This certainly has a better likelihood to work than the 9V ones. And it's certainly convenient if it lets you avoid having to reset you audio setup. But the only real "cost" of not bothering is somewhat sub-optimal mileage on your next tank or so while the trim levels are relearned.

 

Yes except mine is a Solar brand. One thing that must be watched if your using anything like this is that your positive battery is going to be hot or powered when you remove so it can be shorted out. This isn't mentioned in the instruction sheet and seems like it should be.

The audio system was mentioned but my dealer replaced my battery during a series of visits for a transaxle leak and it wasn't on my paperwork. I didn't lose any radio stations. Maybe they used something like that or the radio stations aren't lost.

The relearning is more of a problem with older vehicles that are worn out.

 

I hadn't considered that. So if the + battery terminal were accidentally shorted, would something on the OBD bus be damaged since that's where the jumper battery is connected? Maybe it's better to just connect my jump pack battery directly to the underhood battery terminal so that any shorts wouldn't be back through the vehicle electronics.

 

The wiring for the OBD-II is designed to power it only so the wires aren't made for a dead short but nothing really is?? A slight tap on ground wouldn't but a prolonged short to ground wouldn't melt the wires. I've seen a dead short on a two cell "AA" Ni-MH holder melt the end of holder right off! It only took 10-15 seconds.

You could do that but yours dealing with an extra cables getting in your way. Just stick the positive cable in a leather glove and tape it up or zip tie it so it doesn't slip off.

 

This might be a silly question but what happens if you swap 12v batteries with the car running?

Additionally, has anyone considered replacing the stock battery with a deep cycle battery. The FEH doesn't use the 12v as a starting battery to turn over the engine with a starter motor anyway so why use one designed for that in the first place? I would imagine a sealed AGM type battery would last much longer and as a bonus you could listen to your radio with the engine off for a long long time.

 

There has been much posted elsewhere about 12V batteries in the FEH. If memory serves me right the general consensus is that going with a "better" battery will not return the value. All batteries "go" eventually and the extra expense for a "better" one is not worth it. And deep cycle batteries are not sensible for this usage. I've found the factory ones to last at least 6 years, sometimes more. Save your money for something more worthwhile, is my suggestion.

 

A modern vehicle won't run without a battery and disconnecting a running vehicle could cause a voltage spike.

 

How is a deep cycle battery not sensible? The car doesn't use it to start the engine. Serious 12v power is supplied by the HVDC/DC converter. I'm not suggesting buying an Optima or anything daft like that. I could get a suitably sized AGM type deep cycle for about $100 or so. Honestly, I have no idea what the stock battery cost. I did have to replace mine a few years ago and I suspect mine is about to die again but I don't remember what it cost.

 

The way you use the battery in an FEH is not deep-cycling, no matter what (OK, so if you have those huge drivers for speakers and play mind-numbing bass stuff for hours with the car turned all the way off .... then .... perhaps .... maybe. But you shouldn't be disturbing the neighborhood that way in any case.) The extra cost is a waste. And besides, deep-cycle batteries are "supposed" to be deep-cycled and you won't be doing that hardly ever. The standard OEM battery is as good as it gets for this car. And ... another thing, you'll most likely have to work to find a deep cycle battery that fits. It's an old size (at least in some years). There's a time for the very best and this isn't one of them. Save your money.
Buy a nice little portable radio with a couple of "D" cells and you'll be just fine. ;-)

 

The Optima Yellow Top is $140, about $40 more than an OEM, and it's a perfect fit in the FEH. The Red Top might be slightly less. I won't buy unsealed batteries anymore, just too messy, they alway corrode the battery tray over time.