What to do with a car battery that spilled fluid? - Page 1
Forum section: electronics / general

author: edy
author_rank: Super Contributor
timestamp: September 28, 2018, 05:35:39 am
content: Hi folks,I had a spare car battery in my trunk and I noticed a bad smell about a week ago that I couldn't quite pinpoint. Today I went to the trunk and discovered the battery on it's side. I found it damp around the battery and the cardboard box it was sitting in was wet and damp and disintegrating. Touching the area was moist, I figured it was spilled battery acid.So looking around for answers, I've seen suggestions to first throw a bunch of baking soda on my car carpet to neutralize and clean up the acid. I have no idea how much spilled, but it did soak up into the cardboard box and also some of the cardboard mat I usually have in the trunk... so I am hoping that saved much of it from getting into the carpet.Next, I assume I may still be able to save the battery by adding fluid to it... either distilled water or battery acid fluid from the store. I've never done this before and I don't know if it will revive the battery or worth the try. I was looking for something online at our local auto store (CanadianTire.ca) and I can't seem to find anything.... I searched "battery fluid", "battery electrolyte", "battery acid", etc... Then again, when I look at online videos, it seems they mention to just pry off the 2 large covers on the battery and fill each of the 6 holes (for each cell) with distilled water up to about an inch from the top (to the level of the rim inside).I thank you for any thoughts, suggestions before I blow myself up. I will want to plug it in after to charge it and I don't want any issues. I use the battery mostly as a backup booster or sometimes to power certain devices with an inverter, it's not really under heavy duty use or anything but I do need to keep charging it from the power outlet to maintain it.

author: sokoloff
author_rank: Super Contributor
timestamp: September 28, 2018, 05:39:13 am
content: You top up batteries with distilled water, but you don't fill them from empty with it. You want battery acid.Your local auto parts store probably will have it. Might need to go to the "real" parts store (NAPA or similar where the local shops shop)https://shop.advanceautoparts.com/p/autocraft-battery-acid-cycle-acid/2030000-Phttps://www.oreillyauto.com/detail/b/super-start-4994/chemicals---fluids-16461/maintenance-chemicals-16867/specialty-25137/battery-chemicals-17661/8d0625b693a9/super-start-battery-acid/6qt/4742477Or you could mail order it from an aviation supply house:https://www.aircraftspruce.com/catalog/elpages/electrolyte.phpFor cleanup, you want to neutralize (baking soda is fine) and flush with water, probably multiple times.

author: DC1MC
author_rank: Super Contributor
timestamp: September 28, 2018, 06:10:59 am
content: Recycle the battery, no matter what you do, if the electrolyte loss was not due to evaporation (to top it with distilled water), you'll not be able to easily replace the acid, and in any case the battery won't be reliable and on capacity anymore, in worst case it may start producing hydrogen and causing you troubles.DC1MC

author: Brumby
author_rank: Unknown
timestamp: September 28, 2018, 08:49:57 am
content: I would pull the carpet out of the boot, mix up some baking soda in a bucket of water and dunk it in. Maybe repeat a couple of times until there are no bubbles being made. Even then, your carpet may have been damaged too much and will just disintegrate.I would also remove anything and everything else that may have come into contact with the acid. Treat everything with baking soda (for safety's sake) and toss the stuff you can live without.If acid has come into contact with any part of the car's body, then throw some baking powder on that area and clean up with water. Try not to spread any acidic residue, especially down any cracks or gaps. If any acid has found its way into any crevices, then you could have a bigger problem.Battery acid can wreak havoc with paint and cause rust. I would be more concerned with your car at the moment.The battery might be serviceable. Just stand it up and rinse the outside. Add the proper acid to the cells, charge and see how it goes.

