Conditioning AGM Test Results Before and After

[BFL13]

I have this battery I got (on spec for me--took a chance) a year ago off a guy for $225 (Can).

https://cdn.enfsolar.com/Product/pdf/storage_system/5a695a7096504.pdf?_ga=2.18197561.14003359.155657...

He had it in his basement for a couple years with several others he got for a project he never did. He said he charged them up every so often, and when I got it home it tested ok, so I thought I lucked out on my spec.

So after a year and using/abusing it in the usual way ( I am hard on batteries) but recharging it properly to 0.5/100 but not always at 20%, I tested it for capacity at the 20 hour rate.

It came up short, so I did an 8 hour condition run at 15.5v (16 as adjusted for temp) per Lifeline method, and re-tested.

Results follow, but hard to present the info--please struggle through to understand what happened. I will ask for interpretations, so yes- there is an exam! 🙂

I will show first a "normal" test using a three year old 100AH 27 AGM, then the Before with the big 8D, then the After with the 8D so you can compare normal loaded voltages over times at the 20 hr rate.

Time, Volts, Amps:

0600-start (resting full at 13.0v)
1100- 12.35, 5.1/ 11.9, 12.3/ 12.2, 12.2
1330- 12.1, 5.0 / 11.2, 12.0/ 10.3, 11.1

(lights dim and draw less as battery voltage falls, so the rate gets lower until you add a light)

So second test, way better voltage at first, but then loaded voltage crashed even worse than in the Before test after say 5 hours (out of 10)

In the Before, I stopped the test and voltage bounced right back to 12.4 (supposedly 50%) making capacity 85% of rated using AH drawn.

In the After, I stopped but the voltage bounced right back to 12.4 so I thought it would go higher after a little time, so I restarted the test. Now showing the 27, then the After.

1445- 12.0, 4.9, bounced back to 12.4, capacity 95.8% based on AH

After's results on re-starting: (added a light)
1345- 10.8, 12.5
1418- 10.2, 12.1
1430- 10.1, 12.0
1442- 10.0, 11.9 stopped , capacity comes to 90% based on AH and bounce back to 12.4 ---the bounce back was immediate from that loaded 10.0 to 12.3 (weird) and then it got to 12.4 in half an hour.

So just using AH down and 12.4 as 50% and allowing for temp reduction from 250 rated to 225 actual, 90% is not too bad.

BUT--that big crash in loaded voltage! Just weird. Can't be good.

Next weird thing, not seen before, is the recharge using 20% or over, with the 75 amp charger set to 14.8 (as adjusted for temp)

In the Before and After tests same thing-- instead of kicking off at 75 amps, amps started low and slowly climbed from 44 amps at first to 66 amps after five minutes and 70 amps after another five minutes.

I then jacked up the charger voltage to 15.1 and got the 75 amps. So reduced back to 14.8 and charging settled at about 68 amps then tapered as usual. (it should have hit 75 at first and stayed there for the Bulk stage) I had it down to 0.8a after the first test, so I expect the same today to indicate full (1.25a is 0.5/100).

OK--so what is going on here? I had no trouble with the battery bank (the 250 plus two 100s) last trip in March for a few days doing 50-9Os and ran the microwave etc, didn't see anything weird. Recharged ok at home. Nothing since that would damage anything.

The two 3 year old AGM 27s are doing ok, but this big 8D is having
"issues" being treated the same way looks like. At this time, it seems to be acting normally down to 75% SOC or so, then it goes crazy on the low loaded voltage. But it seems to still have decent AH capacity at 90% of rated. Banked with the two 27s nothing shows as weird down to 50% of 450. 50-90s seem to go well.

What's with that? Thanks

[BFL13]

Mex must be right about the battery and how to attempt to fix it.

I am nervous about trying that. This battery is not a heavy duty constructed Lifeline, able to take such treatment. This one might be able to take it, or not.

I would like to know what might happen if I do nothing and just carry on as before. Need a crystal ball. I don't need to do anything till October now that solar season is here and we stay above 75% SOC, so I have time to decide.

I suppose the 8D has been leaning on the two 27s once the bank gets below 75%, but there has been no sign of trouble. Can still run the microwave, toaster, or kettle by inverter with no alarms.

EG, recent off-grid no solar, after two days needed a recharge of the "450AH" bank on the morning of the third day. Trimetric showed "resting" voltage at 12.4 and AH down 204AH so at 10C that would be right for 50% SOC.

