Battery exploded on the 66 Corvette last night.

[Robert G. Smits]

This was a four year old wet cell battery on a Battery Tender which was several feet away. Can I assume the battery tender created an internal spark?  Is the white substance sulfination?

[Tom M]

Robert,

 

I had that happen to my battery a few years ago. House was struck by lightning. Blew out most of the electronics in the house and the battery in my Packard which I had on a tender.

 

Did you have any stroms in the area?

 

Sorry to see that happen to you.

 

Now I have everything on surge Protectors or go around and unplug electronics when there bad storms in the area.

Edited May 12 by Tom M (see edit history)

[Mark Shaw]

Could be the sun storm that made the northern lights so extensive. 

[wayne sheldon]

Almost thirty years ago, I had one explode in my daily driver old Ford pickup. I do hope the Corvette wasn't seriously damaged?

This type (lead/acid wet cell) battery can explode for many reasons, however, usually a defective connection inside the battery is part of the equation. That "defect" may be a factory defect, failing due to acid damage, or vibration in the hostile environment of running automobiles. Usually (not always!) the acid/water level will get a bit low creating a hydrogen rich and air (oxygen) mixture in the top area of the battery. Some sudden change in the current flow results in a spark inside the battery, which ignites the hydrogen/air mixture and sets it off like a big firecracker!

That sudden change could be any of many things. In my case, I got into the truck and tried to start the engine. The Kaboom shook the whole truck and covered the entire inside of the engine bay with battery acid. A local lightning strike could easily run a discharge or spike through a battery tender. It could under the right conditions even be something as minor as opening the door (dome light!), or nothing gets switch on or off, just slow degradation of a faulty connection inside the battery although some amount of current flow is required (could be as little as an electric clock).

 

Hard to tell from the photos? But it appears that some amount of sulfating of the battery had occurred, and might have played a part in triggering the explosion.

 

I mentioned the acid level maybe being low? In my case, my battery actually gave me a warning for about a week before it blew. It was one of the old Die-Hard type translucent case batteries. You could see enough through the case of the battery to see the acid level. One single cell started getting low (the warning!), and I knew I would have to replace the battery soon. Of course, life and dollars interfered a bit. I watched the cell daily, and kept adding distilled water to keep it well above the plates. The cells if in good order should all evaporate water out of the acid close to evenly. The fact that one cell was going down noticeably faster was an indication that plates were running hotter, in turn speeding up the process of breaking down the water into oxygen and hydrogen (all such wet cell lead/acid (sulfuric) batteries do that to some extent). Keeping the acid level high greatly reduced the chance of a spark triggering an explosion, but didn't stop it.

 

Mark Shaw (who snuck in just ahead of me?), Interesting point. It is possible. Or maybe wasn't?

[zepher]

From the looks of the inside, it looks like the water level was low in the battery and exactly like what Wayne said with the gases in there being ignited.

 

I second, wanting to know how extensive the damage was to your Corvette.

At least the C2 cars still had the battery under the hood and not in the passenger compartment like the C3 cars.

The '78 I used to own had the battery in a compartment behind the driver's seat.

Edited May 13 by zepher (see edit history)

[TTR]

Sorry to read this, but I’ve never been a fan of Battery Tenders. 
I prefer to disconnect the ground cable (not a fan of those add-on disconnect switches either) when knowingly  parking/storing a car for extended period.

 

Speaking of solar storms, my wife, I and another couple (lifelong vintage car enthusiasts and friends visiting from Europe) I’ve known over 4 decades, were staying in few days in Joshua Tree and Friday night discussing these “storms, when my friend made an observation that should one hit our area, everything in the nice house we were staying in and my wife’s (plugged in) Hybrid would likely get screwed, but my (unplugged) PB Roadster with 6V, points and condenser ignition, etc would probably survive.

[Joe Cocuzza]

Luckily, I found out BEFORE anything happened but Battery Tenders/Minders are not "set it and forget it" (infamous line from Ron Popeil) type "tools".

