What type of a circuit would be needed to run a 12 Volts DC to 120 volts AC inverter from a 36 volts DC source?
Edwin
Power Inverter
If you want to run the one 12V inverter from the 36V source, you will need to reduce the voltage with a regulator of some kind. A DC-DC converter ( a kind of switcher) is most efficient but also most costly. A circuit based on an LDO (3 terminal voltage regulator) could be very inefficient, wasting a lot of heat, but reasonably cheap excepting the heatsink and fan you would need.
Much depends on how much current this regulator needs to handle, you didn't say how many watts the inverter is.
Adding other loads in series with the inverter to make up the other 24V is in theory possible but in practice, you can't just use anything especially if the current from the source will be variable according the the demands of the load you plug into the inverter.
For example a resistor will work only if the current is stable and probably glow red hot. Two 12V light bulbs would seem to work but since they are non linear, they tend to act funny when the current changes. Another two inverters maybe but I don't really know the impedance characteristic of the DC side of the inverter. If it acts like a constant voltage load, it would regulate the current in the other loads and the bulbs or resistor might work. In any case, inefficient.
This reminds me of wanting to power an automotive 12VDC amplifier (1000W) from house current 120VAC. In the end, the only really well performing solution is to put another power supply between which cost as much as an amplifier intended for 120VAC in the first place. Hard to win that $ game. (go ahead, price out an 85A, 12V transformer or switcher)
Much depends on how much current this regulator needs to handle, you didn't say how many watts the inverter is.
Adding other loads in series with the inverter to make up the other 24V is in theory possible but in practice, you can't just use anything especially if the current from the source will be variable according the the demands of the load you plug into the inverter.
For example a resistor will work only if the current is stable and probably glow red hot. Two 12V light bulbs would seem to work but since they are non linear, they tend to act funny when the current changes. Another two inverters maybe but I don't really know the impedance characteristic of the DC side of the inverter. If it acts like a constant voltage load, it would regulate the current in the other loads and the bulbs or resistor might work. In any case, inefficient.
This reminds me of wanting to power an automotive 12VDC amplifier (1000W) from house current 120VAC. In the end, the only really well performing solution is to put another power supply between which cost as much as an amplifier intended for 120VAC in the first place. Hard to win that $ game. (go ahead, price out an 85A, 12V transformer or switcher)
a 24V, 2000W inverter costs about $225 and it can handle input voltage nominally from 22 to 30V. Now if you could just loose 6 more volts, you have it. Thats about the same price as the same size 12V inverter.
There must be 36V inverters too but I didn't find one at first glance (at least nothing under $1k). I suggest you search for the right thing. a 200A voltage regulator to reduce the 36V while possible is not very practical. Even dropping 6V at 150A would result in dumping 900W of heat into a heatsink, that's a hairdryer's worth of energy.
Example
http://www.topsalesdepot.com/20wadctoacpo.html
There must be 36V inverters too but I didn't find one at first glance (at least nothing under $1k). I suggest you search for the right thing. a 200A voltage regulator to reduce the 36V while possible is not very practical. Even dropping 6V at 150A would result in dumping 900W of heat into a heatsink, that's a hairdryer's worth of energy.
Example
http://www.topsalesdepot.com/20wadctoacpo.html
The 36 volts power source would be 6 6 volt golf cart batteries. They are on a GE lawn/garden tractor. I could tap onto 2 for 12 volts. The reason
I was wanting to use 36 volts, I have read on some of the forums that it is not good to discharge some of the batteries more than the others. I have read where GE had rotary inverters when these tractors were in production many years ago. I don't know what the difference would be in their inverter and a generator. Maybe my best solution would be to run a motor driven generator. Motors are available that are used to run snow blowers and roto tillers. My intended use would be to power an electric
wood splitter.
Thanks for all the advise and information.
Edwin
I was wanting to use 36 volts, I have read on some of the forums that it is not good to discharge some of the batteries more than the others. I have read where GE had rotary inverters when these tractors were in production many years ago. I don't know what the difference would be in their inverter and a generator. Maybe my best solution would be to run a motor driven generator. Motors are available that are used to run snow blowers and roto tillers. My intended use would be to power an electric
wood splitter.
Thanks for all the advise and information.
Edwin
Re: Power Inverter
Greetings Edwin,
Are you considering modding one?
Comments Welcome!
A golf cart uses 36V or 48V batteries, and an electric motor.Ed446 wrote:What type of a circuit would be needed to run a 12 Volts DC to 120 volts AC inverter from a 36 volts DC source?
Edwin
Are you considering modding one?
Comments Welcome!
Greetings Edwin,
of an inverter, and there are no "adjustments"
or "accessories" that can change the input voltage
range.
A "reference design" inverter could be altered for operation
on a different DC input voltage, but it would likely
involve obtaining custom internal parts.
Most quasi-sine inverters use pulse width modulation
(PWM) at a very high frequency to construct the
60Hz (or 50Hz in other parts of the world) output.
With 36V instead of 12V DC input the switching
devices (PMOSFets, IGBTs) would have lower
current stress and higher voltage stress for a
given output power rating.
Can your input DC be reconfigured for 12V?
Comments Welcome!
DC input voltage is fundamental to the designEd446 wrote:It would be a 2000 watt inverter running a 1800 watt motor. Would the transformer be the best solution?
of an inverter, and there are no "adjustments"
or "accessories" that can change the input voltage
range.
A "reference design" inverter could be altered for operation
on a different DC input voltage, but it would likely
involve obtaining custom internal parts.
Most quasi-sine inverters use pulse width modulation
(PWM) at a very high frequency to construct the
60Hz (or 50Hz in other parts of the world) output.
With 36V instead of 12V DC input the switching
devices (PMOSFets, IGBTs) would have lower
current stress and higher voltage stress for a
given output power rating.
Can your input DC be reconfigured for 12V?
Comments Welcome!
The batteries will stay in the tractor. It has an electric motor that powers it. The model I have is an E 12. I don't remember whether the electric motor is supposed to be a 12 horepower or they rated them to do the same work that a 12 horsepower gas engine. I have not used it in years, but with the price of gasoline I decided it would be a good time to get it working again. Also, if the batteries are charged good, when you turn the key on it will run. My gas powered one would not start the other day when tempeture was about 20 degrees. It has a power outlet to run small 12 volt tools, but I know the wiring for that outlet is not heavy enough for an inverter with any heavy load.
Edwin
Edwin
Greetings Edwin,
respect to chassis common? Some of those tractors also
had 36V outlets for portable tools (although 36V is not
a standard outside of that brand).
A 2kW load is very heavy for low voltage batteries,
requiring close to 200Amps input to a 12V inverter.
Comments Welcome!
Can you reconfigure them to be in series/parallel (for 12V)?Ed446 wrote:The batteries will stay in the tractor.
Is this tapped from one set of batteries to give 12V withEd446 wrote:It has a power outlet to run small 12 volt tools, but I know the wiring for that outlet is not heavy enough for an inverter with any heavy load.
respect to chassis common? Some of those tractors also
had 36V outlets for portable tools (although 36V is not
a standard outside of that brand).
A 2kW load is very heavy for low voltage batteries,
requiring close to 200Amps input to a 12V inverter.
Comments Welcome!
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