I'm taking delivery of a 450h+ in the spring. I will have home charging so will usually charge overnight. I'm expecting most journeys will be within the fully electric range of the car. I will also be travelling from the UK via France to southern Germany and back a few times a year (about 1400km each way).

Now that most of the motorway/autoroute/autobahn service stops mostly have charging stations I'm wondering what, if any, the cost benefits of charging up during the journey vs. using the petrol tank are?

A very rough calculation for a 1400km trip looks like:

Petrol only
assume 15km per litre at motorway speed
assume €1.50 per litre for petrol (averaged between FR/DE/UK)
Fuel consumption: 1400/15 = 93 litres
Cost: 93*1.50 = approx €140
Cost per km: 140/1400 = €0.1

Fully electric
assume motorway speed range of 50km
assume average of €0.50 per kwH
capacity of battery = 18.1 kwH
Full charge cost = €9
cost per km - 9/50 = €0.18

My current conclusion is that there's no advantage in topping up on the motorway (it's too expensive compared to much cheaper charging at home). Also, the amount of pure ev milage gained is a very small percentage of the total.

Has anyone else looked at this?

 

The 450h doesn’t have DC charging so the fastest you can charge is level 2 6.6kw. This great for home charging but for road trips it barely makes sense. If you do find a cheap level 2 near a restaurant then sure top up while you have a meal. Will give you more total range and flexibility but for freeway driving just stay in HV mode and be happy you have zero range anxiety.

 

In the scenario you outlined it will be best to use gas.

I’d say if you can get free/discounted charging while you were having a meal or taking a break then sure, get some EV miles in. But otherwise sitting around 3-4 hours to charge for 40 EV miles isn’t worth it. Also remember that the car still has great fuel economy in hybrid mode.

The EV mode let’s you drive gas free on short trips. The gas engine let’s you drive without range anxiety or long charging stops on long trips. That’s the beauty of PHEV.

 

My plan is to try and use EV mode in the city and Hybrid on the faster roads as the petrol/hybrid is the most efficient. My question is do you use the charge mode on a longer run to make sure you have a full battery so you can go back to EV once your off the main roads. Looking at the comment above it really isn’t worth using public chargers.

 

That was my calculation. Unless you have access to cheap/free power and top up whilst you are stopped for a meal, it doesn't make sense to charge on a longer trip

 

Even using the inbuilt charger? Wonder how much fuel is needed to recharge the battery using the engine in charge mode as you drive along the motorway?

 

As it takes 2H30 on max charging power (6,6 KW) to top off the batteries, a 1H00 stop for a lunch break in a charging station on the motorway should allow you to fill up tour battery up to 35%. At French speed limit on the highway (130 KPH / 80 MPH) you should have 10 km EV range at max with this level of charge and it will cost you probably around 25 euros (according to charge map) . 25 euros will get you around 12 liters of E95 gasoline.
With these 12 liters, you'll probably have a 130 -150 km range.

 

The only valid use cases of the hold charge charge mode (afaik) are to keep a full battery for situations like camping where it’s nice to have power without running the engine, or for rare future cases where cities ban ICE engines completely and you have to have a full battery to drive thru.

For general efficient driving you want to use the battery in normal hv or auto ev/hv mode. If you can’t complete your full trip on a battery then put it in hv on the freeways and use ev mode for streets. Forcing energy to go from the engine to the battery to the wheels is inefficient.

 

Or you have a tank of gas that has been not been used for a period of time. You shouldn't keep the tank of gas for too many months. Do not know what is the best to use up a tank of gas.. 3 months?

 

Even then just drive on HV mode. Use the gas to move the car, not charge the battery.

 

If you just drive locally, how do you force it to use gas? Don't charge the car so the battery goes low?

 

If you put the car in HV mode it will drive like a regular hybrid. So for light usage it will be on battery but with any kind of acceleration it will start the engine. You can put it in HV mode and watch the energy usage screen to see when the engine comes on. HV mode will get great mileage but will def use the engine.

Its possible of course but I think there is almost no chance of having the gas run stale on a PHEV will 37 mile range.