Is flooded equalization charge always timed?

I have (2) of the 6v interstate costco batteries. Would like to do an equalization charge on them. Using the Trojan users guide for directions.

Trojan is saying to equalize for 2-4 hours. But it also says to test specific gravity every hour and stop charging when the SG no longer rises.

Im using a charger designed more for the RC hobby. (icharger 308duo) It has a Pb mode, and i just figured out a way to trick it into charging at 16.17v by telling the charger its a 7cell 14 volt battery and adjust the volt per cell spec to 2.31v.

I seems to work. Within a couple minutes i noticed a smell and could hear the batteries boiling. Stopped and will move them outside before ever doing that again. Theyre currently in the garage with just a side door open.

The charger does have the option to stop charging when the charge current falls to a certain percentage of the set charge current.

I watched the charger and it went up to about 13amps and fell to around 9 within the first 3 minutes.

What is the correct procedure.
1. Start 16.2v constant voltage charge.
2. After 1 hour STOP the charge.....wait a couple minutes???....then test specific gravity? Trojan doesnt actually say to disconnect the charger before testing.

Or since the batteries are only 7 months old should i do a 1 hour equalization charge and call it good? (seems like a lot of people on here mention doing a 1 hour equalization charge once a month)

Or....can you stop equalizing when the charge current falls to a certain percentage of C20? Which might correlate to when the specific gravity stops rising.

Suppose i could test all that myself by recording charge current and testing SG. After a few times i might recognize a pattern. For example maybe specific gravity stops rising when the charger falls to 4amps on a 210ah battery. So end charge current could be set to 2 percent.

Whole reason for asking is to keep the hydrometer use to a minimum and to keep the equalization charge time to minimum.

Thanks for any advice!!

33 Replies

wopachop
Explorer
Sep 15, 2019
Yeah mex bubbling a little too much. I see black splatter spots on the cardboard under the batts. Could also see it splattering up while taking measurements.
wopachop
Explorer
Sep 15, 2019
I'm not too sure the SG was done increasing. Was closing in on 4 hours and my chicka brought home a new puppy. Been playing with him all night. I think I read trojan saying to perform their eq charge and repeat again at another time after 4 hours.

Looking at my notes the weak cells were at 1.291 at 3h 30m and when I checked again at 3h 55m I saw close to the same.

Batteries are label 2/19 and maybe have 10 cycles on them.

Trojan says max capacity doesnt happen until 50-100 cycles is the reason I'm playing around with them in the garage. We don't get out camping as much as we would like.
MEXICOWANDERER
Explorer
Sep 15, 2019
When I wrote BUBBLING it was not a miscue. Acid can either be in the plates or in solution.
BFL13
Explorer II
Sep 15, 2019
My 6s and T-1275s had SG near 1.3 when truly full when they were in good shape, before they got old and tired. So you already proved you don't need to worry about the exact battery voltage wrt the charger voltage--you got the SG where it belongs doing whatever you did.

You can try all sorts of ways, but all that matters in the end is that SG. One case where the end does justify the means? The proof is in the pudding? Whatever works?
wopachop
Explorer
Sep 14, 2019
Im down for pretty much anything. Original plan was to set the charger to 11a and do the 5% charge. With the voltage limit at 16.2v but i was going to watch it and not let it go above 16.0v.

Clicked start and it was up at 16.1x after a minute so i modified the amperage down lower.

I like following recipes. Get a nice baseline before playing with the rules through experience and knowledge like landyacht.

That voltage drop is still messing with my brain. If the recipe calls for 16.0v, shouldnt i ignore what the charger screen says and go with the battery voltage at the terminals? (i guess im gonna keep asking until someone says yes!?!?)

I do see how the voltage drop becomes less as the charging amps decrease. But it appears the charging amps stayed up around 6a and that turned into about 1.5-1.8v difference between the batteries and my charger screen.

It took just under 4 hours. They stopped around 1.290. Took in a total of 24000mah.

They definitely bubbled more than the 1 bubble per second. So maybe i was too high throughout the entire eq charge.
landyacht318
Explorer
Sep 14, 2019
While following a recipe perfectly is of course ideal, often ideal cannot be easily achieved. The goal of EQing a battery is maximum specific gravity with minimal acceptable abuse.

I can get batteries there without following the recipe exactly, I just did so yesterday on what 'might' be the exact same batteries as Wopachop, and these batteries will get drained to 10.5v as they work for a living and their owner simply don't shiv a git. His converter is an Iota dls-45 I installed some 5 years ago. I tell him to plug in for 3 days after an outing then hit the disconnect I added. The interstate gc2s are 3 years old and yesterday was their first watering afaik, and their second EQ besides when i first got them.

The screwy31 has been walking dead for year and years now, often ignored, and still going. The concrete under it is surrounded by a dam of baking soda and chewed away inside that barrier. I bring it up as an example that perfection of process can be skewed pretty heavily, and still yield more than acceptable results.

I took the screwy31 out of my rig in june of 2015, and it mostly sees a 100 watt south facing panel daily and charge controller that attempts to achieve absorption voltage for 2 hours a day. It provides upto 30Ah nightly 5 days a week.

Its charge efficiency factor is horrible, but solar is free, so i dont care.
It's self discharge is likely 2% a day or higher. also not a factor.

It got some attention yesterday only as I had my meanwell unscrewed from my rig's electrical cabinet door and a 2/3rds a gallon of distilled handy.

When it becomes a 10.5v battery, I'll likely core charge it toward a new high $$ AGM, and my equal aged and impressive Northstar-27 AGM will assume its place in workshop duty even if it is still a viable dual purpose cycler and engine starter at that time.
MEXICOWANDERER
Explorer
Sep 14, 2019
Landy this is a recipe. I would LOVE a six-minute cake, however...

I tried 16.2 with a GOOD flooded battery 16.0 yielded the least unneeded temperature gain and gassing. The tops of the batteries stayed drier. After a nine-hours demanded equalization at 16.2 volts, change, to rubber galoshes rubber apron, and biohazard helmet.

The tests were conducted on nearly new flooded batteries :) not The Walking Dead.

Trojan can stuff carbon into a 31 but this is not the norm for a flooded 31 RV battery. :) You did not misidentify your Screwy 31. Kudos!
BFL13
Explorer II
Sep 14, 2019
"Got them charging now this is fun. "

Oh-oh. The bug has bitten! :)
landyacht318
Explorer
Sep 14, 2019
I found on one screwy battery that what took close to 4 hours at 15.5v took 45 minutes at 16.2v.

45 minutes was more desirable, for me.

1.283 might be as high as it goes.
MEXICOWANDERER
Explorer
Sep 14, 2019
Prefer your slightly lower voltage and increased needed time. Don't bake a cake at 2000 F for four minutes. Don't tinker this is a recipe :)

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Is flooded equalization charge always timed?

33 Replies

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