good grief... to think that a 10 year old video contains a far higher amount of relevant and practical information than I can find on any modern content... this right here is what youtube is for. Thank you.

" You can patent anything. It doesn't have to work. "" Greatest comment ever. What a great video. I learned A LOT. Thanks.

I have lived off-grid for 15 years and have been a ham operator for 45 years. THIS DUDE KNOWS WHAT HE'S TALKING ABOUT! The rest are hucksters! I have used an Infinitum desulphator (this is not an ad, BTW, there are other brands as well) for the last 7 years and my average system voltage has gone from 23.9v to 24.8v after about a year's use. I believe adding a desulphator is good maintenance, but it does not restore batteries. Using a desulphator to keep a battery in good condition is not magic. Remember, what he said, taking good care of a battery is what it's all about, not free lunch...This is a first-rate post! Thanks!

Thank you for taking the time out of your day to educate us. Being that we only have about 32,000 days, or 960 months of life, if we live to be 80 years old, time is priceless.

Not only is this instructive, it's informative and explanatory. This is what the internet needs!!! I've been looking this sort of thing up for about an hour and after several youtube videos, this one came up, and I wanted to say Kudos and thanks for this informative video! I like when someone explains how and why something works. Leads to better understanding.

Followup for anyone interested: I still use this battery today 5 years later for various purposes. It has about 50% of its expected capacity and about 200% of the normal series resistance. It is still useful to this day which is better than being thrown out, even if it isn't as good as a brand new one.

This method works 100%! Picked up a use NIB Back UPS and when I opened it I discovered it had been unopened for 16 years. The 12v 5 mAh SLA was totally dead. Watched this video then I proceeded to fill all the cells (all were completely dry) and connect it to my bench power supply pushing it @16v. For the first 24 hours it was only drawing about 1 mA and had only come up to about 6v, at the end of the 2nd day it'd come up to 10.6v but was still only drawing 1 mA and it stayed there for 48 hours, I was beginning to doubt that this battery was salvageable. I noticed it the middle of the 4th day that it was drawing 3 mA and had come up to 11.9v (there might be something to this!) 4 hours later it was sitting @13v and as it stands now I'm draining it down to 10.5v with a turn signal bulb and it's been running for nearly 30 minutes. Amazing that I could bring a 16 year old battery back to life with this process.

Probably the only legitimate video on the subject. Everybody else on youtube nowadays is in love with epsom salts and trickle chargers.

This UT brought back fond memories. My uncle owned a small automotive repair shop. I worked there during a few summers while in HS. I noticed he had a bank of batteries that he had on chargers (all were dumb at this time. LOL). I asked him what he was doing with all these old customer batteries. He said he was reconditions them. I thought it odd at the time, but he seemed pretty confident that it work for some. I guess he was right. I learned a lot about cars. If you maintain the battery, rubber hoses, belts, oil, coolant, and tires even long ago most car almost never stranded one the road. And true today.

This tutorial is packed with the good information and zero bad advice. As a simple safety tip it should be pointed out that flooded lead acid batteries expel flammable gasses (hydrogen and oxygen) during the charging process and should be performed in a well ventilated space. Hydrogen is a lighter than air gas so common sense would say "don't do this in a closet or under a non-ventilated hood. But hey, who needs eyebrows. My old man used to tip them upside down, rinse them out, smack them with a dead blow hammer a couple of times and refill with clean acid solution. I could see the old sulfur and crud poor out and it usually helped on old farm tractor batteries. The main trick is getting the crud (sulfates) to slough off of the plates as he clearly explained in the video.

Thank you . I have a habit of watching your videos for good information . Thank you again and please keep making these great videos .

Just restored 2 100AH scrap yard batteries Using a 20V 90W laptop charger and a 65A load using a similar method to this It took me 2 days to restore instead of 2 weeks just by changing the voltage and load Initially after charging with a smart charger and both batteries linked in parallel they would run the load for about 20 sec before the inverter shut down After recovery they ran the load for about 2 hours I let the battery voltage go up to around 15-17 volts and left it at that voltage with the laptop charger switched on for about 20 min then disconnected the charger and let it rest for an hour then drain it with the inverter then recharge with a smart charger then overcharge with the laptop charger I repeated those steps about 4 times a day for 2 days and now they are in service powering my off grid system

Excellent honest video. Thank you for taking the time to make it! Exactly the no snake-oil engineering approach I was searching for.

