Overcharging my Fiat 500e?

[sariaa]

So sorry if this has already been asked and answered. I searched the forums and didn't see it anywhere.

My boss lets me charge my 500e at work with a 110v, so I now just charge it everyday and not really letting it go below 75%. It takes a while, but I am work so who cares.

I only commute about 9 miles from home to work, and it is a 35 mph road in Miami Beach. So I do a round trip and then charge it in the morning. It charges back to 100%. No problem, all is well.

My question is: am I doing damage to the battery or shortening my battery life by charging everyday like this or am I just ignorant.

Thanks in advance.

Said it once. I'll say it again. I love my 500e! :-)

[Ricksuiter]

Damaging? No. Shortening the potential life? Maybe.

In general lithium-ion batteries like to sit partially charged ideally. They do not like to be deeply discharged repeatedly and they don't like to sit fully charged for long periods of time. The car has electronics which prevent any possible user inflicted damage so there is no input you could do that would harm it aside from possibly driving the car until it shuts down and letting it sit for a couple weeks or longer. That would be a long shot outlier case in my opinion.

As far as getting the most miles out of the battery using about half on a charge before re-charging would be in the ball park of optimal based on generally accepted best practices. That said, your 0 to 100% as indicated on the display isn't really 0% nor 100%, there is likely some hidden buffer in there. The owners manual says to charge it whenever and to keep it plugged in if you are storing the car for a long time so it won't be all bad.

If you really only drive the 18 miles round trip I might suggest you stop charging at home all together just because your work would be paying for your driving and you could make use of those 8 hours more.

[sariaa]

Thanks mucho for this great info! I really appreciate it. :-)

[VeeDubTDI]

I think the impact to long-term battery health is pretty minimal. That said, there's room for improvement. If you're looking to maximize battery life and you're okay with maintaining a lower average state of charge, you could opt to charge the car at work every other day instead of every day. This will run you down to about 50%, which should still provide enough range if you have to run surprise errands or something.

[PLP]

So... I think we should be fine.

After reading some materials, listening to others (despite me thinking they are right or wrong), and doing research, I came to a conclusion that charging to 100% will do NO harm to the battery.
It seems 500e battery has a reserve.

Example - Tesla.
It says not to charge to 100%. In addition, even if you do, the last several % will take long time and very low rate. What does it mean? It means you are topping off the battery. Just like a glass. You pour water 3/4 full quickly, but to get it to the very edge you need to do slowly, otherwise you'll spill.
Same batteries.

Fiat, on the other hand, charges full speed. It means it has room to go to. It may calculate the charge added and stop when it reaches the anticipated 22 (or 24 - depending what voltage you use) kW for the full battery.
If you use Level 1 or Level 2 - makes no difference, and actually - Level 2 will be better for the health of Li-ion batteries as they like higher current charge as opposed to acid batteries. You know those 18650 cylindrical batteries? Used in laptops, flashlights, and many other applications. They like about 1 A charging current and that is at 3 Ah capacity.
Hence, FIAT having 97 cells of 63 Ah each, you can easily see each cell would take 20 A charging current. That is 7.2 kW at 3.75 V nominal for Li-ion.

More problematic might be discharging it completely, though.


Oh, and on the discharge note. At full load you put to the motor 85 kW, plus you can load another 8 kW to the heater. Total of 93 kW. That means the batteries discharge at rate of 255 A each...

(3.75 V x 255 A x 97 pieces = 92756.25 W, i.e. 93 kW)