Ran the 75 amp charger for one hour and 18 minutes at 75 amps then amps started to taper. At two hours of recharge, AH now minus 73AH, so back to about 80% SOC. Drove around some later that day and got some alternator charging and solar exposure, so gained another 35AH before returning to the wooded campsite. So everything looking good and working great.

Lurking in there must have been this 8D with its "issues", but if it has been like that since I got it a year ago, why should I worry about the year to come? Maybe I should just wait and see if anything actually goes wrong and deal with it then. I have five months before 50-90s time starts again.

EDIT--LY says his AGM gets to where its "full" amps acceptance number rises to above the .05/100 and it goes back down after he gives it a good goosing using his conditioning method.

This 8D has been recharged since yesterday's test and at 14.8v, it got down to 0.6 amps, well below the 1.25 amps for the .05/100 rule. I then jacked up the voltage to 15.5 and amps jumped to 2.5 but quickly fell back down to 0.8 (the "wall" Mex talks about AFAIK) so I went to 13.6 Float banked with the two 27s. So today all is quiet on the backyard front (for now anyway!)

[MEXICOWANDERER]

i'll say this just one more time.

Put a FIFTY WATT 12-volt light bulb in series with a positive wire to the battery +

Run a - wire from the charger direct to the battery-

Presto you have an automatic 5 amp current regulator

Go to AMAZON look for a 600 watt 12-60 volt DC/DC booster. There you have whatever voltage you wish and a hands OFF 5 amp current limiter.

There is no Old Faithful effect from a battery recovery exercise. FOLLOW THE CONCORDE MANUAL TO THE LETTER. It would be amazing to lose 1/10th ounce of water.

There are no seals to pop, only valves and they reclose automatically leaving a pristine surface. And NO LEAKAGE. Concorde does not manufacture stuff that demands Okie Tuneup technology.

[GordonThree]

What's the procedure to replace lost electrolyte from the glass mat?

Removing seals and severely overcharging would be outside my comfort area.

[BFL13]

Mex, my highest (adjustable) voltage charger can do 16.5v at most at 45 amps (PowerMax PM3 45LK)

I see para 5.6 here, so that looks like fun! Yipes. I could give it a whirl. (Don't really want to, but if required....)

http://lifelinebatteries.com/wp-content/uploads/2015/12/6-0101-Rev-E-Lifeline-Technical-Manual.pdf

Do you suppose the 8D has been like this ever since I got it a year ago, or did it go this way recently for some reason?

What will happen in the near future if I pretend I never found this out, and carry on as though everything is "just fine"?

EDIT--I don't have a way to maintain constant charge current at 5%
of 24 hr (assume typo for 20 hr?) capacity = 12.5amps. If the charge current is around that amount by a fluke, I can keep it at 12.5 by raising the voltage as the amps taper until I reach max charger voltage 16.5, but then amps will taper. I remember something about light bulbs to help with that, but long gone in memory how that works.

[MEXICOWANDERER]

You're going to need to recovery charge this battery. Yes, it means overcharge to the 17 volt area, which means popping the vents in the process. Outdoors, in a clear area.

Refer to the Lifeline manual for a full run through of this process. It does not mean losing an appreciable quantity of electrolyte.

But results often bring forth magic if the electrolyte did not skin the plates during the overly long hibernation.

Follow the Lifeline manual to the letter. And allow 6 hours for cooldown and vapor purging.

I would heartily recommend wrap around safety goggles, AND a face mask. Gauntlet gloves and a cap of some kind to protect scalp.

Let your instruments and the manual do the thinking. Complete the task then after cooldown resume your tinkering. Sometimes this exercise needs to be repeated so don't be shocked if the first time is not a charm. Let 3 days elapse between events.

[BFL13]

TechWriter, haven't seen you around for a while.

Yes, I seriously want to know what is going on with this 8D. Maybe Mex can explain what is happening with its innards, no idea.

I am not a newbie, so I can deal with things as needs be, but this is a new one for me.

[TechWriter]

BFL13 wrote:
I have this battery. . . I got a year ago off a guy for $225 . . .

He had it in his basement for a couple years with several others he got for a project he never did. He said he charged them up every so often . . .

So after a year and using/abusing it in the usual way ( I am hard on batteries) . . . I tested it for capacity at the 20 hour rate. It came up short . . .

Did you also buy a bridge from this guy?

BFL13 wrote:

. . . so I did an 8 hour condition run at 15.5v (16 as adjusted for temp) per Lifeline method, and re-tested

. . . ( a lot of detailed info) . . .

What's with that?

Seriously, need you ask?