Oil Filled Radiator as Hydro Dump Load W/ Midnite Classic 250 PWM Relay control & Solid State Relay

[Darkstar]

I think you have missed the point. The heater is being used as a dump to burn off extra energy, not actually intended to be used to heat the space durring "normal" operation.

Although the extra heat is welcome in the greenhouse during the winter.

 

[efficientPV]

Problem is most people see water heating as generic and one solution meets every situation. Sometimes you have to dump as with hydro and wind. It may be that PV will just go to waste and collecting any part of it is a bonus. Some are bored with extra panels they are doing nothing with. If you really have to depend on hot water every day something sophisticated is needed and diversion out of a CC just won't do it.

 

[ko6kL]

has anyone found a DC-rated thermostat replacement for the oil filed heater? Id like to run one on 40 volts.

 

[Hedges]

We've seen some marketed, and one guy opened it up to see it was an AC rated part inside.
Reseller had been saying "48VDC" or something like that, and it failed at the higher nominal battery voltage.
Maybe would work for 40V. RC snubber might protect it.
"Pilot duty" controlling a relay coil could be better (snubber still recommended.)

 

[Bud Martin]

This one claims to be DC Thermostat up to 50VDC, not sure what temperature you are looking for, but you can contact them and find out what they have.

DC Water Heating Element Thermostat

Missouri Wind and Solar carries a range of DC or AC water heating thermostats including a thermostat that just keeps liquids from freezing. Use these with our DC water heating elements.

windandsolar.com

Thermostat Features:

• The thermostats remain on until the temperature of the liquid reaches the rated number. For example, the 140 degree thermostat will remain on until the temperature reaches 140 degrees F.
• All of our thermostats can handle 25 amps at 12 volts! No relay needed! (Can handle AC voltage up to 220VAC and DC voltages up to 50VDC)
• Opens circuit on overheat, effectively cutting power to the heater (normally closed connects).

 

[ko6kL]

Some guy was showing off his midnight solar dump unit in a video and was using a solid state relay to control it, is this the way to control the DC with out arcing a contact ??

 

[Hedges]

That should work. Some SSR have triac, for AC only. Some have MOSFET, and support DC.
If any inductive loads, I recommend a snubber, including diode to eat reverse-polarity spikes.
(diode alone can make coil field collapse slowly, but with series resistor, greater voltage developed an faster collapse, which can matter for electromechanical relays.)

 

[ko6kL]

most of the DC controlling opto / solid state relays I saw today at most can only switch 10 amps of DC at 100v

 

[efficientPV]

Personally, most of them are junk and require very large heatsinks. I have an oil filled heater abd I wouldn't put more than 400W into it unless the room is freezing as they get too hot. It is worthwhile to learn how to use a couple FET in parallel to do the switching.

 

[KianMunoz]

It's great to hear about your experiences with oil-filled radiators and your insights on control. Learning to use FETs in parallel for efficient switching sounds like a smart approach.

By the way, if you ever need more information or resources on radiators, you might want to check out Radiator Village. They're the experts when it comes to all types of radiators, and they could provide some valuable insights.

 

[Solarcabin Channel]

I am using a 250/500 watt quartz heater as a dump load over winter.

Works well on sunny winter days to take the chill off the cabin and reduce my propane use without dipping in to my battery capacity.