In my case, thinking it was okay, I left the Battery Minders on (plugged in) my batteries constantly. They are/were advertised as being "smart chargers" that monitor the state of the battery and, according to the manufacturer(s), know when to start/stop charging and when to start desulfation.

Well, both my motorcycle and 6 volt car batteries went dead. I did some investigating and found that both of the batteries were almost bone dry.

I was lucky to have caught it before anything disastrous happened.

Now I connect the Battery Minder(s) about once a month and only leave them on for a few days.

AND I monitor the water level in the batteries on a regular basis.

[Robert G. Smits]

Thanks for all the replies and suggestions. Yes we had a storm with lightning last evening and lost power briefly 

Fortunately the hood was open and the force of the explosion appeared to be laterally toward the fender. A little acid staining on the passenger valve cover. Sure made a mess of my epoxy floor covering though.
I may have to rethink my position on maintainers. I have seven batteries hooked up and have been happy up till now. The battery in my rarely driven Mercedes is 10 years old and still load tests ok. I like Joes idea of hooking them up 4-5 days a month. 

[wayne sheldon]

I almost never have a battery connected to a charger of any kind except when I am home and awake. When trying to bring a battery back up? I unplug it and disconnect the charger from the battery when I go to sleep.

Edited May 13 by wayne sheldon
I hate leaving typos! (see edit history)

[Joe Cocuzza]

50 minutes ago, wayne sheldon said:

I almost never have a battery connected to a charger of any kind except when I am home and awake. When trying to bring a battery back up? I unplug it and disconnect the charger from the battery when I go to sleep.

Me too

[Dr B]

1 hour ago, Joe Cocuzza said:

Now I connect the Battery Minder(s) about once a month and only leave them on for a few days.

I also do not leave tenders continuously on my collector cars. I drive them regularly during our driving season (9-10 months). I put a tender on them once or twice during the winter to make sure they are fully charged. The only vehicle I keep continuous connected to a tender is my motorcycle which I only ride occasionally and has computers and thus a constant electrical drain. I put a lithium battery into it and have a lithium specific battery tender for it.

 

Robert

[Dr B]

1 hour ago, Robert G. Smits said:

have seven batteries hooked up and have been happy up till now. The battery in my rarely driven Mercedes is 10 years old and still load tests ok. I like Joes idea of hooking them up 4-5 days a month. 

Not knowing how often you drive your cars (I try and rotate and drive my cars so each gets driven at least once a month, but it doesn't always work out) some may need charging more than others.  While not a bad idea, keeping track of 7 cars hooking each up 4-5 days a month may be a organizational PITA. I guess you could hook them all up at the same time 4-5 days a month whether they need it or not.

 

Robert

[Trulyvintage]

For any vehicle that you are 

not driving daily or weekly

you should disconnect both

terminals manually or install

some type of disconnect 

at the battery terminal.

 

As mentioned above - if your

water/electrolyte level gets low

that can lead to problems.

 

Battery tenders are not 

a good idea to leave attached

while unattended.

 

 

Jim

[Gtjoey]

From my experience…..

A huge SAFE guard is to have ALL your battery tenders on a SURGE protector strip or outlet , this way when a storm does hit the breaker trips before the surge gets to the battery.

If you have multiple cars as many of us have , I spent the money on a 1 battery tender with multiple lines . I think they make one up to 6 lines at once?

this way it’s One plug . Protect that circuit and you have insurance.

Taking chargers off and on really is not helping the battery last overall as long.

At least no one was hurt.

Good luck….

Gtjoey1314

ps if you wanted to plug and unplug , now your only pulling 1 plug or switch at the protector, if you like doing that.

Edited May 13 by Gtjoey (see edit history)

[TAKerry]

11 hours ago, Joe Cocuzza said:

Luckily, I found out BEFORE anything happened but Battery Tenders/Minders are not "set it and forget it" (infamous line from Ron Popeil) type "tools".

