Energy Dump?

Evan:

I don't quite get understand one thing. What can I do driving down a long hill to avoid charging the battery to the point of having the engine cycle on/off when I stop at the red light at the end of the hill? What and how would I use the energy wasted by the on/off ICE cycle.

Ah, coasting down the hill in neutral would avoid excessive charging, but then we get into the argument of whether it's good or bad to coast in neutral. :mrgreen:

 

a large hill might be better to coast at least part of the way in "B" mode. although toyota does warn that B mode should only be used for short periods at a time.

 

but what is the no arrows mean??

that mean the car is using power out of thin air?

or is it simply a level of power that sits in the transition area where regen, battery and ICE meet?

obviously the power must come from one of these sources. and you must have some petal pressure on the gas to achieve this so the power is most likely coming from a combination either one depending on whether the power demand is going up or down.

i think the no arrow mode is just a bug in the display.

 

if you look at my post about interesting results
http://www.priuschat.com/forums/viewtopic.php?t=3506
you will see when the battery gets to 80% full charge you can't regen any more but if you put it in B mode you get a current draw of 18 amps and the bsoc slowly sinks.

 

i know the SOC display's range is from 30-70% but i didnt realize that a 100% charge was not possible. i figured to prevent overcharging they would cut it off at a higher level than that like 90-95% i would think.

i know that for charging purposes, exact rates arent possible because to many physical conditions affect the effective charge rate including temperature, humidity, etc. but i would think that they would be able to get closer than that since everything is controlled by the computer, i would think that the computer would monitor outside influences and be able to charge higher in the usually rare cases of a large downhill.

although in another sense, i can see toyota's rationale for not wanting to take chances with overcharging since extremely dry conditions could easily increase the charge rate considerably. i guess they wanted a maximum safe margin in all possible weather situations.

still a slightly larger battery would be nice...(if i keep mentioning this in every post, do you think they will get the hint?)

 

no

 

There is not any chance to practice techniques involving the accelerator.

The accelerator is only lightly touched in the tunnel. It is never touched from the tunnel exit until leaving the traffic light at the end of the off-ramp (and even then, just enough to hit the peak of a small rise 50 feet past the signal). There is not much chance to practice anything except holding off on braking. Even then, I am usually braking only for control on the slight curves or to fit in the traffic flow (did I mention the lightly used onramp from another freeway just before my offramp?).

 

just a thought on the use of extra battery capacity, if you pull down the larger battery and then have to run the ICE longer to get it changed to the point where the computer will allow the vehicle to go into hybrid mode, you have used the extra fuel to achieve your results of having more capacity. For most usage the current setup seems to be well thought out. There will always be exceptions to this but for the most part and most users I doubt that another 3-4,000 dollars worth of batterys will be justified

 

Toyota is concerned about balancing marketability with efficiency. How much will the average buyer pay to get the advantages provided by greater battery capacity?

Some folks are willing to invest more capital on acquisition in order to achieve greater efficiency. The average buyer is concerned with the market cost:benefit ratio. But techno-geeks and environmentalists are more willing to spend more money for efficiency. I'd probably spend a few grand and give up a little cargo space in order to get an additional 15 mpg, if I felt comfortable about service and warranty issues.

But this does not sound like a DIY project for people like me. Clipping on a few wires and inserting a pin is one thing. Installing a few cubic feet of battery and all the necessary control aparatus is quite another. I'll probably just have to hope it's an option on the next generation Prius.

 

Danny pretty much hit it on the head...

i wouldnt consider it a viable option for aftermarket battery capacity. modern cars today simply dont allow that much extra room for something that heavy or large. now lets face it. the battery pack for the Prius isnt very large.

it would be much easier from an engineering viewpoint to make the existing pack larger than it would to provide connections to hook up two battery packs. i have examined the existing pack and one thing i quickly realized is that the battery pack in order to be safe is an expensive project. the wiring, connections, insulation, etc is a lot of money. all those would have to be duplicated.

a do it yourself system would be flirting with disaster for 90% of the people out there. not to mention how would you be able to effectively incorporate it into a system that is so tightly and well controlled by computer??

i'd rather have Toyota do it and i feel confident that the new 2007 model will have the extra battery capacity option. Look at the Prius. its very design has tried to make it a no compromise solution. i see AC outlets and an upgraded battery pack running about an extra $1000-1500. ( i dont think the market will bear any more and i think that not duplicating all the hardware mentioned above will make this price attainable)

but i strongly believe that there is a market for greater battery storage. so if Toyota doesnt do it, then an aftermarket company will. also, i priced so high quality NiMH batteries similiar to the Toyota battery pack and even if going top of the line, the cost is a very reasonable $800 to double capacity (or replace the existing pack) obviously the battery pack in the Toyota cost much more than that. (the case is probably worth $300-500 by itself)

also keep iin mind that according to Toyota, not overcharging or draining the battery pack adds 300-500% to the life expectancy of the battery pack, so it aint the batteries... its the computer.

ive yet to hear of a battery pack failure, has anyone heard of one?? there is a Vancouver BC taxi cab a 2001 Prius that was featured on a discovery channel segment that had 230,000 miles on it this past spring and its maintenance costs were 45% lower than other vehicles in the fleet. (in a caveat to Toyotas commitment to customer satisfaction, the show stated that the 2001 wore out tires at nearly double the rate of the fleet. maybe that is why Toyota changed the tire on the 2004)

 

I wish Andrew Grant the owner of the Prius Taxi in Vancouver was an active participant on PriusChat, and I've told him that but he's very active on Yahoo and has in's to Toyota. Not that, that means a lot, but he's very knowledgeable and personable and has a wealth of Prius knowledge. He's currently on his 3rd Prius, a 2k4 after taking his 2nd, a 2k3, and making it his personal car, his first was retuned to Toyota in Japan for tear down and inspection.

 

oh bummer.... i wanted to see him hit 300,000... guess it will have to be another car...

oh well... the perfect acid test for the battery pack is now laying in pieces in a toyota lab.

but that is typical of Toyota...im sure they will learn something as they always seem to.

i can easily picture an american car company wanting to take a great performer like that and putting it in a museum so as to have proof that such a car existed...

 

Toyota has promised him a complete technical report on wear and such but it's been a couple of months since I've personally talked to him, so don't know for sure what has transpired.

 

keep us posted!!!

that would provide a huge incentative for people wary of new technology~!