How to Revive a dead 12V Sealed Lead Acid Battery

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today we show you how to revive a sealed

lead-acid battery using simple methods

and some tricks and I promise you there

will be no epsom salt

involved all you need for this is

distilled water battery acid which is

30% sulfuric acid solution and some

patience because this is good to take

some time so let's get started so I've

got a couple left latest batteries on my

old electric back

they've been refusing to take a charge

the moment I plug them in a charger it

would turn from empty to full in just a

matter of seconds I will show you that

later on in this video the first thing

we have to do is to remove the plastic

cover on the top underneath the cover

you see six rubber caps for the six

sales of the battery remove these caps

and we can take a peek inside the cells

and they look very dry well actually

they are not really wet in the first

place because these are non spillover

batteries they have gels with citric

acid suspended in it but after being

repeatedly charged and least just these

chairs run dry to a point they don't

provide enough medium for the electrons

to flow and no chemical reactions can

occur after all these batteries are just

simple devices that turn chemical

reactions into energy without chemical

reactions to occur there will be no

electron flow and therefore no energy

what we can do to revive these batteries

is just simply by adding more battery

acid and they still wanted to provide a

medium for the chemical reactions to

take place usually you just need at

least eight water not acid to fill up a

flooded lead-acid battery like the 6

volt go kart batteries but in this case

also added citric acid 30% solution I'm

going to explain to you why let's take a

look at the chemical reactions that

occur inside the battery when you charge

or discharge it the forward reaction

occurs when you discharge the battery

the reverse happens when you charge the

battery the left side of the equation is

the charge state the right side is the

discharge State meaning when the battery

is fully charged most of the material

inside the battery is left let oxide and

sulfuric acid when the bearer is fully

these jobs most of the material inside

battery is less sulfate and water we

also call this process so fashion this

lead sulfate will accumulate over time

and then eventually the plates will be

covered with lead sulfate at the same

time so Phil acid will be depleted and

eventually there'll be no more sulfuric

acid inside the battery this is when you

have a completely dead battery some of

the left sulfate are not recoverable and

therefore you cannot return it back into

sulfuric acid when you charge the

battery if you take a look at the

chemical reactions at this time you see

the reaction is now leaning toward the

right side most of the material is now

just lead sulfate and water so by adding

some more sulfuric acid into the battery

I would help it restore the balance of

the reaction toward the left side and at

the same time dissolve some left sulfate

on the right side a process we call

these sulfation right the depth of the

chemistry let's put this interaction I

begin by adding two milliliter of 30

percent sulfuric acid solution into each

cell then I add distilled water all the

way up to the top of the plate basically

the still water is added until you see

water level up to the top of the battery

plate inside the hole as I add more

liquid into the battery you can see the

voltage starts to rise steadily alright

so it's been about three hours since

last time added the Mary acid and

distilled water to the battery and the

voltage seems to be stabilized right now

at ten point seven five it's not

increasing it's not decreasing it stays

at ten point seven five so I've just

plugged in my tawny charger and the

voltage movie leaves just a little bit

down to ten point six five against the

battery is kind of under load right now

let me try to charge the battery and

show you what happened that try to

charge the battery right now with this


okay so it's trying to push the voltage

up and see they're up to twelve point

four now fourteen strike the fourteen at

zero amp no current and it's finished

that's it it's not judging anything to

the memory so this battery does not want

to take a charge so I need to find a

different way to force the battery to

take a charge and that can only be done

by parallel charging so here we have a

full-size lead acid battery is fully

charged twelve point eight volts it's

going to do a parallel charging between

these two batteries so positive here

it's gonna go to positive negative to

negative so god the meter is connected

in series with the circuit okay and here

we go that is very low current zero

point zero two amp that's twenty

milliamp but you know what that's the

old saying goes if you're patient enough

good things will come to you so I'm just

in let this charge for the whole night

and and it's now one o'clock in the


112 a.m. October 30th and we'll come

back in the morning and see what's going

to happen alright so it's not 11:22 a.m.

the same day so it has been about 10

hours let's check and see what we got

here so the current is increased now to

0.3 amp that is pretty good the voltage

is thirteen point one three volts that

is good news

that means the battery is charging just


but at a very slow rate you can see the

mega battery died used to charge this

small battery it's gone now because I

move it down below my table so I have

room on my table to work on other

projects and we routed Y up here okay so

I can hook it up to the smaller battery

and also hook the whole system to my

solar charge controller and it's

charging the big battery and also this

berry because it's connected in parallel

right and I think with the solar panel

connected to this charge controller and

charge the whole thing is boosting the

charging rate a lot now and this number

here has been slowly creeping up over

time when I first woke up in the morning

about couple hours ago it was only about

point two five and it slowly increasing

one by one point two six four to seven

now point three so the charging current

is not static but rather it increases

over time when this Berry is getting

judged more and more it's now 5:44 p.m.

