How long can you "sail" with a full battery?

I've wondered the same.

I just moved to my first house this week, and there's a completely flat 6 km country road that's always empty behind the house.
I'll try running there on the battery in the next couple days, post back here the results if there were no answers.

 

I wonder that too. I will be looking forward to your results.

There is a 4km (~3mi) stretch which I travel regularly. When I turn of from the fast road onto this small road the battery tends to be fully charged. The small road has some slopes but I can do a large part in "sailing" mode. Including braking and accelerating due to traffic. At the end the battery is nearly half full.

So I alway wonder how long I could go on.

 

in my 08, the furthest i was able to gostarting with close to full battery on flat road after getting up to 20mph with ice and staying at 20 on battery was about 1 1/2 miles before the ice kicked in to recharge, no heat, fan or a/c. i'll give it a try in the pip.

 

Hi everyone

I am preparing a long post about EV mode energy flow, so I can answer this question with my car data for a speed of 24Km/h (14.9mph).

First question to answer is: How much energy is available from the hybrid battery? From my own data, going from 60% SoC, which is the target SoC for a 2010 Prius with ICE running, to 40% SoC which triggers the ICE to charge the battery, some 874000 Joules (828Btu or 644630lb*ft) are available. This comes from a confirmed data of 550000 joules for 11%SoC discharge and some 36000 joules per 1% SoC discharge at the range of 8% to 12% differential SoC.

Where do the 874000 Joules of energy go to?

• Car standard electrical system. My car uses 330W in idle with LED lights on, NAVI, Radio, etc.

• Aerodynamic Drag. Using my data at an average speed of 24Km/h (14.9mph) and 610m (2000ft) elevation, the aerodynamic drag takes some 139W

• HSD Losses. It is the remaining electrical energy drained from the battery that is put on the HSD minus the mechanical energy produced by MG2 (and MG1). It changes a lot with the ambient temperature; from my car, at the stated speed, it is 344W for near freezing temperatures and 237W at 25ºC (77ºF)

• Tire Friction. It can be calculated using manufacturer data. In my car I am using Bridgestone EP100 RRC=0.0074 which I suppose is similar to the B250 Ecopia that fits my car. This may be adjusted to temperature using the information of this post Cold weather effects on tires | PriusChat The energy used in tire friction at the stated speed is 885W at near freezing temperatures and 784W at 25ºC (77ºF)

• Transmission Friction. It is the mechanical energy generated by MG2 (and MG1) minus the Tire Friction energy. Again, it changes a lot with the ambient temperature. At the stated speed, is 746w at near freezing temperatures and 624W at 25ºC (77ºF)

Now it is time to calculate the number of seconds that my 2010 Prius can move on EV at 24Km/h (14.9mph) and is:

· At near freezing temperatures 874000 / (330+139+344+885+746) = 357sec which equals to a distance of 2.38Km (1.48miles)

· At 25ºC (77ºF) 874000 / (330+139+237+784+624) = 413sec which equals to a distance of 2.76Km (1.71miles)

I will post the detailed analysis of the energy flow while in EV in some time in PriusChat. However if you want to read a pre-release post, you can find it in the Spanish forum. Below is the link for the English translation using Google.

Traductor de Google

I hope you like it

Big hugs from Frank

 

^^^ Great post Frank! Thanks for the info!

 

1.6 - 2.0 miles slight downhill grade with one stop light, 18mph- 32mph, during the summer - the SoC normally drops about 2% to 5% at the end of this road segment(*) after one initial pulse from 18-22 mph to 25 mph(using the ICE) . This road segment has gently rolling up and down hills with a slight overall downhill grade until the last 100 feet where there uphill climb to a stop sign. During this road segment, the Prius ICE is turned off and the Electric motors off most of the time or at minumum power. As long as I have a SoC greater than 58%(>=5 bars on the HSI SoC display) - I don't have to use the ICE for this segment. The tires are overinflated at 44 psi front 42 psi rear to decrease the rolling resistance.

(*) this segment starts at MD Route 97 Northbound by turning right into Prince Phillips Drive at about 18 mph-22mph. Once driving on Prince Phillip Drive, increase speed to 25 mph then shut off the ICE and coast with as little electrical power as necessary. Continue along Prince Phillip Drive until the intersection of MD Route 108 (this is about 1.6 miles) where there is a traffic light. You continue along Prince Phillip Drive crossing MD Route 108 at this intersection. If you are lucky , you can time the Prius with a green light so you dont have to stop you can continue - driving past a hospital until you get to a stop sign at Prince Phillip Drive and Spartan Drive (about 2.0 miles). Before the stop sign - allow the uphill climb to slow the Prius down naturally braking in the last 30 or so feet.