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Discussion Starter #1
As the title suggests, this morning I had a lead acid automotive battery blow its top off in my basement. I have cleaned up the spill with baking soda, but I am at a loss for what to do with the battery itself. The case is cracked, top blown away (into bits around my basement) and still half full of acid. Should I attempt to transport the battery as is in some kind of container, or should I attempt to neutralize the acid then transport? Is a 5 gallon bucket capable of withstanding this acid?

I am fine, by the way, as I was upstairs at the time. It sounded like a balloon of the same volume popping, only a lot louder!

:unknown:


Mr. Moose
 

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Glad you are ok

I'm very glad you are ok. Any good plastic container should resist the acid. The trick will be getting it into the container. I'm leery of trying to neutralize the acid inside as any base will react quickly and could cause more trouble than it saves.

Definitely use protective googles or face shield, rubber gloves and if possible a protective apron when trying to get the remains into a container. Once it's outside and in a relatively safe place you could probably just flood it with water using a hose from a distance. Normally you add acid to water, not vice versa but if you are outside and away from anything you can hurt, I would probably put the hose on a sprinkler patter and thin the acid down considerably from a distance. If it runs onto the ground, add some lime to totally neutralize it.

Stay safe!

Treefarmer
 

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If it runs onto the ground, add some lime to totally neutralize it.

Stay safe!
The soil is a great neutralizer,,, I would rather loose a little grass for a year than the trunk of my car,,,

Water (LOTS of it) from a distance is the best idea,,, IMHO,,, :thumbup1gif:
 

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Discussion Starter #4
If I add more water it will overflow since the case is cracked. I got a 5 gallon bucket from Home Depot that I thought I could use to contain the sloshing of transport, but the battery is about an inch too big.

I think I am going to dilute it some with the hose then find a larger container to transport it in. There is a hazardess materials redemption center near by, at least the last time I checked.


Mr. Moose
 

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Discussion Starter #5
Oh, here is the pic or it didn't happen pic!

image.jpg



Mr. Moose

P.s. I don't know why it is upside down. I just uploaded it from my iPad and not through tapatalk.
 

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Also glad you and your house are OK. Now I have to ask what were you doing that caused the battery to explode? Sounds like it could be a dangerous occurrence if you were close when it blew up and got acid in your eyes.

Be careful with the acid. Be safe.
 

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Discussion Starter #7
This was one of four batteries we use to run our pellet stove when the power is out. We have an un-interruptible power inverter that was designed just for this operation and has been working great for 5 years, it also recharges the batteries when there is power. I figured this was an appropriate forum since it is the same style battery found in our favorite toys... err... utility tractors. :greentractorride:


Mr. Moose
 

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I keep a deep cycle battery in my basement on a 1.5 amp charger/maintainer to power my wood burning fireplace insert in case of a power outage too. I know that 1.5 amps doesn't really generate enough heat to boil a battery, but i guess that other things can happen and possibly cause a short. Maybe it's time I invest in a battery case to contain any future mishaps? Something like a marine or RV battery box.

Thanks for sharing your story.
 

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The most common reason (but not the only possible reason) for a flooded lead acid battery to blow its top like that is for it to be exposed to too high of a voltage for too long of a time. This causes some serious damage to the battery, creates free hydrogen, and generally destroys the battery.

You say you have 4 batteries in this battery bank. Right there, alarm bells start going off in my head because there's a right way and a wrong way to do that. The common way to do it is, unfortunately, the wrong way and often results in exactly what you just experienced. How are the batteries connected? Series? Parallel? 2-series/2-parallel? If there are parallel connections, how are they made and what gauge of wire are you using to do it? We can probably work out why this happened and try to prevent it from happening in the future with a little more information.

Also, since you're using flooded lead acid batteries, both the IRC and the NEC require that you house the batteries in a vented battery box for the reason you just discovered plus the fact that they make hydrogen when charging.


