto system with froststat is coming on. I have the batteries linked to a battery charger so they should be OK but I'm slightly reluctant to rely on the Webasto (not sure why!). I'm about to remove the Webasto froststat fuse so I can see (remotely) when the electric heaters come into action (Envirotxt and Powertxt both send messages to my mobile phone).

 

Opinions would be welcome on whether to rely on the Webasto or the electric heaters.

[IanD]

10 minutes ago, Bugsworth Tippler said:

This is very useful. I have two 750w electric heaters (the marina supply won't cope with more than 2kW) which I can control remotely. They haven't been on in the recent cold spell as I think my Webasto system with froststat is coming on. I have the batteries linked to a battery charger so they should be OK but I'm slightly reluctant to rely on the Webasto (not sure why!). I'm about to remove the Webasto froststat fuse so I can see (remotely) when the electric heaters come into action (Envirotxt and Powertxt both send messages to my mobile phone).

 

Opinions would be welcome on whether to rely on the Webasto or the electric heaters.

 

Running the Webasto will be cheaper than using shore power, if this matters to you -- burning diesel costs about 12p per kWh if the fuel costs £1.10 per litre, shoreline costs more than this (I pay 25p/kWh) so about 2x difference in cost. Of course you need enough fuel in the tank to do this, and preferably a way to remotely keep an eye on fuel levels... 😉

 

If you're relying on shore power when away from the boat you need a way to send you an alarm if it cuts out, this happened to me a couple of weeks ago and I had to ring the marina to sort it out (they'd been doing some work and had accidentally turned the power off).

Edited December 4, 2023 by IanD

[wakey_wake]

On 02/12/2023 at 12:41, IanD said:

This suggests that if you want to put electric heaters in for frost protection, you need at least 1kW, probably more if you want to protect against exceptionally cold weather. The dual 750W heaters used by [cuthound] look about right... 🙂

That's useful to know for tube heaters. However the more focussed the heating, and better insulated the protected stuff, and the better the control of switching the heat, the less energy you'll need over the whole cold spell.

 

On a shoreline that's "how much does it cost me", but if anyone were thinking of doing it from batteries then it's a critical part of "for how many hours of cold spell could my system sustain this, and what's going to refill the battery after?"

 

On 02/12/2023 at 12:41, IanD said:

And needless to say this only works on shore power, if this is cut any batteries would be flattened pretty damn fast... 😞

Oh yes. On the other hand, an intermittent shore line (such as caused by RCCD trips and somebody coming along later to reset it) may be adequate, as long as the temperature set points have enough space. Stuff doesn't freeze instantly.

 

20 hours ago, Bugsworth Tippler said:

I used an Envirotxt device from this company (no longer produced) for many years to find out the temperature on my boat and recently purchased a Powertxt to control two 750watt electric heaters.

Not wishing to knock the usefulness of these devices but - on the positioning of temperature sensors:

 

Having observed a gaggle of (cheap) digital thermometers both interactively and with min/max after a period of absence from the boat, I would caution that "the temperature" is a concept which could mislead. You will see the temperature at a particular point, plus or minus some imprecision.

 

Although heat will flow from the warmer place to the colder, this doesn't always happen very quickly compared to whatever else is changing the temperature (weather up top, the drink down below). The temperature at points some distance away will differ.

 

If you measure too far from the thing you're protecting then you risk under- or over- protection which are both more expensive than you wanted, in different ways. 😐

 

I expect that if the boat is out of water then things will likely be more uniform - and colder.

However in the water, I've seen cold spots at the top of the cabin (where intuition says heat will rise to) and warmer down in the cupboards and just above the floor board, where my water pipes are boxed in.

 

18 hours ago, Richard10002 said:

I am off grid, so wonder if there are 12v or 5v gizmos that do similar things?

Yes, I have a Huawei 4G (5G?) router running off domestic 12V.

It's on all the time and has to be factored into the power budget as such. It'll take less to run than an inverter on standby or running low-power 240V stuff.

 

I would think that if the 12V always-on power budget is tight then having a small number of multi-function devices would be sensible. Modern microcontrollers are remarkably efficient, but that's not a reason to run a dozen of them each with their own 12V to 3.3V power supply.

[IanD]

27 minutes ago, wakey_wake said:

That's useful to know for tube heaters. However the more focussed the heating, and better insulated the protected stuff, and the better the control of switching the heat, the less energy you'll need over the whole cold spell.

 

On a shoreline that's "how much does it cost me", but if anyone were thinking of doing it from batteries then it's a critical part of "for how many hours of cold spell could my system sustain this, and what's going to refill the battery after?"

 

Oh yes. On the other hand, an intermittent shore line (such as caused by RCCD trips and somebody coming along later to reset it) may be adequate, as long as the temperature set points have enough space. Stuff doesn't freeze instantly.

 

[snip]

 

The figures I gave were for heating -- well, frost-protecting -- the whole of a modern well-insulated 60' narrowboat, with considerably less cold-air ventilation than most (gas-free) so it stays warmer. The total energy needed to do this doesn't depend on any insulation of things like pipes, or whether the heating runs at high power for short bursts (like mine) or much longer periods (electric heaters), or whether it's focused or distributed, just on the outside temperature and what you have the internal temperature set to and how well-insulated the whole boat is.

 

Any feasible battery will run out of juice when powering electric heaters in a cold snap -- mine's 35kWh (700Ah 50V, *way* bigger than most boats) and would still only have lasted two nights and a day last week (1kW average=24kWh/day), and that wasn't close to the coldest weather we've had. For comparison, everything else on the boat (electrics, Cerbo, router, CH boiler/pump, inverter...) uses about a tenth of this.

 

As you say stuff doesn't freeze instantly, but the marina didn't know the power had gone off (24 hours earlier!) until I phoned and told them...

Edited December 4, 2023 by IanD

[cuthound]

2 hours ago, IanD said:

 

Running the Webasto will be cheaper than using shore power, if this matters to you -- burning diesel costs about 12p per kWh if the fuel costs £1.10 per litre, shoreline costs more than this (I pay 25p/kWh) so about 2x difference in cost. Of course you need enough fuel in the tank to do this, and preferably a way to remotely keep an eye on fuel levels... 😉

 

If you're relying on shore power when away from the boat you need a way to send you an alarm if it cuts out, this happened to me a couple of weeks ago and I had to ring the marina to sort it out (they'd been doing some work and had accidentally turned the power off).

 

Running the Webasto will lower the fuel level in the fuel tank, leaving more exposed steelwork for condensation to form on, which in turn increases the chance of getting diesel bug (which lives in the junction between diesel and oil). However the Webasto isn't subject to mains power failures, so you pays your money and takes your choice.