generator stops

[(unknown)]

I have a simple/small wind generator that i want to use to heat up water while camping at my inlaw's farm.  Using the multimeter it produces between 10 and 12 volts dc.  I wanted to hook it up directly to a 12 vold dc water heating element, but when I connect it to the heating element, the generator goes from producing 10 volts to producing .2 volts.  Is the current somehow reversing and working against the generator/wind?  If so what do I need between the generator and the element?

[ghurd]

Sounds like the mill is too small for the heater.

When the heater is large (low resistance), the mill can't keep the volts up.

When the heater is connected, does the mill slow down drasticaly, like almost stop?

Could make it very hard to get started too.

Some kind of circuit that only lets current go to the heater when the voltage is above, say 7V, may help a lot.

G-

[Norm]

  How many 12 volt headlight bulbs will it

light up??

  To do what you want it to do it would have to

be capable of lighting up about 6 headlight bulbs.

  A coffee maker ...if it were 12 volts would require about 100 amps...just to give you an idea

of how many amps it would take to heat up some

water a 60 amp alternator going full blast would

even be woefully inadequate.

   Just trying to give you an idea.

                  ( :>) Norm

[scoraigwind]

Running heaters is much more difficult than running batteries.  Batteries let the machine get up to speed and work as hard as it likes.  Heaters make the machine work hard right from the start and it stalls out and fails to work.

You need a controller of some sort between the wind turbine and the heater(s).  The controller can switch them in at different voltages, or just use one load and 'phase' it in gradually using PWM.  Not many battery charge controllers can do this but solar converters inc. have a product that will do it alongside some capacitors.

[(unknown)]

You mentioned batteries.  Would it work if I hooked my generator up to a 12v 20amp battery (from a scooter my son use to use) and then to the heater element?  If my generator is only producing about 10v would the battery eventualy loose its power (it would run the heater and the generator) and then be maintained at 10v (the heater element is rated for between 6 and 12 volts).  I don't know what the amps are from the generator (how would I find out, all I have is an analogue multimeter).

[kitno455]

heating elements work by having low enough resistance for massive amounts of current to flow, but are of good enough quality not to be destroyed by the heat (I squared R, better to raise I than R). try looking at some of the 'how much power your home devices use' charts, and you will see that things with heating elements are at the top of the list.

if you connected a heating element up to a battery and turbine directly, it would drain the battery, and then after it was dead, it would still stop your turbine cold

you need a way to have less current pass thru the heater, either via inline resistance, or some sort of pulsating charge controller coupled with some caps or battery.

the problem with that is less current=less heat, since current is what drives the heater. so a smaller, higher resistance heater element in a smaller container might be your only option.

look for stuff used in motorhomes maybe?

allan

[finnsawyer]

The simplest solution might be to put two or more heating elements in series.  At least then all the power you get would go for heating water.  Or pick up a 120 volt heating element and try that.  It will have a higher resistance.

Maybe the best thing to do is a series of tests using different values of resistance.  Start with a large value, say a couple hundred ohms.  For each value of resistance measure the voltage across it and calculate the power it's dissipating from Voltage squared over Resistance (VxV/R).  Do this for a series of successively lower values of resistance.  plot the power versus resistance.  If the curve has a maximum that's the value of resistance that you want for the heater, which value may have nothing to do with commercially available elements.  It is also important to do this with a constant wind speed.  

[(unknown)]

Thank you everyone for you comments.  I guess i have some work to do.  I will have to rethink this.