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I am certain there will be comments tell me that I am wrong, and that the Nissan Leaf is far superior to the 1st Gen Toyota Prius. Although, it could be the complete opposite way. We may just see a spike in used Leaf cars for sale.

I want to walk everyone through my scientific reasons why Prius (and especially the worst of them all) is still better than the best Leaf. Not many people know this and probably most Leaf owners do not know it either. I feel it is my duty as a automotive professional to help other become more aware of what they are buying, so they can make an informed decision.

Last night as I was sitting on the couch, I had a friend of mine contact me. He wanted to buy a Leaf for fuel economy reasons. I told him (in a much shorter text message) why he should not and that if he was still interested in buying a more fuel efficient vehicle, that a Prius would be a much better option. What I will tell you and what I did not tell him, is the full gambit of why.

2019 Toyota Prius Interior
Toyota Prius Battery Was Better Initially

You have to understand something here, we are dealing with two types of battery tech that are very different. However, this is no excuse to be lazy about taking precautions when dealing with high voltage systems.

When Prius rolled off the line it had Ni-MH (nickel metal hydride) technology. It was great tech for the time and over the years Toyota has been able to improve on that tech and make it better. They still actually use it today in a few of their hybrids. Ni-MH is great for taking a charge and using the energy it stores rapidly. It was also air cooled, as using a battery and charging a battery at rapid rates creates heat, and a lot of it. Air cooling has been proven to be sufficient and reliable for long term use according to Toyota.

I am not sure what mind bending drug the Nissan engineers were on when they put the Leaf together. While yes, the Leaf uses Li-Ion (Lithium Ion) the stuff you find in laptops and cell phones, they took no thought as to cooling it. At all. Like, they do not even air cool this beast. A big no, no when it comes to longevity and useable miles of driving.

Here is why this is such a major issue. When you charge a battery, it will put off heat energy. When you use a battery it will put of heat energy. This process is called heat cycling and it very detrimental to the lifespan of Li-Ion batteries. Overheating causes the internal parts of the battery to break and thus short it out.

When you have multiple batteries stacked together to create a large energy dense platform, something like heat control is beyond required. These batteries put in a large block like this create what is called capacity, and as parts of the battery begin to fail we lose that capacity which directly translates into loss of actual useable driving miles.

Thus when you do not cool the battery at all, it does not matter what kind of battery tech you are using, it will fail. Thank you Leaf for allowing Prius to take this win. Not that it was needed, we just wanted to rub that in your face a little.

When To And When Not To Drive Your Prius/Leaf.

So now that we know heat cycling will kill the battery, we should take a look at when heat cycling occurs. This is needed in case you are reading this, already bought a Leaf, and are now trying to put a game plan on how to proceed, listen up. First, read the owner's manual. In there it is going to tell you all the conditions you should not use this vehicle, which are as follows.

Avoid exposing a vehicle to extreme ambient temperatures for extended periods. So hot climates and most places where the season "summer" occurs better not use it then.

Avoid storing a vehicle in temperatures below −13°F (−25°C) for over 7 days.Cold climates and wintery places you are out. Avoid leaving your vehicle for over 14 days where the Li-ion battery available charge gauge reaches a zero or near zero (state of charge). Drop at the airport before going to Singapore? Bad Idea. Oh and what time of year would this be in as well?

Allow the vehicle and Li-ion battery to cool down after use before charging. So, absolutely no road trips where we need a fast charge, as the battery was hot coming off the freeway and how we are going to induce heat back into it with a fast charge, with zero cooling, seems legit.

Do (here is one thing to do) Park/store your vehicle in cool locations out of direct sunlight and away from heat sources. Odd, it is like heat kills these things. So strange.

Avoid sustained high battery temperatures (caused, for example, by exposure to very high ambient temperatures or extending highway driving with multiple quick charges). Again, no road trips.

Another "do". Use the normal charging or trickle charging methods to charge the Li-ion battery and minimize the use of public Fast Charge or Quick Charger. Remember children heat happens when electricity flows at high rates. Avoid repetitive charging of the Li-ion battery with high battery state of charge.

So, basically do not drive the vehicle, like a normal vehicle, and probably avoid driving it. Seems reasonable. I bet Nissan went to great lengths to ensure that all the people who bought these things would read the owners manual as well, but somehow I doubt it.

Toyota Prius on the other hand, and especially first generation can be utilized in all conditions. Another win for Prius for sure.

Charging Toyota Prius Battery

If you did not get the message about no fast charging in the previous section, well then there is no helping you. However you can normal charge and trickle charge if you literally have nowhere to get to within a reasonable amount of time. Which I guess if you are retired, and only visit the grocery store, bingo club and your grandkids (who live next door) this car may be right for you, as long as you are not living in extreme climates, which a lot of people are.

Charging takes time and must be done in a controlled manner. Remember charging and discharging causes heat, which is the enemy here. So your best option should you meet the above criteria for climate would be to trickle charge. This takes about 21 hours to do out of a 110V outlet and should give you about 84 to 134 miles of range. This is dependent on many variables that the owners manual is happy to point out.

Things like avoid using the HVAC or heating ventilation and Air Conditioning, when you can, sure make me want to jump in one and take it for a spin on a hot day. Oh wait, Leaf says it is too hot to play outside so, cannot do that. Why even have AC as an option other than for defogging windows? Ask the engineer.

Normal charging will put you out at least 4-7 hours so make sure before you go on that date later, you plugged your car in.

Prius on the other hand self charges, unless you have the plug in Prius like the Prime. Even then the plug in cars can charge the batteries.

Conclusion

If you have met all the criteria as mentioned and are willing to do everything under the sun (lol keeping it out of) that Nissan askes you do, then the Leaf is right for you. In my professional opinion 90% of people who bought one of these (like most consumers) will not read the manual, heed the warnings, or listen to reason when it comes to taking care of these cars. No wonder Nissan had so many warranty claims for batteries on these things.

The solution Nissan had for second generation Leaf, which is the cherry on top of all of this is that the remedy was to add more modules, and still have no cooling. Awesome.

The only way I would take a Leaf over a Prius is if someone paid me to drive it. Even then it may be worth more in scrap for all the hassle it would be to make sure I am driving it in the right conditions.

I hope that you have enjoyed reading about new Prius Technology. Check out my other story 3 Top Tire Brands You Should Consider For Your Toyota Prius to find even more ways to make that fuel sipper go the extra mile.

See you in the next story where I am discussing why the Toyota Prius AWD-e is the best one yet.

Also Watch New tech means more MPG from your Toyota Prius and Click to Subscribe to Torque News Youtube Channel for Daily Toyota Prius and Automotive News.

Peter Neilson is an automotive consultant specializing in electric cars and hybrid battery technologies. He is an automotive technology instructor at Columbia Basin College. He holds a Bachelor of Science in Automotive Service Technology from Weber State University. Peter can be reached on Linkedin and at Certified Consulting