and it has been about 16 hours and the

charging current is now zero point four

M so that's very promising so here is my

beautiful drawing explaining what's

going on so at the beginning we have the

bad battery connected to a charger and

that didn't work right it went from 0%

to fool in just five seconds so that's

where this good battery comes in and it

will jumpstart the bad battery to a high

voltage but without an external charger

the batt battery voltage will increase

up to a certain point where it will

equalize with the good battery and then

the charging rate is gonna slow down

significantly so when things start to

slow down in the deals in external

charger and that we introduce a lot

higher voltage at 14 around 14 volts

instead of 12 or 7 volts

and therefore that will accelerate the

charging current it is not 12:30 p.m. on

November 1st so it has been two and a

half days and now the charging rate goes

down to zero point one amp and right now

suit made the time when I get the most

sunlight but the charging rate is

slowing down so I think we are almost

there it is 12 19 a.m. on November 4th

and it has been 5 days I started on

October 30th last month so the judging

current is now really slowing down point

O 1 so it's almost zero think it shoot

me none right now I'm gonna disconnect

the other battery now it's connected in

parallel and I see the voltage stay the

same so that's disconnected and the

voltage remains the same so that is a

very good sign my next test is to run a

discharge test with my Tony G charger

here to determine the capacity of this

battery we got let this charge at 1 amp

let's start all right I also got my

cooling fan on the bottom here to cool

my charger because gonna get really hot

discharging this battery

right so the battery discharge test is


it took 8 hours 36 minutes to discharge

and it ended at 10.8 votes total

capacity is seven point two seven eight

and power almost seven point three and

power so that is pretty good considering

the rated capacity of this battery is 10

M power and even though the battery is

rated 10 amp hour the manufacturer

tested the battery of a period of 20

hours which is at half an amp this just

rate this battery was tested at 1 amp is

charged right so I could have had more

than this if the one that is just right

at the lower rate right now the battery

is completely discharged in resting

voltage so 11 point 4 volts and last

time it was 110 bout 10 volts off that

is pretty good that's a good sign the

battery is being revived

now let's charge it back up at

one-and-a-half amp

all right so judging is now done it

takes six hour 50 minutes or almost

seven hours and the capacity had put

into the battery is about eight foot one

amp hour and the capacity when it

discharged it was like 7.2 so it does

make sense right because discharging the

battery is less efficient than charging

so it was great

I've noticed on top the batteries just

leave out some liquid a little bit and

this makes sense because added too much

liquid in there I've turned a non spill

beau battery into a speedball battery so

for the first few times when you charge

this make sure that you have the lid

open so that I can vent some liquid out

but once it reaches an equilibrium it

won't spill any more and this process of

losing better liquid happens regardless

the Barry is non spill bow or spear ball

it will still lose liquid inside battery

so that's why at the beginning the Barry

doesn't want to take a charge anymore

because there's no more liquid for the

chemical reaction to happen and by

adding liquid into the battery

accelerate the chemical reactions and

therefore helps it retain the charge

after all this battery is just a device

you convert chemical reaction into

electricity and if chemical reaction

does not occur you want to have


I went ahead and worked on reviving the

second battery just like the first

battery I first added about 2 CC of 30%

battery acid and the rest is distilled

water all the way up to the top of the

plates then I need a pair of charging

for three days then unplugged everything

and let the battery sit overnight the

next morning I came back injected

voltage and it showed twelve point nine

volts so that was pretty promising

then everyone at least Josh test and got

six point eight amp power which was very

close to the first battery although it

was a success with having both batteries

the trick here is patience unlike

reviving lithium-ion memories where you

can get the results almost immediately

reviving left as it memory takes much

longer time and in this case it takes

over three days to fully charge it it

makes sense because a typical 18-6 if

the battery capacity is only about seven

one-hour detain one hour this letter C

battery is about 120 one hour so the

latest battery is about ten to fifteen

times the capacity of a typical 18 650 I

usually walk on and therefore it takes

much longer to charge it especially at

low current

right it's time to test it not a single

12 volts in here and it's at twelve

point eight five volts right now go


check on the voltage now we got you nice

to often have votes and rising

so now put two batteries in series we

got twenty five and a half volts go


let's check on the voltage 25.3 that is

pretty good it's not much in voltage

drop on these berries so how do you

charge have a good time

what do you mean that yes