Fear of Fast Charging

[user 284]

I've been reading the Soul EV manual. Numerous times it warns that using a fast-charger (CHAdeMO), especially in hot weather, can severely shorten the battery's life. So, I've completely avoided fast-chargers, even though some nearby shopping centers have free ones. Am I being paranoid?

 

[ZuinigeRijder]

I've been reading the Soul EV manual. Numerous times it warns that using a fast-charger (CHAdeMO), especially in hot weather, can severely shorten the battery's life. So, I've completely avoided fast-chargers, even though some nearby shopping centers have free ones. Am I being paranoid?

I am not sure if the results also accounts for the Kia Soul EV, because of chemistry differences.

See this document: Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance

Summary

The four BEVs driven in Phoenix, Arizona were faced with a hot climate, and two were fast charged twice as often as recommended by their manufacturer. Despite these conditions, the vehicles were operated without failure for 50 thousand miles. A greater loss in battery capacity was observed for the fast charged vehicles, though the difference compared to the level two charged vehicles was small in comparison to the overall capacity loss. The vehicle operation was, as intended, verified to be very similar between test groups, and the largest difference in conditions noted was battery temperature during charging. Hotter ambient temperatures appear to have accelerated capacity loss for all of the vehicles in the study, though the exact relationship remains to be seen.

And this document: DC Fast Charge Effects on Battery Life and Performance Study – 50,000 Mile Update
Conclusion: NO appreciable difference in capacity loss (~2%) between Level II and DC Fast Charging

 

[wrickcook]

Most shopping centers around me have level2 charging, not chademo (level3).

I would not worry about L2, if that is what you have.
Chademo, I would be more wary of using all the time.

 

[ALF]

I agree. I don't think that there is anything wrong with an occasional L3 charge, just not all the time. Also, those Level 3 charging stations only charge the battery to 80% in order to protect the battery. If you choose to override this default setting, you will notice that the L3 station "slow rolls" the charge from 80% to 100%, at a rate not much faster than an L2 station. I know some EV drivers who use an L3 to get to 80%, then switch to the more ubiquitous L2 stations to get to 100%. Also, this is considered good charging etiquette, since there is commonly someone waiting for you to finish your L3 charging session so they can hook up.

 

[mtndrew1]

I use L3 when I actually need to go on a trip exceeding the car's range but never otherwise. Based on how furiously the battery fan can run when L3 charging the process clearly heats things up which is the death knell for a Li-Ion battery.

I wouldn't sweat using quick charging when it's actually useful but otherwise I'd follow the manual and avoid it.

 

[GizmoEV]

Use it when you need it but don't use it just because it is free. Remember that the level 2 charge rate of 6.6kW is actually quite slow as far as the battery is concerned. It is the CHAdeMO charging that is usually considered quick. Even the old cheap Chinese LiFePO4 batteries I bought in 2009 had a standard charge rate of 0.3C which, if applied to the Soul EV 75Ah batteries, would be a 22.5A charge current (about 8.1kW). As you can see, a 6.6kW charge rate (about 18.3A) is considerably slower. (see http://www.kiamedia.com/us/en/models/soul-ev/2016/specifications for battery specs)

Note too that the Soul EV automatically stops a CHAdeMO charge at about 84% and you have to restart the charger to get another 10% charge into the pack before it shuts off again. I have not found any way to override this behavior. From some testing at a 50kW charge station the charge rate starts to taper down at about 72% and reaches about 6.6kW at about 92% so from there on it is just as fast and better charging etiquette to move to a Level 2 charge station.