D.O.E. Long Term Hybrids Test

[lolder]

Here's a site about Department of Energy tests on hybrids: http://avt.inl.gov/hev.shtml The FFH is included and is in the early stages of their 160,000 mile tests. It appears that the FFH HVB charge/discharge efficiency is 90-92 % if I read the data correctly. That's compared to the 2007 TCH 65-81 % and the 2010 Prius 86-89 % efficiencies. Lots of information here.

Edited March 23, 2010 by lolder

[flavius]

You forgot the link.

[lolder]

Ooops.

[Oman]

I find the Prius fleet mileage numbers bizarre compared to the others. There is a huge drop and then recovery, while the others show a temperature related drop.

 

Jon

 

 

Ooops.

[lolder]

The 2010 Prius and FFH fleet mileage charts don't look like they have many data points and the Prius ones are certainly more erratic. Even the longer term 2004 Prius data is pretty erratic until smoothed. I think we have seen even with the FFH that the higher the mileage is, the more erratic it is because little things start to mean a lot. I find the most interesting fact to be that the mileage doesn't deteriorate with battery deterioration which fits with the understanding of a hybrid. Acceleration, yes but only flat out. The battery deterioration with age of newer technology seems to be much less than measured in the gen. I Prius and even there didn't affect the mpg. That tends to argue against the necessity for arbitrary battery performance targets that the study sets. It's clear that the most important quality is that the HVBs don't have an open circuit failure mode and that seems to be very rare.

[Oman]

I think what this shows is that the manufacturers are (I think rightly so) sizing the battery capacity such that there can be the expected loss of storage capacity over the expected lifetime of the vehicle without harming the mileage towards the end of life. They could shave a few $$ and save a few pounds if they minimized the battery but the savings for the operator would quickly reverse as the vehicle aged. I think that they know both the buying public and the government would be unhappy with that so they are doing it right.

 

Jon

 

 

The 2010 Prius and FFH fleet mileage charts don't look like they have many data points and the Prius ones are certainly more erratic. Even the longer term 2004 Prius data is pretty erratic until smoothed. I think we have seen even with the FFH that the higher the mileage is, the more erratic it is because little things start to mean a lot. I find the most interesting fact to be that the mileage doesn't deteriorate with battery deterioration which fits with the understanding of a hybrid. Acceleration, yes but only flat out. The battery deterioration with age of newer technology seems to be much less than measured in the gen. I Prius and even there didn't affect the mpg. That tends to argue against the necessity for arbitrary battery performance targets that the study sets. It's clear that the most important quality is that the HVBs don't have an open circuit failure mode and that seems to be very rare.

[spacenomyous]

I can't find it anywhere on the net, but I saw or heard something to the extent that in the New England area, (New Hampshire or Connecticut, if I remember correctly), has a sales law that a hybrid vehicle's battery has to last the life of the car.

[acdii]

The thing about the Batteries is simple. They discovered that if a battery has a charge/discharge rate of between 40-80%, they last a VERY long time, which means they last the life of the car. You can thank NASA for this. They have satellites in orbit for decades that run off batteries and solar. The key is keeping the charge under 80%, and the discharge above 40%. The Hybrids do the same thing, so battery life is greatly extended. Also the more the battery is used, the longer it will last.