Very nice and straightforward, and I also appreciate the brief explanation of dubious "alternative" methods… thanks!

This is a helpful video. Nice to see an educational video where the "comments" and "questions" section isn't disabled as i've seen in other videos.

Finally some more videos on stuff I have been doing forever. You can restore lead acid batteries and you can’t restore lithium batteries easily at home. The companies want you to spend money and keep buying more batteries or new technology. I love maintaining and restoring anything I have. Lead acid batteries are perfect for home base solar storage And I easily restore lead acid batteries with Raw solar power without the smart solar charger. I would use lithium for lighter transportation needs. People need to know the truth.

I have restored many car batteries using the old charger method and for the most part, maybe 7 out of 10, would all recover. Some were old truck batteries which take a lot longer to stabilise, but most get there in the end. My reason for needing these old batteries as a kid - C.B Radio, until i was old enough to buy a stable rectified and regulated PSU. I did miss the bubbling sound beside my bed though...lol. Some good info for cycling the batteries you have given. Info I will no doubt benefit from one day. Top vid mate.

Thanks for this; I'll try again. I had no idea that it might have to go on the charger for so long...

I really admire your honesty and your professional presentation, well done, you have a big thumb up from me, thank you so much for all the useful info

This Guy is the only one that makes absolute senses about battery reconditioning. I have to say I fell for the BS put out there on Baking soda and epson salt process. I also spent a lot of money on a Battery Tender pulse charger that he states is worthless. I’m very glad I came across his video. .

I have used this method before in the past (and still do) and it works well the the most part. Excellent video.

Well done young man! Years ago I used a similar method to restore thousands of dollars worth of batteries in building inverting systems. The charger I used was so old it actually had tubes in it!

Thanks for this video! I wouldn't dismiss pulse charging and Epsom salts entirely. Pulse charging allows for a much higher than normal charging voltage to get through the cells to help break up the sulfation, and the cyclic nature mitigates against heat build up as well as creating small oscillations to help mechanically break up the sulfation. Epsom salts don't do anything chemically other than reducing the resistance, which helps promote current flow to also break up sulfation when charging. I am hesitant on discharging the battery completely, but the principle makes sense. People also discharge the battery, reverse charge it, then discharge, and charge it back up again as another method to "shock" the sulfation off. A combination of these methods can often help. But these methods only work when the problem is sulfation. When there's mechanical damage to the plates or if they are shorted out then the battery is junk.

Great advice delivered without BS and with humble qualifiers.

Understanding the physical chemistry is slightly useful and this video is good for this. After 50 years of car battery life cycle experiments I concur with the approach taken here. Cracking that sulphate layer is needed, but not so hot that the plate loses useful material underneath. That's why a pulse charger isn't so good: the plate reforming doesn't work so well with high currents so you lose capacity.

Thank you! I'm glad your blunt Abd straight forward. Love your videos!

Thank you for this tutorial Knurlgnar I tested my car battery from my car (varta d59) with a conductance tester that calculates the amps the battery puts out based on its internal resistance, it tested at 388A out of 540a. I made some tiny 1mm holes on the top and used a syringe to add a bit of distilled water in it each cell, all of them had the plates covered but each one was at a different level. I then put it in an equalising charge at 16 volts for 24 hours, then i did a discharge with an h4 headlight bulb and after recharging it it went to 432A. I just finished the second discharge cycle and i am waiting for it to charge to test again.

Thank you. Nicely illustrated. Time to give it a try on a few batteries I have kicking around.

Excellent video. Thank you! No hate, but I've recovered several batteries with a cheapo pulse charger I got off eBay. It's not 100% and I haven't recovered anything heavily sulfated. There also is a happy medium with it. You can't just put it on every battery and leave it. It will interfere with normal charging at some point. Even so, It has saved me from buying new batteries several times. When the dead battery is a relatively new one that was left to sit for too long, you're glad for the de-sulfator. It has more than paid for itself several times now.

