Best heaters for use with modified sine wave inverter ?

[perkins]

Hi all,

I have finally got my Navitron 2Kw wind turbine up and running and linked into the house. My system works on 2 banks of 10 x 12v 110Ah batteries and a Navitron modified sine wave inverter and seems to give a reasonable reserve of power.
I use it purely to run low energy lighting and also a small electric heater - as we have a stone house, with solid wall which needs the warmth to keep it aired !

The heater I use is an oil filled electric panel radiator - I have been using this to try out the system. The Navitron inverter powers the lighting without any problems, but the radiator makes a very loud buzzing noise when the thermostat is 'on'. It doesn't make any noise if I plug it into the mains.

This, to me, sounds like it is going to shorten the life of the radiator quite quickly. My question to those who have already trodden this long long learning curve is - what are the best room heaters to use with a modified sine wave inverter ?

In the longer term, I may pick up a big UPS unit and rig that into the system, but at the moment, after much messing about getting the system up and running, I don't feel like making any more investment in time or money, without seeing some real benefit first !!

All help, advice and shared commiserations very welcome.

Perkins

[w0067814]

Heaters are nothing more than resistors. I would imagine that your heating element is a wire-wound resistor type and it is the windings that you can hear buzzing due to the square wave electricity feeding them. You don't hear this on the mains because it is a smooth sine wave.

I doubt that the buzzing will shorten the life by much unless the movement is enough to wear through the enamel insulation.

Transformer manufacturers dip their product in slightly thinned varnish, to glue the windings together into one lump which prevents buzzing - I've done it myself by warming up my home-made transformer in a cool oven to allow the varnish to flow easier and dipping it in the pot.

Also, I see little point in inverting up to mains only to run a heating load - you would be better off running the heating load direct from the battery / source assuming that it is close enough so cabling size & losses are sensible.

-Tim

[EccentricAnomaly]

Also, I see little point in inverting up to mains only to run a heating load - you would be better off running the heating load direct from the battery / source assuming that it is close enough so cabling size & losses are sensible.

The only point I can see to inverting up is that an inverter plus mains powered heater might be cheaper than a more-specialized low voltage heater.  Are there cheap low-voltage heaters, perhaps made for trucks, boats or caravans?  A standard wind-turbine dump load would do the job, of course.  Avoiding the inverter would help reliability.

If the inverter is in the house so that its losses contribute to heating then overall they're not really losses.  The same applies, of course, with cabling losses for low voltage.

[peter999]

 12v heater huge amperage, need very heavy cable with high losses if run over any distance.
 
 I would keep cables between battery bank and inverter as short as possible and run the heater off the inverter and accept the losses!!

 If the heater has an electronic thermostat the humming MAY be the electronic not liking the modified square wave!! in which case it will shortern the life of the thermostate in not the heating elements.

I have an electric consumer meter that gets very warm when feed from my back up mod sine wave inverter but runs cold when connected to the puresine main inverter, no moving parts purly electronic!!

Regards Peter


regards peter