I think we all recognise that neither WLTP or NEDC produce result that are representative of "normal" driving. But making % reductions to get real range is very usable. Why is it any harder on EV than on ICE (internal combustion engine)? Or do you mean 30% and 50% would produce numbers that were too small? If so - I agree, except that the % numbers are different.
The WLTP range of my Polestar is 295 miles, but that is the base car without paint, leather, towbar and on 19" rims. Mine has leather, towbar, paint and 20"s. I get more like 200 miles out of a charge, do a fair number of short journeys and don't drive for economy. Am I surprised by this? No - not at all, partly because if I look at polestars website they have a calculator
here that tells me at 70mph in 5C and with 20''s I will get 199 miles. If I did longer journesy and had a lighter right foot the number would be higher. I average 33 to 34kWh per 100 miles - thats not excellent economy, but like I say I don't drive for economy.
When towing - I started out with the assumption I would do 50% range that I do solo. Using a very nifty route planning tool (
ABRP) designed for EVs, I told it I would need 67kWh per 100 miles, that I would have an 1800kg weight penalty and would not driver faster than 60mph. It estimated my 100-0 towing range to be about 100 miles and planned my journey accordingly.
It turns out, (having now done over 900 miles towing) that my average consumption is only 56kWh per 100 miles, and can be as low as 53kWk/100m. That gives me a towing range of more like 120-130miles.
So - my numbers (just to compare to the Touareg) are 292, reduce by 31% to give me 200 real world, reduce by 38% to give me 125 towing. I can work with that just fine.
Of course - thats just me. I don't mind (in fact actively do) take a break from driving every 2 hours (which is about 100 miles) when towing, and recharge while I am at it. If you like to tow for 6 hours straight - a Touareg is a better bet.