'true' full charge via equalization

[sternwake]

I was typing a longer post when I his shift and w at the same time and the whole freaking browser closed.

so this is the brief version using not the dang shift key.

friends 6 month old battery, wal mart group 29.  never sees anything but 30 amp alternator/generator in 72 vw bus.  does get upto 14.6 though, but only at higher rpm.

am installing stereo while he travels
battery resting read 12.53v.
hook up 100 watt solar panel with charge controller seeking and holding 14.5v, 4 hours first day, 7 hours next day.
amperage both days had tapered to under 0.3 amps, and the voltage 2 days after the last charge, read 12.78v.
a week off the chaarger it read 12.75v.

not bad, one might think.  thing spend no less than 7 hours at 14.4v, should be fully charged right? holding good voltage a week off the charger, still close to fully charged, and must still be pretty healthy right?

Today it got 5 hours of 14.7v after topping it up with distilled water. only 3 cells needed any and were only 1/8" below the top of the hanging ars witin the cells, and amperage again tapered to under 0.3 amps at the end of those 5 hours.  5 hours after that voltage reads 12.87.

Normally these voltages would indicate the battery is still healthy and absolutely fully charged, but is it really?

Out comes the hydrometer and all the cells are only reading fair, 1.235 to as high as 1.255.

It should really be 1.275 or perhaps higher.

now since it spent so many hours being held at high voltages, the only way to get the specific gravity back upto the 1.275 range is with an equalization charge, and this requires voltages as high as 16.2 volts.

how the f does one achieve 16.2v with normal equipment?  
well I have an adjustable voltage power supply, and  icould pull it from my van plug it in in my workshop and get the battery to 19.23v if I wanted to.
I could bypass the charge controller and use the 100 watt panel directly to the battery, and hope to achieve and not exceed 16.2v
 but I also have a voltage booster I bought several years back, that so far all I have used it for is making 12v fans levitate at 27 volts.

I hook up my pos schumacher to my workshop battery, which is a 5.5 year old worn out Usbattery group 31 marine which drinks water and is in quite por condition, but I plug the input of the voltage booster to it and the output to my friends wally world group 29, which is the same exact size as the 31, why they call it a 29 who freaking knows.

bump the voltage upto 15.3v watching my clampmeter and amps stay below 2, but once I hit 15.5v the battery nis accepting 5 amps.  Over the next two minutes I raise voltage in stages keeping amperage from exceeding 6.5 amps as the battery starts bubling up a storm.

5 minutes later I dip the hydrometer again and there is no change.  5 minutes after that 5 of 6 cells have risen 0.005. 10 minutes after that and all of them are now 1.260 or higher.  This is accounting for the rise of electrolyte temperature.  it is still requiring 5.5 amps to hold the battery at 16.2v as I type this.

my hydrometer is an otc 4619

https://www.amazon.com/OTC-4619-Professi...B0050SFVHO

it has a thermometer which says to add or subtract based on electrolyte temperature.

The voltage booster/step up converter, is a version of this:

https://www.amazon.com/DROK-Converter-Regulator-Adjustable-Regulation/dp/B00C0251CS/ref=sr_1_fkmr0_1?keywords=drok+voltage+booster+150w&qid=1563258252&s=gateway&sr=8-1-fkmr0

mine was some no name brand which was less than 3$ slow boat from china, shop around on amazon or ebay using step up converter 150 watt dc as search terms. if one has a large battery bank they want to eq all at once they have 600 watt versions too.

The eq charge is really the only way to truly fully charge a flooded battery that is in less than perfect condition.  once eq'd the battery should be at its maximum remaining potential capacity.

the eq charge needs to be monitored. and 16.2 volts held only as long as is needed to max out specific gravity, accounting for rising electrolyte temperature.  held until it no longer rises, even if it is shy of the maximum previously recorded/achieved.

the eq charge should be terminated quickly if the battery starts heating up quickly.  and the battery should not be allowed to exceed 120f ever.  once temp starts rising past 105f it will quickly accellerate from there.

the less time the battery requires to max out the sg, the better condition it is, the better it has been treated since the last eq charge was performed.

the regularly performed eq charge of a flooded battery  can greatly extend its lifespan and performance, but they should not be performed more than necessary and then, only as long as necessary.

the eq charge can negate poor batter charging practices, to some degree, but should not be relied upon to salvage an abused battery.

the eq charge itself is hard on a battery and it offgasses a lot and can be stinky, and one needs to take precautions against sulfuric acid getting on skin, in eyes, on clothes and the mist in their lungs.  baking soda nearby to neutralize acid is wise.

