new battery or try battery tender?

I'd buy a new battery. Used monday-friday is enough to keep a good battery charged.


Except for when it sits "a day or two in -30 weather".

One of my kids has the same problem in Montreal. He parks his civic on the street so cant plug in.

It's probably done.
 
I live in Minnesota. I have a 2008 RAV4 and working from home. I let it sit for 5 days and today, 18F outside, it poped right off. Your battery is dying, in my opinion. You should be able to let it sit 2-3 days with no issue.
 
Except for when it sits "a day or two in -30 weather".

One of my kids has the same problem in Montreal. He parks his civic on the street so cant plug in.

It's probably done.
And at those temperatures, electrolyte will slush or freeze at reduced SOC. That doesn’t help.
 
The % charged screen on chargers that provide such, is pretty much useless in most scenarios, as full charge resting voltage can be as low as 12.62 on some batteries and as high as 13.23 on others, and this will also change with battery temperature. Very few chargers have temp sensors on the battery clamp, making any % charged screen even more worthless.

Im sure we would all be fascinated to know what SLI lead acid batteries are vendor-documented to show >2.2V/cell OCV at 100% SOC.

I agree that the SOC reading needs to be taken with a grain of salt. That said, once operational, a charger with a voltage reading tells the conduction voltage, which isn’t a bad thing. I’ve often wondered if units like the Clore which tell (only) conduction voltage and SOC, somehow correlate SOC to current flowing in. I’ve observed that it keeps an elevated voltage until 97%+.


People really only start using a charger regularly on the less than healthy battery, so the premature float voltage initiation, and the lying green light is doing the battery and the battery owner no favors.

LED adjustable voltage power supplies capable of 30 amps can be had for under 25$, but they are far from automatic. They can however truly fully charge a battery back to its remaining potential capacity for the human who demands it and has the desire to operate it, and an Ammeter and or hydrometer.

Much easier to believe a green light though

Some chargers now have a bad cell or similar warning. Reality is that while you’re correct that many only put on a charger when a battery is getting weak, and may not get the full story, or even be misled by the “green LED”, the reality is that someone who has had to go through that is most likely already monitoring condition of their battery, and planning for replacement.

And in that situation, the performance will tail off again soon thereafter.

It is dubious that anyone is going to go buy LED coltage controllers, and manual power supplies and other things. I find it dubious that most folks will safely remove and attempt to repair/balance their battery (ideally out of the vehicle, since elevated voltages degrade capacitors in various circuits faster), in a situation where a “repair” mode is available. And such modes can be dangerous. If you’ve never seen swollen AGM batteries, or burning, thermally ran-away batteries, you’re better off. The conservative route is better for something that people may leave unattended for days, weeks, or even months.

That said, being more aware of what’s actually going on is a very good thing. Now that one can get dc amp clamp multimeters for
Uni-T B4Q094 UT210E True RMS AC/DC Current Mini Clamp M W Capacitance Tester https://smile.amazon.com/dp/B00O1Q2HOQ/ref=cm_sw_r_cp_api_glc_fabc_MoY7FbKVNX8GJ
 
Both!
My surface reading leads to not trusting battery racks in stores very much, but there's a chance a potentially long-life battery in there waiting.
Put it in and then charge overnight, gives it the best chance of getting a truly full charge early in life.
Then repeat every month or so, and do all the cars while the gear is out.
Apparently alternators never quite get that full charge, and it does affect life.
 
If the battery does not have enough juice to turn over the starter then it needs a charge from a charger. The products like a Battery Tender put out around 1 amp and are designed to maintain a battery rather than charge it.

Charge current battery and test it. People who do DIY car work need a charger, maintainer, tester, hydrometer.
 
Both!
My surface reading leads to not trusting battery racks in stores very much, but there's a chance a potentially long-life battery in there waiting.
Put it in and then charge overnight, gives it the best chance of getting a truly full charge early in life.
Then repeat every month or so, and do all the cars while the gear is out.
Apparently alternators never quite get that full charge, and it does affect life.

Ive seen some batteries in different stores with old date codes, but I’ve never gotten a battery that measured less than 12.7V when I got it home.

But the key is to try to seek out the newest ones.
 
Im sure we would all be fascinated to know what SLI lead acid batteries are vendor-documented to show >2.2V/cell OCV at 100% SOC.

I agree that the SOC reading needs to be taken with a grain of salt. That said, once operational, a charger with a voltage reading tells the conduction voltage, which isn’t a bad thing. I’ve often wondered if units like the Clore which tell (only) conduction voltage and SOC, somehow correlate SOC to current flowing in. I’ve observed that it keeps an elevated voltage until 97%+.




Some chargers now have a bad cell or similar warning. Reality is that while you’re correct that many only put on a charger when a battery is getting weak, and may not get the full story, or even be misled by the “green LED”, the reality is that someone who has had to go through that is most likely already monitoring condition of their battery, and planning for replacement.

