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HectorG

Charging PHV

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I frequently do journeys that only use about half the Battery or a tad less. On my return home I routinely plug the car in for a full re-charge. I think I’ve read somewhere that it may not be a good idea to repeatedly top up the Battery rather than let it flatten before re-charging. Any advice on this gratefully received.

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9 hours ago, HectorG said:

I frequently do journeys that only use about half the battery or a tad less. On my return home I routinely plug the car in for a full re-charge. I think I’ve read somewhere that it may not be a good idea to repeatedly top up the battery rather than let it flatten before re-charging. Any advice on this gratefully received.

According to the information that I've got, at least Prius PHEV gen 1 (as our 2015) can be re charged as often as You want, frequently, without flatten out and without Battery damage.

Not sure about the new 2019 though.

Looking forward to more answers from more experienced PHEV owners.

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I was advised, by my Salesman, that it doesn't hurt to always have the car on charge.

Like you, I do many 'short' journeys, always topping up.

I guess there's software on-board that 'helps'!

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The PHV's Battery capacity is 8.8kWh, but it's managed so that only 7kWh is usable. No need to worry about always topping it up, because it will never be technically 'full' anyway.

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2 hours ago, Ten Ninety said:

The PHV's battery capacity is 8.8kWh, but it's managed so that only 7kWh is usable. No need to worry about always topping it up, because it will never be technically 'full' anyway.

I understood that 8kWh is useable. But I stand to be corrected.

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The most I've been able to put in mine is just under 6.5 kWh, so that leaves just over 2 kWh of unused reserve capacity. 

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I thought I'd seen that 7kWh figure somewhere official, but I can't find the source now. If anything, I think that's probably overstating it. I charge from a 3-pin and don't monitor what goes in each time myself, but somewhere between 6 and 6.5kWh usable capacity would fit with the indicated average miles per kWh and actual EV miles travelled.

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2 hours ago, Ten Ninety said:

I thought I'd seen that 7kWh figure somewhere official, but I can't find the source now. If anything, I think that's probably overstating it. I charge from a 3-pin and don't monitor what goes in each time myself, but somewhere between 6 and 6.5kWh usable capacity would fit with the indicated average miles per kWh and actual EV miles travelled.

I’ve been achieving 4.3 miles/kWh recently and today had a range of 34.5 miles. Amazingly, that computes at 8.02 kWh.

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According to my Chargemaster schedule, over the last year the highest charge has been 6.1 kWh. I still need to delve into what the car gives.

Mind the latest bpchargemaster schedule is a load of rubbish (when did they change?) It has none of my charging taking place from 02:00 so I'll take the readings with a big pinch of salt.

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21 hours ago, HectorG said:

I’ve been achieving 4.3 miles/kWh recently and today had a range of 34.5 miles. Amazingly, that computes at 8.02 kWh.

How are you arriving at your 4.3 figure? And by 'had a range' do you mean the indicated range on startup, or actual miles travelled?

I only ask because on the last occasion that I managed to squeeze out 35 miles of actual EV driving, the MFD (reset just for that journey) was suggesting I was getting over 6 miles/kWh!

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Hi Paul, referring to your original post. When rechargeable batteries first came popular for “everything “ the instruction was to let a Battery run down before charging. This was because the batteries had a memory, and if you keep charging a Battery only partially used then it would memorise this and thus the Battery never worked to its full capabilities. Now, technology has improved the memory issue has gone, so it’s generally acceptable to only partially discharge a Battery before changing it.

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3 hours ago, Ten Ninety said:

How are you arriving at your 4.3 figure? And by 'had a range' do you mean the indicated range on startup, or actual miles travelled?

I only ask because on the last occasion that I managed to squeeze out 35 miles of actual EV driving, the MFD (reset just for that journey) was suggesting I was getting over 6 miles/kWh!

The 4.3 kWh was on the MFD. The range (34.5) was arrived at from adding the distance covered since full re-charge (from memory about 24) to the indicated range left.

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On my mk1 pip when the Battery gets down to about 1kW it exits EV mode into HV mode.  The last 1kW is still usable.  Maybe the mk2 is similar which would make the 7kW figure the EV range rather than the usable energy.