author: edy
author_rank: Super Contributor
timestamp: September 28, 2018, 01:31:38 pm
content: Quote from: Brumby on September 28, 2018, 08:49:57 amYes, I pulled out the carpet/cardboard piece (it sits over the spare tire). Only the carpet in a certain area was wet, it spread to one of the edges and must have dissolved some of the adhesive holding it to the carpet because I see the edge of the carpet loosening in the wet area. I put baking soda on the carpet and rubbed it in... added some water, will now wait it out and let it dry. No spill came in contact with the car, but I will have to check near that edge where the piece sits near the bumper area to see if that is wet in any way and add baking powder directly to the car.As far as the battery goes, I will have to pop it open and see how much fluid is left. If a lot has spilled I will need to add electrolyte, seems that the distilled water will not do the trick as I will just be diluting what is left (it was not lost through evaporation in which case only water is missing). Then I have to see if it is economically viable and risky to start playing with this battery or just forget it.Thanks for all the suggestions by the way. I have been used to mainly SLA batteries and never thought it would tip as I always had it packed tightly with other things around it. You live, you learn!

author: Richard Crowley
author_rank: Super Contributor
timestamp: September 28, 2018, 02:42:42 pm
content: It should not be very expensive to take the battery to a specialist so that they can test the fluid in the cells and refill with the appropriate mixture. Because the fluid loss was not just from evaporation, you lost more than water can replenish. if you try to guess how to refill the battery you risk future problems, possibly severe. Don't take chances with chemical hazards unless you really understand the situation.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: September 28, 2018, 02:50:31 pm
content: What to do with the battery really depends on details of what happened which you did not relate, how it came to spill. However, the remark that it probably will never be right seems true. How much acid or distilled water to add depends on diagnostic tools available to any car mechanic.What I want to address is "keeping a spare battery in your car". This has to be done right or it is a real hazard. Had the terminals shorted out against a piece of metal, given that it is enclosed in a trunk - rather than in a vented engine compartment is asking for more than trouble. A shorted lead acid battery produces hydrogen and oxygen. A serious explosion is possible and one that might also spread the acid and other components of the battery around. It's obviously possible to transport a battery but this must be done thoughtfully and with thought to bumps and motion of a car and even to the possibility of an accident.

author: Cerebus
author_rank: Super Contributor
timestamp: September 28, 2018, 02:57:57 pm
content: Quote from: edy on September 28, 2018, 01:31:38 pmNo, do not let it dry until you aresurethat you have neutralised and removedallthe acid. Dilute sulphuric acid if left to stand in the open air becomes more concentrated acid (from memory the equilibrium point is around 60% H2SO4). Rinse, rinse, rinse again, rinse yet again until you are either thoroughly fed up with the procedure or have actually tested (with indicator paper or similar) that the carpet doesn't still have acid traces in it.

author: IanB
author_rank: Super Contributor
timestamp: September 28, 2018, 03:06:53 pm
content: Echoing what Cerebus said.Do not let spilled battery acid dry. Whatever the acid touched (especially carpet or anything organic), you need to wash it thoroughly and completely under running water (use a hose on the ground or driveway). Wash it and wash it and wash it some more. The baking soda idea is good. Also apply lots of that to any areas that were wetted with acid and wash it through.The same inside your car trunk. After removing the carpet, wash it out with lots of water. Hopefully there are drain holes to let the water out.Once battery acid gets on something, it will tend to corrode it and destroy it over time. You need to make sure all traces of acid are washed away and removed to avoid this happening.The battery may not be salvageable. Probably you should recycle it.

author: G7PSK
author_rank: Super Contributor
timestamp: September 28, 2018, 03:10:02 pm
content: Wash the iside of the boot of the car, acid spilt on the metal work will start corrosion sooner or later, washing up detergent or dishwasher detergent is very good for the purpose and rinse well use a hose, put the carpet through the washing machine with a double dose of soap as well.

author: Brumby
author_rank: Unknown
timestamp: September 28, 2018, 03:21:15 pm
content: Dunking the carpet into a bucket with water and baking soda was my idea for the baking soda to reach every fibre of the carpet. Neutralising the acid is the first priority. Rinsing will dilute and this would be the next step. You know it's been done properly when it passes the litmus test (literally!!).While washing detergents are alkaline and a good way for a final neutralising action - I don't think I would put it in the washing machine. I expect that the extended exposure will have weakened the fibre and the mechanical stresses of machine washing could result in a failure of structural integrity.