And in that situation, the performance will tail off again soon thereafter.

It is dubious that anyone is going to go buy LED coltage controllers, and manual power supplies and other things. I find it dubious that most folks will safely remove and attempt to repair/balance their battery (ideally out of the vehicle, since elevated voltages degrade capacitors in various circuits faster), in a situation where a “repair” mode is available. And such modes can be dangerous. If you’ve never seen swollen AGM batteries, or burning, thermally ran-away batteries, you’re better off. The conservative route is better for something that people may leave unattended for days, weeks, or even months.

That said, being more aware of what’s actually going on is a very good thing. Now that one can get dc amp clamp multimeters for
Uni-T B4Q094 UT210E True RMS AC/DC Current Mini Clamp M W Capacitance Tester https://smile.amazon.com/dp/B00O1Q2HOQ/ref=cm_sw_r_cp_api_glc_fabc_MoY7FbKVNX8GJ


Overall a very, very good post JhZR2. Outstanding in my opinion.

One point though... A Full River AGM TPPL battery or a Northstar TPPL AGM battery could easily be 13.23 100% percent static state of charge batteries.
 
Overall a very, very good post JhZR2. Outstanding in my opinion.

One point though... A Full River AGM TPPL battery or a Northstar TPPL AGM battery could easily be 13.23 100% percent static state of charge batteries.
Thanks.

I just went and looked through the application guide, I didn’t see where they claim anything beyond 12.8 or 13V as 100% SOC.

Have a link?

Thanks!
 
I am on my second Northstar AGM battery, the first was a group 27. When new it read 12.84v off the shelf, and northstar's rather limited spec sheet said full charge resting voltage should be above 13.0v. I kept trying top charges withut a deeper discharge, and it would never rest above 13.0v, until I deep cycled it and then applied 25 amps until the so called smart charger shut off, and then let another charging source hold it at 14.4 a bit longer. From that point it was 13.06v full charge rested

back then Northstar Spec'd 14.44v Absorption at 77f. Their documentation never impressed me. I started following Odyssey's recommendations as to charge specs, as well as those by some highly experienced marine electricians with gobs of experience using 14.7v absorption on TPPl AGMS in deep cycle duty.

I got over 1200 deep cycles over 6 years out of that northstar. 6 years is no benchmark, but 1200 truly deep cycles, about 100 of those to 30% charged and perhaps even a bit less, over 6 years is. There is of course many thousand engine starts and likely a thousand shallow cycles to 80 or 85% as well. the amount of KWH this battery delivered over those 6 years was downright impressive.

I replaced it with a group 31 Northstar agm and the highest voltage one on the shelf out of 6, was only a disappointing 12.74. I did not really stress this and immediately drained it to about 50% State of charge, and promptly applied 40 amps to reach 14.7v held it until amps tapered to close to 0.5, and then and 5 hours off the charger, unloaded, it was still reading 13.17v. I did not wait to see what it would have dropped to. Its been in continuous service ever since and I am not sure what its true full charge resting voltage is, but I expect it too is over 13 volts

In 2015 I got a Lifeline GPL 31XT, fresh from the factory in West covina for a friend's portable powerpack I was hired to make. it read 13.12v, and I brought it to 14.4v, and amps never tapered to 0.62 which is 0.5% of 125 amp hours. I knew new batteries, at this point, to behave oddly, and cycled it, then again, 40 amps at 14.4v and this time amps did taper to 0.62 @ 14.4v, and I removed charger and battery sat for a few days. When I checked voltage at was 13.23v. I wound up using the battery, drawing 2.3 amp hours from it, and did not immediately recharge it, but two days later it still read 13.16v.

More recently I got 8 lifeline GPL-4ct's for a boat. They were about a month old on delivery, each 6v battery measured 6.56v +/- 0.02v when I opened their boxes. That would be 13.12v when wired in series as a 12v battery. I've read Lifeline's PDF many times but I've no recall saying they should rest fully charged over 13.0v.

The point being, that 13v+ resting voltaeg on AGM batteries At least TPPL and Lifeline/Concorde AGM thick positive plate deep cycle batteries, is common.

I've no personal experience with Full river's TPPL offering, just became aware of them, but higher full charge resting voltage can be manipulated with higher electrolyte density and most AGMS are said to be 1.300 or higher whereas most flooded batteries are in the 1.275 range unless intended for tropical locations where 1.265 is more likely.

Pretty sure Odyssey claims 12.8 is full charge resting voltage. I've little experience with Odyssey AGMs, but do respect them greatly.

