It's a slow news day so this might be of interest.

Just from having the doors open and dome light on doing my dashcam install, the underhood battery fell to 9.9v on the SG and wouldn't allow the FEH to start. I could hear a relay cycling about once per second from under the hood when the key was ON. With a battery booster pack it started right up and I continued driving for another week but kept the booster pack with me.

I had planned to get an Optima Red Top from Amazon but Pep Boys had a 20% off coupon that made it about the same price and no core to deal with. The group 35 Optima is a drop in as far as size but the terminal orientation has to be reversed or the leads are too short. So the positive terminal is now towards the driver side of the vehicle, which is reversed from OEM.

I connected the Pep Boys OBD keep-alive box before the battery was disconnected but it did not work for me. Radio presets were lost, ABS light came on, and power braking was initially lost but came back after pumping the pedal a few times.

The original lasted almost seven years and I could have kept it going but was concerned it might do damage to the DC-DC converter from continual charging.

 

I got just less than 48 months on two Motorcraft 12V batteries.

 

Billy, thanks for the tip on carrying a battery booster pack. I had bought one after seeing your post on that.

I considered another OEM Motorcraft but I wanted a sealed battery this time. Although the FEH has a plastic battery tray so corrosion isn't as much of a problem. But I did rot out a battery tray on my '88 Blazer.

Did your Motorcrafts both go 48 months or 24 months each?

 

Both 12V batteries developed a bad cell before 48 months were up. I always carry a 12V portable power pack in case the relays fail to close and the vehicle will not then start. Hooking up the power pack solves the issue.

 

I'm not sure how this could be possible, but I feel two effects from replacing the battery.

-The regen braking in L feels more forceful, more braking.

-The FEH seems more willing to go EV and stays in EV longer.

Possibly both are related to whatever computer and fuel trim resets occurred when the battery was out. Or maybe related to the old battery failing and drawing more charge current from the system. I haven't driven far enough yet to log any change in mpg.

 

A questionable 12V battery will decrease MPG. This happened to me for sure and I posted about it a while back.

Gary

 

Optima manufacturers batteries with the terminals reversed. Those versions have the letter "R" following the model number.

 

Wish I had known that earlier, but the Redtop 35 fits perfectly just by rotating the battery 180 degrees, the terminal wires are plenty long. https://www.greenhybrid.com/discuss/...tml#post244443

I did just call Optima (factory) and was told the Redtop 35 only comes in one version. There is a "reversed post" battery available for group 34, but not group 35, and group 35 is the specified size for an FEH. Puzzling.

 

I just installed a PepBoys Duralast Gold 96R in our '09 FEHL. OEM Battery started to die a few months back. Noticed that if I sat in the car with just the radio playing the battery would die after about 30 minutes. Last night battery died after 10 minutes of listening to the radio waiting in a parking lot so I figured I couldn't put it off any longer. Paid $116.99 incl. $12 core and used this PepBoys Coupon to get $25 off a purchase of $100 or more. It's good until 8/31/2013 if anyone need a battery or anything else at PepBoys..

 

I think that's the coupon I used at PB for my Optima battery. Good deal.