In my case, thinking it was okay, I left the Battery Minders on (plugged in) my batteries constantly. They are/were advertised as being "smart chargers" that monitor the state of the battery and, according to the manufacturer(s), know when to start/stop charging and when to start desulfation.

Well, both my motorcycle and 6 volt car batteries went dead. I did some investigating and found that both of the batteries were almost bone dry.

I was lucky to have caught it before anything disastrous happened.

Now I connect the Battery Minder(s) about once a month and only leave them on for a few days.

AND I monitor the water level in the batteries on a regular basis.

If the battery's were dry why is it the battery tenders fault?

 

I have been using one (battery tender brand) on my motorcycle for years now. I bought a 2 bank charger for my son as a Christmas present this past year and have both his GTO and my Firebird attached. In both of our cases I believe the batteries are sealed so that water cannot be added. I am not sure how to tell if it is low? I suppose for now I will keep using the tender (but I will not tell my son about this thread as he is super paranoid and wont even leave a light plugged in!).  I will plug it into a surge protector for all that is worth. Which is another thing that I have heard conflicting reports on. Just the other day someone was telling me about a slew of appliances being smoked in a storm even with a surge protector!

 

Sorry to hear of the damage to the OP's car. Not knowing the situation completely I would suspect the storm may have had something to do with it though. We got hit and lost quite a few things last winter. 

[ABear]

1 hour ago, TAKerry said:

If the battery's were dry why is it the battery tenders fault?

Depends on the type of battery "tender" you use.

 

Real cheap versions are nothing more than a small 1/2/A or 1A transformer, diode and LED and operate unregulated. Basically it is a single stage trickle charger designed to replenish just enough of the lost charge typical FLA batteries lose. Typical voltage output will be 13.8V.

 

Single stage chargers if left on for long periods of time can and will eventually boil the battery dry.

 

And yes, even so called "sealed" or "no maintenance" FLA batteries will suffer from being dried out.

 

More expensive versions are more sophisticated and will have two or more charging stages which will drop to 1st stage of 13.2V which is the "storage" or "float" stage when the charger has not detected any current drain for a set amount of time. Other stages are bulk/absorbsion of a bit higher voltage (14.6V-14.8V) which applies a quick burst of higher voltage to stir up the battery chemistry and help reduce.

 

13.2V storage voltage is designed to provide just enough trickle charge without boiling the battery.

1 hour ago, TAKerry said:

In both of our cases I believe the batteries are sealed so that water cannot be added. I am not sure how to tell if it is low?

Sealed or no maintenance FLA batteries are typically designed to hide or obscure the filler openings, sometimes under the top sticker they plaster over the entire top.. They are intentionally designed to make it extremely difficult to find and remove the caps. They are there, but well hidden or difficult to remove. Generally I find those types of batteries to be low cost throwaway FLA batteries. Basically if you can remove the caps and refill, you won't add any life to them.

 

Most cases, sealed FLAs use caps that are designed to condense and recycle the water vapors in the battery, they do have vents but overall the battery tends to lose water as they age at a lower rate.

 

1 hour ago, TAKerry said:

I will plug it into a surge protector for all that is worth.

Surge protectors are 100% worthless in the event of a close lightning strike, even a nearby strike on power lines they can only absorb a small amount of surge.. The heart of surge protectors is a MOV device which is also known as a varistor.. See HERE for more details on varistors..

 

In consumer surge protectors they are very small and only are able to absorb small amounts of surge energy before they blow open and you lose all protection.

 

Not much you can do with protecting modern appliances, they are all pretty much electronic/computer controlled, brownouts and rapid up and down voltage variations can easily take them out unlike old school mechanical controls.

 

As far as OPs battery, yeah, it looks like it was heavily sulfinated ted which means the plates were exposed to air and the battery was dried out. Hydrogen build up happens a lot when the battery starts getting dry and all it takes is a internal spark between the plates to set the chain of events in motion.