The other two batteries I own and have been the sole cycler thereof, since they arrived, are just small Asian made AGMS, UPG or UB batteries, commonly installed in lead acid jump starters. one is 18Ah the other is 22AH. both werer 12.84ish on arrival and a few months old. Ther Ub12180 holds 13.16 several days off the charger, but then seems to lose 0.02v per week disconnected from everything. The newer UB12220 holds 13.14v+ several days off the charger, and there after has the same apparent self discharge as the Ub12180.

Either of these batteries, and the Ub12180 is now 2.5 years old, can start my 5.2 liter 2 week cold v8, by themselves, showing just how little CCA is actually required to start an engine, even a relatively large one, and just how degraded a 500CCA( when new) battery can be before it can't do its job.

The UB12180 does take much longer to actually drop to 13.16 than the Ub12220 does to drop to 13.14v after removal from charging source. The newer 12220 drops to 13.14 in ~15 minutes, the older Ub12180 takes hours.

So there is two more batteries which have resting full charge voltages over 2.2 volts per cell.

I often use these batteries to power lights or fans in remote locations, sometimes briefly, but will use my wattmeters to see just how many amp hours I pull from them. I can pull almost 2 amp hours from either battery, and voltage will have dropped to as low as 12.5 when powering the loads, but still rebound, without a charger applied, to over 13 volts.

The spec sheet for either battery says nothing about an resting full charge voltages over 13. it specs your 2.2 volt per cell as maximum, or 12.8v, yet I see well over this, on multiple different voltmeters, even when discharged slightly and voltage allowed to rebound, and this is NOT in hot ambient temperatures and a battery hot off the charger.


Heck i just went out and checked them, and neither have seen a charging source for more than 2 weeks and one was 13.06 the other is 13.12v, but now both are connecte to my power supply and are 13.6v, though i did not bother seeing how much amperage they are consuming at that voltage..

Many times over the years we have butted heads regarding lead acid batteries JHzr2. You seem to be the defender of smart chargers, after I call them out for their chronic undercharging behavior.

This is Bitog, there are hundreds of thread titles starting 'what is the best...whatever, not what is good enough..... whatever.

Ideal battery longevity is achieved by keeping the battery cool, not overdischarging it, and promptly returning it to the highest possible state of charge after any level of discharge, not 92% not 97%, but a true 100% state of charge. Undisputable fact.

You seem to say that 98% charged is good enough, as if that is fact, and imply what you consider is good enough, is indeed fact and good enough for everybody, but that is only your opinion.

For those of you who want to establish 'good enough' for themselves, regarding battery charging, you need to know what is ideal, and how to achieve this. This is the info I try to relate, from many years of experience with many different batteries and close observation of them as they age, on many different chrging sources, using tools and interest to measure and refine.

The green light on a smart charger could very well be good enough, for perhaps a majority of readers here. They are only batteries, only rented, and doomed to failure no matter what, the only variable being time to failure. Most readers here can get a new battery at 20 different spots within a 15 mile drive, or delivered to their doorstep the next day. Even without a warranty to totally or partially cover the cost, it is not a budget breaker for most. Certainly not worth the effort acquiring an adjustable voltage powersupply, hooking up ammeters, voltmeters, amp hour counters dipping hydrometers, making graphs, doing experiments, taking notes, keeping records..its just a battery easily replaced, why bother?

I never meant to imply every person needs to do this, only that if they were to actually do it, they would find the smart charger falls well short of achieving a true 100% state of charge, as its marketing implies.

I ask myself this often, why I go through the effort, when replacement more often is less stressful and easier, even though my batteries provide much of the electricity I use and a significant percentage of their recharging is acheived largely by the sun or my alternators. Their lifespans are important to me, not only to get my money's worth, but to not add any more than I have to to our landfills and atmosphere. Our disposable society, where everything is just thrown away when convenient with little thought to the energy used to make it, or what happens to it after it is of no further use to them disgusts me on so many levels, and makes me ashamed to be a part of it.

So many years ago, tired of having to replace batteries, warranty or not, often, I was bothered by them failing prematurely, and decided that I would get as much possible life from them, and began the process of acquiring the knowledge and data and tools and experience in order to do so .

I got a 'smart charger' used it often, with little improvement in battery longevity in a deep cycle application and got irritated when I'd remove 35amp hours from a 115 Ah battery, and see only 12.15v under a 1 amp load. From that point watch the battery degrade faster and faster and become become more and more useless to the point it was a waste of time and electricity trying to charge it as so much was turned to heat and hydrogen and oxygen. I did blame the battery mostly, rather than my charger, as I was still a fool.

When I got a newer heavier more expensive marine battery from a respected manufacturer, within two weeks of cycling it, was very dismayed at the performance, which I measure by voltage retained with x amp hours removed under X amount of load, which I watch closely and have for many sets of batteries over many years.
While i had resisted previously, I got a good hydrometer, temperature compensating, and saw my so called smart charger, was only returning specific gravity to 1.225, which is still in the red, when it would switch from absorption voltage, to green light float, and 10 hours held at float would do absolutely nothing to further raise specific gravity, but that green light was shining away saying all was well.

