EV range

Martyn1981

I don't follow your concern.

Let's say you are charging the car slowly (little bit less efficient), and the charging losses added to the discharge and motor efficiencies means only 85% of what you bought reaches the road, that upsets you.

But if you buy a litre of petrol, only 20% will drive your wheels, and you're fine with that?

You seem to be focusing on one single element, in an attempt to push a negative, whilst ignoring all of the negative efficiencies from FF's.

How do you feel about GCH? You only get about 80-90% of the energy from the gas you buy to heat your house, whilst you're eating your cornflakes in the morning. But an ASHP or A2A units will give you around 300% heat (seasonally averaged) for your leccy input. Nothing is simple, hence why you need to weigh up all plus's and con's, not just cherry pick one.


Right - Let's start at the wind or PV farm, including transmission losses, distribution losses, charging and discharging losses, roughly 75-80% of the energy reaches the road.

For petrol, we have the exploration, extraction, shipping, refining, transportation, fuel pump losses, before the car discards 80% of the energy in the fuel, as noise, vibration, heat and waste.

But let's just focus on PEV charging losses!

jimbo6977

Martyn1981 said:

I don't follow your concern.

Let's say you are charging the car slowly (little bit less efficient), and the charging losses added to the discharge and motor efficiencies means only 85% of what you bought reaches the road, that upsets you.

But if you buy a litre of petrol, only 20% will drive your wheels, and you're fine with that?

You seem to be focusing on one single element, in an attempt to push a negative, whilst ignoring all of the negative efficiencies from FF's.

How do you feel about GCH? You only get about 80-90% of the energy from the gas you buy to heat your house, whilst you're eating your cornflakes in the morning. But an ASHP or A2A units will give you around 300% heat (seasonally averaged) for your leccy input. Nothing is simple, hence why you need to weigh up all plus's and con's, not just cherry pick one.


Right - Let's start at the wind or PV farm, including transmission losses, distribution losses, charging and discharging losses, roughly 75-80% of the energy reaches the road.

For petrol, we have the exploration, extraction, shipping, refining, transportation, fuel pump losses, before the car discards 80% of the energy in the fuel, as noise, vibration, heat and waste.

But let's just focus on PEV charging losses!

my concern is (/was) one of "weights and measures". 

pay for 1l petrol, get 1l petrol, 
pay for 500g cornflakes, get 500g cornflakes. 

my concern was that selling electricity at charging points was more akin buying a pint in a pub, where you don't generally get a full pint because there has developed a custom of allowing the head to be included in the pint. 

however it has already been clarified that this is not the case, and that the problem is more akin to the drinker spilling his pint on the way from bar to table.  

Jenni_D

Haters gonna hate ... simple as. They'll find any marginal case to denigrate EVs, without considering the whole lifecycle (and how inefficient an ICEV is in comparison). 🙄

Martyn1981

Jenni_D said:

Haters gonna hate ... simple as. They'll find any marginal case to denigrate EVs, without considering the whole lifecycle (and how inefficient an ICEV is in comparison). 🙄

It gets worse, half of my annual charging is from my PV, so I'm the seller and buyer. It seems I'm ripping me off! I'd write to my MP and complain, but I'm not sure he'll take me seriously. Drats.

"Careful Now", "Down with this sort of thing".

ComicGeek

To be fair, the issue of charging losses (and electrical losses as a whole) aren't widely discussed, and haven't been factored into any calculations that I've seen to date for EV running costs.

I was just double checking our EV charging last night - 25.87 kWh provided by the charger, 25.52 kWh into the EV battery, and very similar percentages around 97-99% for previous nights, when we've had night time temps of -3/-4 degrees. I can't get anywhere near the 10-20% quoted by various articles on this issue for home chargers.

Given these really small losses at sub zero temperatures, how much of an issue is this really? ADAC did some tests for charging losses https://www.adac.de/rund-ums-fahrzeug/elektromobilitaet/tests/stromverbrauch-elektroautos-adac-test/ but they're using a 22 kW charge point and for a full charge from empty. According to their figures, our 2 EVs should be 84% and 89%.

The ADAC tests are for a full charge from empty, so is the actual answer that the charging losses are concentrated at the lower and upper parts of the battery charge, which most EV drivers are unlikely to be using on a regular basis.