author: drussell
author_rank: Super Contributor
timestamp: September 28, 2018, 03:54:36 pm
content: All of these recommendations as far as neutralizing are good. Keep adding baking soda and rinsing any possibly affected areas until there is no reaction (bubbles). Then do it a couple more times. You cannot overdo this step. Neutralize and hose down the carpet multiple times also.How charged was the battery probably in when it spilled?If the cells were fairly highly charged, any significant amount of electrolyte loss (there may actually be less loss than you suspect by the sounds of it) needs to be refilled with proper (approx 30%) sulfuric acid. It is not normally readily available over-the counter but any shop that fills batteries from their as-shipped dry condition will have some on hand and will be able to top up your battery for you. (Often for free, especially if it is their brand of battery.)Canadian Tire normally will have some, at least they used to, in-store (I remember buying a motorcycle battery years ago and they stocked them out on the shelves, dry and you took it to the parts counter to be filled before you bought it. Forgot to do that one time and had to go back the next day to have it filled.)If your local CT doesn't have it anymore, find the local Interstate or Exide or whatever distributor you have around you. Batteries are normally shipped dry from the manufacturer to the distributor who then fills them and sends them out within their distribution area.It is also available online, of course. You do not need 98% azetropic lab-strength, you would have to dilute down to 30% anyway.P.S. If you want to really have some fun, go to the hardware store and buy some sulfuric acid based drain cleaner (which is usually close to 98% but has inhibitors added to protect pipes that have to be removed), pull out your lab glassware, set up a distillation apparatus and distill off the sufuric acid. Everyone has a distillation apparatus, right? Sulfuric acid boils at about 280C so, yeah... you know... "fun".Then mix some down into some water to get 30% and put it in your battery. Always add strong acids TO water, not the other way around.I jest, I jest...I do like NileRed's comment at about 7m00, "The entire set-up is then moved outside because boiling sulfuric acid indoors is kind of stupid."https://www.youtube.com/watch?v=4DUGRWjdNLI&feature=youtu.be&t=422

author: Cerebus
author_rank: Super Contributor
timestamp: September 28, 2018, 04:32:12 pm
content: Quote from: drussell on September 28, 2018, 03:54:36 pmReminds me of the "Hazardous Procedures Laboratory" in the Chemistry department at university. It was literally a wooden garden shed bought from the local garden centre and assembled on the Chemistry department's flat roof. Rather than screws it was held together with twists of baling wire so that if it all went "Bang!' the walls would fall outwards like in a Wile E Coyote cartoon.

author: Brumby
author_rank: Unknown
timestamp: September 28, 2018, 04:40:23 pm
content: Quote from: drussell on September 28, 2018, 03:54:36 pmOh ... how the shivers are running down my spine.

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 28, 2018, 04:41:23 pm
content: Quote from: Cerebus on September 28, 2018, 04:32:12 pmI would have built the walls strongly but just have the roof sit on it without being fastened. At least if something goes wrong it turns into an aerospace project.

author: Brumby
author_rank: Unknown
timestamp: September 28, 2018, 04:44:13 pm
content: Not nearly as reusable.Standing the walls back up and re-doing the baling wire is a lot more cost effective than buying a new roof every time.

author: Cerebus
author_rank: Super Contributor
timestamp: September 28, 2018, 04:56:18 pm
content: I think the 'design' was intended that no significant overpressure could develop inside and in particular not enough to launch the roof towards the library steps or the student union but the walls would hang around long enough to catch any flying fragments of glassware.

author: Brumby
author_rank: Unknown
timestamp: September 29, 2018, 08:08:32 am
content: That sounds very plausible.Limit peak pressure and contain shrapnel.

author: Ian.M
author_rank: Super Contributor
timestamp: September 29, 2018, 09:21:40 am
content: The battery is probably salvageable if its caps are removable. However you can't just put more acid in without knowledge of its state of charge. You'll need a hydrometer. Drain off enough acid into a plastic tray to be able to test its density with the hydrometer, and dilute enough battery acid (using distilled water) to the same density, to top up all the cells to their level indicators.

author: maginnovision
author_rank: Super Contributor
timestamp: September 30, 2018, 02:57:02 am
content: Personally I'd recycle the battery, and toss the carpet and cardboard. If you needed the battery buy another. But another cardboard and carpet piece. None of it is worth the hassle.

