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Discussion Starter #1
Since I'm behind the curve on the latest battery tech, can the
resident battery experts please chime in on this.
How or will the different charging rates for the Prime affect/effect overall battery life?
Thanks.
 

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For the Rav4 Prime (upto 6.6 kWh charger), the faster the charging the more efficient and better. There are more overall losses with lower power/slower charging. As long as there is an effective active cooling system there are no battery lifetime handicap for fastest/most power charging.

Some people live the Prius Prime Owner’s manual statement “don’t leave the vehicle with full charge...” and schedule their charging session to complete when they plan to leave, all in the name of prolonging battery life. My feeling is that that can prolong 10s of days over the expected lifetime of 10years (warrantee) constraining your charging that way and it is not worth it.
 

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Discussion Starter #3
For the Rav4 Prime (upto 6.6 kWh charger), the faster the charging the more efficient and better. There are more overall losses with lower power/slower charging. As long as there is an effective active cooling system there are no battery lifetime handicap for fastest/most power charging.

Some people live the Prius Prime Owner’s manual statement “don’t leave the vehicle with full charge...” and schedule their charging session to complete when they plan to leave, all in the name of prolonging battery life. My feeling is that that can prolong 10s of days over the expected lifetime of 10years (warrantee) constraining your charging that way and it is not worth it.
Thanks for the reply.
I do know heat is one enemy. I just wonder how effective the cooling management is in reality. Is there some sort of monitoring of the individual cell temperatures. Is Toyota saying the management is good enough so the pack lasts10 years for warranty purposes? Could the management be better? It's a trust but verify thing for me. Please tell me what the other losses are besides what I assume is cost to charge at 110v. Wouldn't charging at110v generate less heat? Sorry for all the questions!
 

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From reading the manual, the battery cooler only kicks on when the vehicle is plugged into a 220V outlet. However, there's not enough information anyone knows yet to determine whether or not the cooling will actually keep the batteries cooler during the charge cycle vs a 110V charging option.

Fact: Keeping batteries cool during charging will definitely make them last longer.

220V charging (3.3 or 6.6 kwh) is going to be more instantaneous energy/heat than the 110V (1 kwh) option, but we don't yet know how the battery cooler works during that charge cycle. For example, if on 220v, the battery cooler just pre-cooled the batteries before charging, the peak temperature on the batteries may still be higher due to the increase current/wattage after the battery cooler turns off. Alternatively, the battery cooler could stay on the entire charge (thus keeping the battery temp lower than ambient in the summer for example), then it would be better than 110V in both speed, and battery life longevity. The only way to tell is for someone to buy one, hook it up in their garage under both conditions, and figure out a method (via OBDII scanner, or an infrared gun on the underbody) to check the temperature of the batteries during charging.

Honestly, I'm curious myself. I want the Prime, and I also want a charge method that prolongs the batteries under most, but not all, conditions (I want a toyota so it lasts a long time). If no one on this forum can get me an answer anytime soon, I'll try to figure it out myself once I get one, lol.

Relevant: several years ago iPhones came out with the capability to monitor their total battery capacity relative to where it first started. After owning mine for just one year, I realized that the original charging methods I had been using (10W "fast" chargers and wireless chargers, which produce a lot of heat), were accelerating degradation. For the sake of being curious, I switched to a 5W (cooler) charger for several months, and realized that my battery life stopped declining as quickly (I think I lose 1% capacity in the period of 6 months instead of 4-5%). Because of that, I now routinely charge on chargers with lower power output during the night, and only use the 10W charger I have when I'm in a hurry.
 

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It’s hard to compare EV batteries to phones. The chemistry, improved management, and cooling make them much more reliable. I wouldn’t worry too much about the “best” way to charge. Auto manufacturers worked very hard so that you don’t have to!

I used to work for a battery manufacturer.
 

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Discussion Starter #6
Thanks for the info! I'm looking forward to someone doing a deep dive into how it all works.
 

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It is very much in Toyota's best interests to work very hard at improving battery life and efficiency and on the assumption that they have been working on this longer than other manufacturers I decided to back their track recorder. I advise that you follow any guidance given in the owners manual and completely ignore what you may read on social media and even this forum. ( I think I just created a paradox!)
 

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It is very much in Toyota's best interests to work very hard at improving battery life and efficiency and on the assumption that they have been working on this longer than other manufacturers I decided to back their track recorder. I advise that you follow any guidance given in the owners manual and completely ignore what you may read on social media and even this forum. ( I think I just created a paradox!)
Toyota did a pretty bad job with the Prius Primes battery life - a big reason for that is the air cooling, and lack of a good cooling method during charging. (3rd worst here: Here Are The Best And Worst Electric Cars In Terms Of Battery Degradation) So I don't think Toyota "has it all figured out." The Rav4 Prime will have the largest battery Toyota has had to charge/manage in a vehicle, and it will also be a first that's liquid cooled for them, so there's a lot Toyota and this forum will learn over the years I'm sure.

Here's some info from the manual:

155268

155271


155269

155270
 

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It’s been quite some time since the Prius Prime came out and there have been plenty of battery chemistry improvements since. So I’m less concerned about the RAV4.
 

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It’s been quite some time since the Prius Prime came out and there have been plenty of battery chemistry improvements since. So I’m less concerned about the RAV4.
Agreed, chemistry can help slow degradation, but the fundamentals will still remain true with batteries regardless (heat slowly kills). TBH, learning that the R4P was liquid cooled via the A/C was the (final) reason I was willing to buy the car. The reason I care so much about that is because I live in Phoenix, where my garage can get up to 100-105F during the summer time. EV's/PHEV's have had a notably hard time here in Phoenix (Nissan leaf and the ford fusion? I think it was, have terrible battery longevity because they don't have active cooling systems), the batteries get reduced to only half their usable capacity after like 5-7 years. On the other hand, the Chevy volt has a cooling/battery setup similar to the R4P, and many of those cars still have their same usable capacity 8 years later (even here in phoenix). Owning a Volt in Summer--in Phoenix
 
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