I'm running a lawn tractor battery in my Grand Marquis

[ford46guy]

It was sitting for a while and the very old battery can't take a charge. So to repair (new fuel pump and shift cable) and move in the garage it I put in a 230CA/275CCA Lowes/Deka flat top and makeshift terminals to adapt.
Forgot about it for the past 2 weeks..always started up on the first click.

I bet it would never start in the winter. Shows how little CA you need to get things going, and this is a big V8 engine. Battery tests out very close to spec.

 

[thastinger]

Have often pondered how much fuel could be unexpended with starting batteries that weigh less than the FLA tech which comes in OEM SLA batteries. 10 years age I built a battery for my drag bike that was setup as 4S4P configuration and made from the original A123 26650 cells. It weighs 3.5Lbs, charges from standard alternator and has 750CCA but only for 5 seconds...and LiFePo4 batteries don't like the cold. It started my 5.4 F150 with ease and it weighs 70 Lbs less than the OEM battery...problem is lack of capacity...leave your headlights on for 10 min and your out of luck.

 

[SwampSurvivor]

When I bought my Cherokee it had a lawnmower battery in it. I left it in there a few days but ultimately did not trust it for more than that.

 

[Dave9]

Originally Posted by thastinger
Have often pondered how much fuel could be unexpended with starting batteries that weigh less than the FLA tech which comes in OEM SLA batteries. 10 years age I built a battery for my drag bike that was setup as 4S4P configuration and made from the original A123 26650 cells. It weighs 3.5Lbs, charges from standard alternator and has 750CCA but only for 5 seconds...and LiFePo4 batteries don't like the cold. It started my 5.4 F150 with ease and it weighs 70 Lbs less than the OEM battery...problem is lack of capacity...leave your headlights on for 10 min and your out of luck.


Practically no fuel savings at all. Even a light to medium duty truck lead acid battery weights around 46 lbs (group 65 for example is about the same weight as a 5.4L F150 uses, for the heavier "Gold" upper tier CCA batteries), so by the time you set up a much more expensive yet lighter weight battery safely, you'd maybe shave 35 lbs off... of a vehicle that weighs thousands of pounds, you're reducing weight by about 0.7% which based on EPA averages, would result in half that % in fuel economy improvement. EPA states around 1% improvement per 100 lbs.

So say you have a vehicle averaging 18MPG ("big V8" was mentioned in initial post), that approximate 0.35% improvement would result in about 18.06 MPG. At 12,000 mi/year the difference would be about 2 gallons per year, you'd save/make just as much money investing that money in a normal investment with an average return, instead of a lighter battery, or one time making a meal at home instead of eating out would take far less time than constructing such a battery and save as much money.

What's better for the environment? Driving something that gets a lot more than 18MPG.

 

[supton]

Few winters ago the battery in my truck went dead for no good reason--like 8.5V dead. I hooked up my car and the truck cranked over at full speed with less than 30 seconds of jumping -- 20 years ago I wouldn't have believed it, used to be it took several minutes of charging to get any cranking speed.

When I posted about it on here, I was told that the modern gear reduction starters are really good today. Then eljefino posted that he bought a Vic that would die when he removed the jumper cables--it was jumping and running completely over the jumper cables! I suppose it makes some sense, I mean some cars relocate the battery to the trunk, although they don't have to deal with the (typically) cruddy jumper cable connections ("let's wiggle it and watch for sparks, that way we'll know it's good and connected").

 

[AuthorEditor]

Quote
EPA states around 1% improvement per 100 lbs.

It depends on what kind of driving you do too. Once up to highway speeds most of the effort from the engine goes into overcoming wind resistance, which is why you see most big rigs now with all sorts of spoilers and flaps. They are still running close to max weight but saving fuel partly due to less wind resistance. The weight will add a bit of work while accelerating, but once up to speed will make very little difference--I suspect unmeasureable without special equipment. In any case, look at the tiny rechargeable lithium battery packs that can be used to recharge your cell phone and also jump start your car. I've use one about the size of a paperback book to jumpstart a few cars and my motorcycle. I then recharge it with my cell phone charger!

 

[Dave9]

^ Yeah but those little jump starters aren't going to last if you start your vehicle every time with them, cost per start or per year would be even higher, and they usually depend on the existing battery being a little helpful in supplying current in parallel (particularly on a larger engine) unless it's a larger/expensive jump starter so in the former case you aren't replacing the battery entirely with it.

