Battery Maintenance

SWS

Thread starter
Joined
Apr 10, 2004
Messages
397
Location
Tennessee
Thanks to all who have replied - very helpful!

To clarify a few points raised above:

-> For my various cars over 45 years, they were / are my daily-drivers.
The battery slowly degrades until I hear slow-crank over several days. Typical life: 3-4 years.
This is my motivation to try to maintain the battery 'better, somehow'.
(Only once I had a battery suddenly & completely fail - a 2-week old battery with verified internal failure.

-> I bought this car new in 2006 and it is completely stock.

-> Regarding engine-wear driving around town in "D3" (0 to 30MPH), I collected data today during an errand (warmed-up, level road, constant speed -> low load):
"D3" -> 30MPH = 1900 RPM (3rd gear)
"D" -> 30MPH = 1300 RPM (4th gear)
There is only 600 RPM difference.
I do not consider 1300 RPM vs 1900 RPM a wear consideration for this engine.
There is no difference in gas mileage driving in "D3" around town.

Note:
In "D", it will not shift into 5th gear until 45MPH (warmed-up, level road, light load). In 5th gear at 45MPH = 1300 RPM.
So, 1300 RPM seems to be the lowest RPM it wants to cruise at.

When in "D", at less than 40MPH, if there is a small incline or the tiny movement of the gas pedal, then it will immediately down-shift from 4th-gear to 3rd-gear. This is rather annoying since it will up-shift & down-shift a lot driving around town, and for this reason various Honda Forums have agreed that leaving it in "D3" is much better to reduce transmission wear driving around town (for me, typically 30MPH or less).

-> Thanks for the Engine RPM vs Alternator Current Output Graph. I have seen similar data elsewhere, but this is the best format! Note that in a typical cold-start in the winter I am using almost every accessory (headlights, both defrosters, heated seat).
I cannot prove it, but it makes sense to me that a little higher RPM will help the alternator supply the loads, and hopefully recharge the battery at a good voltage.
However, I do have data, repeatable for years: At idle, the alternator voltage actually increases from 14.1V to 14.3V by turning on the bright lights. Whenever I do this, I conclude that that the alternator is healthy.... and I wonder why my battery lasts only 3 years...

Thanks again!
 
Joined
Sep 27, 2015
Messages
4,327
Location
USA
You need to be measuring charge voltage at the battery, ideally on the battery posts (not the terminals), to have a meaningful reading.
 

FZ1

Joined
Feb 7, 2008
Messages
5,798
Location
Texas
This has taken a turn off topic, but bottom line is its not 70% more wear. Maybe 2%.

Alternator curve looks like this, so yes it increases at higher RPMs, but above a certain threshold it is likely outputting more than the battery can absorb.
...so, bottom line is I wouldn't run in low gear for purposes of charging the battery.
Engine-RPM-Amperage-Output-Graph.png
Very interesting, thanks man.
 

FZ1

Joined
Feb 7, 2008
Messages
5,798
Location
Texas
Thanks to all who have replied - very helpful!

To clarify a few points raised above:

-> For my various cars over 45 years, they were / are my daily-drivers.
The battery slowly degrades until I hear slow-crank over several days. Typical life: 3-4 years.
This is my motivation to try to maintain the battery 'better, somehow'.
(Only once I had a battery suddenly & completely fail - a 2-week old battery with verified internal failure.

-> I bought this car new in 2006 and it is completely stock.

-> Regarding engine-wear driving around town in "D3" (0 to 30MPH), I collected data today during an errand (warmed-up, level road, constant speed -> low load):
"D3" -> 30MPH = 1900 RPM (3rd gear)
"D" -> 30MPH = 1300 RPM (4th gear)
There is only 600 RPM difference.
I do not consider 1300 RPM vs 1900 RPM a wear consideration for this engine.
There is no difference in gas mileage driving in "D3" around town.

Note:
In "D", it will not shift into 5th gear until 45MPH (warmed-up, level road, light load). In 5th gear at 45MPH = 1300 RPM.
So, 1300 RPM seems to be the lowest RPM it wants to cruise at.