I'd restart the charger. it would go upto 14.7v for a while, then drop back to float. 1.227, Again restart, 1.229, again 1.231, on and on.

i could not get the smart charger to stay on and maintain 14.4 or higher volts, and I could NOT fully charge it, and the performance during discharge was extremely disappointing. I was dismayed enough I was again blaming the battery, I took it back to the distributor who of course put it on their carbon pile load tester and their midtronics impedence tester, and it read good, stil lhad higher than the spec'd CCA and they were like, no warranty for you.

I had no way to actually hold voltage higher for longer, other than to set my solar controller absorption and float voltages to 16, and make sure the battery was 'fully charged' by 10Am when the sun got strong enough to push the battery upto 15.5+ volts.
The thing was fizzing up a storm when I did so, but the specific gravity was rising, and late afternoon the specific gravity was 1.280 on almost all the cells.

That night the voltage held during discharge was respectable, but the next night was not as good, nor the next, and it kept walking down. My solar was inadequate and often I would plug in and use the smart charger. same results as before, it would simply quit when specific gravity was in the red, and multiple restarts would do little to nothing to further raise specific gravity, as it would keep reverting to float voltage i less than 10 minutes, over and over.

I tried my different smart chargers, the BM 12248 being one of them, with teh same results, and returned it to my friend as 8 amps was just too slow for my purposes and SG was reading even poorer when it switched to float.

I then got a cheapo LEd power supply, adjustable voltage and wattmeters/ammeters, and was able to hold the battery as high as 15.43 volts with it, and I was able, using this power supply, to max out the specific gravity, but it took many many disappointing hours to do so. Dipping the hydrometer often.

That cheapo power supply did not have current limiting on overload and a depleted battery would easily overload it. It would be able to feed as high as 38 amps into the depleted battery, but over 36 amps it made this weird clicking sound, so I limited voltage to keep amperage just under 36, and kept raising it as the battery charged.

Obviously this baby sitting of the adjustable voltage power supply through bulk stage, until absorption voltage was reached, became inconvenient, so i would use my smart charger first, and when I noticed it had quit absorption and reverted to float, I would put the adjustable voltage power supply on it set to 14.8v, with its amp hour counting ability and let it go. Never, not once, did it not require at least 1:45 more time at 14.8v before specific gravity maxed out, and often it was 4 to 5 hours more at 14.8, after removing it from smart charger and putting it on adjustable voltage power supply.

this 130 amp hour US group 31 marine battery, would require the power supply return no less than 15 amp hours into teh battery, in order for specific gravity, adjusted for electrolyte temperature, to reach previously established maximums. The Smart charger was consistently shutting off with teh battery only ~90 to 92% charged, and it was pointless to try and get specific gravity any higher using the smart charger.

I borrowed other so called smart chargers, and they did the same thing, stopping holding absorption voltage well before the battery was fully charged, and switching to float where specific gravity never rose any more. The adjustable voltage power supply was required to hold them at 14.8v for several hours after the smart charger gave up, to even get the cells to 1.265, and as the battery aged it took longer and longer to reach 1.265, and 1.280 was only achievable by holding 14.8 for several hours, then bumping voltage to near 15.5v for no less than 45 minutes.

to be continued...
 
Even at 15.5v it would sometimes take close to 4 hours to achieve 1.280 on all cells.
I then got a better Adjustable voltage power supply. I modified it with more ventilation and heatsinking so it could run flat out for longer, and a more precise potentiometer to change voltage, and upgraded the wattmeter leads to 8AWG to handle 40 amps continuous.
I'd set it at 14.8v, set the timer on my smart phone for 5 to 8 hours, depending on the level of amp hour depleted from it.

When doing EQualization charges and eventually I just started using 16.2v as long as 6.2 amps or less was required to achieve it.

That specific flooded marine battery lasted about 500 deep cycles when i noticed the bottom of one cell getting warm during charging, and it was relegated to light cycling duty, and much less care and feeding. It lasted 4 more years in that duty. I did once see if it could still start my engine near that 4 year mark engine. It did, easily, surprisingly easily, disturbingly easily.

Subsequent batteries get tested, observed, their charging refined from day one, and the smart chargers only get used, when there is a danger of the charging source growing legs and achieving a true full charge is not a concern. If I cannot be there to lower voltaeg when full charge is achieved, then I just set it to 13.6 to 13.8 and bump it to 14.5v+ when i can be there to observe amperage and or dip the hydrometer into the cells.
When freinds or friends of friends bring me a battery to access, the smart charger is useless, as it can't fully charge them and why try to assess them when the starting point is unknown. Often they bring batteries hot off their bells and whistles stage 8 owner fellate smart charger, and I stuff a whole bunch more amp hours into them, each time, without fail, without excessive heating/overcharging and can then load test and access.

