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I'm currently researching ways to use solar to heat the water on our boat.

 

Currently have 550W solar, and a Victron MPPT controller 150 | 35 and a Victron Multiplus Inverter/Charger. The calorifier has a 1KW immersion heater in it which is only powered when on hook up. On days like today the solar has topped the batts up by mid morning and runs everything on the boat (other than the washing machine). I can even use the coffe machine and it copes fine.

 

I'd like to be able to heat the water by using the excess solar, saves running the engine or hooking up when in the marina. I accept that some days it won't get me anything but on others it will or could.

 

I do not want to mess about with arduino's and other "creative" ways of making the kit do what I want, ideally a plug and play solution is rquired. But I accept there may be some woring changes needed.

 

I've found some domestic solar diverters on the web, such as SolarImersion, Solar i-Boost and Myenergi Eddi. 

 

Has anyone used one of these and did it/does it work?

 

TIA 

Paul.

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31 minutes ago, Quattrodave said:

If you fit a dual voltage (12v & 240v) immersion element could you use the 12v immersion as an MPPT dump load?

I don't think the OP will be able to do that as the Victron MPPT 150 | 35 does not have connections for a dump load.

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6 hours ago, PCSB said:

I do not want to mess about with arduino's and other "creative" ways of making the kit do what I want, ideally a plug and play solution is rquired.

 

"I want, I want..." 

 

If/when you find it, somehow I doubt you'll share it with the forum. 

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These little devices look interesting. 

 

Programmable overcurrent relay with hall effect non invasive ammeter 

 

https://www.ebay.co.uk/itm/184692219522

 

You could set it to route power to an alarm at say 25 amps then wire the alarm output through relays to switch on immersion heater. 

 

Not sure it would work but might be interesting to play with. 

 

Its not a dump for when batteries are full but -maybe- could be used to send power to the immersion heater when there is enough of that power. 

 

 

ETA just noticed in the spec it will switch 6A@230vac

Item Type: DC Digital Ammeter

Material: Plastic
Model: SZD07
Input Voltage: DC8-35V
Measurement Type: DC current
Range: 0.3-50A
Sensor: Hall sensor
Sensor Input Current: 25A
Sensor Output Voltage: 2.5±0.625V
Sampling Frequency: 2 times/s
Alarm Output: Upper and lower limit alarms are output from the same relay
Contact Capacity: 6A/250VAC, 6A/30VBC, resistive load
Working Environment: Temperature -10~50℃, temperature <85%RH non-corrosive places
Accuracy Level: 0.5 level

 

 

 

Edited by magnetman
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30 minutes ago, robtheplod said:

If only Victron and other makes made a dump load option that would make it so much easier to do........

I've just emailed Victron as a suggestion.... it would be a killer selling point - a programmable output on their MPPT's where you could switch on/off and set at what state your batteries should be at before it supplies power to the immersion.

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My MPPT 100/20 units have exactly that function. 

 

The 100/30 and the 100/50 don't have it. Nor does the 150/35. 

 

Perhaps a useful argument for having individual controllers for each PV module. 

 

 

Edited by magnetman
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31 minutes ago, magnetman said:

Perhaps a useful argument for having individual controllers for each PV module.

Or maybe not, I've not got enough space in the cupboard for 10 MPPTs! 😁

 

Seriously though, it is a shame Victron don't put the load dump facility on the larger MPPTs. Currently my solar array is pumping around 1kw into the batteries. At the moment I need everything I can get into the batteries but if I don't cruise for a few days it would be good automatically divert excess to do something useful.

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Is that a 12v system? 

 

If you are a heavy consumer it's worth putting in a 48v setup to keep the amps and number of controllers down. The victron 100/20 is available with 48v option.

 

ETA when I mentioned one controller per module obviously this would be two modules as they are 36v nominal and the controller does 100V input. Also thinking of big modules 400w or more. 

 

 

 

 

 

 

Edited by magnetman
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19 minutes ago, magnetman said:

Is that a 12v system? 

No 48v for a hybrid propulsion system. Hence why I gave a power figure going to the batteries rather than saying over 20A.

