Dump Load Idea

[TomW]

Folks;

Hopefully by this winter my tower will be up and shortly thereafter I will have a large zubbly type conversion genny with high voltage ac out for a combination of resistance floor storage heating in my office and battery charging at both the tower and the office area where i use my RE power. Plans call for computer control of what goes where and when based on needs of the various systems.

In my scrounging travels I have come up with a few heaters, kiln elements, etc. that I can use as a power waster at the tower. One other thing I have acquired totally free is a 1KW metal halide light with ballast and a spare bulb. This is one bright lite and on my mod sine inverter it draws about 100 amps [12 volts] so will be a fine dump load through the tower inverter. My concern is that while it will be cool to light up the tower like daytime with excess power I am unsure if the ballast will tolerate a mod sine inverter. It starts up about the same as on grid and gets as bright but it does hum a bit more on the inverter.

My main question is whether or not the ballast [size of a 12 pack of beer] will tolerate the inverter. My system will be fairly complex with multiple transfer methods to the point of use which is 300 plus feet away. The light would be near the apex of the tower under a weather cover to keep it dry.

Thanks in advance for any input on the question.

Cheers.

TomW

[Ungrounded Lightning Rod]

My concern would be what happens when the lamp burns out in a couple years (or the ballast or invertr fail) and you still need a dump load.  Now you have either overcharged batteries or an overspeed mill.

I'd prefer to use a globar or the like for my last-resort.

[JW]

 Tom the ballast should be ok with that, its just a transformer maybe a capacitor or two. Since the transformer is isolating the bulb from the input it might be quite redundant, as far as overspeed. Atleast while your computer is on that channel or function, to dump load to the HID lamp. I had a nice outdoor type 250w HPSodium lamp in a water proof aluminum case that had no ventilation for the ballast, it worked great. Powered it with a little lamp cord, very economical. But if your ballast needs cooling, you might want to water proof it some way, that allows it to cool, it could be a high performance type.

 

[Vtbsr]

Try to match the dump load (watts) to charge you are producing (watts). If dump load is to big,the system will cycle on and off. The volts will drop to fast, dump will shut off and then volts will rise again. The Trace SW inverters have 3 relays that you can set up at different volt limits. My first one controls a  1500 w  water heater element running on 48v dc to give less that the 1500w. If volts run higher that that set point, a 1500 w AC electric air heater will drop the volts very quickly. If i ran just the electric air heater it would come on about every 3 min.and, drop the volts in about 20 sec and repeat.

[TomW]

Guys;

I think I asked the wrong question and supplied too much information.

I believe I understand the how and why of dump loads. I am more concerned about the inverter damaging the ballast or the ballast damaging the inverter.

The light as a dump load was more of an idea for a fun dump load than an all the time method.

Thanks for the feedback.

Cheers.

TomW