Fitting immersion heater

Nabsim

Nabsim

Forum Member
May not be something most people would do in their van but I know some of you have calorifier fitted like me. I have decided I am going to connect the 1Kw element that is fitted to my tank. The element has temperature control built in so I think I only need to fit a breaker and switch.
Here are the fitting instructions but not sure they actually say what’s needed. In my mind I envisage cable from inverter going to a fuse or breaker then an on/off switch then connected to the element. When I search double pole isolating switch is looks to me like a breaker.
Can someone advise what I need please?
Fitting instructions: https://www.surejust.co.uk/immersion-connection-instructions
 
SquirrellCook

SquirrellCook

Forum Member
Mine is switched with a domestic emersion double pole switch. I've tried to keep it simple just in case the worst happens.
As you have been using yours for a while, I'd be tempted to drain it and remove the element to make sure all is good inside.
 
Nabsim

Nabsim

Forum Member
SquirrellCook said:
Mine is switched with a domestic emersion double pole switch. I've tried to keep it simple just in case the worst happens.
As you have been using yours for a while, I'd be tempted to drain it and remove the element to make sure all is good inside.
Click to expand...
Was hoping you would reply 👍
At home the switch for the immersion looked the same as a cooker switch but that was 6 Kw so a lot more power. Just a white facia with a red switch not what it shows me in Srewfix. Is it the cooker switch type you mean similar to this: https://www.amazon.co.uk/BG-Electri...&keywords=cooker+switch&qid=1595332528&sr=8-5

Have you a fuse/breaker as well or just the switch? I will be running mine direct from an inverter rather than going through a consumer unit.
 
SquirrellCook

SquirrellCook

Forum Member
Yes, that's the sort of thing I have. Mines got a neon too. (I like wally lights) My inverter is not big enough to run mine, despite me changing the element to 750 watts. It's connected to the consumer unit with it's own fuse. So only powered by hook up or genny.
 
Nabsim

Nabsim

Forum Member
I am going for a 2Kw (4Kw peak) inverter as posted in a separate thread just trying to get things straight before I do anything.
Am I right in thinking that a 1Kw element at 230v is just over 4 amps?
 
Nabsim

Nabsim

Forum Member
Would this be suitable both as a double pole isolating switch and a fuse? Thinking maybe fit a 5amp fuse if my thoughts regarding amperage is correct
 
SquirrellCook

SquirrellCook

Forum Member
Yes I'd guess around that number and about 100 amps at 12 volts, though with a load like that I'd bet the volts will be below 12. How big is your battery bank? Also what type. Big discharges from a lead acid won't do it any favours.
 
Nabsim

Nabsim

Forum Member
SquirrellCook said:
Yes I'd guess around that number and about 100 amps at 12 volts, though with a load like that I'd bet the volts will be below 12. How big is your battery bank? Also what type. Big discharges from a lead acid won't do it any favours.
Click to expand...
I have 2 x 100ah Lifepo4 battery bank. No idea how long I would need to run inverter for a 1Kw element to heat it up yet. In summer I don’t see a problem as I have surplus from solar, in winter I would need to run genny. I will be up rating my charger before winter so should be running less than last year 👍
 
Nabsim

Nabsim

Forum Member
It gets me confused working from one voltage to another. I dont like hot showers or baths prefer warm but not sure what that equates to temperature wise.

I know we have a member on WC who uses a 12v 300W immersion element with his solar and it produces far more than he needs. I assume a 1Kw 230V element would heat water much quicker than a 300W 12V element does. I also know assume makes an ass of u and me :(
 
SquirrellCook

SquirrellCook

Forum Member
I think 10 litres from 15-80 deg C was 49 minutes using 1kw. The surecal units have a thermostat on them mixing hot and cold water. So the hotter the water in the tank, the more water you will get at your desired temperature.
 

wildebus

Forum Member
To throw a few numbers in here ....
I have a 2000W Water Heater with a quoted capacity of 10L. I find that it takes around 9 minutes of running to take the water to the max temp (high enough that it needs mixing with cold for any kind of hand/face washing).

Personally I would prefer it if I had say a 1kW heater that took twice as long, or a 700W element that took three times longer as it would be more gentle on the batteries as don't think I need the water heated so fast. But I cannot find an alternative smaller element for my heater.
 
Nabsim

Nabsim

Forum Member
I think SureJust sell elements Dave. I was thinking around half an hour but I am plucking figures out the air. Do yo think it is worth continuing with this idea Dave?
 
SquirrellCook

SquirrellCook

Forum Member

Immersion Heater Info - Thermco UK Ltd

Immersion Heater Information Standard Domestic Immersion Heaters Thermco Electricals produce a comprehensive range of standard 2 ¼” BSP 3kW immersion heaters for use in vented cylinders. Produced to conform to European Standard BS.EN60335.2.73 the heaters are fitted with combined thermostat and...
www.thermcouk.com www.thermcouk.com

I'm going to give these people a call when I'm at that stage Dave.
 
Nabsim

Nabsim

Forum Member
SquirrellCook said:
What size calorifier do you have?
Click to expand...
I am fairly sure its the 22litre when I checked it before.

What is confusing me (and always does with conversions) is its a 1Kw element, if I divide 1000W by 12V it gives me 83amps. I was working on an hour if it ran constantly would use 83amps per hour. In practice I was expecting 30 to 40 minutes so more like 30 to 40 amps which wouldn't be a problem for my batteries
 

wildebus

Forum Member
I was going to say that a lower power DC element might be better but ....

Your Batteries are very capable of delivering a high power over a period , but do check what they are rating at for maximum current draw - 200A for a 2kW heater is a lot of current, as still is 100A for a 1000W heater (remember when you divide the 1000W by 12V to get a current, add on 15% or so to cover inverter overhead).

You were thinking also of updating your charger to allow you to make your charging more efficient on the generator. Maybe this is a good time to go for something like the following ...
Multiplus 12/1600/70 -
70A Battery Charger which will work nicely with the Lithiums
1600VA (1300W PSW Inverter) that will run a 1000W Heating Element
Power Assist so you could run your 1000W (I think?) Generator to heat the water through the Multiplus without needing to swap leads and the like and this setup would take care of any incidental loads without having to worry about overloading the generator.
and £100 off with the VAT reclaim?

just a thought?
 
SquirrellCook

SquirrellCook

Forum Member
I plugged in 15 - 80 deg C and that came back with just over 2 hours with a 1kw element.
Dave was using a BMV I think to switch a relay so that only surplus power was used to heat water.
As a stand alone way to heat water i don't think batteries are the way to go.
In the Betty build I will using the engine water circuit to heat the calorifier whilst driving.
When parked up I have been using the 12kw eberspacher to heat the water, but by using left over solar once the batteries are full I can keep topping up the heat.
 

wildebus

Forum Member
Yes, I have the setup such that when the batteries are nearly full I allow the heater to come on to use that free energy.
I can override this manually if I want to, so if I knew I would be driving a fair way that would replenish the batteries, or plugging into hookup where a low battery bank will get charged, I can still heat water even if batteries are much lower.
But .... I don't have a shower room in my van, so I don't take nice long showers (and I like HOT water to shower in as well!). If I did have a permanent shower, I am pretty sure I would be looking at an alternative way to heat water, but that would be the calorifier via engine coolant I think (but I'd also have to carry a LOT more water as well!)
 
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