We get a fair amount of questions regarding Max Regen vs coasting in the Wrangler 4xe. Hopefully we can explain what these mean and how to make the most out of both.
First off, what is Regenerative braking? Put simply the electric motors that drive the Jeep can also instantly become a generator. The generator charges the battery using the momentum of the Jeep. Since the generation of power requires power the charging load on the generator serves to slow the Jeep down. This is essentially acting like brakes without the friction or pad wear. Regen braking puts no wear on the brake pads and will drastically extend the life of them.
4xe Max Regen
When the Max Regen mode is on the Jeep will apply the maximum regenerative braking when the accelerator is released. The amount of braking is considerable and is capable of putting some reasonably nice charge back into the Jeep’s battery. Something no Internal Combustion Engine vehicle can do. Interestingly the Jeep’s accelerator pedal remaps itself when in max regen. Approximately the 1st inch of pedal movement allows you to adjust the level of max regen. This feature is almost like one pedal driving.
Waste More than Gain
Max regen can actually waste energy if not used properly. For example you are rolling down the highway at 65, you get to a slight decline and you let off the accelerator. Max regen will immediately start slowing the Jeep down. Often you will slow so quickly you will need to step on the accelerator to get back up to speed. The small gain from the regen is wasted requiring more energy to get back up to speed. Proper driving in this case is to learn how to adjust the accelerator to not lose speed with max regen unless you are intending to slow down.
This is nothing new really, most people understand the word. This is an almost energy neutral form of driving no loss, no gain. Of course friction and drag is always working against us but allowing the Jeep to coast as much as possible will likely get you max electric mileage. Here’s why.
Coasting requires little thought and is a most natural method of driving…going down a slight decline? Let off the accelerator and allow the Jeep to just roll along. In fact the more you can coast the more energy you don’t use. Just to note, the Jeep has sensors that will apply some slight regen braking even when coasting, this is applied heavier when the Jeep is going down hill. It’s a similar behavior to engine braking. If you watch the gauge you can see the -1 to -5 kW of charge that is coming from coasting. You can slightly apply pressure to the accelerator to all stop the auto regen and truly coast.
Brake Pedal Regen
When max regen isn’t turned on the brake pedal will apply regen braking until the Jeep slows below a certain speed or harder braking is needed. If you learn to take advantage of the regen from the brake pedal a lot of energy can be captured.
My Experience – Coasting Wins
I’ve done a fair amount of testing and observation to decide what works best for getting the most out of electric range. In my 28 mile commute I drive highway, backroads, hills and town so I experience a variety of driving styles and for me max regen wastes more than it gains. Coasting wins every time – now why is this?
On nearly all of my commute coasting is easier on the driving experience and actually saves energy. This is the case since the coasting doesn’t cause the Jeep to lose speed quickly. Using the regen from the brake pedal smartly allows capturing all the energy possible. This avoids having to waste energy getting back up to speed. If you are a “hyper-miler” coasting is your best friend.
I tested outcomes of driving the same commute for weeks and I just couldn’t beat coasting with max regen even if I was paying close attention to the driving. Perhaps your experience is different.
4xe Max Regen Best Practices
There are times you can really take advantage of max regen. Long stretches of downhill are a great opportunity to regain some charge without using the brakes. I’ve already gained 3-5% battery charge on a single long stretch of downhill road. The key here is to use the accelerator pedal to control your speed. Don’t allow the to slow to the point that you need to use energy to speed up.
Back road driving can be fun with max regen if you are in to working the throttle. It’s amazing how curvy back roads can be fun with one pedal driving that max regen creates. With some practice you can learn to use the throttle for controlled regen braking. It’s something similar to running a lower gear in a stick shift and allowing the engine to slow you down. Just like was said earlier, make sure you don’t slow too much to waste energy speeding back up.
In the end you choose
If you want easy, natural driving turn the 4xe max regen off and take advantage of coasting. This seems to fit the majority of driving people do and will likely give the best results in electric range. If you like to be more part of the driving experience and like to hone your skills give max regen a try. Using the throttle to your advantage may add some range but it takes constant input from you.