As far as cleanup, sounds like you've handled it already, but the home remedy method of dealing with this is to ventilate the everlovin heck out of the area for a while and then slooooooowly pour box after box of baking soda onto it until the battery stops doing anything interesting in response to the addition of more baking soda. You can also mix up a solution of 1 pound of baking soda to one gallon of water if you have a situation where you need to flush the area with water (like rinsing it out of something) rather than pouring a powder onto it. As others have noted, lab goggles (preferably a face shield), heavy gloves, and a heavy apron are definitely necessary.
 

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Discussion Starter #10
The batteries were on a wood shelf about a foot off the floor with about a foot clearance on top covered by another plywood shelf. Ventilation is open to the basement. Forgive me if I get any terminology wrong, but we have them set up for capacity, that is parallel (right?). Positive to positive. They are connected by 2 foot 6 gauge pre-manufactured copper terminal wire. Was this the correct way to set it up? In Series would be positive to negative and increases voltage, correct? We did it years ago and have not set up any others since, so I have forgotten if this is correct or not. The battery that exploded was on the end, farthest from the inverter and also was the oldest by purchase date, has the same manufacture month as another, but all are now about five years old and the same capacity. These batteries are not sealed and we checked the water level on the remaining three. Each was above the plates but below the neck, where should it be? My thought on the exploded battery is that it over heated many times, evaporated water and exposed the plates which created an internal short that ignited the hydrogen. Was it co-incidence that the one on the end is the one that exploded? Or was it because it was also the oldest? Obviously, we don't want another explosion and we think we can get away with only two batteries since we now have a generator for long term outages. We are looking into getting battery boxes and most likely will have two new batteries in the near future. Everything is currently unplugged for evaluation and want to make sure we re-connect properly to minimize the risk of a future explosion.
:danger:


Mr. Moose
 

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The batteries were on a wood shelf about a foot off the floor with about a foot clearance on top covered by another plywood shelf. Ventilation is open to the basement.
That's technically illegal and there's pretty good reasons for that (unlike so many laws). You really should have them in an enclosed box that has both and inflow and an outflow connected to the outside world so that the air in the box is completely isolated from the air in the basement. This could save your and your family's life if a battery fails in a way that produces a lot of hydrogen and that explosive gas gets vented outside rather than left hanging around in the basement just waiting for a spark.


Forgive me if I get any terminology wrong, but we have them set up for capacity, that is parallel (right?). Positive to positive. They are connected by 2 foot 6 gauge pre-manufactured copper terminal wire.
Sort of. Adding batteries in series or in parallel adds capacity regardless, they just do it in different ways. Parallel is the simple to understand connection that almost always ends badly. The reason for this is that each connection and piece of wire in the system has a tiny bit of resistance, even if you're using good components and big wires. The problem is that, even though these resistances are tiny, charging current through each battery (as compared to the others)is determined by the difference in resistances, NOT the overall amount of resistance. So if one battery has 0.01 Ohms resistance in its wires and another battery has 0.05 Ohms of resistance (both TINY values), the battery with the lower resistance connections is getting 5x the charging current. Every time you add a parallel connection, you add more connections and more possible paths through the circuit, giving the resistances more ways to get out of balance (from the point of view of each battery). Generally, the rule of thumb for alternative power systems is that you never want to have more than two parallel connections because the odds of something getting out of balance go up tremendously with each new parallel connection.


So there's about an 80% chance that this battery failed because you have the bank connected in 4x parallel. The 2 of the remaining 3 are likely pissed off as well. Typically only one battery in a parallel bank will actually be happy.

The battery that exploded was on the end, farthest from the inverter and also was the oldest by purchase date
So there's a couple of things here that also could be issues. Since it was the farthest from the inverter/charger, it probably had the most resistance in its circuit (compared to the others). Adding to that, you said it was the first purchased, which usually means it has the most charging cycles. Internal resistance in the battery tends to go up as the battery experiences charging cycles. What this means is that you had the least charging current going through this battery. So the battery was likely being chronically under-charged for several years, which is an awesome way to kill a battery. Likely what happened is that this damage made the internal resistance of the battery go up even higher, increasing the amount of heat in the battery as it charged. Eventually, blammo.

has the same manufacture month as another, but all are now about five years old and the same capacity.
So this is another red flag. Batteries really should be bought all at once and placed into service all at once so they have all lived exactly the same lives so they age in concert. When you add a new battery to the bank that has a different number of charging cycles on it, it tends to result in the batteries killing each other well before they're supposed to age and die. Yes, you're correct that they have to be absolutely matched for manufacturer, model, and capacity.