author: drussell
author_rank: Super Contributor
timestamp: September 30, 2018, 06:03:29 am
content: Why would you discard a perfectly good battery just because you spilled some of the acid?What a waste!

author: maginnovision
author_rank: Super Contributor
timestamp: September 30, 2018, 07:12:40 am
content: Because it's not worth the hassle and he should be using a gel or agm battery instead of spilling acid all in his car.

author: IanB
author_rank: Super Contributor
timestamp: September 30, 2018, 07:13:04 am
content: Quote from: drussell on September 30, 2018, 06:03:29 amIf the battery is in the trunk of a car rather than installed under the hood then it is probably not a perfectly good battery. If it was a good battery then it would most likely be in use and not removed from service.

author: drussell
author_rank: Super Contributor
timestamp: September 30, 2018, 08:15:46 am
content: Quote from: maginnovision on September 30, 2018, 07:12:40 amPresumably it was just a spare battery, that doesn't mean it is faulty.Many of us have lots of extra, fully functional, car batteries laying around for various reasons. I currently have a perfectly good, working, charged battery just sitting in the back of my van, likely for just the same kind of purposes as the OP. This is in addition to the starting battery and the auxiliary battery for the stereo. (Two separate electrical systems, two alternators, etc.) I end up using it for something or other, on average, probably every couple weeks. In the winter sometimes I'll carry two with me. One day last winter I used my "extra" battery to boost two people, then swapped it into a friend's work truck when he got stuck at a job site because his decided to short a cell. It was in his truck until the weekend when we got a new one for him. In the meantime I grabbed another one of my spares and stuck it in there in case I needed one. I assume this is the same kind of case as the OP.It is handy to have a spare battery (or two) with me all and if I tipped it over somehow I certainly wouldn't discard it.Some of us have more uses for a lead acid battery than just "bolted under the hood to start the car."

author: Ian.M
author_rank: Super Contributor
timestamp: September 30, 2018, 09:59:10 am
content: +1. However if you are going to tote a spare wet battery around, you do need to secure it properly in an acid resistant container. A loose battery could make an otherwise survivable crash a whole lot worse, especially if the rear seat folds forward to allow long loads to extend from the trunk into the cabin . . . .

author: Cerebus
author_rank: Super Contributor
timestamp: September 30, 2018, 02:27:17 pm
content: Quote from: drussell on September 30, 2018, 08:15:46 amAround here in particular. The limiting noise from a battery is roughly the thermal noise attributable to its Thévenin resistance (i.e. its internal resistance). If you want a really quiet voltage source, use a big lead acid battery.

author: Red Squirrel
author_rank: Super Contributor
timestamp: October 01, 2018, 03:12:26 am
content: Flooded acid batteries are great, they are pretty much the cheapest bang for the buck in terms of performance and longevity. AGM and Gel are sealed thus can't really be maintained and don't tend to last as long either. They can still vent... but only once. Then they're pooched. At like 2-3x the price per kwh they are not always the best solution.I have a couple flooded batteries in service as a UPS. Though I went with the cheaper RV/boat ones that are not true deep cycle, next time I'll go with golf cart batteries. I've had a couple go thermal or short cell on me, which is a bit of a pain because they never make the same exact model for very long so if I go with a system that's larger than 12v it means if one dies I'd have to change out the whole string because I would not be able to get an identical battery. Hopefully when I go with the golf cart ones I won't end up with some that die prematurely. Ideally a decent flooded battery should last 10's of years if well cared for. The telcos still use them a lot as mostly everything runs on 48vdc.

author: Silveruser
author_rank: Regular Contributor
timestamp: October 01, 2018, 03:31:14 am
content: I hope you were wearing old clothes when were handling that acid soaked carpet. I remember the bad old days when holes would appear in my jeans after washing them. it doesn't take much to eat thru cotton.

