Cars-in-Bars Photo Throwdown: Show us your PiP’s Max-Regen!

The screens above say that each symbol = 30wh. The screens on the previous page show each symbol = 50wh.

 

1 minute vs 5 minute tracking. The head unit shows E's for each minute, the Dash display can show 5 minute clumps at 50 or 1 minute clumps at 30.

 

Ok, I never have the 1min. screen up.

 

This was from the descent from Great Smoky Mountain National Park...went from 0 to about 9 miles of charge

 

wow, sweet! welcome to priuschat, all the best!

 

Nice! That's not possible with a regular Prius for sure.

 

Very cool! What was your approximate total drop in elevation?

 

Looks like it was about 4,000' total drop in elevation, over about 20-25 minutes.

I'm betting no one else on the road was getting "cash back" on the way down...

 

Just got back from Sequoia National Park and was able to do my first complete regen coming down highway 180 into Fresno. I started down at 6,000' and charge was complete at 3,000'. I averaged 40-45 mph during the descent. Even without the descent, just driving within Sequoia with the PIP is great as I had occasion to regen 5 miles on a couple occasions dropping from 7,000' to 5,500'-6,000'. Except for when snows, this is a great car up in the Sierra.

 

Obviously doing this every once in a great while probably wouldn't do anything but I wonder what the battery life span would be that did this everyday.

 

There's another UK difference - we get different icons to you - we get full or half capital Es for some reason (the car icon is still used on the non-PiP AFAIK.

 

Yeah, would be nice to get some input from Toyota on this. Certainly it is faster charging than level 2 but slower than supercharging a Tesla. Of course, this is not a Tesla and the batteries may not be designed to do this routinely.

 

Does anyone know what percent of capacity the standard Prius traction battery utilizes? I ask because this battery seems to be routinely subjected to a higher percentage of capacity rapid regeneration from braking than the PIP battery. That is to say, just stopping from 45 mph could fill a large portion of the standard Prius battery but a small portion of the PIP battery. Related to this thread's discussion, I wonder how good this is for the long term life of the PIP battery when achieving repeated max regeneration down mountain roads.

It looks like the non-PIP model is about 1.3kWh and the PIP is 4.4kWh. Does the standard Prius use a smaller percent of its battery capacity because it appears to be able to drive on electric mode for a smaller distance than the proportion suggests? If this is so, that would make sense to protect the standard model from very frequent rapid regeneration cycles.

 

Also, the non-PIP battery is NiMH, not LiON. So it is doubtful that a meaningful comparison can be made

Mike

 

Different battery chemistries, yes, but both are adversely affected by deep discharge cycles. Li-ion has little to no "memory effect" so in some ways its performance may be better here. So it's not a perfect comparison, but there is probably some useful information here.

 

The standard Prius NiMh battery uses from 40% to 80%, so usable 40%. PiP Lithium uses 23% to 85%, so usable 62%. At 23%, PiP switches to hybrid mode and the regen ability is more than a standard Prius. When PiP battery is nearly full, it's regen capability is limited. I think it needs to get down to 75% SOC to start the maximum regen capability (absorb faster than standard Prius).

The standard Prius NiMh battery was tuned for high power. This allows a lot of power discharge and recharge quickly. The trade off is the ability to hold less energy. RAV4 NiMh EV battery could hold more energy because it was tuned for high energy. So, don't worry about the life of NiMh battery from the regen. Toyota designed/sized it so it last beyond the warranty period.

 

What are your thoughts on routine rapid regeneration recharges on the PIP such as going down mountain roads on a daily basis? On the discharging side, it seems this can't be too bad for the battery. For some PIP commuters, they routinely discharge their battery very fast - for example, at 60mph on the freeway, you could do a complete discharge in about 10 minutes. That's faster than a complete regeneration down a mountain road. Does regen produce more heat than discharge? Either way, Toyota probably though about this and designed the battery software to protect it.

 

Given the capacity of the PiP PHV battery, it regens and discharge slower than a standard Prius. There is no concern there and the supplier (Sanyo) designed the cell per Toyota specification.

PiP: 40kW from 4.4 kWh battery is about 9C.
Prius: 27 kW from 1.3 kWh is about 20C.

So a standard Prius can discharge at the rate twice faster than PiP.

Regen should produce more heat than discharge but PiP has two battery fans (and two intakes from the cabin) instead of one. Lithium generates less heat than NiMh. 3x more capacity with 2x cooling.

Ford is using the same cells from Sanyo for their Energi plugins. The difference is they use deeper charge/discharge cycle than PiP. They are using about 80% depth (6kWh out of 7.6kWh) while Toyota is using 62% (2.7kWh out of 4.4kWh).

Honda Accord plugin is using only about 50% depth (3.2kWh out of 6.7kWh). However, it is different chemistry that allows 1 hour full recharge.

 

Just wondering, is Honda using the same LiIon chemistry as used in the batteries on the Boeing 787, which is subject to thermal runaway unless carefully managed?

 

Yup, the same battery supplier to Boeing, Honda and Mitsubishi. Mitsubishi already has recalls for battery overheating. I wonder if Honda would need to do recall for their Accord Plugins.