Glos Guy and Wigwam. Your posts greatly appreciated in my efforts to understand PHEVs. It is all a bit clearer but there still seems to be an element of “there’s no such thing as a free lunch”: if the ICE is making energy to top up the battery then it may be more efficient to have a more powerful ICE and do away with the extra weight of the batteries and the charging bits. I do understand that brake energy will alleviate the imbalance.