Battery Specific Gravity (4 @ 100%, 2 <80%)

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gathermewool

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New England
Vehicle: 2015 Legacy 2.5i, 33k miles (new to me as of a month or so ago)

Battery: Group 25 (pretty small, compared to the size of the tray)
-----Previous owner says it's stock and that she doesn't recall it ever dying

Battery Died: car was being worked on - had to be jumped when I picked it up 3 hrs later
-----Immediately drove home 25 minutes and pulled the battery for charging

Charger: Solar Pro-Logix PL2520 - Will charge at full amperage, then go into desulphate mode (~13.3VDC) then turns off
-----Read 12.8VDC when I hooked it up and 90% charged (yeah, right; surface charge)
-----Still charging at 14.5+VDC on 10A setting 3.5 hrs later, when I went to bed
-----Fully charged (charger turned off) and indicating 13.0VDC when I woke up the next morning
-----Between then and now I've tricked the charger into continuing by turning it off and then restarting it 3 times --> each time, the charger would indicate full within 10 minutes and switch to desulphation mode, which it would operate on for hours (I did not measure the exact time.)


Specific Gravity: while still on the charger @ 13.2VDC I checked the specific gravity with my cheapo hydrometer and found the following:

1. 1.237 (the hydrometer has a big gap between 1.225 and 1.250, so, by eyeball it was nearly halfway between the two)
2-5. ~ 1.265
6. 1.237 (by eyeball, it was closer to 1.250 than 1.225, but still in the unmarked space)


I also load-tested it:
https://youtu.be/kT5BCAVqHHc
 
I'm wondering if I should hookup my dumb charger and give it a good equalizing charge. The problem, is that it will creep up beyond 15+VDC and gas pretty aggressively, so I'd have to keep an eye on it.

I don't think I can equalize by tricking the smart charger to continue to charge @ 13.3VDC across all 6 cells, right?

Any recommendations?

Also, should I turn off the charger each time I check the SG?

Goal: Equalize each cell prior to placing the battery back in-service, if possible.
-----Now that I have my cheap hydrometer, I think I'll pull the 4 year-old battery in the Forester and do the same tomorrow.

I've been feeling very unwell for the past few weeks and, now that I think I'm past the hump, I want to knock out a bunch of chores that I haven't been able to tackle, like simple vehicle maintenance. Luckily for me, the oil change isn't due for another 1.5k and 4k for the Legacy and Forester, respectively.
 
Fully charged should be around 1.265 per cell. Can be higher or lower but they should be even. If it's gassing there is too much current.
 
Originally Posted By: SHOZ
Fully charged should be around 1.265 per cell. Can be higher or lower but they should be even. If it's gassing there is too much current.


Like the title says, 4 out of 6 cells are fully charged, based on specific gravity. The two cells on each end of the battery are still low, 75-80% fully charged.

The battery will gas slightly while initially charging. Batteries will typically gas given an equalizing charge. This does NOT mean there is too much current, depending on the charge scheme.
 
Ok, so I hooked up my dumb charger and found the following:

1. 6A Setting: Voltage rose to and stabilized out at 15.9VDC
-----2.65VDC/cell - likely higher for some of the cells
-----Too high

3. 2A Setting: Voltage lowered to and stabilized out at 14.40VDC
-----2.40VDC/cell
-----A little low for an equalizing charge, but it may work, and it's better than float voltage...
 
a couple hours on a manual charger @ around 14.5-14.8V would be the best way to continue to try to recover - that or a pulse-type desulphating charger. Unfortunately, thats most likely the best you are going to get it on couple year old battery - it looks right in line with what i see most of the time.

What has most likely happened is that a small portion of the lead plates that were sulphated (discharged) has either been shed or broken/cracked off the rest of the plate. Once this happens, it's no longer part of the battery and there's no way to put it back - if electrical current doesn't pass through it, it doesn't shift back into lead, lead dioxide, and sulfuric acid - hence the lower gravity. Another way of looking at it is that those cells are approximately 20% worn.

Watched the video - First off, WOW - can't believe they only use a 360CCA battery. According to dekacatalog.com the OE battery is supposed to be a 490CCA. I don't see any special notes stating that it's anything special, but it might be built more like a dual purpose deep cycle (higher capacity, lower CCA) - a little googling has people saying its a 48AH, which is really high for such low CCA on a typical starting battery. Secondly, while the load tester you have does a great job of simulating starting load (under which, holding 10+ Volts is good), it doesn't tell you the whole story. I prefer a good ole fashion 800-1000A Carbon Pile load tester. There's plenty of batteries that pass a basic cranking test, but when you do a full 15-20 second load test, you can see them start to fail. Sometimes, if there's one or more weak cells, you can actually watch the voltage fall down in steps as they give out. EDIT - Just want to clarify I understand you're not trying to recover or diagnose a bad battery, just trying to get some weaker cells recovered - just throwing out as much info as I can because I'm bored as [censored].