When in "D", at less than 40MPH, if there is a small incline or the tiny movement of the gas pedal, then it will immediately down-shift from 4th-gear to 3rd-gear. This is rather annoying since it will up-shift & down-shift a lot driving around town, and for this reason various Honda Forums have agreed that leaving it in "D3" is much better to reduce transmission wear driving around town (for me, typically 30MPH or less).

-> Thanks for the Engine RPM vs Alternator Current Output Graph. I have seen similar data elsewhere, but this is the best format! Note that in a typical cold-start in the winter I am using almost every accessory (headlights, both defrosters, heated seat).
I cannot prove it, but it makes sense to me that a little higher RPM will help the alternator supply the loads, and hopefully recharge the battery at a good voltage.
However, I do have data, repeatable for years: At idle, the alternator voltage actually increases from 14.1V to 14.3V by turning on the bright lights. Whenever I do this, I conclude that that the alternator is healthy.... and I wonder why my battery lasts only 3 years...

Thanks again!
Different strokes. Unless your Battery is your hobby, they last 3-5 years, and that's what it is. Go to Walmart every 3-5 years and get a new Everstart Maxx for about $100.
 

SWS

Thread starter
Joined
Apr 10, 2004
Messages
397
Location
Tennessee
mk378 - Yes, I measure to the battery posts as the 'gold standard'.
I also measure between the battery clamps and verify it is the same voltage.
Then I move DMM ground lead to the body and engine block to verify the voltage remains the same.
 
Joined
Mar 21, 2004
Messages
27,555
Location
Near the beach in Delaware
You have an East Penn battery which is one of the better battery manufacturers.

I would not try and pry open any part of the battery to get at the battery cells. It's maintenance free. Leave it at that.

Charge it once a month if you like.

Short of moving north there is not much you are going to be able do that will significantly increase its life.
 

gathermewool

Site Donor 2022
Joined
Jan 9, 2009
Messages
9,486
Location
New England
Maybe you missed where I said,

If OP leaves it in 3rd in all off highway driving, I'd say increased engine wear can be more than negligible. At least gas mileage will suffer more that any possible savings from some perceived increase in battery life.
Right…might as well have said, “I’m going to post an opinion on something, but don’t take me seriously, because….we’ll, I have no idea why I’m posting actually...because not engineer” o_O
 
Joined
Jun 12, 2004
Messages
2,686
Location
Athens, GA
Not wanting to wade into all of the arguments, but.

Both of my J-Series cars are hard on batteries and always have been. The Accord made it 3 years on the OEM battery and goes 2 years like clockwork on the Walmart $60 battery.

The Acura has made it 4 on the Optima that is in it now, but that is getting weak as well, and it sits on a maintainer most of the time.

You can try what you want, but I just drive the car(s) and consider the battery what it is..a consumable. Mine have never failed to the point I couldn't start the car with a small jump pack and be on my way to buy a new one.
 
Joined
Oct 16, 2010
Messages
2,464
Location
california
Maintenance free flooded batteries are designed to fail before ever needing to be rewatered.
They have calcium in the plate paste, which reduces offgassing which reduces water loss.

Maintenance free flooded act like AGMS, in that when fully charged the amperage they accept, at absorption voltage tapers to very low numbers.

But this can take many many hours, and most chargers will not hold absorption voltage for this long.

Isolating the battery from engine heat and keeping it cool, and as close to truly fully charged as you can achieve, is as good as one can get.

The best lead acid battery kept chronically undercharged will not last as long as the worst lead acid battery kept at or very near truly fully charged.

Squeezing in that last 1% can be many many hours of holding the battery at absorption voltage.

One needs to know how much amperage the battery is accepting, at absorption voltgae( 14.2 to 14.8v) @ 77f
accepting 20 amps, no where near fully charged.
accepting 5 amps likely in the 90% to 95% charged range
Accepting 1 amp likely 98% charged
accepting 0.5 amps or less, likely in the 99.5%+ charged range

the amount of amperage any specific battery accepts will vary with age, temperature, condition, state of charge and the voltage actually reaching the battery terminals.
Battery A is not really directly comparable to battery B.
Best to compare battery A, to Battery A when it was newer.

