# Towing uses insane amounts of energy and power [git b85c4a930b]

Towing vehicle: EV 150kW 2200kg
Towed vehicle: EV 1030kg with “enough” in tyres

Max speed is 12km/h and 6 minutes until empty?!

(2200+1030) * (100/3.6)**2 / 2 / 150e3 = 8.3 seconds from 0 to 100km/h based on kinetic energy alone. What is going on?

Towing vehicle:

Towed vehicle:

you’re towing a car using an electric engine, that’s the problem.

towing basically adds the entire other vehicles weight to your vehicle, and your electric car there seems like its already almost full on weight.

A 150kW electric engine. That is 200 horsepower or 2-3 times as much as a normal gasoline-powered car.

as i understand it from this page, the engines don’t actually matter, its your cars aerodynamics and vehicle weight. more weight = less efficiency for fuel, less speed. and towing is SUPER inefficient for aerodynamics (though admittedly i have no idea how that system works.)

also for refrence, a v12 diesel engine has about (and i googled this) 1900 hp. (though that particular engine says its used on a yacht, assumedly powering the turbine in the back.) v12 car engines about 600-700, going off luxury sportscars of the modern times.

most of the random cars in cata use inline-4 or V6, with V6 being about 300 hp

Towing isn’t super inefficient for aerodynamics. The cable itself has minimal air drag and should make the whole system behave as if you had an 8 wheeler with summed mass with a 150kW engine. Since you have 2 cars in the system, you have double the aerodynamic drag. But at 12km/h that is negligeable.

The only non-negligeable variable here is rolling resistance. Does anyone have a formula for that?

theres this from the vehicle parts page:

as well as the section in engines:

safe and maximum velocity

which is what i’ve been refrencing…
but other than that i’d say we would need mlangsdorf, whos likely to come in here and yell at me for spreading false information again~

Another example: This time a 2200kg EV loaded with loot towing a 700kg EV (batteries removed):

Speed does not want to increase past 12km/h, according to the -650%/hour figure, engine power is 144kW (2*40000e3 / 3600 * 6.50).

EDIT: mathed wrong

Something must be way off, as I’m also unable to [G]rab and pull a ~130 kg motorcycle with a str6 character.

The power drain is severely wrong, but fixing it has been complicated.

The slow towing speeds was caused by essentially the towed vehicle having its parking brake on. I submitted a fix for that issue that got accepted yesterday; please update and see if that fixed things.

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Given that the towed vehicle in question also was an electric car, I wouldn’t have been suprised if it had interfering regenerative brakes… I doubt(ed) that it’s a game mechanic as of now, but who knows…

…Now I have a new item on my todo list… damn it.

strength 6 is decidedly low strength, when 8 is considered ‘average’, motorcycles are heavy!

Thank you, that fixed it. Now the problem is towed vehicle’s inertia ramming into my car’s trunk! Have to slow down really… slowly, one notch down then idle 5 times.

About the handbrake: I can “pull” it, but I cannot “unpull” it. The menu only offers to pull it again. I suppose it gets unpulled on use? Strange.

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Yeah, I noted in the PR that fixed the bug that “the developer isn’t responsible for your towing vehicle getting rammed by your towed vehicle.” Just think of it as a preview of multi-second brakes.

The hand/parking brake can be applied while driving, and it’s assumed to be set when a vehicle’s engine is off. Conversely, it’s assumed to be unset when a vehicle’s engine is on. So turning on the engine of a vehicle, even if you don’t intend to drive it, makes it easier to Grab or push with another vehicle.