sgmrock

On previous long road trips I have always averaged about 15.2 mpg. Not bad considering 35" muds, weight and the aerodynamics of our JK. I got a new battery, Sears Die Hard Platnum, and did a trip from Denver to Moab to Grand Canyon to Durango and back and got an average of 19.3 mpg! Nothing else was changed. I wouldn't believe it if it didn't happen to me. Anyone else have a similar experience?

GoodysGotaCuda

Not really possible that the battery itself did it. Only thing it may have changed is the adaptations when you disconnected it...

Calypso

Tailwind!

07rubigreen

Ok this is almost too strange because I was about to post what you posted word for word. I replaced my battery with a Sears Die Hard Platinum also and the next week of driving my MPG went up substantially from what it normally is. It seems to have gone back to "normal" now after a couple of weeks but I couldn't think of any reason why a battery would have caused this. Anyways, regardless of what anyone tells you here, I experienced just what you described.

Uncle Miltie

The biggest reason it probably happened is that your old battery was probably getting weak and required the alternator to constantly be in charge mode. If the vehicle voltage drops below a certain level (I believe it's about 12.5V), the charge mode kicks in, kicking out between 13.9 - 15.5 V from the alternator. During that time, the engine is consuming additional fuel due to the extra work it's producing to keep the battery charged.

Now it's likely not the ONLY thing that caused this, but it can be a contributing factor. Also think about how you drove - the single biggest contributor to gas mileage changes is how heavy your lead foot is. Also your tire inflation being correct and air filter and fuel system being clean are big factors.

In any case, I got 20.5 mpg last weekend driving my Jeep back and forth across Michigan to pick up my daughter from Grandma's house. Best I've ever done, but I also kept closer to the speed limit and never revved over 2500 rpm...

Have Fun Out There...

RedRock GatorRaider

It's just your ECM resetting. After you disconnect the battery the Average MPG resets. It always starts high, even climbs a bit, until it eventually settling down to the same crappy mileage we are used to.

GoodysGotaCuda

Not quite. When your engine is running, you better be above 13v or something is wrong. If the engine is running and it's close to 12.5v, you are not charging OR you are winching or something and the charging system cannot keep up. The alternator is always "in charge mode" or it would be running off the battery (bad), it depends on the electrical load, but after a few miles down the road the battery will be at some level of charged even if it was 'low'. If the battery was able to start the vehicle, the parasitic draw on the alternator to charge a battery from 11v or from 12.65v (100%) is extremely little...

Also you shouldn't be over about 14.5v. Start going into "range" of 15.5, lights can potentially start to blow out (usually takes a little higher than that, but it's on it's way). That is too high. 13.5-14.5 is a good "normal" range for a 12v electrical system going down the road.

sgmrock

That could be the case for most folks except, I reset my average mpg before every trip....even this one. So I started out at ZERO....
We just did a quick trail run up to Twin Cone today, average mileage, including 14 miles in low range, 18.1...

ronjenx

Different gas on the trip? Maybe less ethanol in some of it?

Being on this road trip could have caused you to be more relaxed, making you a more efficient driver.

Did you verify the mpg the old fashioned way?

Absolute

I just installed this Battery on Saturday, I can only hope this is true. I'll find out soon.