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RE: djgiron: "The real benefit is coming down the other side where you can use the weight to recharge the battery for the next pass!"
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That's true, and having the ability to use "regenerative braking" (really, it's regenerative coasting) is nice in that it saves the brakes while recharging the EV/hybrid battery, which indeed is pretty cool.
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However, when it comes to towing with an EV, one needs to be cognizant of the fact that when the EV battery gets back up to maximum SOC, one's "engine braking" goes away. So if one is descending a long grade and the EV battery fills up before getting to the bottom, be prepared to have to start using the friction brakes - EV trucks aren't like diesels which have effectively unlimited engine braking. In most cases it probably won't be an issue with EVs towing, but it can happen, and the driver just needs to be prepared for it so they're not taken by surprise on long, steep downhills.
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