Battery drain climbing hills?

Well I just got back from a road trip, Edmonton to Vancouver and back. Took the Coquihalla From Kamloops to the coast, notorius for some very long steep grades.

So I've heard rumors of the battery being drained when climbing steep hills and I was curious to see this for myself, being my first venture outside of the prairies with my new prius.

On the way home the roads were clear and dry so I set the cruise on 120kmh all the way back to Kamloops. On some of the steep climbs i took a glance at the energy indicator and noticed that most of the time on the really steep climbs the cruise had no trouble maintaining my desired speed and rather than pulling power from the battery to assist the ICE on the climbs, the ICE was charging the battery 90% of the time while still pulling me and my luggage at a steady 120kmh up the mountain. At the same time I had instant fuel economy displaying on the HUD and it rarely showed more than 15l per 100km in fuel consumption on the steep climbs. The Battery never lost more than 3 bars on the display from full. It actually went to full charge more often on the long descents.

So what is this battery drain that some speak of? Is it only at very low speed on steep grades?
From what i've seen, even driving up some of the steep hills around vancouver the ICE appears to do the majority of the work, powering the electric motor and charging the battery at the same time as needed to keep an optimal charge level.

 

Just got back from a trip edmonton to vancouver. Lots of mountain climbing along the way. I found if I drove 70+ mph on cruise up a steep grade the ICE would charge the battery while maintaining cruise speed. If I kept my cruise speed at 60 mph climbing those same grades the battery would switch more often to assisting the ICE. In all cases the battery level never drops below halfway on a climb no matter how steep it is and how hard you floor it.
From what I've read the battery drain was a problem on the gen 2 prius. The software has been improved for gen 3 which eliminates the battery drain under heavy load. The more powerful 1.8l engine probably helps too. It seems quite capable of pulling the car up the steepest grades on its own if it has to.

 

Having just recently moved to Vancouver I can confirm hill climbing has nil effect on battery SOC. the 1.8 seems to have enough grunt to haul itself up the north shore mountains without hardly any battery assist.
What I do notice is rush hour traffic really drains the battery more than anything! Got stuck in some traffic yesterday evening on my way home from downtown. driving in normal mode, the car insisted on using up the battery till it got down to 2 bars, at that point I was back on the highway for a bit so it charged back up.
Little concerned this may shorten battery life, yet not much I can do about it I suppose besides avoiding heavy traffic areas when possible. Wish the toyota nav had a traffic avoidance feature!

 

I am continually amazed at this car and how everything works together so smoothly and efficiently, despite all the electronic wizardry going on under the hood as you drive along.
The beauty of it all is as you say, the driver does not have to worry about any of it, the car does what it needs to take care of itself, just drive. I like that.

 

Ah I believe you are in the US where Toyota has Entune with traffic alerts?
No such thing on Canadian vehicles.
I suppose I can just use my iphone or garmin unit for nav which has traffic. Just would be nice to have the function in the built in unit as its otherwise pretty nice to use.
I notice there is a traffic function displayed in the options in my display audio nav but it is greyed out. Maybe a future option Toyota Canada may implement?