Lots of expereince gained since I got all irritated at my first smart charger, lots of different batteries charged, tested, recharged and tested again.

The smart charger, all the smart chargers I have used tried, borrowed and quickly returned to their owners, or batteries that were brought to me fresh off the owners smart charger, on abused batteries, simply cannot maximize specific gravity and achieve true full charge.
Time and again, over and over, without fail.
Many of these batteries brough to me, which I held at 14.8v for hours and hours and then sometimes as high as 16.2v, lasted for several years more before being replaced and some are still going and this is despite not ever being brought to a true full charge ever again by their vehicle or their so called smart chargers, if they ever used them regularly, as I recommended when I returned their truly fully charged battery to them.

So when I see someone saying they charged their battery to 100%, because the green light is shining proudly and or some state of charge display on their so called smart charger says so , I find that laughable, as it is based on hope, and a green light. The 100% charged claims are not based on actual data, and many years of experience with intense interest of actually achieving a true 100% full charge on a range of batteries, both starting, marine, and true deep cycle, AGMs and flooded.

Smart chargers can certainly be good enough for the average joe, but do not believe they are capable of actually returning a battery to a true 100% state of charge. ESPECIALLY a battery a few years old and which has lived its life 85 to 95% charged, which likely encompasses about 90% of the lead acid batteries in the vehicles on the planet, at this moment.

A hydrometer, and or an Ammeter, and a charging source actually capable of holding absorption and perhaps equalization voltages, can and will easily prove this to anybody who cares enough to actually do it.

it All this is necessary? no, Not unless one absolutely demands maximum possible longevity from their lead acid batteries.
I won't argue this.

It would be great, in my opinion, if people here would provide actual data on what their specific charger actually does on its various settings,, not what its marketing claims it will do, and then we could access which commonly available chargers are the best bang for the buck with a wide pool of data for that assessment to be possible. But people with the interest and tools and time would need to participate, and without the hydrometer on a battery with accessable cells, it is impossible to really access how much more charging is required to see where true 100% state of charge lay.

Every smart charger I have tested on anything but a very healthy battery from a relatively high state of charge, has fallen well short of achieving true full charge. I've certainly not tested them all, and will not, as I have deemed them a waste of time in my uses as a frequent deep cycler of lead acid batteries, and one who is brought batteries to charge and access the condition of from both friends, acquaintances, and 'other'.

Sometimes with the 'other' and i can't be bothered to actually care about the battery or collect more data and experience, then, I just use the smart charger
and no doubt it easily starts their engine when I give it back.

But friends.....their batteries leave my workshop stuffed to their maximum potential, and the smart charger plays no part in achieving that, as it is a colossal waste of my time.

But obviously, so is my posting about it here.
 
Wrcsixeight...

Very, very good post ^^^^^^^^^^^^^^^^

I would say someone living off grid with a battery bank, rv using a battery bank, or even someone with a bass boat trolling motor battery would be wise to listen and learn from your experience, expertise and knowledge base.

Especially if those people buy a Northstar TPPL AGM or Lifeline AGM or Trojan AGM etc etc.

In order to maximize their batteries value and usage potential.

If I were to get say a Northstar TPPL AGM for a trolling motor.... I would ask you for your help in how to properly charge those batteries. Candidly... I'd want you to be on a phone face call with me while doing some of that.

Because... That type of charging with a power source like that and all the necessary tools I would want someone like you to educate and train me how to do it correctly. That is serious work and attention to detail doing that is very, very important.


Has for typical car starter batteries...

For me... A smart charger is ok enough right now. I know it's not the best and will not do what it claims to do. I know that from learning from what you have stated so well here. I just want it to be just a bit better than not doing nothing at all. I certainly do understand that it is not the "best practice" in comparative terms to using all the tools you have. And... I am ok with that.

One thing I found interesting the other evening... I did a voltage check on my wife's 98 Camry AGM battery from AZ. It was 12.30 volts temp at 48°F. Not an expected finding... Well I turned the headlights on for a half an hour... Then pulled the battery and put it on my 3 amp smart charger. It said the battery was 80 percent charged... It took 3 hours and 10 minutes for it to be "fully" charged... It still had 14.54 volts going to the battery even after the green light was blinking indicating that the battery was "fully" charged. It did that for another 30 minutes. Unplugged the charger and put the battery back in the Camry. It was at 12.82 volts.

Checked the battery earlier this am... Temp was 38°F... It was at 12.62 volts. Car had not been driven for 9 hours. Much better and more like the result I would have liked to have seen the other evening.

