What brand water heating elements ,used for diversion load

[Taos]

Im thinking of heating water using the diversion load feature on the classic 150 , i dont have a large pv system 1320 watts ,48 volt system , i was looking at wiring my water heater lower element using 48 volts D.c. off the batteries through a solid state relay controlled by the classic ,the only water heating element i could find was at missouri  wind and sun  48 volt D.c. 600 watts , i was wondering if anybody uses this brand and are they satisfied with the product or is there another brand you can recomend  , im thinking the wattage would be about right 600-700 watts, also can anybody recomend a brand for the digital relay to control the heating element. 
Thanks
Don

[russ_drinkwater]

I have 2 in 24 volt and 2 in 12 volt from the same source, but have not tried them as yet.
From memory they were supposed to be made in the states. I stand corrected if this is wrong.

[solarvic]

I bought the water heater element that has the thermostat mounted on the front of the heating element. It has a can on the front of the element that has a wire molded into the element. To start you can not get a wrench on the element to tighten it up so it will not leak. So I used a rubber strap oil filter wrench on the can and it just twisted off the element. I sent email that was unanswered to the seller from miourri asking him how to tighten the element into the water heater. So I cut the thermostat wires and tried wiring it direct. after about 10 minutes I could no longer hold onto the wire because it was overheating. The wire is too small of guage. Looks to be about #12 and the element needs close to 30 amps. I do not recommend this unless you want to have a fire. I might try one that you can connect direct to the element with the correct wire size. Solarvic

[dgd]

Solarvic,
Are you sure you bought a DC water heating element from Missouri W&S?
Last time I checked with them its only the AC elements that have a thermostat included. That would explain the small size power cables as they are designed for only few amps of AC current at AC voltage (110v to 240v)
If you try connecting to a DC source then the wires will burn up as the current is just simply too great for the wire to cope with. The thermostat switch contacts will also fuse together or burn up.
That can is just a cover to stop prying fingers getting a shock. It certainly is not strong enough to be used for torqing up the element into a tank.

dgd

[solarvic]

Yes I am sure that is where I bought the water heater element. It Has the brand name SES on it. Looking at it now. It has 24 volt and 600 watt stamped on the front of thermostat. There is also one on ebay I saw a few days ago that was 48 volt. Everything I said in my post is my experience with it.  If you want to blow $59.95 plus shipping you are welcome to. Also I do not have any faith that those thermistats that they sell there are good to use on a dc water heater element. There is a youtube video where this guy showed the original ac water heater thermostat arcing and he tried one of the ones mis wind and solar sells and it arced also. If I decide to get a dc water heater element I will get one that you directly wire to the element.  To start with I will probably wire it direct to a circuit breaker and see if it really can heat up 50 gal. of water. If it can I will probably connect the water heater thermostat to a ssr relay to turn on the element if needed and use a charge controller to make the power available when the voltage goes beyond a voltage set point. I might not even bother as I have a new hybrid water heater to install and it is only needs 400 watt to operate the heat pump. I like heat pumps but the present one ( Geospring)  has a broken heat pump so am just running it on the elements. Since it is already 8 years old I don,t want to spend the money to get it fixed. Cheaper to buy a new one. The geospring has a 10 year guarantee in the parts but you have to pay the labor. They require you to have a repairman come and look at the water heater to see what parts you need, $200.00 service call, Then they send the parts to him and he charges another $200.00 service call plus labor. I read this on a forum and for the service calls and labor the guy had $495.00 in labor and the parts were covered under warranty. So the new replacement only cost $999.00 plus sales tax and the power co pays you a $300.00 rebate. Plus the new rheem has a lot of improvements and the energy factor is a lot higher and it has ducts on it where you can send the cold air outside if you want to and you can duct the intake to somewhere to get warm air.

[dgd]

Solarvic,
Since the element is marked for DC use, it seems jusy crazy that it would include a thermostat and wire of small gauge. 12v at 600watts is 50 amps, so that would need something much larger than #12.
Pity about the labour costs, the Rheen looks the way to go 

dgd

[solarvic]

I figured about 30 amps. I tried a 20 amp dc breaker that listed that it would trip at 25 amps, and it did. Then I connected it to a 30 amp dc breaker that trips at 35 amp and it didn,t trip so I think I was preety close at figuring 30 amp dc at 24 volt. I want to do all the experimenting on the old waterheater before I install the new one. It has a 4500 watt 240 volt ac element. The new one I got has a 5500 watt 220 v ac element. On another forum the moderater said he figured you should be able to get about 48 watt of heat on the 4500 watt ac element. Don,t know for sure if that is enough to heat much water. Maybe I might get around 55 watts with my 5500 ac heating element .The formula is 2.4705 watts for 1 hour to raise 1 gallon of water 1 degree F. in an hour. I don,t have a calculater but I think but if anyone does maybe they would like to figure the math problem. Think 50 watts for 24 hours and 50 gallons of water. How many degrees can you raise 50 gallons of water in a 24 hour period. I am thinking you could heat continuously and not overheat the water. I Could set the ac water temp really low and  probably het the biggest share of water with dc. I guess tomorrow I will connect to dc and see what it does.  solarvic