These batteries are not sealed and we checked the water level on the remaining three. Each was above the plates but below the neck, where should it be?
Flooded batteries need checked weekly for "working" banks and no less than monthly for stand-by banks. If you want to get the most life out of your batteries, water level isn't the key, concentration of the solution (meaning ratio of acid to water) is what you want to track, and that's called specific gravity. There's nice little meters you can get where you put a drop of the battery acid in them and then it tells you the specific gravity. They're actually the same kind of thing, just calibrated differently, as the testers to tell you if your antifreeze in your car is at the right concentration. The manufacturer of the battery will publish a data sheet about the battery that includes the allowable range of specific gravity. Depending on whether you are high or low, you either add a little water or let more evaporate.


My thought on the exploded battery is that it over heated many times, evaporated water and exposed the plates which created an internal short that ignited the hydrogen. Was it co-incidence that the one on the end is the one that exploded? Or was it because it was also the oldest?
The answer is almost assuredly "all of the above". The biggest risk factor is the 4 in parallel with the inverter/charger at one end. The next biggest risk factor is that all the batteries weren't all exactly the same in terms of life.

Ok, so series vs parallel for you...

That's sort of a tough question at this point. If you had asked that question years ago before you started buying anything, the answer would absolutely have been series. Series is easier to keep balanced/maintained, has fewer overall problems, moves half the current to get the same work done, allows for the use of much smaller (cheaper!) wire, and is more efficient. The corner you're painted into now is that you've bought a 12V inverter/charger. You can't just re-wire the battery bank to 24 or 48 volts because your existing inverter/charger only works on 12V. If the money for a new inverter/charger isn't a hardship for you, I'd start over with 2 larger batteries connected in series to get 24V and then use a matching 24V inverter/charger. If that's too much cash to swing, then you should just get two larger batteries and leave them in parallel but connect them so that the inverter/charger is connected to the positive of one battery but the negative of the other battery. If that doesn't make sense, I can draw a picture, I guess. Wait... I have a picture from a lecture I gave on this topic!



OK, that shows a 2-series/2-parallel setup, but the idea is the same. See how the green lines that lead outside the battery bank are connected to opposite "corners" of the bank? That helps eliminate a little of the problems with running 2 parallel circuits. It's not perfect, but it does make it better. So, to use just 2 batteries at 12V, you'd sort of squish that diagram together sideways until the batteries overlap. You'd end up with a green line on the left connecting the positives with the connection to the inverter/charger on the top battery and a green line on the right connecting the negatives with the connection to the inverter/charger on the bottom battery.

Like I said, going in series with a new inverter/charger would be the optimal solution but it costs money. 2 batteries in parallel connected at opposite "corners" with your existing inverter/charger would be your best lower cost alternative.
 

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Williaty makes some interesting points,,, :thumbup1gif:

If I were faced with this situation,,, first of all,,, the batteries would be stored outside of my home.

Next,,, recognizing this is an emergency use tool,, I would use the KISS method to resolve the issue.
If I had 4 batteries, there would be four chargers. 6 batteries, six chargers.
Then, when needed the batteries would be connected for use as necessary.

Series, parallel, whatever....
This is assuming this is not a day to day use,,, emergency only.

I keep no-ethanol gas for my generator,, and add the gas to the tank ONLY when the power goes out.
No "old fuel" issues.

Disconnected batteries are easier to connect than cleaning up a blown battery,,,,

One more thing,,, I would only use the new intelligent charger(s)
I hate trickle chargers,, too much chance of over-voltage charging of the battery.
 