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On 9/30/2019 at 7:50 AM, altocumulus said:

Mind the latest bpchargemaster schedule is a load of rubbish (when did they change?) It has none of my charging taking place from 02:00 so I'll take the readings with a big pinch of salt.

Chargemaster data has always been iffy. YMMV

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2 hours ago, johalareewi said:

Chargemaster data has always been iffy. YMMV

They've changed the display. But it still only gives time cable connected and time cable disconnected - bares no relationship to actual charge time. I notice they now have an option to add a  tariff to work out price - but I guess it doesn't allow multiple tariffs nor takes account of price changes from a given date.

 

All I can say is I'm glad I'm not paying for it - and I won't subscribe once the 3 year period is up!

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2 hours ago, johalareewi said:

On my mk1 pip when the battery gets down to about 1kW it exits EV mode into HV mode.  The last 1kW is still usable.  Maybe the mk2 is similar which would make the 7kW figure the EV range rather than the usable energy.

Maybe - I still find it interesting the way it all works - once the EV mode is exhausted, there's still the ev part of the HV available. But once the EV is exhausted the car won't accept any harvesting unless the charge mode is activated.

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As the owner of a gen 4 PHV for about 5 months here is my two-pennorth.

We always top up when possible, irrespective of remaining miles indicated and no issues observed.

I believe the same 8.8  kWh HV Battery is used for both EV and HV driving, controlled by the on-board computer. In EV mode there is about 7KwH available (from full) which gives a theoretical EV range of between 35 and 38 miles (Actual range depends on driving style, terrain and temperature). I usually achieve about 30-32 miles before the HV kicks in. I have now got into the habit on long journeys (about 90 miles) of manually choosing HV for steep hills and city driving - The former uses Battery power at a frightening rate and hybrid mode is good in towns. I then use the stored Battery power for steady speed and wherever possible use the adaptive cruise control - it seems to be more economical than me (and it is so easy on A roads)

In EV mode the regenerative energy, from coasting and braking, is added back to the EV mileage. In HV mode the computer feeds electric support from the Battery as available and recharges on the fly. Note it maintains the EV part of the Battery if you change over manually to HV, but allocates all regenerative energy to HV driving. 

Finally the Charge Mode will keep the ICE running at all times and recharge the EV Battery up to about 25 miles EV range. This tends to add 1 mile per 1 mile travelled in HV mode but drops fuel consumption to under 50mpg. I have trialled it and it I have concluded it is a cost neutral gimmick unless you are going into a low carbon zone.

Since getting the car we have done about 6000 miles of mixed motoring and, by using EV wherever possible, are achieving an average of about 120 mpg.

I hope this helps

Tony B

 

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20 hours ago, HectorG said:

The 4.3 kWh was on the MFD. The range (34.5) was arrived at from adding the distance covered since full re-charge (from memory about 24) to the indicated range left.

Had you reset the consumption figure for that journey? I just can't square 4.3 miles per kWh with travelling 34.5 miles based on what my car tells me about my journeys. The MFD says  I've been averaging 5.5 miles per kWh in the summer, and 34-35 miles has been about my limit of real EV travel. However, we all know Toyota moves in mysterious ways when it comes to reporting consumption and range figures on the MFD, so anything is possible! 😄

6 hours ago, johalareewi said:

On my mk1 pip when the battery gets down to about 1kW it exits EV mode into HV mode.  The last 1kW is still usable.  Maybe the mk2 is similar which would make the 7kW figure the EV range rather than the usable energy.

It will be the same for the PHV but I think there's still going to be a chunk left unused for longevity. Ancient Nerd measured 6.5kWh going in, but there's charging losses to take account of which would probably bring that below 6 in terms of actual Battery charge. Add the extra for HV mode (I'd guess around 0.7kWh based on the US Prius Gen4 ordinaires with li-ion batteries) and that's still not more than 7kWh in total available to use across EV and HV. 

