2017+ usable capacity

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nitrobenz

New member
Joined
Sep 24, 2021
Messages
4
Hey Focus Electric enthusiasts! I'm looking at buying a 2018 focus and wanted to see if the battery is still in good shape. I've read a bunch of times on here that the earlier models with the 23kWh battery originally had about 19.5kWh available usable capacity. Unfortunately for me nobody mentions the usable capacity of the larger battery in the later models.

A little napkin math tells me that 19.5 is about 85% of 23, and going from there 85% of 33 is about 28.5kWh usable on the 2017+ Focus Electric. does that sound right?

That's just for the baseline of course. Then from there I can do a drawdown or--with lower accuracy-- multiply the avg consumption times estimated range to get the current approximate usable capacity?
 
Brand new, I think that larger battery is 29kwh down to 0%

Take the one you're looking at, top it up to 100%, clear the trip and then run it down to 0. It can be heater, AC, freeway driving, regen or no, it tells you how many kwh can be counted out to get to 0%.

I think I lost about 5% in my first year with the larger battery, but it varies with a lot of factors.

I should have some logs somewhere from right after the swap. I'll see if I can dig them up.

Update: it may be 28kwh from 100% to 0% with one more kwh as the emergency reserve that's there for all of them.
 
Got it, thanks for the clarification.

Unfortunately someone else bought the car before I could get there so I won't be able to do a drawdown on that particular one. If the dashboard displays average consumption (310Wh/m) times the full charge estimated range (92mi) is accurate to rough capacity, then that one had about 28.5kWh available, which would suggest to me that it was probably 29 when new.
 
I wouldn't take that alone to estimate the capacity, if only because the estimations may not be done on the same timescales.

If you need the quickest check that should be somewhat accurate, set a trip destination that is about 100 miles away while the battery is at 100%. The range meter will have a blue outline that tells you the average Wh/mi you can expend and make it there before running out. You take that value and multiply it by the trip distance and you get the capacity it is using to make that calculation. You lose a little accuracy simply because you aren't working from an explicit Wh/mi number but on a scale of 0-600Wh/mi, you should be able to estimate the value it's showing to within 10Wh/mi or so.

Edit: you'll want to do it with the AC/heat off and the battery below 97F so it's not powering the compressor.
 
I suggest using Forscan and an OBD reader to get the capacity from the battery module. I use OBD Link EX USB reader, as my Bluetooth reader doesn't work well with this car. Much faster than trying to do a rundown test. Good luck with your search.

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