Home made water heater element - dump load

[gadget]

I have been working out details on my dump load and am thinking about building one since there does not appear to be one that fits my needs.

I have 1200w of solar that I want to divert to heat water using a C60 control between the batteries and the load.

I was thinking I could pick up some 16 gauge nichrome 60 and make a two foot simple coil. I would pick up a pipe plug and drill two holes. Run the wire through the holes to the outside and mount some wire lugs. I would insulate the nichrome with epoxy. I would use pretty heavy copper for the lead wires.

resistance for the element would be .5 ohms and about 1500w driven at 27 volts. Does this make sense?

Has anyone attempted this yet? I've done lots of searching and have not found any info yet. Only info I found is the nichrome 60 is common for water heating and also nichrome 80 is used. I found 10 feet of the 16 gauge nichorme 60 for $10 shipped on ebay.

-gadget

[ChrisOlson]

Has anyone attempted this yet?

I never used nichrome, but back when I was still messing around with low voltage water heating I used regular old hardware store variety stretchy springs to make water heating elements and never had any problems with them.
--
Chris

[OperaHouse]

I don't know why everyone is in love with nichrome.  Unless you want to make something red hot it serves no purpose.  I would never use a low voltage heater.  Cable losses are just too great.  But if I did do something like this I would use an external length of thin wall stainless tube and use that as the element.  Insulate it thermally and let it gravity feed into the tank. It would also need an electrical break at one end.  I will be heating water this summer and will be doing it with a modified inverter.  Then I can have the inverter right next to the battery and the heater next to where I use it without a lot of electrical and thermal losses.

I doubt with that thermal density that epoxy would last long coating nichrome element.

[gadget]

I don't know why everyone is in love with nichrome.  Unless you want to make something red hot it serves no purpose.

I am guessing because it is cheap and works well? It is used in water heating elements so I would bet it works fine @130F.

I doubt with that thermal density that epoxy would last long coating nichrome element.

I don't plan on coating the whole element, just for electrical isolation where it goes through the plug. There are allot of epoxys that can handle 130F so that should work ok.

[Watt]

I don't know why everyone is in love with nichrome.  Unless you want to make something red hot it serves no purpose.

I am guessing because it is cheap and works well? It is used in water heating elements so I would bet it works fine @130F.

I doubt with that thermal density that epoxy would last long coating nichrome element.

I don't plan on coating the whole element, just for electrical isolation where it goes through the plug. There are allot of epoxys that can handle 130F so that should work ok.

Be careful, just because you will be heating the water to 130f doesn't mean the element wire will be 130f.  And, if the element wire will be insulated through the plug, and be part of the resistance for the element, the wire will be much hotter than the ambient material.  I suppose the wire temp. will be dependent on the assembly scheme.  Good luck and keep us posted.

[gadget]

Be careful, just because you will be heating the water to 130f doesn't mean the element wire will be 130f.  And, if the element wire will be insulated through the plug, and be part of the resistance for the element, the wire will be much hotter than the ambient material.  I suppose the wire temp. will be dependent on the assembly scheme.  Good luck and keep us posted.

Good point, I will extend the conductor in a bit to the water before it goes to the resistive load