author: edy
author_rank: Super Contributor
timestamp: November 23, 2018, 02:36:02 pm
content: So let's look at a scenario of a battery that spilled battery acid... Can you still charge it and will a charger recognise when it is at full capacity?REASONING:1. The amount of electrolyte (sulphuric acid) is reduced, but the concentration is the same (as long as you don't try to top up the battery with water).2. It should be able to charge "full" but it will act as a lower mAh battery? For example, if you lose 20% of electrolyte, will battery just have 20% less capacity?3. Charging the battery will take less time, but the charger should not know or care what the mAh of the battery it is... the sensing circuit is looking at the voltage or current sense or internal resistance and should be able to show a "Green" when it believes the battery is full?I am imagining that the level of electrolyte, given that it is the same concentration as previous (and not diluted) should just act as a reduced size of battery, but otherwise should work the same. If 20% less electrolyte, then 20% less capacity, takes 20% less time to charge, but charger still can "sense" when it is *fully* charged (fully for it's new diminished capacity). Is this thinking correct?Let's say, you just need this battery to run some small appliances around the car... like a vacuum, or an air-tire inflator, a light or some other 12V car-related thing for a short time which doesn't really need much cranking amperage. Does it even have to be fully charged? Could you say get away with charging it up to say 25%, so long as it reads above 12V on the multimeter (actually 12.65V in real-world testing and 25% after about 1 hour of charging at 2 Amp)?More importanty, WILL IT BLOW UP WHILE CHARGING?I don't want to dump the battery if I just need it once in a blue moon for a short use low-current draw application like those mentioned (inflating tires, vaccuming, etc)... much easier to run around with it than pop the hood and connect to car battery. If I can top it up for an hour every month, even if charger says it never gets above 25%, but multimeter reads ~12.6V I would imagine there is still enough capacity to run these things. Maybe not enough to crank a car though.

author: vk6zgo
author_rank: Super Contributor
timestamp: November 23, 2018, 03:37:18 pm
content: My first reaction was:-Nah! Your battery has gone to "battery heaven", but thinking a bit more about it, I remembered a common practice when I was young.At that time, you could buy a "dry charged" car battery.The manufacturer charged it up, then removed the electrolyte.This left the plates still possessing the chemical changes which had taken place during charging.They came complete with a sealed container of electrolyte with which you refilled the cells of the battery.You were then strongly advised to put the battery on charge for a while, but on several occasions, I used the battery immediately.There was plenty of current capacity to start my car, the generator (at that time) took over the job of charging.I'm not sure if the electrolyte was from a previously charged cell, or something that emulated that, or if it was just a standard acid/distilled water mix.If the latter, & if your battery was in a good state of charge prior to the accident, maybe you can just introduce standard electrolyte, after disposing of any remains of the original stuff.I have not seen "dry charge" car batteries for many years---the ones I have bought over the counter in later years were already charged.Maybe they still transport them dry charged, but don't trust the "General Public" not to stuff it up!

author: drussell
author_rank: Super Contributor
timestamp: November 23, 2018, 03:52:07 pm
content: Quote from: edy on November 23, 2018, 02:36:02 pmIs this just a generic question or are we still talking aboutyourspilled battery?If we are still talking about your particular case, you still never answered the most important questions from the beginning of the thread:What was the state of charge when some electrolyte spilled?How much electrolyte seems to have spilled?What is the current level of the electrolyte compared to the top of the plates?Attempting to operate a battery with cells that have plates which are even partially uncovered is likely to quickly destroy the battery. The electrolyte must always at least fully cover the plates.

author: edy
author_rank: Super Contributor
timestamp: November 23, 2018, 03:56:43 pm
content: The the main issue seems to be that we don't know what the ion concentration was in the electrolyte and the lead plates themselves prior to the state of the spill. There was some exchange that took place, but with loss of electrolyte we have skewed the balance (unless we lose an equal amount of lead, which is not possible). So the relative concentrations will be off. Nevertheless, not all the lead is immersed in the electrolyte so feasibly the portion of plates which are not in the electrolyte cannot exchange with it, only the portion immersed in the electrolyte does. That could then theoretically balance things out again. That's why it is not advisable to add just distilled water. And unless I know the exact concentration of acid to add, it may also be inadvisable to add regular strength acid, again the concentration and balance will be off.Basically the battery is no longer reliable, may not be safe to charge, and only has a limited capacity and use. For the time being if I can tap ~12V off of it for a few minutes to run something that will work. But I have a feeling that even in a state of just "sitting around" it will lose the charge quite rapidly. In fact, in the 2 hours since I stopped charging it (where it maxed out at 25% according to the charger) it has dropped from 12.65V to about 12.2V. What is to say that in another week it won't be under 10V? I don't know... But if that happens then I can't rely on it, it would be idiotic that every time I needed it I would have to spend 1 hour to charge it up to 12V first. Unless it holds a charge for several months and is ready for me to use at a whims notice, it isn't practical. I usually would trickle-charge a car battery on the shelf every 2-3 months just to keep it "topped up" and ready to go in case of emergency.

