Changed my Battery, increased MPG by 10%

[imzjustplayin]

Originally Posted by add|ct

^Interesting, I know my battery is somewhat low on fluid currently, it looks to have sweated some recently(possibly from the alternator having to run at full-recharge from jumping it off a while back now, 3-4 months). I never re-checked the fluid level under the caps, but did put it on a slow charge overnight about a month after the initial 'headlights left on for 2-3 hours bit'.

FWIW, this Civic calls for a 51R, and it currently has a 51 installed. Of course, the battery cables are connected to the correct post, but still makes me wonder.

It's a good idea to get a hydrometer and measure the specific gravity of each battery cell. I did this and found I had one cell that was severely undercharged and another that was also quite a bit undercharged. I "manually" equalized the battery and now they're pretty close to being all the same level and it definitely has helped. The battery came with the car when it was new and I'm trying to extend its life as much as I can. Don't add distilled water to the cells until you're absolutely certain the battery and its cells are 100% charged. If it's severely low on water and the battery is 90% charged, you can also add water. Commonly people add water when they see the levels are low but don't know that the levels go up when you charge the battery, resulting in a spillage of battery acid.

[theclencher]

Originally Posted by bowtieguy

seriously tho, the battery was on it's way out. besides, i think replacing a battery before it fails is good maintenance...especially for your wife's car. i think the married guys know what i mean

Many years ago I noticed a definite reality: odds are, if it's a nice new car a woman is in it. If it's a beat up old P.O.S., a guy is in it. Fair? I think not. Maybe I'll pretend not to know anything about laundry, cooking, or vaccuuming so that women are stuck with it all? Think that'll work?

[bowtieguy]

clencher,

i have a house full of women, so i don't have any luxuries to speak of. that said, i'm the only one employed, so i don't know what (inside) house work is, nor should i

i don't mind driving the lesser car however. truth is my dream car would be a 4 door, 4cyl luxury car...acura or lexus perhaps.

[1993CivicVX]

Originally Posted by add|ct

Staying on topic, I've wondered this for the VX I drive.

It had a Die Hard battery, but it's not reverse in the position of the Pos/Neg posts. The positive is positioned closer to the passenger side, while the negative is closer to the driver's side. This vehicle spec's for a 51r, IIRC. Would that make a difference?

For the record, the battery has been drained "completely" or close to it once, and near completely a 2nd time, in the last 2 years. Ran a slow charge all night twice after each incident. Added one engine ground(4 gauge wire), and cleaned up the others. The alternator was inspected by a Honda Master Tech and was within spec.

Still, I wonder if a new battery would improve MPG any or idling conditions.

My battery is very weak at this point (kept alive by the warm weather). My idle is as good as it ever has been, so from my experience I can't say that a strong battery would have much bearing on that issue. The only way I would see an improvement in fuel economy is because I'd be able to do more engine off coasting. But I'm curious to learn more about voltage or other factors possibly having a bearing on fuel economy.

[add|ct]

Originally Posted by 1993CivicVX

My battery is very weak at this point (kept alive by the warm weather). My idle is as good as it ever has been, so from my experience I can't say that a strong battery would have much bearing on that issue. The only way I would see an improvement in fuel economy is because I'd be able to do more engine off coasting. But I'm curious to learn more about voltage or other factors possibly having a bearing on fuel economy.

I feel similarly. Makes me wonder how well my engine is grounded(decently I imagined...in other words barely)...I did add a 4 gauge speaker ground wire to assist on the engine grounding and cleaned up the original ground wires for the transmission and engine.

[imzjustplayin]

Originally Posted by add|ct

I feel similarly. Makes me wonder how well my engine is grounded(decently I imagined...in other words barely)...I did add a 4 gauge speaker ground wire to assist on the engine grounding and cleaned up the original ground wires for the transmission and engine.

The best thing you can do is get a multimeter, use the OHMs function and measure the ohms from various ground points on the car. If the ohms are above 0, it's time for a good cleaning and or repairing. I also noticed that o2 sensor output is ignored on our civics when the o2 sensor's ground reaches above like 1 ohm of resistance. Good to have a multimeter with at least 1 decimal place, preferably two decimal places.

[add|ct]

My dad has an old multimeter, so I'll check youtube on how to use it.

In other news, I ran by a local O'Reilly Auto and did the 'free battery' test with the engine cut off. The guy checked for the group size and CCA ratings, then within a minute he told me: Bad Battery.

The car starts fine, but I'd imagine this winter will be a different story. I checked the fluid levels tonight and from previous servicing last summer, after a drain on the battery then, it still had plenty of fluid.

Last year, both of the cells nearest each post were near dry or basically dry. Again earlier this year(March?), another 'headlights left on b/c of no buzzer' incident for 3 hours!!! I needed a friend with a bigger truck to jump start the car off after sitting for 10 minutes with his vehicle running connected to my battery, it worked enough to get the car home(even while stopping at a gas station on the way back), but I didn't charge it slowly until 3-4 weeks later. Fast forward 3 months and here we are. Starts fine, AC isn't very cold(not sure if that matters), but my fuel economy is down and the interior console lights flicker intermittently. Though the headlights appear to be okay.

[imzjustplayin]

Cars will definitely crank to as low as 10.5v, however a battery voltage of only 11.9v is considered "fully discharged". I suggest you buy a good battery charger and maybe even one that has a desulfate function on it, though you'll have to keep the battery disconnected for some time when you do run the desulfate function. I currently have a battery charger but it doesn't desulfate and so I can only charge my batteries to a maximum of 12.4v (after 24 hours of letting the battery sit) instead of the battery's full charge voltage of 12.7v.

Some chargers I've been looking at:
http://www.amazon.com/gp/product/B00...A2U296R8AN80PO
http://www.amazon.com/gp/product/B00...=AR8XJJ19SNPNX

and one cheap charger that I can leave inside of the engine bay of my car:
http://www.amazon.com/gp/product/B00...=ATVPDKIKX0DER


BTW, autozone will charge your battery for free if the need ever arises, though they use a fast charge and that damages the battery a bit.

[add|ct]

^That's good to know in an emergency, especially if I continue with this battery until the winter and it gonks out on me. It'd probably fail to start first thing in the morning.

I do have the battery slow charging tonight at 12V 2A. I plan to leave it on there for 15-16 hours, and have the battery re-tested tomorrow at another location.

Last year when I stopped by to have AutoZone perform the free battery test, they told me I had a bad voltage regulator. So, I had my mechanic service the alternator/make sure it was within spec and he said it was doing it's job fine. It was putting out 68A(70A rated alternator), with some other 'stats' I can't recall.

My only concern is, if you had a 'relatively' "bad" battery, that still cranks your vehicle could it still shorten the lifespan of the alternator or cause other symptoms/performance issues from the alternator working itself more?

[imzjustplayin]

It's been noted that having a weak/bad/discharged battery can burn out your alternator since it's constantly running at peak in order to keep the voltage in spec. Most people who know about this agree that it's not a good idea to charge your car battery with your alternator. It's interesting that you mention the dichotomy between the autozone testing of the alternator and your mechanic's testing of the alternator giving completely different results because as it turns out, a discharged battery will skew the on car alternator testing. My battery charger I use has an alternator check and the car consistently failed this check before I had equalized the battery's cells but after equalizing, it passed.