 

Batteries do age out, best I have had done was about 11 yrs but typically 6-7 yrs before that battery starts getting too weak to start the vehicle in cold weather.. So, vehicles not used during cold weather can hide a weak worn out battery for a long time.

[60FlatTop]

12 hours ago, wayne sheldon said:

I almost never have a battery connected to a charger of any kind except when I am home and awake. When trying to bring a battery back up? I unplug it and disconnect the charger from the battery when I go to sleep.

Only the small compressor stays on when I am away from the garage. And it is leak free.

 

I was recently telling my wife that I had to walk to four locations to turn on and off the lights in my garage. There is a gang switch by the door that I could tie them all into but I told her I preferred the routine of the walk around.

 

That probably goes back to the days of closing up my grandfather's shop. He would hold up four fingers and say "There are four things to do before you lock the door". Seems that enumeration process stuck through life, both for me and anyone under my supervision.

 

Just reminded of my time teaching trades apprenticeship. First day of class and laying down the rules "OK, there are ten steps to making coffee. I want you to know that if you leave out the step where you put the water in you will NOT get a 90% grade. Same goes for this class". And a lot was based on numbered sequences.

 

Oh, one of my grandfather's step was unplug the compressor, and for good reason. Not like mine.

[Dr B]

35 minutes ago, ABear said:

Sealed or no maintenance FLA batteries are typically designed to hide or obscure the filler openings, sometimes under the top sticker they plaster over the entire top.. They are intentionally designed to make it extremely difficult to find and remove the caps. They are there, but well hidden or difficult to remove. Generally I find those types of batteries to be low cost throwaway FLA batteries. Basically if you can remove the caps and refill, you won't add any life to them.

This raises a secondary issue of the type of battery.  I have been using the AGM (Optima) batteries in all my collector cars for some time now.  Whether these are better or worse is up for debate/discussion (and I am CERTAIN it will be!).  I find them easier to install (some cars have ridiculous locations for the battery needing contortions to get them into place and I worry about spilling acid on the car). I also have a sense they are "safer" than lead acid batteries.

 

Robert

[Mark Shaw]

6 hours ago, Gtjoey said:

A huge SAFE guard is to have ALL your battery tenders on a SURGE protector strip or outlet , this way when a storm does hit the breaker trips before the surge gets to the battery.

If you have multiple cars as many of us have , I spent the money on a 1 battery tender with multiple lines . I think they make one up to 6 lines at once

I did this too.  However, since have several collector cars that had 6V batteries that eventually expired.  Instead of replacing all of them, I keep one Optima battery connected to a charger on a table and only install it to drive each car.    

[TTR]

15 hours ago, TTR said:

 I prefer to disconnect the ground cable (not a fan of those add-on disconnect switches either) when knowingly parking/storing a car for extended period.

And by "extended periods" I mean something longer than a month, which in the case of something like my Roadster doesn't really happen often and with properly sorted (6V) electrical system, I just leave the battery connected all the time.

I think it's on its 4th battery in 30 some years (& never been on a "tender" of any kind). 

Only meaningful reason/use I could see for a "tender" would be in some modern vehicles with various computers and other electrical features requiring an power maintenance to prevent battery running down during extended storage periods.

 

Edited May 13 by TTR (see edit history)

[ABear]

12 minutes ago, Dr B said:

I have been using the AGM (Optima) batteries in all my collector cars for some time now.

AGMs by nature, do not off gas acid (which is why FLA batteries tend to corrode at the terminals), they do have a few good benefits like lower internal resistance which leads to less voltage drop for heavy draws and faster recharging, they are spill proof and can operate pretty much any position other than upside down, they have lower self discharge rate than flooded lead acid. They do have very good vibration resistance over FLA so they tend to do better if you have a lot of mechanical vibration.

 

Downsides are they are more expensive up front, for the same size as FLA, AGM may have lower CCA than FLA they are also subject to drying out as they do have a very limited amount of moisture and you can not add more and over charging them does release moisture through a VRL cap. They can be a bit picky on charging voltages, less tolerant than FLA as they are very similar to Gel cells as far as charging voltages.

