Whats the most efficient way to hill-climb??

I suggest trying to keep the instantaneous MPG (iMPG) at least half the vehicle speed. This generally will keep ICE (internal combustion engine) RPM within efficient ranges across a wide range of speeds. See this for more.

On steeper hills, you will lose speed with this. Safety is my first priority, so if I need to push it harder to avoid creating a hazard, then so be it. Part of my hypermiling strategy is seeking routes favorable for hypermiling, which includes those with lighter traffic where lower speeds are better tolerated.

Part of optimizing fuel economy in hill country is efficient hill descent. See this discussion, with particular attention to gliding and "warp stealth." To the extent it is safe and avoids speeding tickets, I optimize my downhill runs by gliding or WS to allow momentum to partially carry me up the next uphill. Then when possible and if needed I let speed decay on the uphill -- assuming I can keep the ICE within efficient ranges -- to allow full use of glides or WS on the next downhill.

Bottom line: keep the ICE within efficient ranges going up, allow full use of momentum going down.

 

Living in Arkansas we have many hills here. Some are subtle and low grade, some are outright steep. I know this may sound silly but I try to use as much momentum going into the next hill as I can, I get up to speed and keep my mpg around 50 if possible to maintain that speed. I then coast halfway down the next hill, then start building up speed for the next one.

It absolutely kills my mpg! I swear whoever designed the roads and lights in my town works for big oil. Go up a big hill, lets put a light halfway down to ruin your momentum going up the next big one. I have changed my commute to go up steep short hills, and down long hills for more coasting, this has helped my mpg a bit.

Before driving a Prius, I never realized how many hills are in the area, or how steep they were.

 

Maximizing MPGs on hilly terrain is a subject with several sub-points to discuss. I'll refer to two of them here:

First, if you are this serious about maximizing MPGs, then you probably practice P&G once in a while, and perhaps even "super highway mode" (a variation of P&G, but at highway speeds where the engine doesn't shut off). I'm not sure about specific RPMs, but the general theory is that you should take advantage of the ascending hill climb to conduct your "pulse", and the descending portion as your "glide". There may be an optimum RPM, but I think it would depend upon the ascent grade and your speed. I would just concentrate more on the MPG readout than the RPM, but also keep the RPM reasonable (never go max throttle unless you absolutely must).

Second, on hilly terrain you also want to consider management of the battery state of charge. When approaching a familiar hill, and you know that the following descending portion is relatively steep and/or long (forcing you to brake and charge the battery a good bit), then I would lay off the accelerator just before you reach the top and try to discharge the battery a little in anticipation of a whole lot of charging. The objective here is to try to avoid the condition of hitting the max charge cutoff of about 81% in the battery. Continued braking beyond that point will be completely wasted energy.

 

What part of Ark? Based on your post, I'm guessing somewhere in the west. I'm in Pickles Gap, near Conway.

 

SHM has its uses but hilly terrain like the OP asks about is not one of them. SHM uses just enough ICE power to barely keep the ICE under load, which on level terrain involves an ever-so-gradual speed decay. A detailed discussion of SHM is found here.

 

I understand your point. But SHM, or whatever you want to call my version of it, can be very useful on highways with moderate rolling hills. There's a lot of rolling hills on the highways here in San Diego. On the flat stretches, I use SHM just as advertised elsewhere. But I do it with anticipation of the next hill such that I'm always finishing up a "low throttle" stretch just before beginning an ascent, then I use the ascent for the "high throttle" portion. I strive for a steady throttle position that will leave me going about 5-10 mph faster when I reach the top, then I immediately adjust the throttle so that during the descent I actually lose 5-10 mph by the time I reach the bottom.

I find that this method yields higher MPG than either trying to maintain a steady speed or trying to maintain a steady throttle.

 

http://priuschat.com/forums/newbie-forum/37699-priuschat-glossary.html

Have you seen this link? Maybe it will be helpful to you.

 

See the links I provided.