Lower Power element for small GE water heater?

[sedin26]

I have a 10 Gallon GE Smartwater Electric Water Heater with a single 1500W element. I'm using a micro-hydro power system that used to run this ok but, for reasons I won't get into, the capacity is reduced and I now don't have enough power to sustain the 1500W load.

I'm wondering if it is possible to get a lower wattage element to use? I do realize that this would take a lot longer to heat the water but that isn't really a concern as long as I can actually run it.

I may be able to use a 1000W element but even lower would be nice.

[hj]

750 watts is the smallest 115v element.

[Bob NH]

The simplest solution would be to wire a high-current diode in one leg (the hot leg) of the circuit. That would limit the power to half the cycle and would nominally deliver half the power. The inertia of the hydropower rotor system should be able to smooth out the speed without any problem.

If you have a 120 Volt system you are using about 12.5 Amps. I would get at least a 25 Amp diode rated for at least 200 Volts Peak Inverse Voltage (more is better).

I did a search at DigiKey.com on the first link plugging in 25 Amps as the current value. One of the selections is a 25 Amp diode with 600 PIV rating for $5.67. Maybe you could find something at an electronics store but I didn't find any at www.RadioShack.com

http://search.digikey.com/scripts/Dk...keywords=diode

http://www.vishay.com/docs/93506/9350625f.pdf

EDIT: hj's response came in while I was searching. If you can get a 750 Watt element that is the cleanest solution.

[sedin26]

Thanks for the replies. The 750W element sounds like it would be ok for my situation. Interestingly, this thread already comes up third on google when searching for 750w 115v element

My next problem - I'm in the sticks so would prefer to source this on the net but I don't see anywhere to grab one. Any ideas on that?

Would a plumbing supply house have one or perhaps Home Depot?

[hj]

Any place that handles elements can order one. They are too small to be a normal stock item, in most cases. You should also be able to locate one online. Graingers.com will have them, but usually only sell to licensed contractors

[sedin26]

I haven't been able to find any of these online anywhere so I will try to call "local" supply houses (I'm not exactly close to anhing though)

Any chance one of you has seen one of these online somewhere?

[jimbo]

Keep in mind that a hair dryer or toaser is using about 1200 to 1500 watts, so 750 watts is pretty minimal for a water heater , but it would eventually heat the water .

[sedin26]

That's ok - I would expect it to be very, very slow at recovering.

If I can actually find one of these, I'll pick it up and try it.

Keep in mind that a hair dryer or toaser is using about 1200 to 1500 watts, so 750 watts is pretty minimal for a water heater , but it would eventually heat the water .

[Bill Arden]

Can the hydo-power generator create lower voltages?
(some of the older core regulators are adjustable)

The power increases with the square of the voltage so dropping the voltage to 90 volts would reduce it to 844 watts.

Math:
1500W/120V = 12.5 amps.
120V / 12.5 amps = 9.6 ohms
90^2 volts / 9.6 ohms = 844 watts

one other thought would be a Stove top dimmer or a Variac

But yes, a lower wattage element would be the simplest solution.

[sedin26]

I have tried that - I can get it down to about 98 volts before it stops working - it can almost run (and likely would if I unplugged everything else)

If I can't find a 750W element, I'll grab a 1000W and I think I can make that work at certain times.

It would be easier if I was near a city.