Moving Battery to Trunk

[bheadrick]

I was wondering if there would be any mpg benefit of moving your battery to the trunk. I'm sure there would be a greater benefit for rear wheel drive vehicles, but not sure about front wheel drive.
It's generally cooler there, so this should help the battery maintain the charge as well as improving the battery's longevity. Granted, more wire running the length of the car could add resistance losses, but with a 4GA copper wire, I'm sure the loss would be minimal. I haven't seen it mentioned here, and I thought perhaps it would be in the realm of things that have been discussed.

[Tesla]

No
Unless you have another purpose, there will be no benefit to fuel economy.
Most std battery locations have battery set in a cooler area under bonnet with insulating covers/boxes, so that should be fine, an additional vent can be added using flexible hose if you feel additional cooling is required.
Running the accessories won't be an issue, but, look at the size of the wire that goes to the starter motor, as you increase the length of that wire, you will also need to increase the diameter so you don't lose voltage.
More cost/complications & no benefit, why would you do it?

[Frank Lee]

I'm eagerly awaiting the logic for this one.

[Sven7]

If you road race regularly... you still won't see improvement at the pump. But your Sentra will be just a teeny bit better balanced.

[bheadrick]

I know BMW has batterys trunk-mounted for the sake of weight distribution. A lot of other racing enthusiasts mount their battery in the rear for the same reason.
My logic was that that the cooler temp might be better for the battery, but yeah, it doesn't really stand up to scrutiny.

[mans]

if anyone touches your car you should get a car wash cuz the fingerprint could cause bad aerodynamics, that would reduce your mpg.

always remember that.

(don't mean to be rude, just lets please stick to things that can save you more than .0001 cent in gas per year) like $5 per year minimum ;-)

[shovel]

My CNG powered Tempo had the battery in the trunk, because some parts of the fuel system needed the room up front. Having the battery taking up space back there was annoying, even if it saved a whole gallon every 1000 miles (by magic?) I'd still rather have it up front.

[RunningStrong]

Originally Posted by bheadrick

My logic was that that the cooler temp might be better for the battery, but yeah, it doesn't really stand up to scrutiny.

I thought batteries preferred moderate warmth?

[redpoint5]

The theory posited by the OP appears just as absurd to me as it does to many others, but it's great that the question was asked anyhow. Approaching a problem from many different angles is important, and I would encourage others to be so bold when they have an idea.

While I may have a strong aptitude for physics, I would find other subjects such as physiology quite challenging. I would hope to find people that are considerate with my wild questions/interest.

All this to say that the OP is a brand new member, and I look forward to continued contributions to the efficiency discussion.

Originally Posted by RunningStrong

I thought batteries preferred moderate warmth?

Most chemical reactions are aided by heat, and that is why batteries in freezing temperatures perform so poorly. Obviously you don't want to cook the batteries either.

[Ladogaboy]

My car's battery is located in the trunk, and that is done primarily for weight distribution purposes. As far as I know, it has no affect on mileage whatsoever. Also, something to consider: If you are running the battery in the rear, more wiring is required to connect it to everything in the front of the car (such as alternator, ignition system, ECU, etc.). That extra wiring does add some weight and some impedance, so that would offset any potential gains from battery efficiency.

That being said, I have been thinking of ways to maximize my battery terminal location. I can easily upsize or downsize my battery; run two batteries in parallel; and have easy access for alternative charging methods.