Jenni_D

FWIW I always charge to 100% (LFP battery pack), but I'm never down as low as 0% before charging.

Also FWIW - my EV Fuel Consumption spreadsheet (that I referenced earlier in this thread) calculates both running costs; per charge into the car and per charge delivered.  

Petriix

My calculations always factor in the charging losses because I only monitor metered electricity vs miles covered. I'm not really concerned about the reported miles per kWh figure. So I look at exactly what I paid for the miles covered. Worked out at a little under 1.5p per mile for 2022 (~£170 for ~12,000 miles). 

JKenH

Herzlos said:

jimbo6977 said:

Jenni_D said:

jimbo6977 said:

regarding charging losses, if a petrol pump was sending only 85-95% of the recorded amount of petrol to customers' tanks the station would be shut down and the owner prosecuted. but in EV world this is all tickety-boo it seems. 

🙄

Another pointless whataboutery. How much energy is expended (lost) pumping the fuel? How much is lost getting the fuel to the filling station? How much is lost in producing the fuel? (And all this before we consider the energy transfer efficiency of an ICE engine).

it's not whataboutery, it's simple case of paying for quantity M of a product and receiving quantity M x 9/10

regardless of how the product got to the dispensing point, and what the customer does with the product afterwards, how is this acceptable?

How much petrol do people waste driving to petrol stations?

Electricity efficiency losses happen with every electrical device, it's just how it works and I can't really see it being a sticking point for anyone?

I fill my petrol car up when going to Asda or Morrisons for a shop or just occasionally when I drive past a petrol station on route. Because the car is capable of going around 500 miles a tank (almost a month’s worth of driving) I find I can fit a fill up in without going in a detour. At our local Asda the diversion to the pumps as you go in is no more than 10 yards.So, no, I don’t waste petrol driving to petrol stations and I doubt many others do either.

That wasn’t the case with my EV. While I would do most of my charging at home when I was on a long run I usually had to go on a detour to find a charger. In fact it often turned out to be several miles as my first choice charger rarely worked. In fact, advice given to me on the G&E MS board was to avoid motorways for charging - drive a mile or two off the motorway and the chance of finding a working charger are much better.

For anyone who doesn’t have home charging then the likelihood is they will waste even more electricity driving around looking for available working chargers.

As to the efficiency losses I am always amazed that EV enthusiasts suffer only minimal charging losses whereas the professionals who set out to measure charging losses scientifically find the figures are much higher. The same happens when journalists undertake road tests and calculate real consumption compared to owners who rely on what the dashboard read out says. Any report that says a car is travelling 3miles/kWh will usually be challenged (where comments are allowed) by someone saying I can get 4 (or sometimes 5) miles/kWh all year round. It’s human nature to want our choices to be validated.

I understand all the points about how inefficient ICE engines are and well to wheel emissions etc but this is a money saving forum and concerned with efficiency at the wallet. If EVs suffer 10-15% charging losses then anyone budgeting/comparing costs needs to know the true cost per mile which one has to take into account actual miles travelled /kWh from the battery and charging inefficiencies. It isn’t made clear just what the dashboard shown consumption does actually include on an EV. It may or may not include battery preconditioning, preconditioning the cabin, non driving consumption (HVAC), monitoring programs and just general loss of charge over time when the car isn’t being used. (The latter may not be significant if you are driving your car everyday but if your annual mileage is low it may come into play.) It almost certainly, though, doesn’t include the losses incurred in charging.

If one wants to do a true comparison of EV consumption  with ICE consumption the only reasonably accurate way of doing that is to charge the car to 100%, measure the miles driven then charge again to 100% and measure the electricity the charger daws from the grid. A Zappi charger, like I have, has that facility and presumably so do other smart chargers.  Similarly with a petrol or diesel car, you can do what I recently did filling up until it clicked off, driving until the tank is almost empty and refilling at the same pump. FWIW my Golf 1.0 petrol estate recorded 50.7mpg against fuel added/miles driven figure of 48.6mpg. If you think that’s poor then 390 of those miles were driven in sub-zero temperatures.

