Help me decide BEV or EREV

[SpaceEVDriver]

I don't have a good idea, but we can make some educated guesses and build an estimate.

Let's assume someone gets 85% of the EPA range estimate at 60 mph.

0.85 * 500 = 425 miles total.
0.85 * 350 = ~300 miles on gas.

Assuming a 15 gallon tank, that's 300 miles / 15 gallons = 20 mpg. The BYD Shark sees something similar.

And---because we chose 60 mph = 1 mile / minute---it's also 300 minutes / 15 gallons = 20 minutes per gallon. Or 3 gallons per hour at highway speeds.

If the tank is a 10 gallon tank for the same range, it's 30 minutes per gallon, or 2 gallons per hour. A smaller number is better here.

If it's a 20 gallon tank for the same range, it's 15 minutes per gallon, 4 gallons per hour.

If the range is 350 instead of 300 at 60 mph, then things improve by about 16% or 1/6th.

Expanding on this a bit...

If you assume something similar (20 mpg for a modern gassy truck), and a 20 gallon tank. Also assume the standard 5,000 miles service interval.

5000 miles / 60 miles/hr =~ 83 hours.

I would guess the Harvester genset will have a service interval of around 100 hours or 6000 miles. Or maybe up to 7500 miles/125 hours/6 months.

 

[R1TVT]

Expanding on this a bit...

If you assume something similar (20 mpg for a modern gassy truck), and a 20 gallon tank. Also assume the standard 5,000 miles service interval.

5000 miles / 60 miles/hr =~ 83 hours.

I would guess the Harvester genset will have a service interval of around 100 hours or 6000 miles. Or maybe up to 7500 miles/125 hours/6 months.

Agreed. And considering other applications and similar engine and generator considerations, I was thinking 100-hour service intervals would make sense in this case too. TBD!

 

[LastDayScout]

Expanding on this a bit...

If you assume something similar (20 mpg for a modern gassy truck), and a 20 gallon tank. Also assume the standard 5,000 miles service interval.

5000 miles / 60 miles/hr =~ 83 hours.

I would guess the Harvester genset will have a service interval of around 100 hours or 6000 miles. Or maybe up to 7500 miles/125 hours/6 months.

That seems a little low. But I’m basing this on Kubota engine oil change intervals. Some of those are as much as 500 hours now. I can see it being something like 200 hours or once per year.

 

[SpaceEVDriver]

That seems a little low. But I’m basing this on Kubota engine oil change intervals. Some of those are as much as 500 hours now. I can see it being something like 200 hours or once per year.

I don’t think we can use tractors as the example. The parameter space of efficiency vs power vs longevity is a different set of trade-offs for tractors vs gensets. We might be able to use small diesel-electric hybrid locomotives, but I’m not familiar with their trade-offs.

Most gasoline generators have a service interval of 50 to 100 hours, and ones in high-temperature operations have higher frequencies. I think a well-designed genset engine with well-designed thermal management could get away with 200 hours service interval, but it would need to have its RPM set so it’s in the perfect part of the power band for longevity, which would then set up a trade-off between service interval, fuel efficiency, and power output (range). Maximum efficiency for a generator is generally in the 50% to 80% load. But running at 50% load means a bigger engine and a more frequent service interval if you want to be able to run of out gas before you run out of battery as the quote from Jamie goes.

I think it’s safe to say it’ll be between 100-200 hours, with my guess closer to 125 hours.

 

[LastDayScout]

I don’t think we can use tractors as the example. The parameter space of efficiency vs power vs longevity is a different set of trade-offs for tractors vs gensets. We might be able to use small diesel-electric hybrid locomotives, but I’m not familiar with their trade-offs.

Most gasoline generators have a service interval of 50 to 100 hours, and ones in high-temperature operations have higher frequencies. I think a well-designed genset engine with well-designed thermal management could get away with 200 hours service interval, but it would need to have its RPM set so it’s in the perfect part of the power band for longevity, which would then set up a trade-off between service interval, fuel efficiency, and power output (range). Maximum efficiency for a generator is generally in the 50% to 80% load. But running at 50% load means a bigger engine and a more frequent service interval if you want to be able to run of out gas before you run out of battery as the quote from Jamie goes.

I think it’s safe to say it’ll be between 100-200 hours, with my guess closer to 125 hours.

Fair point. Completely different duty cycle and environment. Also the relative amount of oil capacity to displacement makes a difference too. I doubt it would have a very large oil pan though due to space constraints. That is unless it is dry sump and then who knows what the limitations are for their chosen location. I am really only interested in this discussion due to my curiosity about the engineering and compromises they have to make.