On such a small CCA battery being used from the factory, I would expect to replace it in the next year or so depending on what your buying situation was - A LOT of wear and tear on factory batteries occurs in shipping and at the dealership before it even gets to you due to lack of driving to keep charged. BTW, I may be incorrect, but I would assume that the B5 sticker on the battery corresponds to February 2015.

LAST EDIT, I SWEAR - the two outside cells being the weakest is extremely common. I don't know why, but I would assume because they are the most exposed to heat and cold cycling.
 
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My thinking would be to possibly buy a larger battery with the correct polarity obviously. My car calls for a group 35 but a group 24 actually fits as well. If possible I bet you could a much better battery with much higher reserve capacity, and higher CCA as well.
 
group 25 is pretty tiny - not a lot of options in that size. you could stick a group 26 in there but it's smaller. Otherwise, most any aftermarket replacement will have considerably higher CCA. The one I carry that covers 90%+ of the market is an extremely conservatively rated 550CCA and is made by East Penn (Deka - the best batteries period).
 
Well a group 24 has the exact same height and width... Length is 10.3 long vs the group 25 at 9.1 inches long. So if the tray has the length available in extra room over 1.5 inches.. Group 24 would be a possibility here. I would bet that tray is just like mine was... It had more than enough length wise to fit a longer battery.
 
joeparker54,

Thank you for the great response.

1. I'll keep it on the dumb charger until I go to bed tonight, checking the voltage every 15 minutes to see if it creeps back too high. I'll then check and report back the specific gravities. It will be very interesting to see if the low cells raise or, if like you say, they're erroded to the point where it's simply not possible.

2. The Solar charger supposedly, when it finishes bulk-charging, the literature says it will sense if there is sulphation and extend charging to desulphate, as indicated by a blinking charger indicator. Voltage during this transition will shift from 14-15VDC to 13.2-13.4VDC (float charge.) The thing is, every time I trick the charger by turning it off and then back it will bulk charge for a very short period, but will enter and maintain a float charge for what seems like the same period of time.
-----So, it's obviously not that smart, if it completes the desulphation (float charge) cycle, but can be tricked into doing it again, over and over again.

3. Load test: yea, it's a very cheap tester and gives only a very rough picture of the battery's condition. For instance, I kept the four year-old battery out of my old Civic and it shows as "weak" using this load tester. Do you know where I could find a good carbon pile load tester? I'd like one of these. I'd like to also build my own power supply, so that I'm not trying to jury rig a situation in which I can get a proper voltage for equalization.

4. Subaru batteries are known for their comically low CCA. I've always wondered why, to be honest. I hope it's more about durability than them cheaping out. The battery in our Forester is now 4 years-old and does well, except during REALLY cold starts (e.g., -10F or lower).

5. I'm at the point, where I'll replace either battery at the first sign of slow cranking. I put my batteries on a charger every month or so to keep them topped up, but that doesn't amount to a hill of beans in most cases, since batteries don't play by our rules...

Originally Posted By: joeparker54
LAST EDIT, I SWEAR - the two outside cells being the weakest is extremely common. I don't know why, but I would assume because they are the most exposed to heat and cold cycling.


Haha, no worries. I honestly never knew the outer cells were commonly the lowest. Learned something new today, thank you!
 
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Originally Posted By: bbhero
My thinking would be to possibly buy a larger battery with the correct polarity obviously. My car calls for a group 35 but a group 24 actually fits as well. If possible I bet you could a much better battery with much higher reserve capacity, and higher CCA as well.


Originally Posted By: bbhero
Well a group 24 has the exact same height and width... Length is 10.3 long vs the group 25 at 9.1 inches long. So if the tray has the length available in extra room over 1.5 inches.. Group 24 would be a possibility here. I would bet that tray is just like mine was... It had more than enough length wise to fit a longer battery.


I asked the previous owner if she had the battery replaced, because the battery looked tiny in the tray! Turns out, group 25 is the stock size.

Group 24 will fit and is commonly what people use. I plan to use this when I replace the battery. If this thing gives me any trouble as it gets colder it's getting replaced with a group 24 immediately.
 