A failing battery only requires only an amp or 2 more to be held at float or absorption voltage compared to when it was newer and healthy.
The 'weak battery taking out an alternator' is an incorrect old wives tale with perhaps the exception of a battery with a shorted cell.
It is just as logical to say do not charge two smartphones at the same time, as it will overload the alternator.

The alternator only makes as much amperage as required to maintain a system voltage.

If a battery only needs 5 amps to be held at absorption voltage, then revving the engine higher is not going to speed up charging.
Only when the DC loads are huge, and the battery well depleted, able to accept 25+ amps, is when one might see a benefit from higher engine rpm.

The power curve of any particular alternator is highly variable.
Some only start making juice at 1900 rpm, alternator rpm, not engine rpm.

Hot idle, in drive, foot on the brake, and the fully fielded hot alternator might be max out at 45 amps. and a few hundred rpm more likely raises the max potential output in the 85 to 90 amp range. Max output might be at 2400 engine rpm on one alternator, and @3200 rpm on another, and it will only make max output if there are loads capable of using that much.

A well depleted healthy battery can easily accept 50+ amps.
Headlamps are about 15 amps
the Hvac blower motor on high is 12 to 18 amps.

My particular vehicle needs about 8.2 amps just to run the ignition and fuel pump, at idle and 12.2 amps at 2000 rpm.
Something more modern could be significantly higher.

Ammeters are wonderfully enlightening.

I have a battery which when held at 14.7v, when it is fully charged, amperage it accepts will taper to 0.0x, the x as I dont trust my ammeters to read less than 5 hundredths accurately and most only read tenths.

If I start my cold engine and my alternbator brings the battery to 14.7v, when amps again taper to 0.0x, all the energy taken from the battery to start the engine has been replenished. This takes abour 45 seconds.

Right after engine starting 75 amps quickly tapers downwards, and right about 45 seconds later the battery is back where it was before starting.

Short trip driving, to alone, be accountable for bad battery life, would have to have the short trips each being less than a minute.

Now parasitic draws,or courtesty headlamps and all other loads can bring a battery down to 90% charged, and starting the engine takes it to 89.97% charged. 45 seconds later is it back to 90% charged. Getting it to 100% will take on the order of 2 more hours.

80 to 100% charged takes no less than 3.5 hours, assuming the battery is newish, and healthy, and being held at absorption voltage for that entire 3.5 hours.
Lower voltages and less healthy batteries will require much much more time to come anywhere near truly fully charged.

How to know? use an ammeter.

Attempting to get maximum longevity from a lead acid battery can be taken to ridiculous extremes.
Requiring time and equipment costing far more than a new battery.

Keep it cool, put a charger on it regularly to try and get it as full as the charger can actually achieve, try to never drain it dead.

Or just dont think about it and carry a jumperpack or cables
 
Joined
Mar 16, 2018
Messages
403
Location
Green Bay, Wisconsin
Driving Pattern:
-> Mostly stop & go city driving, less than 5 miles per trip.
-> I typically drive around-town in "D3" to rev the engine higher.
-> I drive it continuously for 20 miles at least once per month.
The D3 theory is something I wouldn't spend any brainpower on.
You're not driving enough.
Either drive more, or put a battery charger on more.

The solar chargers can work quite well inside the car if you park outside or your garage gets a lot of light.
A solar charger can be put in a garage window, but that's not much different than using a wall battery charger since both would either need to have the car hood open, or hardwire cables to the battery and have a quick-release charger plug in the front grill or other accessible place.

A voltmeter can be a somewhat decent gauge to see what state of charge your battery is in. Check the voltage after driving a good while, or after putting a battery charger on, and then check the voltage again after the car sits for a couple weeks. You might be surprised at how much voltage it can lose from sitting.

For much more accuracy on the state of your battery, get one of the little electronic battery load testers for around $20. It can tell you volts, % of charge, cranking amps, and ohm resistance. Very useful for battery concerns.
 
