My 07 FEH AWD has about 45k miles on it. It will be pushing over 50k when winter comes. I usually start to look out for 12V battery issues at 3-4 years and 50k miles. I know our cars are "special" and don't use the 12V battery the same way as a regular car. How long do you think ours will last?

 

I got 50 months before a developing a bad cell and need for battery replacement.

 

I just passed 50K miles and 33months on mine. No problems yet. {knock wood}

 

Still on the original battery on an '06 with 155k mi on the clock. One never really knows, however. This is all anecdotal. It'll go when it wants to.

 

111,000+ miles and 5.5 years on my original stock battery.

I just got new tires and the free "100 point inspection" and they said my 12v battery was "marginal". I don't know how they know that, but I'm still driving on it.

I'm concerned about the 330v/14v DC/DC converter now.

When my car was "new" the scangauge voltage was always 14.0 to 14.2 v.
Lateley, it shows 13.0 to 13.2 v. Still ok, but what's changed?

??? Ideas?

 

The lead plates get sulfate coated, when it get thick, it falls to the bottom, shorts out then your dead!

 

2009 FEH 38,000 miles, owned for less than 2 years. 12v battery junk, out of warranty by 2000 miles.

 

Okay, I actually looked at my Odometer this time.... 112,622 miles.
Manufactured in 12/2004. Original battery.

Checker / O'Reilly AutoParts has replacement batteries for $82.95.
2 year free replacement and 72 months pro-rated warranty.
This battery is the same size, but has 12% greater capacity than OEM.

Ford dealer quoted me a Motorcraft OEM battery at $109.99 with 3 year free replacement, and 100 months pro-rated warranty.

So it costs $27 more than the store brand, and has 28 months longer warranty, and the warranty is worth about $1 per month, so it's basically a push of where to go to get one.

I however, will probably go with the store brand for $27 less, since I probably won't keep the car 100 more months ( 8.5 years ) since it is already almost 6 years old.

FYI- I left my FEH parked for a week, with A) a cell phone charger plugged into the always hot outlet and B) My electric trailer brake controller plugged in and C) two scan-gauges plugged in.

All take trivial power, but greater than zero.
My FEH sounded sick when I opened a car door ( doors still unlocked by remote ) but the 12v system was down to 8v and wouldn't turn on the contactors ( high power relays ) for the 330v battery. The 330v battery is what starts the car. The FEH wouldn't start.

Since I knew what was going on, I took a 12v camping lantern that also has a power port for charging cell phones, etc, and plugged that into the car... boosting the voltage.... the contactors worked, and the FEH started normally.
Just proof the 12v is important, and you don't need many (12v) amps to start the car. You don't need jumper cables or a donor car. A very small 12v source will work, if your hybrid battery in is good shape and mine was ~43%.

My 12v seems to have recharged, and has been fine the past 48 hours.