- First Name
- Andy
- Joined
- Nov 19, 2019
- Threads
- 59
- Messages
- 1,658
- Reaction score
- 1,264
- Location
- SanFrancisco
- Vehicle(s)
- JL Wrangler
- Banned
- #16
Indeed there are many aspects of ESS, at least on the 3.6L JL, that make less than a well received system. Many people don't like by default that their engines will shut off at traffic stops. Then there's wear and tear on the components, and mentally getting use to the idea that an engine that turns off in the middle of traffic doesn't mean doom and gloom.
To some extent there is tradeoff in these systems between simplicity and reliability. And sometimes the added complexity, whose intention was to add reliability, designed wrong, only adds complexity, worse, reduces reliability as well.
A fair number of vehicle ESS systems run on one battery. Their thresholds for how long an ESS event lasts, which is based on monitoring battery voltage during the ESS event, must be more stringent than most 2 battery systems because that one battery has to be left with enough power to crank the engine.
Perhaps Wrangler engineers figured that with all the aftermarket appliances owners have, implementing a one battery ESS system might result in ESS events lasting only seconds before cranking the engine was necessary, not achieving the gas savings that EPS CAFE standards mandate and that ESS was created for in the first place.
Studies have shown that mileage gains begin at about 7 seconds of engine off time.
So a two battery system was chosen, but IMHO, that second battery should have been more substantial, particularly because in the 2018 design, that battery was mission critical to get the vehicle cold cranked. Worse, since the two batteries are connected in parallel most of the time, particularly while the vehicle is parked and no alternator is operating, either battery can be a parasite to the other bringing them both down. A more robust factory system might have broken the parallel connection while parked, if the voltage of one battery were going down far more than the other battery's was going up.
But all design decisions have costs passed in part on to the buyer, and bean counters can put pressure on engineers to design it less expensively.
On top of this also looms the somewhat unspoken truth that limitations in design, almost unique to the Wrangler, come in the form of 3rd party solutions (Genesis) that other vehicles don't as much enjoy.
To some extent there is tradeoff in these systems between simplicity and reliability. And sometimes the added complexity, whose intention was to add reliability, designed wrong, only adds complexity, worse, reduces reliability as well.
A fair number of vehicle ESS systems run on one battery. Their thresholds for how long an ESS event lasts, which is based on monitoring battery voltage during the ESS event, must be more stringent than most 2 battery systems because that one battery has to be left with enough power to crank the engine.
Perhaps Wrangler engineers figured that with all the aftermarket appliances owners have, implementing a one battery ESS system might result in ESS events lasting only seconds before cranking the engine was necessary, not achieving the gas savings that EPS CAFE standards mandate and that ESS was created for in the first place.
Studies have shown that mileage gains begin at about 7 seconds of engine off time.
So a two battery system was chosen, but IMHO, that second battery should have been more substantial, particularly because in the 2018 design, that battery was mission critical to get the vehicle cold cranked. Worse, since the two batteries are connected in parallel most of the time, particularly while the vehicle is parked and no alternator is operating, either battery can be a parasite to the other bringing them both down. A more robust factory system might have broken the parallel connection while parked, if the voltage of one battery were going down far more than the other battery's was going up.
But all design decisions have costs passed in part on to the buyer, and bean counters can put pressure on engineers to design it less expensively.
On top of this also looms the somewhat unspoken truth that limitations in design, almost unique to the Wrangler, come in the form of 3rd party solutions (Genesis) that other vehicles don't as much enjoy.
Sponsored