author: mbest
author_rank: Contributor
timestamp: November 23, 2018, 04:00:51 pm
content: I just recycled/returned for refund mine when I stupidly did this.My trunk carpet/liner was plastic so the acid didn't destroy it, but it did strip the paint off the bottom inside of the trunk.I used baking soda to neutralize what I could, and washed the carpet and inside of the trunk at the car wash.

author: edy
author_rank: Super Contributor
timestamp: November 23, 2018, 04:07:54 pm
content: Quote from: drussell on November 23, 2018, 03:52:07 pmYes, yes and yes... As far as state of charge, no idea. I had charged it up maybe 1-2 months prior to the spill, the amount spilled is not known. The battery may have been used a couple times to run a tire-inflator. The battery was already *OLD* (5 years?) and was out of my car since it had some issues on some cold winter mornings when it couldn't crank my engine on, that's why I decided to replace it.... so my car had the new battery and the one that spilled was my OLD one that I was still keeping around and trickle-charging every 2-3 months (to keep it charged) and I would use it periodically for things like tire-inflator or sometimes crank another small car for a friend in need.So this OLD battery case is completely black, I cannot see through the battery. I popped open the vents, there are 6 holes, I looked down each and see no liquid because this battery has some other material in the way (not sure the construction but there is no obvious liquid level visible from at least the top holes). Also I don't know if a proper battery of this type would have a thin layer of liquid at the top or not. All I know is, it has dipped below whatever black thing I am seeing practically at the top of the battery (which leaves only about 2-3mm to the vent holes anyways). If the liquid dropped only 5mm I still would see none of it, that's how close these black plates are to the holes. Not sure how I am supposed to visualize the liquid inside any other way, unless I turn the battery over and try to spill more out and see how far I have to tip the battery (not what I want to do). Battery is already a "write-off", I know. I will not be able to restore it as I don't have enough information nor skills to determine and create my own sulphuric acid mix for it, determine the concentration, the composition of the plates, nor do I want to take a chance.SINCE THE SPILL...I successfully cleaned up and neutralized my car, carpet and board and stuff in the back. So far all looks good, no obvious damage. Will keep an eye on things, I know this can take time.Meanwhile, I had this spilled battery sitting for the last 2 months in the garage. Today I tested it, it had dropped down to ~10V. I charged it at 2A for about 1 hour and it went up to 12.65V and my charged showed 25% for a while... but didn't seem to want to push any higher. Maybe I didn't leave it long enough, I don't want to risk any explosion, etc... so I took it off the charger. It has since dropped over the past few hours to 12.2V but remains stable around there. I will be able to track the charge over the next few days, weeks and months and see if it remains stable. If it stays around 12V for at least a few months at a time I can use this for simple things to power some low-current draw 12V devices, I imagine that shouldn't stress the battery much. The amount of energy I can store in it I will have to determine... if I see the voltage dropping too quickly I know there is little to no capacity left, or that I am continuing to ruin the battery (as I said, it is a "write-off" and I don't intend to or hope to restore the battery anyways, just want to see if still any good to power the occasional 12V tire-inflator when needed).

