Coffee Can Heater

Here is a video showing a homemade 12 volt heater made from a coffee can. This could work in a car or you could use it as a dump load for a wind turbine charge controller. Either way, it is about 600 to 800 watts depending on battery voltage. The trick is to measure the amps at various lengths until you get the amps you need. If the ni-chrome wire you find is too thin to carry the amps you need, then you may have to double or triple it up. For instance, if you want a 500 watt heater or dump load, and you are using 12 volts then you just do the math. In a car application or in a dump load application, it would be about 14 volts. If you were just running the heater off a battery that started at 12.7 volts, then for the math use 12 volts because the battery always drops once the load is applied. In this example, we will say 500 watts at 14 volts. So, 500 / 14 is 35.7 amps. But, let's say that when you apply the voltage to the wire and at a certain length it starts to glow red and you show 20 amps. Then you would need test a length to get about 18 amps and then run two pieces in parallel. If you need a way to measure amps that are higher than your meter can handle, just use the stainless steel bolt trick as seen on this older blog entry. http://poormanguides.blogspot.com/2009/05/updated-chargerdesulfator.html



Richard