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Parallel is the simple to understand connection that almost always ends badly. The reason for this is that each connection and piece of wire in the system has a tiny bit of resistance, even if you're using good components and big wires. The problem is that, even though these resistances are tiny, charging current through each battery (as compared to the others)is determined by the difference in resistances, NOT the overall amount of resistance. So if one battery has 0.01 Ohms resistance in its wires and another battery has 0.05 Ohms of resistance (both TINY values), the battery with the lower resistance connections is getting 5x the charging current. Every time you add a parallel connection, you add more connections and more possible paths through the circuit, giving the resistances more ways to get out of balance (from the point of view of each battery). Generally, the rule of thumb for alternative power systems is that you never want to have more than two parallel connections because the odds of something getting out of balance go up tremendously with each new parallel connection.


So there's about an 80% chance that this battery failed because you have the bank connected in 4x parallel. The 2 of the remaining 3 are likely pissed off as well. Typically only one battery in a parallel bank will actually be happy.
I would like to know how you came to the conclusion that one of the batteries in the above example would receive 5 times the charging current because the resistance in its leads is .04 ohms less than the other battery.
 

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I would like to know how you came to the conclusion that one of the batteries in the above example would receive 5 times the charging current because the resistance in its leads is .04 ohms less than the other battery.
When calculating current through legs of a parallel circuit, the ratio of the resistances, not their magnitudes (absolute amounts) matters. That's the hardest thing to wrap your head around because we all intuitively think in series circuits where the total amount of resistance determines how much current goes through. So we intuitively think "0.04 Ohms? That's basically no difference at all! Therefore, the currents must be equal!". In reality, those resistances are very different when compared to each other. The parallel branch with 0.05 Ohms of resistance has five times the resistance of the parallel branch with 0.01 Ohms of resistance. Since the voltage across both is equal (due to being in parallel), the current in each leg is a factor of 5 different because of the 5 times difference in resistance (V=IR).


If you really want to have your mind blown, in a 4-parallel battery bank, it's not uncommon to end up with a factor of 50 difference in branch resistances if you make even tiny irregularities in your wiring! If you want an hypothetical example, I could maybe work something up tomorrow, but I am way too tired to do the math to make the example come out to match the conversation right now :lol:
 

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If any acid got on concrete, you need to dump LOTS of baking soda/water on the concrete. It will continue to eat a hole for years if you don't neutralize it soon. Get rid of the wood that contacted acid as well, you'll never get it all out.
 

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When calculating current through legs of a parallel circuit, the ratio of the resistances, not their magnitudes (absolute amounts) matters. That's the hardest thing to wrap your head around because we all intuitively think in series circuits where the total amount of resistance determines how much current goes through. So we intuitively think "0.04 Ohms? That's basically no difference at all! Therefore, the currents must be equal!". In reality, those resistances are very different when compared to each other. The parallel branch with 0.05 Ohms of resistance has five times the resistance of the parallel branch with 0.01 Ohms of resistance. Since the voltage across both is equal (due to being in parallel), the current in each leg is a factor of 5 different because of the 5 times difference in resistance (V=IR).


If you really want to have your mind blown, in a 4-parallel battery bank, it's not uncommon to end up with a factor of 50 difference in branch resistances if you make even tiny irregularities in your wiring! If you want an hypothetical example, I could maybe work something up tomorrow, but I am way too tired to do the math to make the example come out to match the conversation right now :lol:
I don't have any trouble wrapping my head around a parallel circuit....I have an electrical engineering degree, and I have 25 years of experience in the field. This isn't a simple parallel circuit. It is a series/parallel circuit because the internal resistance of the batteries. Draw it out on paper using 6 resistors, use Kirchoff's laws to solve it, and you will see what I'm talking about.
There will be a difference, but not the degree that you are saying. The lead resistance is minuscule compared to the total resistance of the circuit.
 

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I don't have any trouble wrapping my head around a parallel circuit....I have an electrical engineering degree, and I have 25 years of experience in the field. This isn't a simple parallel circuit. It is a series/parallel circuit because the internal resistance of the batteries. Draw it out on paper using 6 resistors, use Kirchoff's laws to solve it, and you will see what I'm talking about.
There will be a difference, but not the degree that you are saying. The lead resistance is minuscule compared to the total resistance of the circuit.
I don't have a 4-wire ohmmeter to measure resistances this small. However, I do have an various ammeters that will measure the currents in play in my test battery banks and the battery banks I've rigged up for classes. The currents in real life measure to be as out of balance as described above. Real life measurements of functioning circuits are sort of the final word on what reality does.
 