Good deal. I'm glad that the group 24 will work. I greatly respect your head work and trying to make the old battery work. I do think that's pretty cool. I just would likely not have the patience for it.
Ohh and I am glad that you are feeling better. I understand how that can be as well. I hope that you continue to do good and feel good to do what you like to and want too. So, I'm pulling for you BIGTIME in that.
 
bbhero,

Thanks, brother. The past few weeks have been pretty rough, but things are getting better. I've had great support from everyone around me, which has helped tremendously.

I typically spend way too much time on things I don't fully understand. Once I figure it out and find a good path forward I usually throttle way back.

In this case, I'm messing with the old battery on the weekends and my in-service batteries every so often to see how they respond. If my janky equalizing charge shows positive results I'll add it into my PM schedule somehow. Battery University says that an equalizing charge could be anywhere from monthly to every six month, but then goes on to say that it should be done if the specific gravity differs by 0.030, which sounds like a good plan to me. I'm currently at 0.028, which is why I thought it would be a good candidate for this test.
 
Well, it looks like my dumb charger, on the 2A setting, will lower voltage to 14.10VDC. So, that's too low for a proper equalizing charge, but I wonder if, over an extended period of time, it would provide some equalization. What do you guys think?

Does it make sense to leave the dumb charger on over night, so long as the voltage settles in the low 14's?

The 6A setting still raises the voltage to 15.9VDC very quickly, which I think is too high, even for short durations. Any suggestions on whether this high voltage will work if used in short bursts, or will it only result in excessive corrosion with no real benefit?

//

UPDATE: I only had time to check one cell, but the specific gravity seemed to not have changed. I probably should have had my wife take a picture from before to now to see, but it's still in the between area on the hydrometer, so not it hasn't risen much, if at all.
 
Dont waist your time,go straight to Costco pick up AN, INTERSTATE BATTERY WITH AFULL 42momth free replacement.Costco is only second to REI when it comrs to returns,dont look BACK!
 
Equalization is a forced overcharge and Quality Deep cycle batteries, that require equalizations on a regular basis, when deeply cycled, recommend voltages as high as 16.2v.

Gassing is going to happen, it has to happen, and is nothing to fear unless you put the battery in a closed container and open it with and look inside with a match, or huff it.

The 16.2 volts assumes a battery at 77F degrees, Lower tmeps require higher EQ voltages, higher temps should lower voltages. NO lead acid battery chould be charged above 120f degrees and they can heat quickly if higher amp recharged from a well depleted state when thay can accept a lot of amps for a long while.

Sometimes restarting an Automatic charger over and over will result in the same short period in bulk mode. Often a high load to drag down voltage will allow the battery to accept higher amps for onger and get SG closer to the maximum, which might be as High as 1.310 on some cold weather batteries.

Establishing a baseline maximum specific gravity when the battery is new is wise. Stating all batteries when fully charged are 1.2XX, is not wise, and if one were to dip a lot of cells on many different batteries one will find many cells always read low some read high.


I have one older quality marine battery mad e By USbattery that has been out of main deep cycle service for over 2 years now. i took it out of service as the cell closest to the negative terminal refused to go over 1.260 when all the other cells were 1.280. An Extended equalization would not budge this cell. The very bottom of this cell would heat up about 10 degrees more than the rest of the battery.

2 years later this battery is still able to maintain 12.8+ volts a few days after being taken off the charger, the 1.260 cell still maxes out at 1.260.

It only gets shallowly cycled and often gets topped off then held at 13.2 to 13.7 volts, whatever my Dumb 'Smart charger' deicides is best, is kept pretty cool. Sometimes if I have my Adjustable voltage power supply in the area I will bring it to and hold it at 16.2v until 5 cells read 1.280 and the one cell 1.260. But mostly I determine state of charge by how much amperage the battery accepts at the voltage it is being charged at.

Interstate are a battery marketer, not a manufacturer. Interstate starting batteries are made Mostly by Johnson controls and they will employ anybody who will maximize their proifit margins. Many are made in Mexico or Saudi arabia these days. A few years ago on this forum JC batteries were apparently the best ever battery. Now apparently that title has moved to East Penn/Deka, at least on this forum.

Opinions........

A happy Lead acid battery is a cool fully charged battery that is kept cool and fully charged. These two factors will have much more to do with a battery longevity than who made it, except on this forum where apparently the sticker and legend speak louder.

If your battery can maintain more than 9.5 volts when cranking your engine there is little reason to replace it. When it dips below 8v and winter is coming then consider it.

How quickly a Digital multimeter responds to changing voltage when cranking is a huge uncontrollable factor though.

Don't fear offgassing, it has to happen for a battery to actually reach full charge. Just keep the electrolyte level above the plates and use eye protection when looking into cells and keep ignition sources away from a charging battery.