That 'feels' about right based on the distance I can travel. Even allowing for my MFD electricity consumption figures to be as overstated as the MFD mpg ones are, if the 7kWh was just for EV mode than I'd routinely be getting 36-38 miles of actual travel. However, I've actually only passed 36 miles maybe once or twice. 

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3 hours ago, Ten Ninety said:

Had you reset the consumption figure for that journey? I just can't square 4.3 miles per kWh with travelling 34.5 miles based on what my car tells me about my journeys. The MFD says  I've been averaging 5.5 miles per kWh in the summer, and 34-35 miles has been about my limit of real EV travel. However, we all know Toyota moves in mysterious ways when it comes to reporting consumption and range figures on the MFD, so anything is possible! 😄

 

I didn't reset the MFD for the journey. I will try that next time. I'm still trying to get my head round all the data available and how to harvest it.

I'm quite impressed with the mpg since I returned from my long trip to Newcastle to pick up the car - 629.3 mpg over 715 miles with 93% EV ratio. It would seem the PHV is ideal for my normal daily use with my camper used for long journeys and holidays.

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@HectorG

I've used the Charge mode to go from zero to 12 miles, on a journey from the Harris border to Stornoway, using a long downhill stretch to advantage. The onboard figure still gave me over 80MPG for the journey. I've noticed, by experience, using longish downhills can be useful!

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3 hours ago, altocumulus said:

...using longish downhills can be useful!

even in an ordinary Prius!  It takes quite a long time (and a while after the top gauge bar lights up) to fill the HV Battery to a point that it refuses to accept any more regen, The first time I encountered it (after 50,000 miles without even seeing all bars lit) and it took some 4 miles going down a 20% gradient.  When reaching level ground the car behaved like an EV as the Hybrid system desperately tried to use up the energy and make some space.  There was no EV button on this model but for a while I could accelerate to about 60 mph without the engine starting.

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On 10/2/2019 at 11:16 AM, PeteB said:

...as the Hybrid system desperately tried to use up the energy and make some space. 

Those were the days.  Mine would even spin the ICE when stationary to burn off the extra HV.  Now I have the PIP i can see how much charge is generated by the same hills that maxed the gen3 out.

 

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On 10/1/2019 at 7:58 PM, Ten Ninety said:

Had you reset the consumption figure for that journey? I just can't square 4.3 miles per kWh with travelling 34.5 miles based on what my car tells me about my journeys. The MFD says  I've been averaging 5.5 miles per kWh in the summer, and 34-35 miles has been about my limit of real EV travel. However, we all know Toyota moves in mysterious ways when it comes to reporting consumption and range figures on the MFD, so anything is possible! 😄

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(Cocked up quote above)

This is my second response: I’ve  now discovered another layer to the MFD giving miles per kWh on a daily and monthly basis!

Now I’m more used to driving the PHV I’ve increased my miles/kWh score to be consistently above 5. The last few days I’ve been getting 5.2/5.3 and on a couple of days I’ve achieved 5.6. I’m not sure how  accurate these figures will be because, even if only 7kWh is available that computes to a range of 39.2.......or am I missing something?

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20 hours ago, HectorG said:

(Cocked up quote above)

This is my second response: I’ve  now discovered another layer to the MFD giving miles per kWh on a daily and monthly basis!

Now I’m more used to driving the PHV I’ve increased my miles/kWh score to be consistently above 5. The last few days I’ve been getting 5.2/5.3 and on a couple of days I’ve achieved 5.6. I’m not sure how  accurate these figures will be because, even if only 7kWh is available that computes to a range of 39.2.......or am I missing something?

That's much closer to my experience. I expect the onboard miles per kWh figures are overestimated by a small margin, probably similar to the mpg readout optimism. Still, I don't believe we have 7kWh available for EV mode - at best that figure would includes the HV Battery range as well, like Alan suggested above. The highest estimated range I've seen is something like 42.5 miles after extended periods of summer driving with no heat or air-con but I've never seen anything like that in reality - somewhere around 36 miles has been my best.

However, that was enough for me to achieve my 'holy grail' in August this year after many attempts - my entire commute both ways (~65 miles) completed with a readout of 199.9mpg. If only I could get a charge point at work - then I might have a go at matching your 629mpg!

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