I use "OctopusGo" which gives 4 hours at 5p which will give you about 90-100 miles over night which is enough for most people's daily use and if you need longer then after 4: am it switched to the daytime 15p rate. This will workout a lot cheaper than EDF. Or if you regularly need more than 4 hours charge there is "OctopusGo Fast" which give 5 hours at 5.5p and the daytime rate is 13.5p.
Use this referral link and you'll get £50 credit to your account and so will I so Win Win
go to share.octopus.energy/zappy-guppy-175
If you've an estimate of your monthly EV mileage assume 3 to 3.5 miles per kWh and you'll get an estimate of your monthly kWh needed for charging. Now calculate the OctopusGo at 5p or OctopusGo-Fast at 5.5p
Check your current electricity usage from you bill. probably simplest to take their stated annual estimate which will be based on past 12 months and divide by 12. Now unless you run your washer/dish-washer or heat hot water tank overnight you could assume most of that current use is in the day and would be at the day time rate. Use this figure to calculate the cost at day rate at 14p for OctopustGo or 13.5p for OctopusGo-Fast for the cost of your regular usage.
You can now get the comparison between the two Octopus tariffs. Personally I don't find I need to charge every night so I have time shifted my Hot-water heating from Gas onto 4 hours of 5p electricity and time shift Dishwasher on time to after 1pm and therefore even on days I don't charge my ZS 40% of my electricity is at 5p rate on Octopus Go.
Use this referral link and you'll get £50 credit to your account and so will I so Win Win
go to share.octopus.energy/zappy-guppy-175