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I don't have a 4-wire ohmmeter to measure resistances this small. However, I do have an various ammeters that will measure the currents in play in my test battery banks and the battery banks I've rigged up for classes. The currents in real life measure to be as out of balance as described above. Real life measurements of functioning circuits are sort of the final word on what reality does.
You have allot of useful information in your post, all the stuff you said about proper maintenance is really good information. I don't want to dwell on the one point I believe to be technically incorrect, So I will just make this one point.
I don't agree with your fear mongering about parallel banks of batteries. It is commonly done on large UPS banks in data centers. I see it all the time....for decades.
If the bank is fed from opposite corners, it balances out the differences in lead resistances.
Even if you don't do that, you wont see the magnitude of imbalance due to lead resistance, that you are claiming.


Take this example:
In your house, you have a 100 watt lamp plugged into an outlet 20 feet from your main panel. Now say you have another 100 watt lamp plugged into an outlet on the same circuit 100 feet down the line.
Using your logic, the first lamp would be drawing 5 times the current of the second lamp. It just doesn't work that way. The wire resistance just gets added to the load resistance for each branch and the current is calculated for each branch accordingly. Of course the lamp further down the line will draw less current because of the increased wire resistance, maybe 5% less; not 90% less.

As a practical matter, I don't think too many homeowners would go through the trouble to maintain a bank of batteries properly and safely....I'm sure we can agree on that point.
 

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I don't agree with your fear mongering about parallel banks of batteries. It is commonly done on large UPS banks in data centers. I see it all the time....for decades.
Industrial level installs are also likely to get a lot of things right that a home user doesn't, though. Large wire is going to be used. The terminals are going to be machine crimped for a large degree of homogeneity between connections. The joint between the terminal and the lug on the battery was cleaned properly and installed with a calibrated torque wrench. They're likely using a buss bar/start topology rather than a daisy chain. All of those things reduce the risk of dramatically differing resistances between banks.

For that matter, the medium-sized data center I worked in got all-new UPSes while I was there and I was involved in installing them. All of the cabinets had multiple batteries in series running them up to some rather high voltage and then each series bank fed a single inverter. Multiple inverters were then connected in parallel and phase-synchronized. I'm sure that other manufacturers do parallel connections between batteries, though.

I, of course, lobbied for the flywheel-based UPS just because it's faaaaaaar more cool :laugh:

Take this example:
In your house, you have a 100 watt lamp plugged into an outlet 20 feet from your main panel. Now say you have another 100 watt lamp plugged into an outlet on the same circuit 100 feet down the line.
Using your logic, the first lamp would be drawing 5 times the current of the second lamp. It just doesn't work that way. The wire resistance just gets added to the load resistance for each branch and the current is calculated for each branch accordingly. Of course the lamp further down the line will draw less current because of the increased wire resistance, maybe 5% less; not 90% less.
In your example, the difference is that the magnitude of the resistance of the lightbulb dwarfs the magnitude of the resistance of the connections in the circuit so the dominant factor is the resistance of the lightbulb, not the ratio of the resistances in the connections in various branches of the circuit.

It may be that a battery bank is a corner case due to the fact that the internal series resistance of the battery is very close to the same as the possible resistances of the connections giving the connections more importance than you'd expect in the final result. Again, you can't argue with measured results.

Take a look at this page from someone in the industry. Even with perfectly identical resistances in every connection and wire, they show a 2:1 difference in currents between batteries. This gentleman both did a simulated circuit to predict the imbalance and then physically constructed the bank and measured the results to confirm the prediction. Keep in mind his test was with perfectly identical, professionally made connections. The average homeowner will not produce connections that equal from one to the next, resulting in much worse imbalances.

As a practical matter, I don't think too many homeowners would go through the trouble to maintain a bank of batteries properly and safely....I'm sure we can agree on that point.
Yep, I'd love to see people maintaining the batteries well and safely. If they get that far, I'd consider it a win regardless of how they're wired up :lol:
 

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Wow guys.

But,
ImageUploadedByTapatalk1446411131.445789.jpg













:mocking:
 
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