I just saw one of your battery revival attempts, try this if you have the time and effort. There's an old trick that used to be used here in Sweden for tired batteries with thick plates. The old ones didn't have as soft lead clay so what we did was; 1. Discharge the battery to less than 10%. In the end, use an iron rod or similar to completely discharge it. 2. Charge the battery in reverse polarity, make sure it doesn't get hot. - If so, decrease the current. Leave for 12-48 hours on a dumb charger. 3. Do as point 1. 4. Charge with normal polarity. (5. Small particles of lead may be present on the bottom and making a soft short circuit. If so, drain the battery, rinse it several times until clean. Fill with 32-37% H2SO4 and charge as normal. Leave on a dumb charger for overcharging for 12-48 hours.) Get back to me if you try it, it’d be fun to know the results.

Thanks so much for the information! This is a fantastic tutorial as are your other videos on reconditioning batteries. I was struggling with getting severely imbalanced SLA Group 4D batteries back to health, (they were only 6 months old and in light cycle use) and your videos pointed me in the correct direction. What I found, and what helped me: The key is to not stop at the voltage of the 20 hour rate, but make sure the resting voltage after discharge is at the 20 hour rate. I had tried to recondition stopping at the 20 hour rate (10.5 volts in my case) but that did not work. my batteries were not improving. I tried slow recharge with 2 ohm resistor for a week, recharge at 1 volt over the upper limit (condition equalization charge) for 24 hours, charge at 14.8 volts for 2 days, 40 amps for 10 hours, nothing worked. Then I thought about what you said about referencing the spec sheet in one of your reconditioning videos and getting amps through the battery - I'm theoretically putting a ton of amps back into the battery, its not holding the charge - it wasn't even going to heat, it was just doing nothing..., so maybe I'm not discharging enough 10.5 and stopping is just not enough? That was the case. After complete discharge cycles so my resting voltage was at the 20 hour rate spec, the batteries started to improve with the reconditioning you outline. I had 10 out of 26 Group 4D batteries like this, so far I've got 4 recovering, 2 back in service. I read up on how imbalances that ultimately lead to sulfation like this can happen, turns out it is manufacturing defects! Improper ratios of the lead + active materials (tin/calcium/etc) during manufacturing causes the internal cells to become imbalanced when lightly discharged and slowly recharged. (however the manufacturer of these batteries will not refund me or give me replacements, soooo I won't ever purchase from them again) but your methodology works to bring them back into balance and back into service. I just hope I don't have to do this too often, because it is ridiculously time consuming :) Thanks for your videos! Useful and accurate information that solved my problem!

It is refreshing to watch & listen to your video. The incredible videos that are a compendia of lies, misinformation, & just plain nonsense , are ubiquitous on the net. I would have thought that most adults were topically familiar with the chemistry of a lead/acid storage battery. Thank you for revealing the FACTS !

Thanks, nice style of presentation and you seem to know your stuff. I'll definitely give it a try.

Excellent tutorial and very professional.

Man, I can watch this video over and over! Thanks so much for sharing!

Excellent. A process that I have used and thought to be very helpful. Thanks for sharing and the edification.

You speak good sense really helped me out thanks!