Took the Camry out for a quick spin around the neighborhood.... About 3 miles. Checked battery after that to see if alternator was doing anything... It was at 13.22 volts.... Obviously a surface charge no doubt. But it would indicate the alternator did something to push some charge into the battery... Which if the voltage was the same as before I drive the car then I would have been concerned about that alternator not working right.

I have checked the 98 Camry battery before and it typically has been 12.75 to 12.85 with temps running between 70-88°F. This battery is only 1 year and 7 months old at this point.

So again... The 12.30 reading was well off a normal finding. I guess either the lady or I had left a light on in the car in the last several days before that low reading.

I am glad that at least I have 2 chargers available... One 3 amp smart charger and a 10 amp charger.

Again... I really, really appreciate your high, high, high level of experience, expertise and knowledge base.

And if I ever get a big-time legit TPPL AGM battery... I am going to get all the necessary components needed to really take care of it properly. And... I would ask for your help, education and training in utilizing those tools properly.
 
Open circuit voltage of a battery is only accurate, as to inferring an accurate state of charge of that specific battery, when one has not presented any discharging or charging to it for several hours, and has previously established baselines on that specific battery for future comparison.

When taking the voltage reading, one needs to know the parasitic draw on the battery that the vehicle is presenting at that moment to the battery, or has recently presented. If the doors are open and the interior lights are on, the parasitic load can perhaps be significant and voltage will read low.

Knowing the amount of parasitic load on a battery, without a clamp on DC ammeter, is difficult. The clampmeter is very helpful, and one can determine how much load there is with doors open, and how long a certain parasitic load might last X amount of time after the doors are shut, before being reduced. AC and DC Clampmeters are usually full function Digital multimeters as well, so useful for more than just measuring current flowing through one wire without having to open the circuit. Beware the cheaper of clampmeters might only read AC current, not both AC and DC

A battery accepting 3 amps, with none of those amps are powering loads on the battery such as interior lighting, is a battery no where near fully charged, and especially if the voltage the battery is being held at is only 13.2. when the 3 amps was measured flowing into the battery.

The Green light on a charger might simply be saying, the battery is charged enough, to start the vehicle, as opposed to it trying to imply the battery is fully charged. To guess what the charger is trying to say, one needs to not only know the voltage of the battery at its battery terminals, but how many amps the battery is accepting at that voltage. 3 amps flowing into a group 24 at 14.5 volts is a battery far from fully charged, and if 3 amps is flowing into it at 13.2v it is even further from being fully charged


Again I am not saying all smart chargers are junk and unworthy of use. Any charging source applied to a less than fully charged battery is beneficial.

I am stating that Ideally, the battery is brought to a true 100% state of charge, and when one acquires the tools to reach this benchmark, and expends the effort to use them to verify, they will find their smart charger falling short of the benchmark true Ideal 100% State of charge in all but the healthiest of batteries that were put on the charger while still at high states of charge.

Now it is arguable how much getting only 92 to 98% charged ultimately has on lifespan of a battery. I will say the more deeply the battery is cycled the more important it is to reach a true 100% state of charge regularly in order to achieve good or better battery longevity and reliable performance during that lifespan. In deep cycle usage I will state my opinion 98% is only half as good as achieving a true 100%. Some Modern vehicles that sit undriven for weeks are in effect deep cycling the battery. A battery only 30% charged is likely to still be able to start the modern fuel injected engine, so that ability does not imply health, or state of charge of the battery, yet such an ability is often used as proof the battery is 'still going strong' here and elsewhere online.

In starter battery duty only with very light depth of discharges on a relatively new battery 98% vs 100% might make so little difference as to be ignorable and certainly not worth the effort of acquiring the tools which can hold the battery at high voltages until the ammeter or hydrometer indicates it is indeed fully charged.

How much extra life can be expected from true 100% recharges occurring, compared to 98%, has too many variables to quantify accurately.

'Good enough' and 'i feel', is an opinion, and one ultimately cannot eliminate all teh variables to perform an accurate test of two batteries, one reaching 100% regularly and one reaching only 92%. Its like saying this oil is that much better than that oil, without having two absolutely identical new engines treated Exactly the same for a period of time/mileage, and the ONLY variable is the oil itself. This is basically so unlikely to occur, even in a lab testing environment, as to approach on the impossible. So to determine which oil might be better one does oil analysis, with all its faults, as a clue, and perhaps can see how clean their engine is, under a valve cover as another clue, and perhaps say this oil is quieter than the other old oil they just replaced as yet another clue. Ultimately what it comes down to is all these impressions do not mean one oil or the other is indeed superior, only that the few measurement tools used 'might' indicate one oil or the other 'might' indeed cause less wear. Mostly it is about what feels good, brand loyalty, bragging rights, as for one or the other to be proven superior, the engines would have to be identical in every way and treated exactly the same and then torn down and measured to a level of precision no one outside a lab, being well paid to do so, could ever achieve.

