Best Charging Practice

[ACHumm]

Hi Everyone!

My first post.
Just got my RAV4 EV and have been loving every mile.

I tried to search for this on the forum, but couldn't find this topic. Sorry if this is a repeat thread (if it is please point me to the right place).

What is the best charging practice for the RAV4 EV battery.

I have a JuiceBox that can supply the full 10kw to the onboard charger.
Should I always use the full power available?
Does it hurt the battery chemistry to keep the charge mode in extended range, even if I don't charge it all the way up (lack of time usually)?
Is the charging curve different in extended mode, than normal mode? Specifically, if I have it in extended range, does it charge the bottom 80% of the battery more slowly/faster then if it's in normal charging mode?

If it doesn't matter then what's wrong with keeping it extended range mode, and then occasionally getting a few more electrons in the battery.

Thanks

SteveG

 

[Kohler Controller]

Hi SteveG,
Welcome aboard.

These questions have been answered but I'll give you the Cliff's Notes Version.

Yes, charge at full power. Even at 10kW, to the battery its very slow (5 hour charge rate). Charging at slower rates does not provide any advantages.
Charging happens the same way during bulk charge (up to 80%) in both normal and extended charge modes, so no, it does not hurt the battery chemistry to have it in either mode and not finish charging.

It is my opinion that extended mode charges the cells until they reach 4.15V/cell or 95% SOC, while normal mode only charges each cell to 4V or 80% SOC.
Charging from 0-80% SOC (bulk charge) is the same for both modes.

Generally speaking, the higher the charging voltage, the more stress is put on the electrolyte, so in theory exposing the cells to 4.15V may shorten its life compared to a pack that never sees above 4V. However, I've been cycling some cells which shows not too much difference between the two settings, which surprises me. I will post the results later this week.

I use normal charge most of the time during the week where I know my usage is predictable (60 miles round trip), and extended charge on weekends because they are less predictable.
I also used extended charge mode through the winter as the cold knocks about 20% range out of the pack and extended mode gives it back to me.
Normal Mode is my standard, but I don't stress about hitting Extended at any time.

 

[ACHumm]

Thanks Kohler (or is Mr. Controller?)

All great information, thanks.
I'm proud to be part of this exclusive group of RAV4 EV owners.
I hope to contribute meaningful content as time goes on.

SteveG

 

[TonyWilliams]

The longest life of the cells is at or about 50% charge! and really cold! but not frozen (about -30C).

Anything warmer, or greater or lesser charged will degrade the cells faster. The worst case scenario is very hot cells fully charged. The second worst case is very hot cells that are depleted, although fully depleted (not possible in modern BMS equipped EV's) can "brick" the battery pack with just one occurance.