Summary to help locate details in video. 0:00 How to identify when rechargeable lead-acid battery is failing. 2:34 Two "recovery" methods that knurlgnar24 does not recommend: (i) adding chemicals to the cells and (ii) pulse charging. 3:40 Introduction to recommended 5-step procedure. Equipment needed: Non-smart (old) battery charger, low-ohm resistor (such as an incandescent light bulb), voltmeter, and clamp ammeter capable of measuring at least 5 amps. 5:14 Step 1: Connect non-smart charger through a low-ohm resistor to the battery. [Be careful where you put the low-ohm resistor. It can get hot if the battery starts to accept more current.] 7:48 Step 2: Monitor current until it rises to and stabilizes at 1-4 amps. Add distilled water [carefully!] to keep battery plates covered if possible. It may take up to a month before the charging current stabilizes at 1-4 amps. If it never reaches 1 amp, the battery is not recoverable. Buy a new battery and recycle the old one. Some vendors will pay you a "core charge" credit if you return your old battery to that vendor. [Determine details before purchase.] 8:20 Step 3: Assuming charging current stabilizes at 1-4 amps, leave the charger connected for an additional 48 hours. 8:42 Step 4: Disconnect the charger, wait 24 hours, and measure the battery's voltage. If not 12.5 V, reconnect the charger for another 48 hours. Repeat step 4 as needed to bring the voltage to 12.5 V after 24 hours of no charging. If you still can't get 12.5 V after a week or two of repeating step 4, recycle the battery. Successfully passing step 4 means that the battery is desulfated. 9:50 Step 5: Cycle the battery about 5 times by partially discharging through a load and recharging. 13:23 Final comments

Right.. proper battery maintenance is key. Learning about batteries is very important because how the battery is used will for sure extend the life cycle. A car battery is designed to stay fully charged unlike a cellphone battery is designed to be fully drained and fully charged and once the cycle is started the battery will last longer. Here’s another example like a power tool battery (Milwaukee ) fully charge it and the first time the tool stops working because of the battery getting low, it needs to be fully charged and not drained below the threshold or so low the charger won’t charge it because of the voltage being too low. You guys probably know all this stuff but I’m just sharing what I know about batteries and hopefully it’ll help someone else. Great educational video!

I am glad you emphasized the futility of restoration of a sulfated battery by pulsatile means! Snake oil analogy for those eager to pay for it!

One of the best, no SHIT, video that I have seen. I loved it!

Between all the video i wayching about reconditionning battery i just watch the right one with the right step by step. Thank you

Thanks for taking the time for the video...I'm going to give it a try..thank you

this video helped me recover both of my optima batteries ! I could not do it with smart chargers. Smart chargers could only get me to 12.5v resting - with a 10 AMP manual charger and a few weeks of patience I have both batteries at 12.8v. Thank you !

After watching a few years back I have revived a few batteries using this method. What I use rather then old charger is just a small 10w panel and controller hooked up to battery until it holds 12.5 then I cycle it...after about 4-5 cycles I can usually use it again to start a car. It takes quite a few weeks sometimes longer but doesn’t cost anything to leave them hooked up on a panel.

I agree that this process takes time, but it is worth it in my opinion. You have essentially explained what I do when messing about with rechargeable batteries. I have never tried additives and found this method has a high success rate with batteries showing around 10 volts. Some of them were only half full of electrolyte when recovered. I use the ones recovered to form a reserve energy source when the Hurricanes hit and the power is out for a few days. (After my generator runs out of fuel.)

Ok this is THEE BEST VIDEO ever out there on restoring lead acid batteries!! Well done!! Thank you.

Thank yoh for your honest opinions in your presentation. I think pulse chargers also have their place if they are properly utilised. I'm planning of building a diy version of that, and I will share the results if I do.

I use my DLS-45 as you describe and it works well for it. 45A is faster than optimal for charging batteries but I haven't had a problem with outgassing or overheating even when charging single batteries. You just have to watch them more closely and it's best to not start with a warm battery. It does start tapering fairly early on in the charge cycle so it's not like it does 45A the whole time - probably just the first 20 mins or so on a normal deep cycle battery.

Thanks. Just got handed a treasure trove of batteries and already finding some good ones. This method may help me get the most and the best out of the pile. I'm actually looking for several with a decidedly dead cell or two, reducing the voltage to 8.1 to 10.4 that can be used to run transmitters requiring that voltage range. Ah rating can be also reduced as the transmitters are low power. Tired batts can also be used for lighting and other appliances not voltage sensitive or appliances that designed to operate at a 'failing' batteries maximum voltage... Get creative!. To the heckler, Yes, I do in fact plan to go to MARS and will need this information. There i will likely find a colony of vulcans and fellow geeks. We will gladly watch from a far as the earth denigrates. Have a nice time.