Joined
Jun 28, 2003
Messages
6,638
Location
Illinois
I tried a solar charger on my lawn mower battery over the winter once. Dried it up and it was worthless in the spring.

We made and developed the maintenance free AGM battery back in the 70's. As long as they are not overcharging they should not need any water. If it is being overcharged then either fix that or get a different style battery.

The maintenance free ones that are not sealed and use the Calcium in the grids is old technology and has been around since the 60's. They have a reduced CCA ability due to the calcium v antimony. But there is a lot less gassing. Antimony is still used in the negative grid as an alloy.
 
Joined
Jul 29, 2013
Messages
1,895
Location
Villa Park, IL
Best thing you can do for a battery is put an insulative wrap around it. Keeps it from extreme lows in winter and extreme heat in the summer.
any suggestions on how? Google searched hasn't turned up many great ideas, does anyone here have suggestions on how to protect the car battery from engine heat? not worried about the extreme cold as my vehicles are parked in a heated garage.
 
Joined
Aug 9, 2005
Messages
743
Location
Chicago
Maintenance free flooded batteries are designed to fail before ever needing to be rewatered.
They have calcium in the plate paste, which reduces offgassing which reduces water loss.

Maintenance free flooded act like AGMS, in that when fully charged the amperage they accept, at absorption voltage tapers to very low numbers.

But this can take many many hours, and most chargers will not hold absorption voltage for this long.

Isolating the battery from engine heat and keeping it cool, and as close to truly fully charged as you can achieve, is as good as one can get.

The best lead acid battery kept chronically undercharged will not last as long as the worst lead acid battery kept at or very near truly fully charged.

Squeezing in that last 1% can be many many hours of holding the battery at absorption voltage.

One needs to know how much amperage the battery is accepting, at absorption voltgae( 14.2 to 14.8v) @ 77f
accepting 20 amps, no where near fully charged.
accepting 5 amps likely in the 90% to 95% charged range
Accepting 1 amp likely 98% charged
accepting 0.5 amps or less, likely in the 99.5%+ charged range

the amount of amperage any specific battery accepts will vary with age, temperature, condition, state of charge and the voltage actually reaching the battery terminals.
Battery A is not really directly comparable to battery B.
Best to compare battery A, to Battery A when it was newer.

A failing battery only requires only an amp or 2 more to be held at float or absorption voltage compared to when it was newer and healthy.
The 'weak battery taking out an alternator' is an incorrect old wives tale with perhaps the exception of a battery with a shorted cell.
It is just as logical to say do not charge two smartphones at the same time, as it will overload the alternator.

The alternator only makes as much amperage as required to maintain a system voltage.

If a battery only needs 5 amps to be held at absorption voltage, then revving the engine higher is not going to speed up charging.
Only when the DC loads are huge, and the battery well depleted, able to accept 25+ amps, is when one might see a benefit from higher engine rpm.

The power curve of any particular alternator is highly variable.
Some only start making juice at 1900 rpm, alternator rpm, not engine rpm.

Hot idle, in drive, foot on the brake, and the fully fielded hot alternator might be max out at 45 amps. and a few hundred rpm more likely raises the max potential output in the 85 to 90 amp range. Max output might be at 2400 engine rpm on one alternator, and @3200 rpm on another, and it will only make max output if there are loads capable of using that much.

A well depleted healthy battery can easily accept 50+ amps.
Headlamps are about 15 amps
the Hvac blower motor on high is 12 to 18 amps.

My particular vehicle needs about 8.2 amps just to run the ignition and fuel pump, at idle and 12.2 amps at 2000 rpm.
Something more modern could be significantly higher.

Ammeters are wonderfully enlightening.

I have a battery which when held at 14.7v, when it is fully charged, amperage it accepts will taper to 0.0x, the x as I dont trust my ammeters to read less than 5 hundredths accurately and most only read tenths.

If I start my cold engine and my alternbator brings the battery to 14.7v, when amps again taper to 0.0x, all the energy taken from the battery to start the engine has been replenished. This takes abour 45 seconds.

