Wooo hoo, I am in hot water, the good kind..

At last !!! I now have solar powered hot water that is easy to maintain !!!

I hooked up 160 V of direct DC, direct from my solar panels that I am now using as a dump load to my water heater. After my battery is charged, I have tapped into my solar panels that power my battery, and then divert that power to my water heater.

So much energy I was wasting not having a dump load after my batteries where charged, I have a 43 gal tank that I was not using because I was using propane to heat my water, but now after the batteries are full, I divert the power direct from my solar panels to this tank, I measured over 125 degree water yesterday, and took a nice shower yesterday and today with that hot water, the tank is very well insulated as it only looses like 5 degrees overnight.

This will save me a good deal on propane over time I estimate. It is another step for freedom using energy that I was not using….


I have been doing this for 4 days now,  and water is heating up to 120 -135 deg.      I love not buying propane!

Can you provide more detail?

John F Dean wrote:Can you provide more detail?

I started experimenting with using solar direct to a hot water heater element  Connection is simply solar panel then connect to heating element,   with a 55 gal barrel of water.      


I started with 2 panels then worked up to like 9 panels  each 260 watts ratted but give me 220 watts in practice.


After I was comfortable with this,   I then want to my present solar system which has over 2000  watts of solar going to an inverter to batteries.
To this system I   added a Y connector to both Positive and Neg to the power coming in from my solar panels directly before the charge controller.

Now from here I added an electric car relay so I could control the connection, and ran both positive and neg directly to my hot water heater.


Once my solar charged battery is full around 2 PM each day, I then trigger the relay set on a 2 hour timer to direct power from the panels to the hot water heater element,   the 2 hour limit prevents a boil over of the tank, it is manually triggered,    I test the  temp of the water coming out of the tap before I trigger it so I know it will not over heat.

Heating element is rated at 3800 watts,  so I am well within spec.

All this time I could of been using that extra power,  I just got brave enough now to try it.

Mart Hale wrote:

John F Dean wrote:Can you provide more detail?

I started experimenting with using solar direct to a hot water heater element  Connection is simply solar panel then connect to heating element,   with a 55 gal barrel of water.      


I started with 2 panels then worked up to like 9 panels  each 260 watts ratted but give me 220 watts in practice.


After I was comfortable with this,   I then want to my present solar system which has over 2000  watts of solar going to an inverter to batteries.
To this system I   added a Y connector to both Positive and Neg to the power coming in from my solar panels directly before the charge controller.

Now from here I added an electric car relay so I could control the connection, and ran both positive and neg directly to my hot water heater.


Once my solar charged battery is full around 2 PM each day, I then trigger the relay set on a 2 hour timer to direct power from the panels to the hot water heater element,   the 2 hour limit prevents a boil over of the tank, it is manually triggered,    I test the  temp of the water coming out of the tap before I trigger it so I know it will not over heat.

Heating element is rated at 3800 watts,  so I am well within spec.

All this time I could of been using that extra power,  I just got brave enough now to try it.

Congrats on the dump load. A few questions and some possible next steps.  Any idea if the relay is rated for the string voltage? It would be a likely fail point. Does your charge controller have a dry relay for triggering a fan? Many of them do. Using that voltage trigger is a great way to automatically trigger the switchover. Finally if you do not have ac going to your water heater you can use it's thermostat to cut power to the trigger of the relay to avoid boil over..things to think about
Cheers and congrats!

David Baillie wrote:

Mart Hale wrote:

John F Dean wrote:Can you provide more detail?

I started experimenting with using solar direct to a hot water heater element  Connection is simply solar panel then connect to heating element,   with a 55 gal barrel of water.      


I started with 2 panels then worked up to like 9 panels  each 260 watts ratted but give me 220 watts in practice.


After I was comfortable with this,   I then want to my present solar system which has over 2000  watts of solar going to an inverter to batteries.
To this system I   added a Y connector to both Positive and Neg to the power coming in from my solar panels directly before the charge controller.

Now from here I added an electric car relay so I could control the connection, and ran both positive and neg directly to my hot water heater.


Once my solar charged battery is full around 2 PM each day, I then trigger the relay set on a 2 hour timer to direct power from the panels to the hot water heater element,   the 2 hour limit prevents a boil over of the tank, it is manually triggered,    I test the  temp of the water coming out of the tap before I trigger it so I know it will not over heat.

Heating element is rated at 3800 watts,  so I am well within spec.

All this time I could of been using that extra power,  I just got brave enough now to try it.

Congrats on the dump load. A few questions and some possible next steps.  Any idea if the relay is rated for the string voltage? It would be a likely fail point. Does your charge controller have a dry relay for triggering a fan? Many of them do. Using that voltage trigger is a great way to automatically trigger the switchover. Finally if you do not have ac going to your water heater you can use it's thermostat to cut power to the trigger of the relay to avoid boil over..things to think about
Cheers and congrats!

ha ha ha check the ratings and weep :-)


900v   at 500 amps

https://batteryhookup.com/products/te-connectivity-ev200aaana-500a-0-900vdc?_pos=2&_sid=4cb0b1b91&_ss=r


It is designed for an electric car so yes, it is not a weak point, but thanks for pointing that out   :-)

David Baillie wrote:

Mart Hale wrote:

John F Dean wrote:Can you provide more detail?

I started experimenting with using solar direct to a hot water heater element  Connection is simply solar panel then connect to heating element,   with a 55 gal barrel of water.      


