Precisely my point. But as long as the trailer is attached its analogous to driving up hill both ways (continously). Yes, SoC depleats and or the charge / discharge cycle causes thermal management to kick in. Try driving around with the extra load and no assist. :shock: Yes, on downhill slopes SoC would recharge, only to be rapidly sucked down again.james said:As far as IMA and so on go, I don't see how pulling a trailer (particularly a very light one) would be any different than extended hill climbing.