 

Your suggestion was fine for certain circumstances, so just having a bit of a grin really and pondering why Victron don't put the dump load facility in the bigger MPPT units. The boat builder has used a 150/45 unit in my boat which is fine for the 10 x 175w panels I have (2 strings of 5 paralleled). Appears to be working well and yielding above my expectations (based on the Victron modeller). So overall I'm happy.

 

Also a shame for the OP's situation as his MPPT also rules out a super easy fix.

 

 

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5 minutes ago, jpcdriver said:

No 48v for a hybrid propulsion system. Hence why I gave a power figure going to the batteries rather than saying over 20A.

 

Your suggestion was fine for certain circumstances, so just having a bit of a grin really and pondering why Victron don't put the dump load facility in the bigger MPPT units. The boat builder has used a 150/45 unit in my boat which is fine for the 10 x 175w panels I have (2 strings of 5 paralleled). Appears to be working well and yielding above my expectations (based on the Victron modeller). So overall I'm happy.

 

Also a shame for the OP's situation as his MPPT also rules out a super easy fix.

 

 

I think there is a load option on the larger MPPT units if you buy more hardware. Maybe Victron took the view that people spending good money on larger controllers are likely to be happy to spend more on a fully networked system. It is called Victron VRM or something. 

 

A bit cynical but it could just be a profit-driven choice to not have the load bus on the larger controllers. 

 

Or heat management issues? 

 

 

 

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4 minutes ago, magnetman said:

A bit cynical but it could just be a profit-driven choice to not have the load bus on the larger controllers. 

 

Or heat management issues

Yep, I could go with either or possibly even both of those.

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Don't some battery management systems have programmable outputs for a relay, such as used by some home brew lithium systems. If the OP has one them maybe setting it very close to the maximum charging voltage would do the job?

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2 hours ago, magnetman said:

My MPPT 100/20 units have exactly that function. 

 

The 100/30 and the 100/50 don't have it. Nor does the 150/35. 

 

Perhaps a useful argument for having individual controllers for each PV module. 

 

 

shame they dont do it on the bigger units - it would be far more useful as you'd deliberately over-spec your solar so you could plan a dump to the immersion (that sounded better in my head!)....

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I agree. I've got two liveaboard boats.  One with 1.1kw of solar the other with 1.2kw and both of them do have a lot of surplus output. 

 

However due to a lack of washing there is not a true need for hot water.

 

Definitely an interesting topic though. 

 

 

 

 

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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 ...

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7 hours ago, robtheplod said:

If only Victron and other makes made a dump load option that would make it so much easier to do........

 

 

22 hours ago, jpcdriver said:

I don't think the OP will be able to do that as the Victron MPPT 150 | 35 does not have connections for a dump load.

 

Nearly all victron units have programmable outputs.  Program the output go high when the charger goes into float (batteries charged) this can then switch a large relay to turn your dump load on....

 

Edit:

I was just looking for the setting on a Smart Solar Controller so I could screen shot it.... I can't find it... I'm now wondering if its available on the Smart Solar Controllers.....

Edited by Quattrodave
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1 hour ago, 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 ...

 

A coil on the main feed cable  after the CU and just before the meter  if it registers -ve current  then you are importing if +ve then you are exporting. 

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  • 6 months later...
On 16/06/2022 at 18:05, PCSB said:

I'm currently researching ways to use solar to heat the water on our boat.

 

Currently have 550W solar, and a Victron MPPT controller 150 | 35 and a Victron Multiplus Inverter/Charger. The calorifier has a 1KW immersion heater in it which is only powered when on hook up. On days like today the solar has topped the batts up by mid morning and runs everything on the boat (other than the washing machine). I can even use the coffe machine and it copes fine.

 

I'd like to be able to heat the water by using the excess solar, saves running the engine or hooking up when in the marina. I accept that some days it won't get me anything but on others it will or could.

 

I do not want to mess about with arduino's and other "creative" ways of making the kit do what I want, ideally a plug and play solution is rquired. But I accept there may be some woring changes needed.

 

I've found some domestic solar diverters on the web, such as SolarImersion, Solar i-Boost and Myenergi Eddi. 

 

Has anyone used one of these and did it/does it work?

 

TIA 

Paul.

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

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5 minutes ago, rusty69 said:

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

 

 

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.

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