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Jason has already explained the PTO situation, but I'll just add that the tractor for which the PTO is intended would have an engine running at constant speed, and a PTO shaft turning at a relatively constant 540 RPM as a result. The "live" engine PTO would be similar, but would still vary in speed as the engine speed varies, which wouldn't work very well. A hydrostatic drive from the PTO could adjust to keep the blower speed constant, but only if the PTO is turning at a reasonable speed, which means only the engine PTO would work.

An electric drive adds the potential to have energy storage (the battery that Jason didn't want to include but is now considering) so that the power source doesn't need to be constant.
 

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Discussion Starter #22
So how does this sound:
If I run a motor at 600amps, and I have an alternator charging the 48v pack at 100amps. Theoretically, if I run the blower for 1 minute, and idle (or drive) for 6 minutes...I should have the same amount of energy in the battery bank at the end. Is my thinking correct?

would lead acid batteries be an alright option for me? I mean I need weight. I could use 5000lbs, but lead acid won’t be enough on its own lol.
 

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Thanks Brian. Having spent hundreds of hours on farm tractors, I understand the 540RPM blower side of the equation and didn't ask about that side if the problem.

He could just put a 50HP gas engine on the snowblower, which has a speed/load governor, and call it a day.

Cold weather is a crappy application for batteries and controlling and managing the generator energy (which is only good at a speed where the voltage is greater than what the battery stack is) and motor speed is nontrivial.
 

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So how does this sound:
If I run a motor at 600amps, and I have an alternator charging the 48v pack at 100amps. Theoretically, if I run the blower for 1 minute, and idle (or drive) for 6 minutes...I should have the same amount of energy in the battery bank at the end. Is my thinking correct?

would lead acid batteries be an alright option for me? I mean I need weight. I could use 5000lbs, but lead acid won’t be enough on its own lol.
You can't "idle". You have to run the generator at least at a speed where it produces 48 V and manage the throttle when it kicks in, asking for more power from the engine. You get zero power when the generator spins below the battery voltage. You also can't overspeed the generator as you run the truck with the engine pto on. Your math is kinda ok, but your generator and motor efficiencies need to be factored in on top if what you think you need to make for power into the system, not to mention your batteries (lead acid's probably your best option) will be sluggish in the Minnesota winter temperatures. Could be 20% more?
 

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He could just put a 50HP gas engine on the snowblower, which has a speed/load governor, and call it a day.
True; often straightforward is good. :)
If the hitch and truck can handle the weight of the engine mounted directly on the blower, that works... and is like every walk-behind small snowblower... but that's a lot of engine. The engine could be mounted on the truck and drive the blower via the PTO shaft, but that would put the motor between the truck's frame rails, which means a very custom truck.
 

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You can't "idle". You have to run the generator at least at a speed where it produces 48 V and manage the throttle when it kicks in, asking for more power from the engine. You get zero power when the generator spins below the battery voltage. You also can't overspeed the generator as you run the truck with the engine pto on.
True, but when the blower isn't actively moving snow the truck is presumably maneuvering, not just idling. Alternator manufacturers publish charts of current production versus speed (assuming a constant-voltage load) and substantial output requires more than a regular idle, but not high engine speed. The easiest alternator mounting is to the engine, so the PTO doesn't matter, and the alternator drive ratio is planned so that engine redline doesn't overspeed the alternator.
 

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So how does this sound:
If I run a motor at 600amps, and I have an alternator charging the 48v pack at 100amps. Theoretically, if I run the blower for 1 minute, and idle (or drive) for 6 minutes...I should have the same amount of energy in the battery bank at the end. Is my thinking correct?
To a first approximation yes, but...
Your math is kinda ok, but your generator and motor efficiencies need to be factored in on top if what you think you need to make for power into the system, not to mention your batteries (lead acid's probably your best option) will be sluggish in the Minnesota winter temperatures. Could be 20% more?
Maybe even more than 20% loss, due to the lead-acid batteries (which agree are practical for this unusual application).
 

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If the hitch and truck can handle the weight of the engine mounted directly on the blower, that works... and is like every walk-behind small snowblower... but that's a lot of engine.
A single cylinder 650 petrol engine has the power that you would need. My 650 motorcycle is 39 kW. Connected directly to the snow blower with the right gear ratio would be more efficient and simpler than a generator and battery setup.

Another option would be to go with a battery only system and charge it at night. What is the total run time of the blower for a shift?
 

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A single cylinder 650 petrol engine has the power that you would need. My 650 motorcycle is 39 kW. Connected directly to the snow blower with the right gear ratio would be more efficient and simpler than a generator and battery setup.
An engine of that displacement would need to run at high speed to produce the peak power required, and if used to drive the blower without some variable-ratio transmission it would need to run at that speed all of the time (because changing the blower speed is not practical)... not good. General-purpose small engines around 600 cc are typically V-twins producing only 20 HP at 3600 RPM.

Another option would be to go with a battery only system and charge it at night. What is the total run time of the blower for a shift?
That's more EV-like... but that's a lot of battery. With a huge engine running in the truck already, why not use it?
 
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