 

Hydrogen discharge tends to be lower in AGMs than FLA which makes them a bit safer in some respects, however they can go into thermal runaway if abused with constant overcharging (common characteristics of Gel cells) with excessively high charging voltages (your charger should be rated for AGM or have AGM setting). In older vehicles charging voltage is typically set to 13.8 for 12V batteries or 6.9V for 6V batteries which should be OK but may undercharge them some.

[JACK M]

I keep my tenders on a timer.

An hour a day.

[Robert G. Smits]

Photos of my epoxy floor. As you can see from the damage the battery was not dry. I am leaning toward the internal short theory. Thanks again for all the replies.  I have gained a new respect for batteries. Not sure why second photo is rotated. I reloaded it three times

[zepher]

Many years ago I had a battery tender boil the liquid out of a motorcycle battery so I no longer use them for long periods and never unattended. 

[ABear]

1 hour ago, Robert G. Smits said:

As you can see from the damage the battery was not dry.

The use of the term a battery has gone "dry" basically means the water level has dropped below the tops of the plates. Does not always mean the battery is 100% devoid of any electrolyte.

 

The plates must be covered in electrolyte at all times to avoid exposing the plates to air. Once exposed to air the plates break down and degrade, sometimes this can create bridging (short circuits) between the plates in a cell.

 

The lower electrolyte level also gives more room for hydrogen to build up within the cells which is a bad thing..

 

More hydrogen plus air and a spark from a plate to plate short and you get a big boom.

 

Typically they don't explode on their own without a little help like drawing current (IE starting) or trying to jump start or hooking up a charger to it.. If they had a power interruption, a spark could have been internally generated when power was restored in the case of a battery tender.

[TTR]

10 hours ago, TTR said:

And by "extended periods" I mean something longer than a month, which in the case of something like my Roadster doesn't really happen often and with properly sorted (6V) electrical system, I just leave the battery connected all the time.

I think it's on its 4th battery in 30 some years (& never been on a "tender" of any kind). 

I think only time the battery in my Roadster has been disconnected for "extended period" in past couple of decades was two years ago when I was rebuilding its engine (+ overhauling the clutch, transmission & steering gear) over 7 months.

[Larry Schramm]

Better?

 

[Larry Schramm]

For winter I usually take all of the batteries out of the vehicles and bring them into the shop where I rotate a charger on them to keep them topped off.

Edited May 14 by Larry Schramm (see edit history)

[jimy]

13 hours ago, JACK M said:

I keep my tenders on a timer.

An hour a day.

I also use a timer for our boat battery.  I have a weekly mechanical timer and just push one of the tabs down.  So perhaps just an hour or so per week. 
 

jim 

[charlier]

I have been using the "Battery Tender" brand charger/maintainers for the last 20+ years on my old vehicles and my non daily driver pickup. No timers, no unplugging them unless I am using the vehicle. I do have them plugged into surge protectors for what it's worth. During that time I have made a habit of checking the electrolyte level in each of the batteries a few times a year. I also check to see that each battery is not swelling by touching all sides of each battery. Some of these batteries are "maintenance free" normal (non AGM) batteries. One of these batteries is completely sealed and cannot have it's electrolyte topped off. That type I will avoid in the future.

 

I have to peel back the big stickers on the tops of these batteries to check and fill them with distilled water.  I just did this the other night and found a few cells in a couple of the batteries needed to be topped off. While the electrolyte was still covering the plates it was not at the normal level I keep them at. I also checked the deep cycle battery in my car trailer as well. 

 

I also periodically test each of the batteries with a load tester. One of those batteries is an old Sears "Diehard" battery back when those batteries were built well and lasted. Prior to this battery, the longest lasting battery I had was 10+ years. This battery is 16+ years old this year and is still alive and kicking. 

 

I do thank my lucky stars when it comes to lightning. About 10-12 years ago my next door neighbor's tree was struck by lightning. That tree is around 30 feet from the corner of my house. I had no damage to any electrical equipment in my house or my car trailer & truck. Like I said.... lucky.