I like this guy’s style. He knows his shit and dgaf what you think of it.

Thanks for the video. Answered my questions about my speed charger always cancelling the charging.

Great video thank you for your time & effort

Hey man, I just wanna say thanks for this. I have a fully dried out 6v 7.2Ah SLA which I have decided to try to recover and so I have followed your method here (almost) to the letter. I modified the voltage and current respectively & cracked the lid and refilled all cells with de-ionised water. I don't have a dumb-charger but I do have a small power supply gutted from an HD Freeview decoder that happens to have an 8v 500ma rail that the battery lived on for 48 hours or so. It is now at the end of it's 3rd cycle and has just discharged over 5Ah @ 900mAh according to the accucell 6 I'm charging it on so I'm confident this can go back into service for a while and am fairly impressed to get over 60% back! So, once again, thanks! I'm sure other methods out there work just fine but this worked a charm for me. I will update you with the results of the 5th cycle and the other sla's i'm gonna try and recover.

Thank you for this clear, instructional video. Time to hit the garage now.

Thanks for the info....was wondering what I should try...

With lead-acid, it may be worth replacing the H2SO4 electrolyte if cells are accessible. If cells are 'lead sulphonated' then the battery equation says that some of your electrolyte will be JUST WATER. Have a nice day.

Damn dude ur good at the whole information conveyance thing. Thanks

Thank you for this very informative video!

It's funny that I just came across this video. A few weeks ago, I decided to try recharging this car battery that I've had for years. It's been dead, in my garage, on the ground, for at least two winters. I thought for sure that the plates were trashed. So, I busted out my battery maintainer and connected it to the battery. It gave me a green light, which means it's done charging. So, to trick it into charging, I put my test light in the circuit and walked away. I came back two days later, to find it charging. I took the light out and let the charger continue. Three more days passed, and it was full. I disconnected it and let it sit another two days, before checking the voltage. It was just over 12.6, which looked good. Then, I put a small load on it, similar to what you did, with a inverter and a 90 watt halogen bulb. The voltage dropped quick, so I charged it up again, and repeated the test. It got stronger, probably enough to crank an engine over or at least run my inverter for a few hours. I've done this trick a number of times I've the years, but this was the first to a battery that sat through a couple winters without a charge, and was brought back to life! So, I too, will disagree with pulse chargers, as I've used them to resuscitate a LA battery from 0 volts to 12.6.

Excellent! Found it very informative! And no bull shit! Loved the video!

I actually have good experience with pulse charging, I made my own pulse source of 25 kHz frequency, and in combination with cycling i just revovered one battery from some 30% capacity to almost 80% (Ah). First I was cycling with overcharge, but I had small improve increments. Than I implement pulse charging instead my standard charger, and I keep on overcharge (battery voltage between 15-16V) for about 1-2 hours. Continue with cycling, and than it start to improve in much bigger increments.

Very good explanation. Thanks!

I made a highly concentrated epsom salt by filling one cup of epsom salt then mixing it with a little bit of water, then i emptied the battery electrolyte, then added the epsom salt to one of the weak cells that was not bubbling while charging but i didnt charge it affter adding the salt, i just poured the salt into the dead cell, i left it for 24 hours, and now it is accepting a charge and bubbling, then i emptied the epsom salt, gave it a rinse and added the sulphuric acid electrolyte again, now it is reaching 13v