I do expect that the EPA made their estimation using special equipment, but indeed it is only an estimate, that will depend on several factors. Either way the point remains that it's not worth doing to save a little fuel compared to any other way to save fuel. If someone has done every last thing on earth to save fuel besides this and needs to keep at that hobby, sure it's your vehicle and your money and time to do whatever you want.

 

[bullwinkle]

Weight is important to MPG in stop & go and uphill & downhill driving, but once you get up to speed-wind resistance, rolling resistance, friction, even gearing is where the improvements happen.

 

[thastinger]

Originally Posted by Dave9
Originally Posted by thastinger
Have often pondered how much fuel could be unexpended with starting batteries that weigh less than the FLA tech which comes in OEM SLA batteries. 10 years age I built a battery for my drag bike that was setup as 4S4P configuration and made from the original A123 26650 cells. It weighs 3.5Lbs, charges from standard alternator and has 750CCA but only for 5 seconds...and LiFePo4 batteries don't like the cold. It started my 5.4 F150 with ease and it weighs 70 Lbs less than the OEM battery...problem is lack of capacity...leave your headlights on for 10 min and your out of luck.


Practically no fuel savings at all. Even a light to medium duty truck lead acid battery weights around 46 lbs (group 65 for example is about the same weight as a 5.4L F150 uses, for the heavier "Gold" upper tier CCA batteries), so by the time you set up a much more expensive yet lighter weight battery safely, you'd maybe shave 35 lbs off... of a vehicle that weighs thousands of pounds, you're reducing weight by about 0.7% which based on EPA averages, would result in half that % in fuel economy improvement. EPA states around 1% improvement per 100 lbs.

So say you have a vehicle averaging 18MPG ("big V8" was mentioned in initial post), that approximate 0.35% improvement would result in about 18.06 MPG. At 12,000 mi/year the difference would be about 2 gallons per year, you'd save/make just as much money investing that money in a normal investment with an average return, instead of a lighter battery, or one time making a meal at home instead of eating out would take far less time than constructing such a battery and save as much money.

What's better for the environment? Driving something that gets a lot more than 18MPG.

Agree with about all your points, but on economy of scale spread over 100s of thousands of vehicles, cutting 55 or 60 Lbs from each will add up to a considerable fuel savings. Aluminium bodies pickups aren't the norm because anyone believes AL is stronger than steel pound for pound. I'm not intending to get into the carbon footprint of mining rare Earth elements as I believe that to be carbon negative effort, however, Ethanol as a fuel source is also carbon negative and we keep doing that. I'm not a tree hugger but FLA battery technology has severely lagged behind in technological advances over the years, they are too heavy for the capacity.

 

[eljefino]

Yeah I jump started a Grand Marquis with bad alternator and totally dead battery. Used the side terminals of my 4 cyl Saturn and ten gauge cables.

That v8 was so well balanced once the first cylinder got over it's compression point, it just turned over faster and faster until it caught.

 

[AuthorEditor]

In my experience the problem with the Grand Marquis and the Crown Vic is the location of the starter where it is sure to get liberally doused with whatever you are driving through. Here in the Northeast that is a slurry of slush and road salt for much of the winter, soon rendering the starter useless no matter how big your battery. Plus, it's a pain to change because you can't reach the bolts without a Rube Goldberg assembly of socket extensions and wobble joints. In any case IMHO it is best to use the biggest battery that fits and ignore the weight which would be almost unmeasureable in terms of gas mileage. The average American would save more on gas if they went on a diet.

 

[user52165]

I used one of these:

https://www.amazon.com/gp/product/B00EJPOQRU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

to start a SBC 350 10.5 compression ratio engine. Won a $50 bet with a friend. Taken from my generator when it was 2 years old, now 3 and still doing fine.

Full disclosure - I have upgraded cables - 1 gauge - and an ungraded starter - a high torque, gear reduction type.

Not the normal battery, one time use only.

Chrome batteries rock - highly recommend them.

 

[user52165]

Oops - a typo - that is a upgraded starter.

BTW - that battery actually weighs only 3 lbs. The weight in the specs is shipping weight.

 

[bbhero]

I don't think FLA batteries could change but so much...

Even AGM battery coming into use hasn't saved much weight either... In many cases the AGM batteries weigh more than their FLA counter parts. Heck, even a group 35 AGM battery weighs 39 pounds vs a flooded group 35 battery which weighs 37 pounds for the high end flooded battery...


Only lithium ion batteries would weigh less...

But I don't know if that would be economically feasible for almost 95 percent of the general public.

I use a lithium battery in my stethoscope because it is well lighter than a typical alkaline battery... It also last 6 times as long too.