 

[wayne sheldon]

"In theory, theory and practice are the same. In practice, they are not." Albert Einstein.

 

Surge protectors are a crazy subject, needing lengthy dissertations to even begin the foundation of mutual understanding.

Doing communication systems contracting, and specializing in cutting edge technologies in addition to our "bread and butter" work? We got into some pretty wild stuff from time to time. We became part of the teams building early non-government LANs (local area networks). Many of these systems were the forerunners of the internet. Connecting multi-million dollar computers separated by some distance requires special care and knowledge. While we did not work directly with the power systems, we had to work with those that did, and that was interesting.

Basically, ninety-nine percent of "surge protectors" are nearly useless ninety percent of the time! There are a lot of very important numbers in the rating formulas, microseconds, Joules, response curves, and if one doesn't know what the numbers mean and how they relate to each other? (Believe me, I DO NOT know enough about it myself, but I know enough to know how much I do not know!)

The biggest problem with surge protectors is that most of them are too slow. Most common surge protectors respond around one- one hundredth of a second. The problem is, that most surge damage from a significant surge occurs in the first one- five hundredth of a second (numbers are approximations). 

If your battery tender/charger uses a transformer to drop line voltage down to battery levels? The transformer itself tends to muddy the AC cycles somewhat as well as the spike's highs, and might buy your surge protector a few microseconds. But a few microseconds is all it will buy. A fully electronic battery tender for all practical reasons won't help at all in adding surge protection. A fully electronic battery charger will most likely become a blob of ashes and melted mass in about one- one hundredth of a second, by which time the surge spike will have already gone through and done its damage to everything in its path.

Any good surge protection MUST be fully and PROPERLY grounded! Although, common plug-in surge protectors are a case of "can't hurt and might help (maybe?)".

 

[Dr B]

10 hours ago, wayne sheldon said:

"In theory, theory and practice are the same. In practice, they are not." Albert Einstein.

 

Surge protectors are a crazy subject, needing lengthy dissertations to even begin the foundation of mutual understanding.

Doing communication systems contracting, and specializing in cutting edge technologies in addition to our "bread and butter" work? We got into some pretty wild stuff from time to time. We became part of the teams building early non-government LANs (local area networks). Many of these systems were the forerunners of the internet. Connecting multi-million dollar computers separated by some distance requires special care and knowledge. While we did not work directly with the power systems, we had to work with those that did, and that was interesting.

Basically, ninety-nine percent of "surge protectors" are nearly useless ninety percent of the time! There are a lot of very important numbers in the rating formulas, microseconds, Joules, response curves, and if one doesn't know what the numbers mean and how they relate to each other? (Believe me, I DO NOT know enough about it myself, but I know enough to know how much I do not know!)

The biggest problem with surge protectors is that most of them are too slow. Most common surge protectors respond around one- one hundredth of a second. The problem is, that most surge damage from a significant surge occurs in the first one- five hundredth of a second (numbers are approximations). 

If your battery tender/charger uses a transformer to drop line voltage down to battery levels? The transformer itself tends to muddy the AC cycles somewhat as well as the spike's highs, and might buy your surge protector a few microseconds. But a few microseconds is all it will buy. A fully electronic battery tender for all practical reasons won't help at all in adding surge protection. A fully electronic battery charger will most likely become a blob of ashes and melted mass in about one- one hundredth of a second, by which time the surge spike will have already gone through and done its damage to everything in its path.

Any good surge protection MUST be fully and PROPERLY grounded! Although, common plug-in surge protectors are a case of "can't hurt and might help (maybe?)".

 

Wow, I am always amazed at the diverse knowledge of the people on this forum! 

 

Thanks,

 

Robert

[EmTee]

For the 'interested student'...

 

https://www.polyphaser.com/News/DownloadFile?downloadGuid=c0794f4b-be88-47e7-9a13-6c9d7055b3d6