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Welding machines are no longer confined to factories, as DIY enthusiasts, hobbyists, and pretty much everyone can buy a welding machine for their home workshop. But is it possible to run a welding machine on solar power? Or is this tool going to consume too much energy?
A 24V, 150 amp welder requires at least 2 kwh of solar power to run for 30 minutes. A 3000W solar generator or 7 to 8 x 300W solar panels can power a welding machine with five hours of sunlight.
How to Calculate Welder Solar Power Requirements
The welder power requirement formula is:
Voltage x amps / efficiency = watts / kilowatts
To give an example:
24V x 150 amps / .85 efficiency = 4,235 watts or 4.3kwh rounded off.
A welder needs 4235 watts to run for 1 hour. For 30 minutes you need about 2200 watts and so on.
From here it is easy to figure out what solar generator size or number of solar panels are needed.
To use a welder for 30 minutes you need about 8 x 300W solar panels or a 3000W solar generator. To weld for an hour, you have to double that to 600W for a generator or 16 x 300W solar panels.
That seems like a lot and it is. But keep in mind these figures assume the welding machine runs continuously. In fact, welding is often stop and go (more on this shortly). You turn the machine on, weld for 5 to 15 minutes then turn it off. After several minutes you turn the welder on again and repeat.
You will probably use the welder for 15 to 20 minutes an hour, so the power usage will likely be in the 2000W to 2500W range. This will also depend on the voltage, amps and efficiency. The higher the volts and amps, the more watts the welder will use up.
The efficiency rating is self explanatory. Like solar panels, welding machines are not 100% efficient so you have to account for it in your calculations. This is the case when inverters are used with solar batteries.
Which Welding Process is Best For Solar Power?
The most popular welding types are MIG, TIG and stick. But there is no single best welding for solar, because it depends on the job you have to do.
MIG welding is the simplest to learn, and it uses affordable wires. The output quality is good and needs little cleanup.
TIG welding is more complex than MIG, but you get better looking results. It is ideal for jobs that demand precision and detail.
Stick or arc welding is also easier to learn than TIG. You can do it outdoors, doesn’t require a wire feeder and produces solid welds. Quality is lower than MIG and TIG though, so that is something to consider.
The power requirements for each varies. You will find TIG, MIG and stick welders in varying specs, so the choice really depends on what type of work you have to do. Here is a general guide on what you can do with each welder type.
|Welding Speed||Slow||Fast||Very Slow|
|Metal Thickness||1/8″ and Above||24 Gauge Minimum||22 Gauge and Above|
|Metal Type||Stainless Steel||Aluminum and Stainless Steel||Any Metal|
How to Run a Welder on a Solar Generator
A solar generator is more convenient to use for welding than a solar panel, as a single power station can generate up to 5000W. In contrast you have to install several solar panels to produce the power required by welding machines.
There are a lot of different welding processes, so their power usage will vary. The same thing can be said with solar generators because the output depends on its charge and specs. But there are some general guidelines that you can follow.
When looking for a solar generator for welding, check how its amps and voltage support. A 5000W generator can handle 20A at 240V or 40A at 120V. This is just an example as the numbers will depend on the system.
Some generators and welders are measured in kVa (kilovolt ampere). Multiply this by 800 to find its watt equivalent. A power station with an 8 kVa rating is 6400W (8 x 800 = 6400).
Starting and Running Watts
Before you buy a solar generator, check the surge and running wattage. Some appliances like refrigerators need more power to start up (the surge watts), then it starts running regularly (running watts). The surge watts is higher than the running watts, so don’t confuse the two when looking for a solar generator for your welder.
A solar generator can supply the surge watts for only a few minutes. A welder does not have surge watt requirements, but the generator running watt must be equal or more than what the welder needs.
A solar generator with a 2500 surge watt and 1000 running watt capacity cannot power a 2000W welder. But a generator with 2500 watt surge and 2000W running watt can. It is best if the generator has more than 2000W running watt capacity, but if you won’t run the welder continuously it will do fine.
But if you use a lot of welding tools and work on large projects, you might need something like the Bluetti AC200P, which has a maximum 4800W surge peak. This packs a lot of power and is not everyone, but if you need power it is right up there.
But if you only weld occasionally,, there is the TPE Portable Power Station, with 1000 running watts and 2000 surge watts capacity. This is a good option if you are also new to welding and want to see if solar power is for you.
How Much Solar Power Does a Welder Really Need?
Before you purchase a welder, check the spec sheet and make sure your solar power system meets the requirements. The most important are the minimum circuit size, the optimum circuit size and the primary voltage.
Aside from the conversion formula above, here are some important points to remember.
- High powered welders – 200A and higher – need a 50A breaker minimum.
- 208-240V welders can operate up to 180A, but it requires a 30A (minimum) or 50A (optimum) breaker.
- A 115V-120V welder works fine with 20A-30A breakers, and you can run this up to 140-150A.
The thicker the metal you want to weld, the more amps the welder needs. One amp of power is required for each .001″ thickness of steel. Some general guidelines.
- 140A welders weld steel up to 1/4″ thick
- 180A welders weld steel up to 3/8″ to 5/6″ thick
- 200A welders weld steel up to 5/16″ thick
- 250A welders weld steel up to 1/2″ thick
As an example: if you have to weld 3/8″ steel, you need a 24V 180A welder which uses 4320W an hour (more or less, depending on the efficiency). But as you will read shortly, the duty cycle and welding output determines how much power you will really use
How Welding Duty Cycles Affect Power Requirement
Earlier we pointed out that welders are not used continuously, so it won’t use up that much power. Welder size is measured in volts, amps and duty cycle. The duty cycle indicates how long the welder can operate at a given output without overheating.
Duty cycles are in 10 minute cycles. A 23V 180A welder with a 20% duty cycle can run for 2 minutes then has to cool down for 8 minutes. A 30% duty cycle means the welder can operate for 3 minutes and cool down for 7 minutes before resuming. This is not like running a TV on solar power which you can keep open for hours.
The duty cycle is determined by the welding output. Lower welding outputs increases the duty cycle and vice versa. If instead of 23V 180A the welding process is 19V 110A, the duty cycle increases to 60%.
You can see just how much these factors affect its solar energy requirement. The lower the welding output, the less power required. Whether you use solar panels, batteries or a generator, you can control the output.
Can You Run a Welder on Solar Panels?
It is possible, but only for short periods. You should also have a battery bank and a pure sine inverter because relying on solar panels alone is impractical. Without a battery bank you’ll be relying entirely on sunlight. If the sky turns overcast or it suddenly rains you’re out of power.
A combination of 4 x 100W solar panels, a 200AH battery and 1800W pure sine wave inverter can run a small welder for short periods. The solar panels charges the battery, so you will be running the welder through the inverter. However this setup is very limited. Consider doubling the number of solar panels and use a 300ah battery instead. That should be all right for occasional welding work.
Technically, you can run any welder size as long as you have enough solar power. Powerful solar panels and batteries are a given, but the welder will run only if the inverter can handle the power being supplied by the battery. Remember, solar panels charge the battery, the battery supplies the power to the inverter which goes into the welder.
Don’t forget the charge controller too. This is the device that regulates current flowing in the battery and is very important. All these components must be installed properly. Before using it, make sure there are no signs of problems and they are ready for the welder.
Welding machines are heavy duty tools, so it’s to be expected they will consume a lot of power. But it is a testament to how much solar energy has evolved that you can now run these without electricity. If you want to use a welding machine, yes you can do it.