EV Discussion thread

JKenH

https://forums.moneysavingexpert.com/discussion/comment/82024121#Comment_82024121

I also found that with my Leaf which had no battery heating or cooling. I would find that for the couple of miles or so I would get less than 2miles/kWh. I try not to use my Golf for short trips (less than 10 miles). The Picanto takes a couple of miles to warm up and that is perhaps why its overall mpg is similar to the Golf (or perhaps it’s the fact that my wife seems quite happy to cruise in third gear if I am in the car with her.) Even with the Golf I always find th return trip from the supermarket is better than the outward journey and it is pretty flat round us. Another factor I notice in the Golf (and same for all cars) is how much more efficient it is on a busy free flowing motorway than an empty one as you are always getting a tow.

pensionpawn

https://forums.moneysavingexpert.com/discussion/comment/82018855#Comment_82018855

Indeed! If the government want to see EVs wheelspin out of the showrooms, they should through their weight into accelerating (pun intended) the roll out of V2X capability. That's what I'm waiting for and sticking with my ICE vehicles until then.

1961Nick

https://forums.moneysavingexpert.com/discussion/comment/82024121#Comment_82024121

The Wh metric is very useful when a journey is marginal on range. Managing the energy consumption can make the difference between having to make a charging stop & not. Slower can easily result in a faster journey time especially if a diversion to find a charger would be necessary. In a Model 3 the difference between 65mph & 85mph can be 1 mile/kWh… so 75 miles less range on a full battery.

On a very cold day without a pre-conditioned battery/cabin, the Model 3's energy consumption can be more than 1kWh/mile for the first mile or so. If every journey you did was a mile, you'd still be getting the equivalent of 100+ mpg (IOG). Try that in a diesel & you'd get <20mpg, a ruined engine & a blocked DPF every 6 months.

JKenH

https://forums.moneysavingexpert.com/discussion/comment/82024218#Comment_82024218

Apologies if this has been asked before but has anyone on here any experience of the round trip losses with V2L/V2H/V2X. Maybe I should just ask Google.

edit: I have asked Google and the results are not good.

A critical yet underexplored aspect of bidirectional V2X operation is the energy loss associated with

the discharge phase, which introduces a second stage of power conversion. An empirical study that

simulated V2G operation in a laboratory environment measured round-trip efficiency (RTE) values

ranging from 53 percent to 62 percent, which is substantially lower than the commonly assumed 80

percent to 85 percent 

https://calnext.com/wp-content/uploads/2025/12/ET25SWE0028_V2X-Round-Trip-Efficiency-Market-Study_Final-Report.pdf  

Netexporter

Whatever the answer is, it will be magnitudes more efficient than using fossil fuels.

JKenH

https://forums.moneysavingexpert.com/discussion/comment/82024233#Comment_82024233

…but not, perhaps, as much as we might have assumed.

born_again

https://forums.moneysavingexpert.com/discussion/comment/82024212#Comment_82024212

At 2 kWh/Mi that works out at 80 mpg compared to ICE.

Martyn1981

https://forums.moneysavingexpert.com/discussion/comment/82024233#Comment_82024233

Early days still, but the US is slowly shifting to BEV school buses. As the yellow school bus isn't used for other purposes it sits around most of the day. So the idea/plan is that they can charge through the late morning, early afternoon off excess PV, for travelling purposes, helping to time shift demand. Then also provide V2G support during the early evening peak period, helping to further reduce FF use.

pensionpawn

https://forums.moneysavingexpert.com/discussion/comment/82024227#Comment_82024227

Even if this is true, that's still 40 kWhrs available for house / export, or ~25 kWhrs if sticking to 20%-80% guidelines… At 12p export and 22p import, it's still worth while…

Grumpy_chap

https://forums.moneysavingexpert.com/discussion/comment/82024223#Comment_82024223

It doesn't need to be a cold day. As I noted upthread, on our trip to Great Yarmouth, the short term energy peaked, or at least the peak that I noticed, was 1,114 Wh/mile. That was the scorching hot end of May Bank Holiday weekend.