However using this oil analogy to a battery, we can say the Oil and filter combo, proven to cause the least amount of wear, will allow the engine to ultimately last longer.
The battery treated ideally, will too, last longer than one which is treated to a subjective 'good enough'.

Ideal lead acid battery treatment, is well established. Do not overdischarge, keep cool, and recharge to a true 100% state of charge after any level of discharge. 'Good enough treatment' is an opinion, and endlessly arguable, but Ideal, is not.

While I have the most experience and the most in depth recent experience with Northstar AGMS, and have taken the most efforts with these high$ AGMS to record trends and tendencies and keep records, I am often brought regular car starting batteries to charge and access the health of. A much more accurate assessment can be done from a known 100% charged starting point, and achieving that ideal is impossible with a so called smart charger. Less than Ideal and 'good enough' can be used over and over again to try and prove a point, pointlessly, but Ideal is a benchmark, with little to no wiggle room.

For others, not demanding maximum longevity, Achieving ideal is not worth the effort, in my opinion. But remaining ignorant of what Ideal is, is also undesirable in my opinion.

Ignorance to what Ideal is, is likely blissful, and I love to be ignorant of many things I have little to no interest in.

Lead acid batteries do not fall into that category, and while I am a student of other battery chemistries, I have little to no experience with cycing and observing them closely, and might provide data on my experiences with them, if I have gathered any, but draw no conclusion or spout any opinion as conclusive fact.
 
The diverse membership of BITOG is what makes it so outstanding. The OCD nature of many of us (OCPD in my case) should make it easy to accept other's passions. I recently observed this in a retirement financial thread I started 2 weeks ago. I appreciated comments from both those with passion to study investments as well as those similar to me, an investment layperson.

I am glad to see the "head butting". The expertise shared from those with a passion helps us laypeople increase our awareness and make improvements, even if "good enough" remains our goal.

Carry on head butters!
 
Open circuit voltage of a battery is only accurate, as to inferring an accurate state of charge of that specific battery, when one has not presented any discharging or charging to it for several hours, and has previously established baselines on that specific battery for future comparison.

When taking the voltage reading, one needs to know the parasitic draw on the battery that the vehicle is presenting at that moment to the battery, or has recently presented. If the doors are open and the interior lights are on, the parasitic load can perhaps be significant and voltage will read low.

Knowing the amount of parasitic load on a battery, without a clamp on DC ammeter, is difficult. The clampmeter is very helpful, and one can determine how much load there is with doors open, and how long a certain parasitic load might last X amount of time after the doors are shut, before being reduced. AC and DC Clampmeters are usually full function Digital multimeters as well, so useful for more than just measuring current flowing through one wire without having to open the circuit. Beware the cheaper of clampmeters might only read AC current, not both AC and DC

A battery accepting 3 amps, with none of those amps are powering loads on the battery such as interior lighting, is a battery no where near fully charged, and especially if the voltage the battery is being held at is only 13.2. when the 3 amps was measured flowing into the battery.

The Green light on a charger might simply be saying, the battery is charged enough, to start the vehicle, as opposed to it trying to imply the battery is fully charged. To guess what the charger is trying to say, one needs to not only know the voltage of the battery at its battery terminals, but how many amps the battery is accepting at that voltage. 3 amps flowing into a group 24 at 14.5 volts is a battery far from fully charged, and if 3 amps is flowing into it at 13.2v it is even further from being fully charged


Again I am not saying all smart chargers are junk and unworthy of use. Any charging source applied to a less than fully charged battery is beneficial.

I am stating that Ideally, the battery is brought to a true 100% state of charge, and when one acquires the tools to reach this benchmark, and expends the effort to use them to verify, they will find their smart charger falling short of the benchmark true Ideal 100% State of charge in all but the healthiest of batteries that were put on the charger while still at high states of charge.

Now it is arguable how much getting only 92 to 98% charged ultimately has on lifespan of a battery. I will say the more deeply the battery is cycled the more important it is to reach a true 100% state of charge regularly in order to achieve good or better battery longevity and reliable performance during that lifespan. In deep cycle usage I will state my opinion 98% is only half as good as achieving a true 100%. Some Modern vehicles that sit undriven for weeks are in effect deep cycling the battery. A battery only 30% charged is likely to still be able to start the modern fuel injected engine, so that ability does not imply health, or state of charge of the battery, yet such an ability is often used as proof the battery is 'still going strong' here and elsewhere online.

In starter battery duty only with very light depth of discharges on a relatively new battery 98% vs 100% might make so little difference as to be ignorable and certainly not worth the effort of acquiring the tools which can hold the battery at high voltages until the ammeter or hydrometer indicates it is indeed fully charged.

How much extra life can be expected from true 100% recharges occurring, compared to 98%, has too many variables to quantify accurately.

