hypermiling by coasting in neutral

Yes kind of makes sense. Except that many people then, including my own grandfather, drove cars with two-stroke engines and freewheel systems so they had zero engine braking ability.

Most of newer trucks here (which can be a lot heavier than semi-trucks in USA) have automated manual transmissions. Those do automatically coast on neutral.

You can put it in neutral to relax your feet. If you start at above 42MPH there’s no danger. I do this sometimes.

Yes I know about redused resistance. I did that with my manual transmission car all the time. And still every time I drive manual transmission car (basically every week) I do that.

But you can drive over 100MPH in gear also. But you need to go by speed limit (and conditions) with or without being in gear.

 

You can't shut it off and leave it in neutral. When you shut it off, it puts itself into park automatically. Most times that's handy. Occasionally, it's a major pain. When we got rear ended, the bonehead who thought his phone was the most important thing in life crushed the back of our car all the way up into the back seats, including our brand new 12v battery. The flatbed tow truck driver had to drag it up onto the truck.

 

This stymies me too. Typically when I want to roll a car out of garage to the driveway to wash or vacuum. Not sure about second gen, but with third there's around 10 seconds of EV grace period after start up, that can get you moved a few feet without start up, if you're quick about it.

The lack of Neutral when off can also confound things in pull-along style car washes. The latter are best avoided, or at least keep all accessories, AC etcetera off, for the duration, since the car can't charge in Neutral.

 

Towing and N are NOT the same, unless you are towing in READY and in N.

N is an active computer choice to net zero power in both Motor/Generator 1 and 2.

The Prius never shifts gears. R just spins M/G2 the other way to go backwards, nothing shifts.
P does insert a pawl into the gears so they can't move but otherwise is just like D.
B uses software to maximize engine braking while decelerating, but is otherwise just D.
N does not shift, the computers make sure no power goes in or out of either M/G, so the engine has nothing to push against.

If you could get to N without READY M/G2 would generate power when turned, but have no where to put it. Toyota (correctly?) thinks this is bad. Certainly they have promised First Responders that no high voltage will exist unless the car is READY, so Toyota would be lying if N was available out of READY.

(As and example on Page 19 of this manual https://techinfo.toyota.com/techInfoPortal/staticcontent/en/techinfo/html/prelogin/docs/3rdprius.pdf
"Positive and negative high voltage power cables connected to the HV battery pack are controlled by 12 Volt normally open relays. When the vehicle is shut off, the relays stop electrical flow from leaving the HV battery pack.

Both positive and negative power cables are insulated from the metal body. High voltage electricity flow through these cables and not through the metal vehicle body. The metal vehicle body is safe to touch because it is insulated from the high voltage components.")

 

Jimbo may have already explained this well enough. But if not, note that the Prius has no mechanical disconnect between wheels and drive system, so if the wheels spin, some motors or the engine must also spin. This is a very bad thing when towing.

Note also that on a normal automatic transmission car, you can't leave the car off in neutral and still take the ignition key away from the car. The key is held captive until the transmission is put in Park.

It is a safety requirement. N is how the operator disconnects power from a runaway engine to the wheels. Most runaway engines these days are caused by pilot error, not mechanical or electrical malfunction, but N is still a universal path to regaining control.

 

Yes, I carry a jump pack to jump others. No way I would risk the $4,000 repair bill for jumping wrong.

 

There's nothing wrong with jumping at the battery, except that it's more difficult. The under hood point is just handier. Just be really careful with polarity. Also: jumpstart should be considered for emergency only. If you're regularly jumpstarting something is wrong with that picture.

 

While not technically correct, that is still excellent advice.

The Prius has a smaller 12V battery than regular cars, in part because it doesn't need a 12V starter. It also has a 12V inverter to drive the electrical system, which seems to be more fragile than the alternator systems of traditional cars. This means that certain common jumpstarting errors that normally cause only a brief spark on regular cars, will kill a Prius and cause a many-thousand-dollar repair bill.

Numerous owners with dead jump-related Prii have been lucky and only blown the 'fusible link'. While more difficult and expensive to replace than a standard fuse, it is still far cheaper than replacing electronics. But not all cases are this fortunate.

A Prius ought to be able to jumpstart another Prius just fine, if done correctly. A very few members here who more fully understand the issues, have repeatedly jumpstarted regular cars too, some trucks even.

But I won't do it, as the cost of an error is so enormously high. And I have a feeling that there are certain other inter-vehicle electrical compatibility issues in a few instances that we don't fully understand. A portable jump box is much cheaper and safer. If pressured, I'd even pay for a stranger's service call out of my own pocket before I'd jumpstart from my Prius.

 

We drive around with Clore JNC660 jump pack in the hatch sub-floor tray.
It's kinda heavy/bulky, but under 5" thick, fits nicely.

 

I always freak out when the battery goes full green and I still have a long ways to go. Once though I did notice that the engine revved up when the battery hit full green.

 

If you use B from the summit, you may find you get much closer to the bottom before full green. The first time I used B, it was counter intuitive that the engine would be busier the harder I braked.