DC Water Heater Element - Missouri Wind & Solar

[Benzimidazolone]

Has anyone tried the DC water heater element supplied by Missouri Wind and Solar for domestic hot water supply? The elements have a thermostat, so you don't have to worry about over pressurizing/overheating things and they have DC rated contacts so you don't have to worry about burning the switches. The issues seems to be that they are only 700 watts. Therefore, you could hook up 2 X 48v panels of approx 350 watts in parallel. You would have to do both the top and bottom elements but you would only have 1400 watts of power (and probably less because you would not size at the very upper limit). Is that enough power to hear a typical 40 or 50 gal tank (I realize it depends on how much hot water you use). My location is in the Bahamas (200 miles east of Miami) so I have lots of sun and my incoming water is typically 70F or higher. Any input would be appreciated

 

[OzSolar]

Any input would be appreciated

Generally speaking those are meant for dump loads to protect a wind turbine from overspeeding and self destructing. As odd as this sounds they aren't very good for heating domestic water because they are so small.

You'd have to get deeper into the details about how much hot water you need per day and how to actually make the PV modules stay on their MPP to deliver the nameplate wattage for more than a few minutes per day if you really wanted to dig into this. It takes 1 BTU to raise lb. of water 1 degree Fahrenheit, 1 kWh = 3413 BTU's and down the rabbit hole we could go.

Could that heat enough water for one or two people per day? Maybe... 4 or more people..... no way.

May I ask why you aren't already using the tried and true solar batch water style of heater that works so well in non freezing climates?

 

[Benzimidazolone]

I already have a Heliatos system that I took down because I put on a new roof. The system works fine but needs another couple of panels to give enough hot water. It is also a bit messy (water pipe on the roof...and I have some extra solar panels.

 

[fr8tdrvr]

Look into:

Off-Grid H Model Overview

cyboenergy.com

 

[Nobodybusiness]

Has anyone tried the DC water heater element supplied by Missouri Wind and Solar for domestic hot water supply? The elements have a thermostat, so you don't have to worry about over pressurizing/overheating things and they have DC rated contacts so you don't have to worry about burning the switches. The issues seems to be that they are only 700 watts. Therefore, you could hook up 2 X 48v panels of approx 350 watts in parallel. You would have to do both the top and bottom elements but you would only have 1400 watts of power (and probably less because you would not size at the very upper limit). Is that enough power to hear a typical 40 or 50 gal tank (I realize it depends on how much hot water you use). My location is in the Bahamas (200 miles east of Miami) so I have lots of sun and my incoming water is typically 70F or higher. Any input would be appreciated

Do a Google search for review of Missouri Wind and Solar first.

 

[OzSolar]

Do a Google search for review of Missouri Wind and Solar first.

That's some good reading.

 

[OzSolar]

Look into:

Off-Grid H Model Overview

cyboenergy.com

From what I can see you cannot use that and meet NEC Code that requires a utility accessible disconnect. In essence that's no different than plugging a microinverter into an 120v outlet. We used to call it guerrilla solar.

 

[Stephen InGeorgia]

I called about these small, dedicated inverters. One was 1800$ and the other company was 1575$ Both way expensive.

 

[Leeds]

From what I can see you cannot use that and meet NEC Code that requires a utility accessible disconnect. In essence that's no different than plugging a microinverter into an 120v outlet. We used to call it guerrilla solar.

In that link they're not crossing streams, so to speak.
The Grid AC and the CyboInverter AC are powering different elements on different circuits within the water heater. The utility has no business having or needing a disconnect on a device that's not connected to their grid AC.

 

[efficientPV]

you could hook up 2 X 48v panels of approx 350 watts in parallel

You do have to worry because it is the open circuit voltage that matters for the switch contacts. Lots of reports of these MWS switches burning up. I use the figure of 1KWH to raise 6 gallons 60F. Having a higher inlet temperature helps a lot. With direct connect you will not get full power calculated by a solar calculator. Consider half that value because most of the day the resistance will be a poor match.

 

[wshankmo]

Do a Google search for review of Missouri Wind and Solar first.

We're very proud of our reviews with the BBB.

 

[Nobodybusiness]

We're very proud of our reviews with the BBB.

Yea anyone can pay to have them dismissed.

Don’t try to BS me or anyone else in here.

We all know who you are and what you have done.

Goodbye now.

 

[wshankmo]

Yea anyone can pay to have them dismissed.

Don’t try to BS me or anyone else in here.

We all know who you are and what you have done.

Goodbye now.

This is incorrect. You cannot pay BBB to have them dismissed. If you can, why would I have any bad reviews - which, go figure, we do.