Solar Diverter

[Tacet]

2 minutes ago, Alan de Enfield said:

 

A 1kw immersion heater WILL take about 40Ah out of the batteries.

It rather depends on how long the immersion heater is on

[rusty69]

Just now, Alan de Enfield said:

 

 

If you've got 'spare' (surplus) leccy then why not just plug the immersion heater into your inverter - just remember to switch it off before the 'Sun goes down'.

 

Doesn't get any more 'plug and play' than that option.

 

A 1kw immersion heater WILL take about 40Ah out of the batteries.

 

It's a good thought. The ones I have seen, particularly in the youtube  video above have some kind of variac to dial down the immersion power. It seems a more elegant way of regulating the power usage rather than relying on a time switch or manual intervention.

 

I do have a 1KW immersion.

 

 

[PCSB]

9 minutes ago, rusty69 said:

Did your research prove fruitful in your quest for 'free' hot water?

Not in the way I had hoped for, no. I had hoped it would be easy to use a domestic off the shelf type device, but the ones I contacted said no. I don't yet have enough solar (590W) to run the immersion directly via the inverter but one of the 12volt groups on FB has solar dump design that may work but is a faff. It was the faff I was trying to avoid.

 

Currently planning some changes to the electrics once we are out of warranty, nothing major just some additional monitoring and am planning to swap the immersion timer to a switch so may do the solar dump at that time too.

[rusty69]

Just now, PCSB said:

Not in the way I had hoped for, no. I had hoped it would be easy to use a domestic off the shelf type device, but the ones I contacted said no. I don't yet have enough solar (590W) to run the immersion directly via the inverter but one of the 12volt groups on FB has solar dump design that may work but is a faff. It was the faff I was trying to avoid.

 

Currently planning some changes to the electrics once we are out of warranty, nothing major just some additional monitoring and am planning to swap the immersion timer to a switch so may do the solar dump at that time too.

Ok, thanks. Yes, I've seen the one on the facebook site, which I think is what the youtube video posted is based on.

[Alan de Enfield]

4 minutes ago, Tacet said:

It rather depends on how long the immersion heater is on

 

Yes - I could have worded it better - it makes it more difficult as the Immersion will (probably) not be running continuously anyway.

 

Would you prefer 40 amps per hour ? (🤣)

Edited January 5, 2023 by Alan de Enfield

[Tonka]

On 17/06/2022 at 18:30, PCSB said:

I got a reply from Immersun who are the company behind SolarImersion, sadly it seems a no go ...

 

"Hi Paul,
 
Thanks for your enquiry however IMMERSUN is only compatible with grid tied system as it needs to be able to detect exported power in order for it's mechanism to work."

 

I wonder how it detects the exported power though ...

Same way as the Solic 200. There is a current loop which you put on the main wire by the company fuse. Turn off the solar pv. Turn on a load to make sure that the house is drawing power. This checks that you have the current loop around the correct way. Then turn on the solar pv. You can now turn off your load. 

You get some strange readings at the immersion if you put your multimeter on it. I was getting 36 v and 70 v when i expected 240v but according to the company this is normal

[PCSB]

9 minutes ago, Tonka said:

Same way as the Solic 200. There is a current loop which you put on the main wire by the company fuse. Turn off the solar pv. Turn on a load to make sure that the house is drawing power. This checks that you have the current loop around the correct way. Then turn on the solar pv. You can now turn off your load. 

You get some strange readings at the immersion if you put your multimeter on it. I was getting 36 v and 70 v when i expected 240v but according to the company this is normal

I shall take a look at the Solic 200, many thanks.

[Jess--]

1 hour ago, Tonka said:

You get some strange readings at the immersion if you put your multimeter on it. I was getting 36 v and 70 v when i expected 240v but according to the company this is normal

to an immersion heater voltage does not need to be at a fixed level (just within sensible limits) as it is a purely resistive load

for example all of the list below should power a 1 kw immersion heater perfectly

25v@40A 

50v@20A 

100v@10A 

200v@5A

240v@4.17A 

 

with solar controllers using tracking to get the highest wattage out of the panels they may just dump the panel voltage straight through

[David Mack]

1 hour ago, Tonka said:

 

You get some strange readings at the immersion if you put your multimeter on it. I was getting 36 v and 70 v when i expected 240v but according to the company this is normal

The immersion heater is purely a resistive load. The only way the solar controller can put in the power available if that is less than 1kW, is by dropping the voltage.