Hello. I use a different approach. I use a laboratory power supply unit (lab PSU for short) that can output between 0 and 30VDC (selectable via knob). My model allows up to 3A maximum. It should have similar results to your method shown here but MUCH quicker. So for example let's suppose the internal resistance of the battery is abnormally very high. To compensate for that, we maybe have to initially put 20V or even the full 30V to the battery terminals but since the lab PSU has current limiting, I can set that at anything I want from 0 to 3A. Let's suppose I set it at 2A. Now it wont matter how much initial voltage I put to the battery terminals since the lab PSU will not flow more than 2A and will adjust the voltage accordingly. What usually happens on a bad battery is the voltage will start out high, then creep down as the battery takes on some charge. When the voltage gets down to more normal levels (such as 14V for a 12V battery), I can then pull it off of the lab PSU, drain it slightly to remove surface charge and to prep it for a normal smartcharger. Then just let the smartcharger do its thing. So what you do in possibly a month, I can do MUCH quicker. I agree that cycling an old battery helps the Ah capacity as even letting a battery sit in a nearly full charged state seems to somewhat hurt the capacity slowly over a long period of time. I have seen an old AGM battery that had only 48 minutes of runtime at about a 500W load jump up to 63 minutes the very next cycle cuz that battery was sitting for years (but fully charged before each drain test). Also, why burden yourself having to keep checking if the load voltage is 11.0V when you can just let the power inverter inform you when it drops to between 10.5 and 10.7 by letting it sound the audible alarm? That is what I do. I put the load on the battery via the power inverter then I go in another room on my computer and just listen for the alarm then quickly turn off the power inverter and immediately recharge the battery using my standard smartcharger. I think it is also a good idea to charge a battery at different charge rates. The idea is each different charge rate has pros and cons but it should improve the overall health of the battery to sometimes blast it with high amperage but other times use a more reasonable amperage and if you are not in a hurry, sometimes use a rather low amperage. For example, on a 100Ah AGM battery, sometimes I hit it with 25A, sometimes with 12A, and sometimes with 8A initial charge current setting. One last thing: using incandescent lamps is a very good idea for a load, especially if you live in a cold climate cuz the heat will be put to good use. However, a lamp rated at say 100 watts at 120VAC will NOT be 100 watts if powered by a cheap non sine wave inverter. Those usually have less output voltage such as 110VAC and thus the actual wattage of the lamp will drop to something like between 80 to 90 watts. I normally use a pair of 300 watt lamps but connected to an inverter, I suspect they are considerably lower such as 240 watts each. So I call the entire load (including the power inverter) about 500 watts total. The actual wattage is not critical since I use it for all the drain tests so I am just checking the relative capacity of different batteries (or of the same battery after cycling).

Tried it and it WORKS!!!!

I have recovered various varieties of lead acid batteries over the years, from my experience it sometimes helps to get a fairly high voltage across each cell, obviously this can lead to localized heating if part of the cell is in partial recovery. This is a merit to pulse charging, to get fairly high peak voltage but with a low duty cycle the heating and localized gassing can be minimized. A GE publication many years ago regarded sulphation as a reversible failure but also suggested current limited charging that could reach about 11v per cell. In my experience conventional wet lead acids will recover after many years of neglect, other types are more tricky. Obviously not all failures are reversible!

Please do a short series of videos all about automotive batteries. I'd pay to watch them. Your knowledge is unparalleled.

A good replacement for the 2 ohm resistor would be a headlight lightbulb. They should limit the current to about 2 amps.

Thanks for your input, I think it's worth checking out. Maybe between my shop teacher and my science teacher were together on this project I could get their opinion

It's nice to see so many people who are into battery culture.

Good video. Tried this with a couple of small (3 Ah) APC UPS batteries I was going to toss out that have been sitting around for years. The APC doesn't maintain the battery properly and so the batteries die after standby use with hardly any cycling. One was bone dry. Topped off with tap water (very soft water here). One battery took a charge, the bone dry one did not Got 8 seconds while running the inverter under load. Tried this a few times without improvement. Then tried an Everstart marine charger with de-sulphating mode a couple more times and got it up to 5 minutes, which is what APC is the run time on these small paper-weight UPS. Not really worth it for a $15 battery but an interesting proof of concept, both for the battery and the marine charger.

@ 3:10 Epsom salt is magnesium sulfate. It increases conductivity at the expense of positive plate corrosion and drastically accelerated self discharge. Keep watching for a better solution...I was shooting a video on adding the Epsom salt method that I have had mixed results with and I have to say this is by far the best way to restore a lead acid battery. Do you know if you add the Epsom salt and keep the battery on a float charger will that offset the accelerated self discharge problem?