16.2v is the maximum voltage, some will say 15.5v.  I have found that what took 4.5 hours at 15.5v took 45 minutes at 16.2v, and no longer fvck around with 15.5v.

the 100ah 'fully' charged battery will require about 5 to 6.5 amps in order to be brought upto 16.2v
one does not want to reach 16.2v with more than 6.5 amps or initiate an eq charge on a battery that has not already spent several hours at higher absorption voltages.  

if a 100ah battery requires 10 amps to get to 16.2v i lower voltage until it is accepting no more than 6.5 amps, and then raise it in stages.

the whole eq stage i not a set it and forget it thing, it should be closely monitored, especially y the first few times.  later on one can  know that it takes a certain amount of time at 15.5 to 16.2v to maximize specific gravity and just aim to achieve that, but ideally they should be dipping the hydrometer more often and checking for abnormalities.

obviously one can skip doing eq charges and get acceptable lifespans from their flooded batteries.

'acceptable' is subjective. opinion.

those who have not been able to recharge properly as often as they know they should, can greatly extend their battery life by performing an eq charge, when they have the opportunity to do so.

the eq charge is the abused battery's best chance of being returned to its maximum remaining potential capacity, but it is not a guarantee that an old sulfated battery can be restored to usefulness via performing one.

one cannot really hook this directly to the output of most chargers, a battery must be in between the two.

[sternwake]

after i clicked 'post reply', I returned to the 16.2v eq'ing battery. The workshop smelled like charging battery, rotten eggs. not unexpected.

my clampmeter revealed it was accepting 7.2 amps, the thermometer indicated it was 97 f in ~75f ambient.

I left it too long while I typed the post above. i dipped the hydrometer and saw only 1.260 to 1.265 on all cells, and while the electrolyte was not gray with flakes( a bad sign), it was agitated and somewhat cloudy with micro bubbles in it.

The specific gravity willl likley read higher tomorrow once it settles a bit. 16.2v is likely a bit too aggressive on this battery, judgine by how agitated the electrolyte was and the massive jump in amperage required to push it from 15.4 to 16.2 volts.

I likely left it at 16.2v about 15 to 20 minutes longer than needed, indicated by the 7.2 amp figure, having risen from 6.2 when i left it, also by the temperature rise.

it would have been best to know the maximum specific gravity of this battery when it was new and fully charged. If I knew it was only ~1.265 I would have stopped earlier, but I expected 1.275 or higher.

flooded batteries intended for warmer climates might have electrolyte only in the 1.260 range when the battery is fully charged, while those intended for cold climates might be as high as 1.310, but it is obviously best to know before initiating an eq charge, as to what number to aim for.

the marine battery in this example was built december of 2018, and in use since mid january. I doubt it was ever discharged below 80% and I doubt it ever saw anything near 100% since purchase. it was made in mexico, distributed by johnson controls, not sure of its weight. 122ah at 1hr rate, and 875 marine cranking amps(32f) no cca rating(0f)
i don't know what it cost, but i suspect the 95 to 110$ range.

my experinece with wally world group 27 batteries in deep cycle service, was not great, but back then I was not able to really achieve true full charges, nor perform eq charges. back then i was one of those who ignorantly believed the charge controller reverting to float meant the battery was full, which is quite foolish.