Baking soda nearby, perhaps already dissolved in some water is good at neutralizing the acid, should things get ugly.
 
wrcsixeight,

Great post. You were referring to deep cycle batteries, but what would you recommend I do with what I have? At 15.9VDC, the battery gassing is low to moderate. Could I try an extended equalization at this voltage? When I checked, the battery was pulling ~1A at this voltage, after fully charged.

The below-quoted made me
13.gif


Originally Posted By: wrcsixeight
Gassing is going to happen, it has to happen, and is nothing to fear unless you put the battery in a closed container and open it with and look inside with a match, or huff it.


UPDATE:

To clarify somethings, I'll refer to the two lowest cells by number, with number 1 being closest to the positive terminal and number 6 being closest to the negative terminal.

I played around with a few things to determine the behavior of my dumb charger, which was described above. After doing some reading, I determined that short bursts at 15.9VDC would be ok, so I did two 30 minute equalization periods at that voltage, with rests in between. I did not have a means to determine cell temperatures, but my basement is about as close to 20C as you can get and the battery felt room temperature on the case.

Cell 1: Zero to minimal change in SG - still indicates in the area between 1.225 and 1.250

Cell 6: Slight improvement - the needle is now just into the range indicated by the clear rectangle inside the radius of 1.250 (so, I guess it's not 1.250, but with the accuracy of the hydrometer to say that it's close to 1.250)

Side Note:
I can't explain why, but I noticed my dumb charger was causing voltage fluctuations in both the 2A and 6A settings. The 2A setting would mostly remain at 14.4VDC, but would lower to 13.3VDC for a bit, then return to 14.4VDC. The 6A setting would mostly remain at 15.9VDC, but would lower to 14.5 for a bit, then return to 15.9VDC. The Fluke leads were not moving and both the charger and battery where in a stationary, non-vibrating location. I lifted the charger by the handle and gave it little shake and nothing changed (I'm not sure why I thought something inside being loose would exhibit this behavior and not something more serious, but I gave it a try.)
 
If some of the cells are damaged due to shedding of plate material. Then trying to bring them up to the others only will overdrive the already charged cells.

Have you ever added water to the cells? And be sure to temperature compensate the gravity readings. The outside cells will be cooler on charge.
 
Originally Posted By: SHOZ
If some of the cells are damaged due to shedding of plate material. Then trying to bring them up to the others only will overdrive the already charged cells.

Have you ever added water to the cells? And be sure to temperature compensate the gravity readings. The outside cells will be cooler on charge.


The plates were covered, but the battery was at 12.6VDC (didn't have a hydrometer to chech SG at the time) when I purchased the vehicle - PO had a new DD, so the Legacy sat. I charged the battery and, after being fully charged I added a very small amount of distilled to bring each cell up to where it should be.

I cheched the SG's this morning. The smart charger was connected, but not charging (it shuts off) and monitors battery voltage only after the charging cycle is complete. Based on past data, I conservatively guess that the battery has been resting for > 4hrs, so it should be at room temperature, around 70-75F.

The hydrometer label says that it's temperature compensated, but I have no idea how it achieves this. I feel it's best to bring the battery into my basement, so the readings that I'll take in the future will be standardized. I plan to bring the battery in once every 3-6 months. If my schedule doesn't allow this, then at least yearly extended charges and SG checks.

For now, I run an extension cord through my front door and charge it ~ monthly to keep the battery as fully charged as possible. It may be a waste, since it seems most modern ECMs seem satisfied maintaining battery SoC between 80 and 90%, and this may occur very quickly after I charge it back to 100%. Once we trade up from the condo to real house with a garage, I may jury rig something to allow for easier topping-off charges more frequently than monthly.

[digression] I have plans for block and oil pan heaters, too, so the effect of shorter trips can be all but negated and we'll have instant heat when leaving. Might be a pipe dream, but we'll see. Likely, I'll do it for my wife's vehicle only, since I tend to bundle up and don't mind the cabin being chilly during my 20 minute commute to work.

[/digression]
 
sounds like that battery is headed for the recycling pile soon.
unless the 2 low cells got overwatered i would schedule replacement before first cold snap.
sounds like you have a perfect storm for getting stuck somewhere.
undersized and damaged.
you could try floating it a while at around 15.5-16v at low current.
i use a 1a dumb charger to do that.
but 2 low cells in the absence of spillage or overwatering is a warning to replace.1 low cell is the same.
hopefully it holds out long enough to find a good deal/coupon code,ect for its replacement.
as for the voltage dropping thats likely a heavy load dropping the line voltage.
measure line and see if it drops when the battery voltage does.
 
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