Appreciate the no BS video. There is a good book online: "THE AUTOMOBILE STORAGE BATTERY ITS CARE AND REPAIR 0. A. WITTE". It was written in 1922 and the information is still valid today - the technology barely changed.

I filled my sulphated deep cycle batteries used for my inverter with additives and it has lasted about 4 month with good result. Before I did that it would only hold charge for 30 minutes, but now it has even recorded 8 hours.

excellent common sense approach without all the snake oil that many try to sell

I have found that although the battery voltage may reach a fully charged state, once I performed a load and capacity test, the battery was quite down on the specifications. I used a Power Products analyzer for a load test and a Torkel 860 for the capacity test. Finally a battery video that makes sense considering all the BS found on KZfaq and forums. Having worked in a battery lab, I have yet to see any charger with a so-called desulfation mode that works. And the key to long battery life is care and maintenance. My car batteries have all lasted over 15 years and I also choose a flooded lead acid battery because they can be maintained.

I have never charged a dead battery before, I have 2 ,12v batteries for my Grandsons electric bike, exactly what you were doing, after watching your video I got my 12v battery recharged. Thank You 😎

Nothing ventured nothing lost right? I've done this before myself, usually just to eek a little more life out of a battery that was junk otherwise. Another old trick was to 'drop' the battery a few inches a half dozen times, letting it settle for 30 minutes, then overnight charging it. Also worked a couple times. Side comment, I am in love with this guy! I love the geeky needy guys, they are just great!

You can do this with a power supply pretty easily, too. Sometimes, that can be adventageous because you can run slightly higher voltages. Some cases of battery issues can be solved by running around 15.5-18.5 volts for a few hours until current increases, then dropping back down to 14 or 10. As for pulsed charging, it works when combined with other methods, but it has a correct and incorrect application. A capacitor-regulated pulse charging approach can be extremely effective for certain types of issues. Those little pulse devices are garbage.

Thanks for the video. I realise this video is a few years old, so maybe smart chargers have improved since it was made. I don't know about snake oil, but I have just recovered a 12v battery off my scooter with the desulfation mode on my smart charger. I had to repeat the process six times before it brought the voltage to a properly charged point. It started at 13.2v "fully charged" Now it's reading 14.3v.

Thank you, very helpful, will try

We have a battery running for 14 years already. And I think it lasted so long was because it was kept full all the time. 150Ah lead 12v. Using dc bulb just 30 watt max for half the battery life. inverter only for charging. 100w Solar connected with controller. Now using the same battery with inverter. Still giving very good backup. Thinking of buying a working second hand battery and use this method using power supply for cheap. Thank you for this video btw!

I work for a large industrial battery company and we have pulse chargers but we do not promote that they are better at desulfation which in my experience of two years they do not but the pulse charge is promoted to save electricity costs for people with many batteries to charge daily. Our guidelines for desulfation require a steady low amperage charge for 48 hours and then put them on a load bank to test for bad cells.......sometimes repeating the process two to three times to fully desulfate. This guy knows what he is talking about.......any other way is a gimmick or quick fix.

i like your style sir.waitng for your next video

I remember seeing small ads for battery rebuilding supplies back in the late 50s. The old batteries that had visible asphalt around the cells were rebuild able.. The visible cell connectors on top of the batteries were also another indicator. The connectors were cut and the asphalt scraped out with a hot screw driver. THe cells could be pulled and examined. some times the plated could be washed and reused.. or replaced.

Thanks! Great information.

Great video.

I used Epsom salts and it works. This summer the battery in my van started dying. It would barely crank over. I charged it and only got a few starts out of it during warm temperatures. I charged it again and left it in the van overnight and the temps dropped to 45 degrees overnight. It lost it's charge and wouldn't start. Just clicked. Since I have another van I left it sit for weeks while I researched how to revive a car battery. I stumbled onto a blog about Epsom salt. I removed about 1/3 of the acid using a turkey baster. I heated up a half gallon or so of distilled water on the stove until hot and kept adding Epsom salt a quarter cup at a time until it was ridiculous. Stirring it the whole time. The solution was slightly thicker than water but it was totally clear. I filled the battery, put the caps on and shook it good. I charged it on an old charger for 48 hours. I let it sit for a day and it slightly discharged. I charged it again for 24 hours. The temperature outside is cold. This is Wisconsin. The van has started every time over the last four days and today the temp is 21 degrees. Today the van started like it's a new battery. The battery is FIVE YEARS OLD. Just a month or so ago it was crap.