If you go to the EV charging losses thread which I linked you will see when someone does this with a Tesla over an extended period the actual consumption is quite different from the headline consumption. 

Edit: here is (part of) the Tesla owner’s experience.

The average charging efficiency during these 130 cycles is 76%. 
Meaning, if I input 100 kWh to the charger the car uses 75 kWh to propel
it forward, on average. The minimum is 56% and the maximum is 97%. The 
higher efficiency (97%) has been achieved when using a Tesla 
Supercharger in the summer, driving immediately after completing the 
charging. The lowest (56%) efficiency was during winter with a long 
stand still and probably several cases of preheating the cabin before 
driving. 
This indicates that the numbers from ADAC are quite accurate at least
compared to my numbers. Another take from this is that the efficiency 
depends on several factors, like temperature, standstill time and 
preheating.

https://forums.moneysavingexpert.com/discussion/6267900/ev-charging-losses-and-vampire-drain

Grumpy_chap

JKenH said:

For anyone who doesn’t have home charging then the likelihood is they will waste even more electricity driving around looking for available working chargers.

Wouldn't those individuals very quickly get to know which public chargers in their locality are reliable or not and which tend to be available at the required times?  If so, the driving around to find a working charger would reduce to a point of being negligble.

JKenH said:

As to the efficiency losses I am always amazed that EV enthusiasts suffer only minimal charging losses whereas the professionals who set out to measure charging losses scientifically find the figures are much higher.

If EVs suffer 10-15% charging losses then anyone budgeting/comparing costs needs to know the true cost per mile which one has to take into account actual miles travelled /kWh from the battery and charging inefficiencies.

It isn’t made clear just what the dashboard shown consumption does actually include on an EV. It may or may not include battery preconditioning, preconditioning the cabin, non driving consumption (HVAC), monitoring programs and just general loss of charge over time when the car isn’t being used. 

The lowest (56%) efficiency was during winter with a long 
stand still and probably several cases of preheating the cabin before 
driving. 

AIUI, charging losses and vampire drain are two different factors.

Charging losses are definitely the difference between energy drawn from the electricity meter through the charger and the difference to what actually gets stored in the car's battery.

Vampire losses are a different thing.  I actually asked up thread what these vampire losses are and why they are significant on an EV but not an ICE. 

If I take an ICE to the airport and leave it for two week, the alarm, clock, etc will have been active in that time but the teeny 12V battery will have enough charge to start the car engine.  It's only if there is a fault somewhere that the power sapping over two weeks would be noticed by the driver.

With EV, the reported power drain is something apparently far higher.  There could be some loss of battery holding the charge.  But it does seem as though a lot of this "vampire drain" is features that the EV offers but are not directly to do with the operation of the car. 
 - Enhanced security with a suite of cameras recording all directions all the time. Possible with an EV, impractical with an ICE.
 - Cabin heating when it is cold weather ahead of getting in to drive away.  I think this is common for EV's to heat while parked, so using mains power rather than reducing the vehicle range in driving.  Controlled by an app.  I guess an ICE could also have similar, I even think some higher-end ICEs do have this type of feature.  For some reason, with an EV, the power used is a massive amount but the ICE running the engine while stationary to heat the cabin is no issue.
 - What else?

Comparisons about EV / ICE "vampire drain" should be on a like-for-like consideration.  I can also see that is not always as easy as it sounds - particularly the cabin heating and whether convenience changes behaviour.  With my ICE, I start and drive and the interior soon warms up.  With an EV, plugged in and app control, I think I would use the feature to warm the interior before departure.  Nothing is as simple as it seems.

JKenH

Grumpy_chap said:

JKenH said:

For anyone who doesn’t have home charging then the likelihood is they will waste even more electricity driving around looking for available working chargers.

Wouldn't those individuals very quickly get to know which public chargers in their locality are reliable or not and which tend to be available at the required times?  If so, the driving around to find a working charger would reduce to a point of being negligble.

Yes, the locals would, but they would be scrapping over fewer chargers, in this example 4 instead of a theoretical 10 charging sites. It might still though involve a longer drive to get to the working charger if the ones near your home aren’t working and you need a charge for a big trip the next day.

Local knowledge though doesn’t help the visitor.