my experinece with the group 31 us marine battery now on my workshop floor, surrounded by baking soda and half dissolved concrete, was the best of the 12v flooded batteries i cycled hard and heavy, but that battery required 14.9v absorption and 15.3v float solar settings for the rest of the day, then 45 minute 16.2v eq charges every 2 weeks, when I was discharging it 45 to 65ah each night every night. I got around 550 deep cycles out of it before taking it out of my van and making it a workshop battery in june 2015. Its first 3 weeks of cycling it was getting a few hours of 14.4v each day via 200 watts of solar, and I found specific gravity down at 1.220 or less at the end of those 3 weeks, after noticing poor voltage retention and buying the hydrometer. Had I known I was badly undercharging it every day in those first 3 weeks, and figured out what it needed to return near maximum specific gravity earlier, it likely would have been in service in my van for longer, but I caught it too late.
It really helps longevity to figure out what a battery requires to be returned to full charge, as it is used, as it wll be used, in those first few cycles. 200 watts of solar getting this g31 us battery to 14.4v and holding it there for 3 hours was well short of what it required when taking 35+ amp hours from it the night before.

the usbattery is not dead yet, but 100 watts of solar panel cannot get its voltage above 14.0v, and the battery is fizzing constantly when being charged and sometimes when discharging. it no longer sees any deep discharges, goes through water quickly, and loses voltage pretty quickly powering about 3 amps worth of fans and leds in the workshop. Still going though. It was a 140$ battery in november 2013. I doubt it could still crank my engine or maintain 10.5+ volts discharging it more than 65 amp hours , but I will not be testing it for that capability. It can and does supply 5 to 20 amp hours each night i am in the workshop. and voltage will fall to the 11.7 range at ~20ah from full under a 3 amp load, which is quite poor.

I dipped one of its cells tonight, the one which still had enough electrolyte to actually float the hydrometer's float, and it read 1.255.

If I only ever used 20 amp hours each night, and had no way to determine health or state of charge, I might even say it is 'still going strong' when it is far from that, and could become a 10.5v battery any day now, which will be sad as I like having 12v lights and fans basically powered by the sun, in the workshop.
this battery is not sulfated, most of the plate paste has shedded and rests on the bottom of the cells. a prolonged eq charge would just cause more shedding and no real increase in capacity.
if it were sulfated then 100 watts of solar would easily and quickly raise its voltage to 14.7v, and voltage would quickly fall to low levels under light loads. It would appear like a much uch smaller battery, instead of a 64lb group 31 that it is, once rated at 130ah capacity at the 20 hr rate, and 565 cca.

[sternwake]

21 hours after I ended the EQ charge, and all the cells are reading between 1.265 and 1.270.

Its resting voltage is 12.87v.

I bet it will retain a much higher voltage when starting that 1.6 liter aircooled vw engine than before.

[sternwake]

5 days later with No loads applied what so ever, full charge resting voltage has fallen to 12.83v.

I did not bother checking specific gravity since. It is now reinstalled and actually secured, rather than loose in the engine bay, and checking specific gravity in place would be impossible without spewing sulfuric acid everywhere.

This battery is as good as it is going to get at this point in its life.

The EQ charge is the best way to accomplish 'as good as it is going to get'

[sternwake]

Here is a link to the same voltage booster I used to EQualize charge the battery at 16.2v.

A whole 2.79$ free sipping slow boat from China.

https://www.ebay.com/itm/150W-DC-DC-Boost-Converter-10-32V-to-12-35V-6A-Step-Up-Voltage-Charger-Power-AT/292409304867?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20160323102634%26meid%3D7657913fc82649e9be4524ee63d8b39d%26pid%3D100623%26rk%3D3%26rkt%3D6%26mehot%3Dpp%26sd%3D202692780913%26itm%3D292409304867%26pg%3D2047675&_trksid=p2047675.c100623.m-1

Hard to say one does not have the tools to perform an EQ charge.

Thus device can also be used to power many 19.5v laptops directly from their 12v battery. My laptop has a third pin so this could power it, but not charge the battery.

I out a 60mm fan across the heatsinks on mine 150 watt DC voltage boost converter, as i had one laying around.

Keep in mind that if one employs this Dc booster to do an EQ charge, they will likely need another battery inbetween regular charger, and thie booster device adn battery to be EQ'd, althuogh one could skip the charger on batttery one and just EQ one battery off another battery.

Those with older buzz box transformer based chargers shoule be able to hook this boost converter directly to it's clamps through some wire, but the buzz box charger should be 6 amps or greater.

I'll pull my old buzz box out one day and test this.