good video. No BS, just the facts. I liked it

WOW very well explained, Thank you

Slow charging for a long period of time, and then cycling does work. Works very well, indeed. Typically in cases I've used the battery tender charger that is only rated for 750mA, and it applies the bulk charging mode until the battery reaches 14.3V, then drops to float/absorption mode. After that, then I'll discharge battery until 1.8V/cell, or 10.8V for 12V battery at a rate of 10/C or 10% of rated capacity. Whatever method to do this will work, the inverter is a nice idea because some of them have low voltage shut off at around 10.8V. The process usually takes two weeks a month, which may seem like a long time, but not really when you spend maybe 20 minutes hands on with the battery. I've managed to salvage a good number of batteries using this method. This process has worked on SLA, engine starting, and AGM batteries. Just like the video author stated, some batteries are just not recoverable. And, if you use your resources, free or very inexpensive used batteries are everywhere.

I love the free harbor freight volt meter..the ones they cant even give away..lol everyone has had one of those

Good video. I have a "Plan B" if you can get hold of sulfuric acid. I managed (with a bit of difficulty) to get 2 litres of 98% pure sulfuric acid (H2SO4). I had a car battery that was rated at 45 Amp-Hours and at 6 years old it could only deliver 0.4 A-Hr (at 6 amps). I put 6 ml of pure sulfuric acid (if you're American you'll have to convert, sorry, we haven't worked in the imperial system for 50 years) into each cell and charged it up and it immediately produced 11.14 Amp-Hr (discharged to 12.12 volts so it was actually a bit better than that if I'd let it drop further). After a week it measured only 7.93 Amp-Hr so it's declined but it's still much better than it was. It has a desulfator electronic circuit on it that puts very high voltage pulses into the battery 1000 times a second and I'll leave it on for a month or so. I built it from scratch years ago and even if it does nothing I'm sure it won't hurt it. Time will tell if this method (adding H2SO4) will permanently increase its capacity but I think it probably will. If you plan to try this read up on how to handle concentrated H2SO4 before you start, it's dangerous!

A battery that was $60 in 2013 is probably twice or more now. Great video. thanks for sharing

A resistor can be made with simple SS wire wrapped around a non-conductive core. You can use an ohm meter to confirm the number of turns. I used .024 SS aircraft lock wire for one I needed to replace a blown power resistor on an automotive cooling fan.

The plates are actually made of a hard lead mesh impregnated with a soft lead paste. Scrubbing would remove the paste, and to get them apart you would need to cut and re-cast the lead straps holding the plates together. A better way to clean them is to empty the electrolyte, replace with distilled water, and charge. empty, charge, repeat, etc. Then refill with the proper ph acid. This will remove nearly all of the sulfation, whereas this procedure only removes some of it.

Excellent info. Thanks.

If you don't have a 2 ohm resistor, you can attach 5 10 ohm resistors in parallel or 10 20 ohm resistors, etc. I have a Schauer battery charger similar to the one in your video. I've had that forever. It still works. Thanks for the video. It was informative.

Great video, I have really enjoyed watching it. I have also watched your entire series on making a sine wave inverter from an old UPS which I intend to use for an old UPS I have. I appreciate the level of detail that you go into, and although some concepts and ideas may go over my head I feel like I'm really learning some things which is not always the case on the Interwebs today! Question: Have you tried this method on multiple batteries at one time, or is this only useful for a single battery at a time? I have a great deal of SLA batteries that I would like to recondition, some of which are really dead, some only "mostly dead" in the words of Miracle Max. Any tips would be helpful, but my end goal is to recover enough to use with the UPS and convert into a working solar generator with battery bank backup. Thanks!