Birdlip Hill, Gloucestershire

[Chris Macnamara]

For anyone who knows it, it's a really big hill rising up steeply to a roundabout, where it switches back to go a similar upwards distance to the top, then plateaus. All in, I guess it's a little over a mile long.

If I had a full charge of Battery at the bottom, and put my soon to arrive gen 3 Prius into EV mode, and if I went slow enough, could I get to the top, without having used any fuel? Not that you'd do that on this section of road, as you'd cause a massive pile up.

Then, if there was a similar hill downwards immediately after, could I roll down it, and fully charge up by the bottom??

Cheers

Chris

[Jan&tone]

IMO unlikely. - if your engine was fully warmed up and with a full Battery, as soon as you put any pressure on the gas pedal to help you up the hill your ice would start up. You would definitely get round the roundabout on EV only, but again going up the second hill the ice would start.

This is only my opinion based on 2.5 years with a gen2 and nearly a year with a gen3. Others may have differing opinions.

As far as the downhill stretch goes, on a gen2 yes you would fill up the Battery, but the gen3 charges less when coasting downhill (by coasting I mean in drive but no pressure on the gas pedal). The gen3 seems to charge more with the brake depressed than the gen2 did, and less than the gen2 when coasting.

Tone

[Terry953]

For anyone who knows it, it's a really big hill rising up steeply to a roundabout, where it switches back to go a similar upwards distance to the top, then plateaus. All in, I guess it's a little over a mile long.

If I had a full charge of battery at the bottom, and put my soon to arrive gen 3 Prius into EV mode, and if I went slow enough, could I get to the top, without having used any fuel? Not that you'd do that on this section of road, as you'd cause a massive pile up.

Then, if there was a similar hill downwards immediately after, could I roll down it, and fully charge up by the bottom??

In a nutshell NO - I know the Birdlip and it's a pretty challenging hill, if fact I think in any situation the engine would start to prevent the Battery getting too low anyway.

You have no control over the engine as it's controlled purely by the computers, about the only control you have is when you first select EV to prevent it starting but it will override that if the Battery discharges or your speed goes over the 20mph [for an Auris].

The recharging is very rapid, I was amazed the first time I studied it how quickly it re-charged, forget about comparing it to a normal car alternator or mains charger its in another league.

Have fun TerryB

[Seamaster73]

Even the ramps in a multi-storey carpark are enough to kick the Auris HSD I've got on loan out of EV mode.

[DrCez]

If I had a full charge of battery at the bottom, and put my soon to arrive gen 3 Prius into EV mode, and if I went slow enough, could I get to the top, without having used any fuel? Not that you'd do that on this section of road, as you'd cause a massive pile up.

Then, if there was a similar hill downwards immediately after, could I roll down it, and fully charge up by the bottom??

The concept is okay but the Battery on the Gen 3 Prius is a few orders of magnitude too small to manage the climb.

To try to give an idea of what it can manage: on my daily commute I descend into a valley, which typically gives the Battery a full charge, and then climb up the other side in slow moving traffic (at about, say, 10 mph). Usually the Battery is down to 2 bars (at which point the engine kicks in) by the time I reach a roundabout (Aberdeen's notorious Haudigan); according to the map this is a vertical climb of about 25 m.

If I enter a multi-storey on full charge I can probably manage to ascend a maximum of 4 or 5 levels before the battery runs low - in the same ball park as the 25 m climb mentioned above. I tend not to use EV mode - I find it kicks me out for all sorts of reasons so I get on better by keeping the acceleration low enough to stop the petrol engine kicking in.

I don't know Birdlip Hill but I've had a look online and it looks like the A417 climbs about 140 m to the roundabout, and almost 200 m to the very top. Faced with that sort of climb I'd forget EV (and mpg) and try out the PWR button When it arrives, the plug-in Prius might stand a chance so it would be interesting to see how that got on with Birdlip Hill, although I don't know if it would be able to go fast enough for the other traffic in EV.

Recharging is not symmetrical - i.e. the car needs more than a 25 m vertical drop to fully charge. Anecdotally I think my car will fully charge coming down one particular hill which has a vertical drop of about 75 m. That said there are a couple of roundabouts including one at the bottom so it might charge up more efficiently if the car could coast more (I'm on the brakes all the way and almost at a standstill for the roundabouts). So if you can coast/brake and avoid the accelerator you'll easily charge up coming down Birdlip Hill - in fact I'd imagine you'll get the extra bar at the very top of the battery to light up which is something that only happens on long hills as the car will try to get rid of excess charge before that happens. It might even be a candidate for using the "B" position on the gear selector, something which I very rarely get to try out.

[CO2SLAVE]

Hi Chris ,

I think I get where you are coming from on your question , but I think the main point worth mentioning here is that the conversion of kinetic energy into HV Battery power is only about 50%

efficient so in theory if started with a flat Battery you went a mile down a 15% decline you would only then get halfway back up the same 15% incline before running out of Battery power.