[rusty69]

12 minutes ago, Jess-- said:

to an immersion heater voltage does not need to be at a fixed level (just within sensible limits) as it is a purely resistive load

for example all of the list below should power a 1 kw immersion heater perfectly

25v@40A 

50v@20A 

100v@10A 

200v@5A

240v@4.17A 

 

with solar controllers using tracking to get the highest wattage out of the panels they may just dump the panel voltage straight through

That's an idea, my panels are 78 V @ ?A, but the immersion isn't 12V dc.

Edited January 5, 2023 by rusty69

[magnetman]

2 minutes ago, rusty69 said:

That's an idea, my panels are 78 V @ ?V

Was there meant to be a W?

[rusty69]

Just now, magnetman said:

Was there meant to be a W?

Nope.It was spose to be A.

 

Will you be picking up on my mistakes all day? Asking for a friend.

[magnetman]

Just now, rusty69 said:

Nope.It was spose to be A.

 

Will you be picking up on my mistakes all day? Asking for a friend.

No. 

[Jess--]

I was going to suggest just sticking a changeover switch to allow switching the solar panels directly to the immersion instead of the solar controller (assuming under 1kw solar)  for a manual solution

 

[ditchcrawler]

7 minutes ago, rusty69 said:

Nope.It was spose to be A.

 

Will you be picking up on my mistakes all day? Asking for a friend.

In this case it was important, I assumed the output voltage of your panels to be 78 volts,  Wattage was a possibility but I wasn't expecting it to be the current, which without knowing the voltage doesn't mean much

[rusty69]

1 minute ago, ditchcrawler said:

In this case it was important, I assumed the output voltage of your panels to be 78 volts,  Wattage was a possibility but I wasn't expecting it to be the current, which without knowing the voltage doesn't mean much

It's only important to me, and I knew what I meant.

[Tonka]

25 minutes ago, Jess-- said:

to an immersion heater voltage does not need to be at a fixed level (just within sensible limits) as it is a purely resistive load

for example all of the list below should power a 1 kw immersion heater perfectly

25v@40A 

50v@20A 

100v@10A 

200v@5A

240v@4.17A 

 

with solar controllers using tracking to get the highest wattage out of the panels they may just dump the panel voltage straight through

This is the reply i got from Solic to the question

"It changes voltage to get the right power, don’t measure output voltage.

The formulae is Watts = Amps X Volts.

Also you often get strange reading on the output side of SOLiC as is Phase angle.

Thanks"

[Alan de Enfield]

Will a 230v AC immersion heater run on the 120v DC output of my Solar Panels ? (obviously it will via the inverter but I read Jess's post as suggesting it will run directly)

[Thames Bhaji]

There’s a bit more to the calculation to find what power you will get at different voltages. 
 

First find the fixed resistance of the heater (ohms) which is the existing voltage divided the current at that voltage (the current being power divided by voltage). 
 

Then find the current you would get with a new voltage, using ‘new voltage’ divided by the resistance from above. 
 

Once you know the current, you can multiply it by ‘new voltage’ to give the new power output you will get at that voltage. 
 

I think I’ve stated that right? 

Edited January 5, 2023 by Thames Bhaji
Added bit to find out current at initial voltage. I’m sure this could all be simplified into a single equation but I can’t be bothered 😊

[PCSB]

36 minutes ago, Alan de Enfield said:

Will a 230v AC immersion heater run on the 120v DC output of my Solar Panels ? (obviously it will via the inverter but I read Jess's post as suggesting it will run directly)

I don't see why it wouldn't as has been said it is a resistaive load like an incandescent light bulb

[rusty69]

7 minutes ago, PCSB said:

I don't see why it wouldn't as has been said it is a resistaive load like an incandescent light bulb

Immersions have thermostats though, so worth checking that bit.

[Thames Bhaji]

OK, so power = V squared over R. If you halve the voltage, you’ll have quarter the power. 
 

[magnetman]

High voltage DC is a different thing to AC. 

 

I don't know all that much about it but doesn't DC cause a lot of arcing when switching? How would one be able to safely switch it. 

Edited January 5, 2023 by magnetman
Typos

[PCSB]

3 minutes ago, rusty69 said:

Immersions have thermostats though, so worth checking that bit.

Yep, it's been a while since Iopened one up and that one was just a bi-metal type so ac or dc wouldn't matter in that case (I think! ...)

[Thames Bhaji]

3 minutes ago, rusty69 said:

Immersions have thermostats though, so worth checking that bit.

I’m doing something similar at the moment. The higher DC currents involved would likely kill the thermostat on a mains heater. I’m planning to switch mine with a solid state DC relay which can handle the current (and hopefully the repeated switching).