'Good enough' and 'i feel', is an opinion, and one ultimately cannot eliminate all teh variables to perform an accurate test of two batteries, one reaching 100% regularly and one reaching only 92%. Its like saying this oil is that much better than that oil, without having two absolutely identical new engines treated Exactly the same for a period of time/mileage, and the ONLY variable is the oil itself. This is basically so unlikely to occur, even in a lab testing environment, as to approach on the impossible. So to determine which oil might be better one does oil analysis, with all its faults, as a clue, and perhaps can see how clean their engine is, under a valve cover as another clue, and perhaps say this oil is quieter than the other old oil they just replaced as yet another clue. Ultimately what it comes down to is all these impressions do not mean one oil or the other is indeed superior, only that the few measurement tools used 'might' indicate one oil or the other 'might' indeed cause less wear. Mostly it is about what feels good, brand loyalty, bragging rights, as for one or the other to be proven superior, the engines would have to be identical in every way and treated exactly the same and then torn down and measured to a level of precision no one outside a lab, being well paid to do so, could ever achieve.

However using this oil analogy to a battery, we can say the Oil and filter combo, proven to cause the least amount of wear, will allow the engine to ultimately last longer.
The battery treated ideally, will too, last longer than one which is treated to a subjective 'good enough'.

Ideal lead acid battery treatment, is well established. Do not overdischarge, keep cool, and recharge to a true 100% state of charge after any level of discharge. 'Good enough treatment' is an opinion, and endlessly arguable, but Ideal, is not.

While I have the most experience and the most in depth recent experience with Northstar AGMS, and have taken the most efforts with these high$ AGMS to record trends and tendencies and keep records, I am often brought regular car starting batteries to charge and access the health of. A much more accurate assessment can be done from a known 100% charged starting point, and achieving that ideal is impossible with a so called smart charger. Less than Ideal and 'good enough' can be used over and over again to try and prove a point, pointlessly, but Ideal is a benchmark, with little to no wiggle room.

For others, not demanding maximum longevity, Achieving ideal is not worth the effort, in my opinion. But remaining ignorant of what Ideal is, is also undesirable in my opinion.

Ignorance to what Ideal is, is likely blissful, and I love to be ignorant of many things I have little to no interest in.

Lead acid batteries do not fall into that category, and while I am a student of other battery chemistries, I have little to no experience with cycing and observing them closely, and might provide data on my experiences with them, if I have gathered any, but draw no conclusion or spout any opinion as conclusive fact.



What I put in my post was not an ARGUMENT....

Nor opinion.....

Just reality,...

Me like 99.9999 percent of people are not going to spend the money needed for all the extra tools to maximize a STARTER battery's life....

Key word.... STARTER... Battery....


A battery bank is a while different circumstance...

Living off grid...

In a rv...

A trolling motor...

Where one spends $300 to $350 plus on a single battery... Or say in excess of $1000 on a battery bank....


Then.... It makes sense to truly put all the time and extra tools expenditure to maximize those batteries usage potential.



And I know daggone on well enough that 12.30 on a low tier AGM at 49°F is not a normal expected circumstance....

It's not.

Period.... End of discussion.....



You need to stop arguing.... Just to argue...



That would be as stupid as me telling you... With a straight face that your blood pressure being 198/100 with you just laying there is an expected normal finding... .

It is NOT.... Something is not right there...Time to get concerned and do something. .


Just like 12.30 is way off....


Stop arguing....




I freely and readily acknowledged what is true in my post there....


That a smart charger is NOT ..... Going to be the "best practice".... I believe your post and experience 100 percent.

That was clearly stated and understood in my post...


Again.... There's a world of difference living off grid or having a rv battery bank or even a trolling motor battery set up vs a routine starter battery....

If you cannot comprehend or understand that huge of a difference in COST and application.
.

I can't help you...

But it is a very, very, very large difference.


Again.... If I were to get a very high end TPPL AGM battery setup.... I would definitely want your help with that.

I sincerely appreciate your experience, expertise and knowledge base in regards to this topic.
 
BBhero my intention was not to argue with you, just share more info and experience for others to better understand.

Sorry if my tone came off insulting or argumentative, that was not my intention when typing, and I'll have t rethink how my online tone sounds, if I continue to spend the time and effort to contribute, which I keep telling myself, I should not.

Have a good year all.
 
Hey wrc68...

I really, really, really appreciate your post there...

I respect your knowledge tremendously...

To me... You are like a professor teaching about this topic.

You are one of the best... And I mean best guys on here teaching about how this stuff works... Or does not work.

You are an asset to this board...

And I am very grateful you are on here.

And if you ever needed any help with my area of expertise and experience... Related to healthcare circumstance...

All you need to do is send me a msg... And I would do as much as I could to help you. And that is the real deal.
 
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