As regards using EV mode they are times when it is useful like when moving your car a short distance but in general it is better to let the computer in the car decide when to deploy the battery power.

there is already a thread on this subject that was started when I was wetter behind the ears :)

http://www.toyotaownersclub.com/forums/index.php?showtopic=126336

[bobm]

Hi, I know BIRDLIP very well and in my Gen3 there is no way you could use the EV mode to climb it and bearing in mind the speed limit is for 60, just put it into power mode and see it 'fly' up there On the way down I always place the car into B mode and it controls the descent in a very good way and of course recharges the Battery totally.

[MichaelM]

Going DOWN Birdlip was the first time my Gen 3 Prius showed 100% charge on the hybrid Battery.

i.e. EVERY bar was full on the Battery charge indicator.

[flow]

Forget EV mode going up Birdlip - Power mode eveytime for me. Even first thing in the morning when it oftens clogs up, in start stop traffic, its still hard to make much use of ev mode due to the incline.

You'll be surprised how much power & torque is available in Power mode though.

[Thrawn60]

Even the ramps in a multi-storey carpark are enough to kick the Auris HSD I've got on loan out of EV mode.

Yeah, I have the same problem when I stayed in the other condo. Was parking on 6th floor, so each time I went "uphill" the ICE would start, then shut down once I was up, and restart again... was wondering if it would damage the motor since I would not consider it normal driving.

Any one knows if excessive multi-storey parking lot driving is bad for the car?

[sjrainsford]

Even the ramps in a multi-storey carpark are enough to kick the Auris HSD I've got on loan out of EV mode.

Yeah, I have the same problem when I stayed in the other condo. Was parking on 6th floor, so each time I went "uphill" the ICE would start, then shut down once I was up, and restart again... was wondering if it would damage the motor since I would not consider it normal driving.

Any one knows if excessive multi-storey parking lot driving is bad for the car?

I'd doubt it's bad for the car. The engine stops and starts much more than you think, even at very high speeds where you can't often feel it. The only way you can often tell is that you can feel a slight kick as the engine fires back up. It's very inclined to stop especially when going down hill.

[Terry953]

I'd doubt it's bad for the car. The engine stops and starts much more than you think, even at very high speeds where you can't often feel it. The only way you can often tell is that you can feel a slight kick as the engine fires back up. It's very inclined to stop especially when going down hill.

Absolutely - For Auris owners watch your 'Energy Meter' to see what is driving your car at any second, you'll notice the engine cuts in and out like a fiddler’s elbow :D

[sjrainsford]

I'd doubt it's bad for the car. The engine stops and starts much more than you think, even at very high speeds where you can't often feel it. The only way you can often tell is that you can feel a slight kick as the engine fires back up. It's very inclined to stop especially when going down hill.

Absolutely - For Auris owners watch your 'Energy Meter' to see what is driving your car at any second, you'll notice the engine cuts in and out like a fiddler’s elbow :D

If it's the same as the Prius energy display, then that's not quite true. They only tell you what work if any the engine is doing, not actually whether it is actually running or not.

[Cyker]

Is it the Battery or the electric motor that's holding it back?

Could the electric motor push the car up the hill on its own? What's the torque and HP ratings for it?

[sjrainsford]

There are two electric motors, the one that drives the car in EV mode however runs out of puff when just over 20mph. It will get you over 30mph but that would be on the flat. It struggles on inclines.

[Jan&tone]

There are two electric motors, the one that drives the car in EV mode however runs out of puff when just over 20mph. It will get you over 30mph but that would be on the flat. It struggles on inclines.

Once the ICE is warmed up you can easily do 29 or 30 on EV, if conditions are right you can also do up to 70 without using the ICE too!

There are several places on the m25, m3 and A3 where I've done just that with the cruise control on....

And don't forget those interminal queues at Dartford going north approaching the tolls, I once did the whole journey from the M20 junction to the tunnels without the ICE coming on once... Pushed the consumption figures up nicely too!

[Thrawn60]

Even the ramps in a multi-storey carpark are enough to kick the Auris HSD I've got on loan out of EV mode.

Yeah, I have the same problem when I stayed in the other condo. Was parking on 6th floor, so each time I went "uphill" the ICE would start, then shut down once I was up, and restart again... was wondering if it would damage the motor since I would not consider it normal driving.

Any one knows if excessive multi-storey parking lot driving is bad for the car?

I'd doubt it's bad for the car. The engine stops and starts much more than you think, even at very high speeds where you can't often feel it. The only way you can often tell is that you can feel a slight kick as the engine fires back up. It's very inclined to stop especially when going down hill.

Ok, I will keep driving there then :) and true the ICE does go on and off all the time, just thought when it was every 15 sec, then it might strain some components.