I started with 2 panels then worked up to like 9 panels  each 260 watts ratted but give me 220 watts in practice.


After I was comfortable with this,   I then want to my present solar system which has over 2000  watts of solar going to an inverter to batteries.
To this system I   added a Y connector to both Positive and Neg to the power coming in from my solar panels directly before the charge controller.

Now from here I added an electric car relay so I could control the connection, and ran both positive and neg directly to my hot water heater.


Once my solar charged battery is full around 2 PM each day, I then trigger the relay set on a 2 hour timer to direct power from the panels to the hot water heater element,   the 2 hour limit prevents a boil over of the tank, it is manually triggered,    I test the  temp of the water coming out of the tap before I trigger it so I know it will not over heat.

Heating element is rated at 3800 watts,  so I am well within spec.

All this time I could of been using that extra power,  I just got brave enough now to try it.

Congrats on the dump load. A few questions and some possible next steps.  Any idea if the relay is rated for the string voltage? It would be a likely fail point. Does your charge controller have a dry relay for triggering a fan? Many of them do. Using that voltage trigger is a great way to automatically trigger the switchover. Finally if you do not have ac going to your water heater you can use it's thermostat to cut power to the trigger of the relay to avoid boil over..things to think about
Cheers and congrats!

Yes, my Outback does have a built in relay,   but at this point I don't want to imagine the relay being triggered automatically as I imagine a possible boil over....    Using the thermostat to control power to the relay is an option, but I am not sure I trust this relay yet...     In times past I have seen relays stick....    I don't like using a mop and a bucket.

ha ha ha check the ratings and weep :-)


900v   at 500 amps

https://batteryhookup.com/products/te-connectivity-ev200aaana-500a-0-900vdc?_pos=2&_sid=4cb0b1b91&_ss=r


It is designed for an electric car so yes, it is not a weak point, but thanks for pointing that out   :-)
Ooowe... Pretty!
NIce relay!  Once you get confidence in it you use the dry relay from the charge controller to "close on rise" as they say to provide the low voltage trigger to the relay. In line with the trigger voltage is the tank thermostat which is a simple "Open on rise" mechanical switch interupting the signal from the charge controller relay if the temperature gets too high. I'm sure this is all known to you just posting it for clarity for others.
Enjoy the hot showers!
Cheers,  David  

David Baillie wrote:


ha ha ha check the ratings and weep :-)


900v   at 500 amps

https://batteryhookup.com/products/te-connectivity-ev200aaana-500a-0-900vdc?_pos=2&_sid=4cb0b1b91&_ss=r


It is designed for an electric car so yes, it is not a weak point, but thanks for pointing that out   :-)

Ooowe... Pretty!
NIce relay!  Once you get confidence in it you use the dry relay from the charge controller to "close on rise" as they say to provide the low voltage trigger to the relay. In line with the trigger voltage is the tank thermostat which is a simple "Open on rise" mechanical switch interupting the signal from the charge controller relay if the temperature gets too high. I'm sure this is all known to you just posting it for clarity for others.
Enjoy the hot showers!
Cheers,  David  

--------------------------

The water heater is not by the charge controller,    but what you said gives me an Idea...

If I understand what you are saying the thermostat does not need electricity itself to run as it is mechanical,    Thus......    I could run 2 wires  from the thermostat back to the loop that controls the relay so that if it gets too hot the mechanical thermostat will open the circuit that powers the relay and shuts off the operation.      

I guess I can test for continuity on the thermostat by turning the thermostat to a low value and heating the tank hotter than that to verify if the thermostat is  doing what i would expect it to do.....

I like that safety measure.....     thanks for the input.

Mart Hale wrote:

David Baillie wrote:


ha ha ha check the ratings and weep :-)


900v   at 500 amps

https://batteryhookup.com/products/te-connectivity-ev200aaana-500a-0-900vdc?_pos=2&_sid=4cb0b1b91&_ss=r


It is designed for an electric car so yes, it is not a weak point, but thanks for pointing that out   :-)

Ooowe... Pretty!
NIce relay!  Once you get confidence in it you use the dry relay from the charge controller to "close on rise" as they say to provide the low voltage trigger to the relay. In line with the trigger voltage is the tank thermostat which is a simple "Open on rise" mechanical switch interupting the signal from the charge controller relay if the temperature gets too high. I'm sure this is all known to you just posting it for clarity for others.
Enjoy the hot showers!
Cheers,  David  

--------------------------

The water heater is not by the charge controller,    but what you said gives me an Idea...

If I understand what you are saying the thermostat does not need electricity itself to run as it is mechanical,    Thus......    I could run 2 wires  from the thermostat back to the loop that controls the relay so that if it gets too hot the mechanical thermostat will open the circuit that powers the relay and shuts off the operation.      

I guess I can test for continuity on the thermostat by turning the thermostat to a low value and heating the tank hotter than that to verify if the thermostat is  doing what i would expect it to do.....

I like that safety measure.....     thanks for the input.


Yup I think you have the idea. its really a single long line interrupted by the charge controller relay if the battery voltage goes too low and by the thermostat if the temperature in the tank goes too high... What might mess you up is voltage drop in a long low voltage run of wire but at low amperage its not that bad and the trigger voltage is very flexible. The outback puts out 12 volts and I believe up to 2 amp... you'll have to check that its been a while.