Right after engine starting 75 amps quickly tapers downwards, and right about 45 seconds later the battery is back where it was before starting.

Short trip driving, to alone, be accountable for bad battery life, would have to have the short trips each being less than a minute.

Now parasitic draws,or courtesty headlamps and all other loads can bring a battery down to 90% charged, and starting the engine takes it to 89.97% charged. 45 seconds later is it back to 90% charged. Getting it to 100% will take on the order of 2 more hours.

80 to 100% charged takes no less than 3.5 hours, assuming the battery is newish, and healthy, and being held at absorption voltage for that entire 3.5 hours.
Lower voltages and less healthy batteries will require much much more time to come anywhere near truly fully charged.

How to know? use an ammeter.

Attempting to get maximum longevity from a lead acid battery can be taken to ridiculous extremes.
Requiring time and equipment costing far more than a new battery.

Keep it cool, put a charger on it regularly to try and get it as full as the charger can actually achieve, try to never drain it dead.

Or just dont think about it and carry a jumperpack or cables
I recently read flooded lead acid batteries should not be float charged indefinitely, even at <13.6V, because it corrodes the positive plates. I had never heard this before. is there any truth to it? i hope not, i have a bank of grp29 marine batteries that have been floating for 8+ years.
 
Joined
Aug 23, 2010
Messages
3,717
Location
pa
retired + drive little so my batteries get a top up monthly with my C-Teck 4.3 Muse charger, longer top up is best. i have 7-8 year old batteries in bikes + cages, traded a kawi KLX 250S with a good working 8 YO OE flooded battery + bike was rarely used. a boss on my construction site had a 10 YO OE batt in his ford pickup BUT he drove a LOT being a good boss on jobs farther from home!!
 
Joined
May 6, 2005
Messages
8,722
Location
San Francisco Bay Area
I recently read flooded lead acid batteries should not be float charged indefinitely, even at <13.6V, because it corrodes the positive plates. I had never heard this before. is there any truth to it? i hope not, i have a bank of grp29 marine batteries that have been floating for 8+ years.

Depends on what that means. A traditional float charge is where there's a small current continuously placed on a battery even when it's fully charged or perhaps just a manual charger where it's considered low enough that it shouldn't damage a battery. Or at least that's the theory.

What we have today are mostly maintainers - especially those that are running some firmware that controls the charging algorithm. They will charge up to a full charge, stop charging, and monitor the charge level before recharging. There might also be some sort of time component such as waiting several hours after a full charge before it will apply current again - as long as it's still connected. Even my older Schumacher 1.5A maintainer (or small battery charger) with a coil transformer and completely analog charging circuit will cut off current when full (green light) although that one will almost immediately start charging with a depressed voltage such as me opening the door (where the light turns on). My other chargers don't do that.
 
Joined
Oct 9, 2004
Messages
12,571
Location
Cincinnati, OH, USA
2-3 years out of an East Penn? I think I would be load testing batteries, and maybe your starter, before assuming the battery is failing. The MGM in my sig has a AAA EP battery in it, using a 10 watt solar maintainer, and is 7 years old, minimum. It did come from Nashville TN, too. My son's '07 2.4 Accord cranks pretty slowly with a NEW battery...
 
Joined
Jan 25, 2009
Messages
682
Location
Georgia
Here's the Cliff Notes

1) Battery maintainer - 1.5 amp - quality brand
2) Insulation for the battery
3) Keep the posts and the top of the battery clean with battery cleaner (or baking soda with a toothbrush)
4) Keep it garaged - fewer temperature variances
5) Combine rides and keep it running if you're in a low crime area. (Prolongs starter life too.)
6) Make sure the battery is properly clamped to the point where it does not move around
7) Battery terminal protector will be helpful too
8) Turn the radio, A/C, headlights, and all other power items off before shutting down the car
9) Replace the battery terminals if you see substantial rust or prolonged build-up
10) Brag about your battery longevity 10 years from now at BITOG so that I feel this post was worth it.
 
Top