PHEV - should I bother charging?

lbreeze321

This is my first ever post so please be kind!

I'm starting to wonder whether it's currently worth charging my BMW 330e PHEV or not. I have a home charger and currently on a standard variable tariff (so capped at the energy price guarantee). 

In the cold we get about 20 miles from the battery which apparently has a capacity of 10.4kWh (advertised at 12 but some are apparently "reserved" and not charged/depleted to increase battery life). A full charge costs somewhere in the region of £3.40-£3.80.

The same 20 miles at a fuel cost of 150p/l and an approximate petrol only (or at least starting with no charge) mpg of 48 (obtained from a BMW forum) costs about £2.84. 

It's not an exact science but have I missed something? It would be good if there was a calculator that could determine the break-even point based on electricity/petrol prices! 

Petriix

You should get more than 20 miles from the battery and you probably aren't getting 48 mpg in the cold so it's not easy to tell. Your electric miles will be saving emissions so, even if the cost is close, you should be charging. You'd probably save money overall if you switch to a cheaper overnight tariff (like Octopus Go) and also shifted some of your home usage (washing and drying, dishwasher etc) to overnight - as long as you don't have really high, unavoidable peak usage.

Keep_pedalling

You seem to be getting less than 2 miles per kWh which is very low, so I presume you are running in pure electric mode for the first 20 miles then switching to petrol once it has run out, which means you are using the the battery for traction and warming the cabin up from cold. Starting from cold I don’t think you would get 48mpg running on pure petrol for those first 20 miles either. The cost per mile would seem to be similar. At leat in this cold weather. 

lbreeze321

Thanks for the suggestions/info.

The range displayed on the dash is usually around 20 but yes i'm specifically talking about during the cold weather. In the spring/summer it goes up to a more expected 25-32. 

I run the car on the Hybrid Eco mode most of the time so it dictates the usage but generally that's battery only unless I heavily accelerate or go over c70mph. Very true RE 48mpg on pure petrol - that figure was quoted for a long journey with no charge but the battery will have charged during the journey and been used occasionally so I think you're spot on. 

RE energy tariff, I don't think it's worth the change for us specifically as the "regular" usage is more expensive. With 2 people working from home most days, electricity is used throughout the day too much. 

Either way, I think given everything I will continue to charge the car. The main reason I got the PHEV in the first place was to reduce emissions but wasn't ready for full EV yet. Thanks

Petriix

If you're at home all day then solar panels would worth considering, then an off-peak tariff works very well.