author: drussell
author_rank: Super Contributor
timestamp: November 23, 2018, 04:52:53 pm
content: Quote from: edy on November 23, 2018, 03:56:43 pmYou're overthinking this. The actual concentration of the acid is notthatcritical.Check the electrolyte SG now (if you can, are all your cells below the plate tops?), topping to JUST above the top of the plates with distilled water if the plates are exposed (which it sounds like they are.)Put it on a trickle charge of 1-2A (even 4A if that's as low as you have) for a couple days until the terminal voltage on the charger gets up to the full 14 or so volts at least once, then check the electrolyte SG again. If it shows that it is normal, full charge, say at least above about 1.260, you're probably fine. Take the surface charge off with a couple amp load for a moment and check the terminal voltage. It should be up around 12.6 open circuit when fully charged,after removing the surface charge. If both the terminal voltage and the SG say you have a fully charged battery, you probably do. You only need to boost the concentration if the battery tries to charge but runs out of "oomph" with the electrolyte SG remaining weak.You can almost just sense, or intuit what it needs, though I do suppose this is just something I've learned the "knack" for over the years observing and maintaining hundreds and hundreds of lead acid batteries.QuoteDon't try to charge it with the plates exposed, you'll destroy a battery that is probably just fine with rapid corrosion. This usually leads to highly increased self discharge or accelerated cell death.You're totally overthinking the exact concentration, though.I have used batteries here that wereobviouslyfilled with way, way too strong of an electrolyte solution when new, like they still show off the chart SG even when fully discharged. It will shorten the working life of the battery, sure, if it's not at least close to where it should be but there is far more "give" in the chemistry than you think. If it is too weak you won't be able to get full capacity, sure, but there is a pretty hefty excess to begin with in a new battery, stoichiometrically.QuoteHow do you know? you haven't even tried it properly yet.It will absolutely be safe to charge (unless you pump tens or hundreds of amps into it with exposed plates and cause it to arc over, electroboom style or something)Top it with water, do a proper charge and see what the SG says. If it seems to charge well but the SG is still low, you can solve that by completing the top-up with some stronger acid if you really want to (which is why we only wentjustabove the plates at first, keep the concentration upandallow room to add actual acid if necessary) but it would probably live out the rest of its life happily even if (at worst with a bit reduced capacity) with a reduced concentration electrolyte unless you managed to spill so much that the plates are currently more than, say, about an inch exposed. It is most certainly not going to explode or burst into flames if your acid concentration is a little weak.If you can still see electrolyte in there, you can probably just dilute. If you can't even find any traces of electrolyte in there, I would just fill it back up with proper concentration as if it were new, maybe diluted atinybit extra since it sounds like the cells were fairly low when you spilled it in the first place, but running the concentration a bit strong will actually help a tired cell perform better for the remaining life.QuoteDon't judge the self discharge until you at least cover the plates and charge it. You cannot tell anything without at least doing standard proper maintenance before attempting to judge performance in any way.Personally, I would probably top off the electrolyte, charge it up, check the SG and do a 100A load test to see what it drops to in a 10 second starter simulation, then if everything looked at least somewhat normal I would put it on an equalize-level charge (bring to about 15.5 volts) for 15-20 mins to get the bubbles really going to mix the electrolyte and clean the plates with the small, controlled overcharge. If anything, that would pull a little bit more of any of the sulfates back into the H2SO4 electrolyte where it should be in a charged cell.

author: drussell
author_rank: Super Contributor
timestamp: November 23, 2018, 05:11:31 pm
content: I have to run for now, sorry I cannot respond to your most recent post right now, unfortunately...What kind of battery is it?Any chance of a photo so I know which manufacturer and case style we're talking about?

author: edy
author_rank: Super Contributor
timestamp: November 23, 2018, 05:33:53 pm
content: The battery is the original that came with my 2011 CR-V. I found a picture of the same battery here:It is Group Size 51R: 31500-SDA-C01 Honda battery. There is no other labelling on the battery, no branding, just says "Made in China" on a sticker on the side. Otherwise complete unlabelled around the whole side and bottom. The top has the usual vent covers and warnings about spillage and venting and explosion, nothing else. It says "addition of water not required", and there is a hydrometer "eye" which is obviously NOT showing green at all.So if I follow your instructions correctly, you are saying to add distilled water until I at least see a thin layer of liquid when I look down the vent holes (submerging whatever dark material I see in there very close to the holes), and assuming it doesn't dilute the acid that much, I can try to trickle-charge it and see what happens? I don't have any tools to measure SG, and the hydrometer may or may not really show anything different if I am diluting the acid, whether or not I charge it up or not. But I guess the safest recourse at this point to avoid having exposed led plates is just submerge it all even if I risk diluting down the acid with a bit of distilled water?