Kaboom... or how NOT to charge batteries.. or "my personal chernobyl"...

[JackConrad]

Jim,
   The first time I equalized my house batteries using my Heart Interface inverter, I blew the fuses in 2 of our automotive type radios in our bus. Since that experience, I disconnect everything from the house batteries except the cables from the inverter.
    The equalization time and voltage are both controlled by the inverter. I think the time is 8 hours and the voltage is high 15s or low 16s.  Jack

[boogiethecat]

I was using a hi-tech electronic style bench supply that will put a constant current into a load regardless of what the load voltage is.  By default this will cause the battery voltage to be a bit higher than normal, but the voltage is, in this case, determined by the battery and where it "wants" to be, not by the power supply.  The actual voltage was around 14.6 or so, with a healthy battery (these "were") the voltage rises only enough to accept the charge.
  Equalizing a battery does this but only for 10-15 minutes at a time- some chargers  do it longer, some (intellipower, my favorite)  once a day, others do it once a month.  There doesn't seem to be any agreement within the industry as to how frequently or how long is good or bad.  The desired effect is to simply create some bubbles that stir the liquid, and de-stratify any layers of more or less acidity that may have been set up in the cell.
  What I was doing was "conditioning", which is definitely more severe- you put that same "equalizing" charge on the battery but for 48 hours.  It's purpose is to dissolve as much sulphation that has built up over time as you can, taking a "weak" battery back to normal capacity.  It actually works quite well on a slightly sulphated battery.  When I started these, their fully charged specific gravity was only around 1.200  and 6 hours before they blew up, it was just around 1.260.  This is because when I started, there was enough sulphate crystals on the plates that wouldn't dissolve and turn back to sulphuric acid during a normal charge that the battery had a reduced capacity.  Doing a conditioning charge gives the crystals time to dissolve and turn back to acid, and restores the capacity to a near-new state.  If a battery is heavily sulphated, this trick probably won't do any good. But if it's light sulphation as these were, it works well....unless they decide to melt down!!!!...

So your question, is an equalizing inverter dangerous?  No, not at all for wet cells, as long as you maintain water levels properly. In fact if you have wet cells and like them, it's essential for their long life.
With AGM's it's not necessary and can even damage them, because they don't have liquid inside so to speak, and "overcharging" them during equalizing will result in gassing which means lost electrolyte and eventual failure.

Oh yeah, most inverters do the equalizing by applying a fixed higher voltage, like 14.7 - this is easy to do electronically, and safe.  As I said, I was applying a constant current, which involves a lot more electronics than you'll find in a standard RV inverter or charger, and it's "usually" safe.  But apparently only "usually" 

Here's 2 photos of where I am today with this.  The acid is drained out now and as of that moment the batteries quit gurgling.  So now all I have to do is carefully pump the spent electrolyte into some hazmat containers, wash off the outsides of the batteries with a lot of baking soda, and shuttle it all off to the battery warehouse who said they'd gladly take it all to the recyclers for me, for free!!  Then a final cleanup and I'm all ready to try it again! (actually not!!! These were almost my last set of wet cells, when the last three I own slow down I'm gonna scrap em and convert to AGM's)
...note the nice splat they made when the kaboom happened.  Can you imagine having your face in the way? Ugh!!!!!

[luvrbus]

Don't think for a minute a AGM won't make a mess my new 300amp 6v (6) LifeLine vented and exploded in my battery compartment taking out all 6 of the high dollar batteries along with leaving a mess I am still working on to clean up. 
With still no answer from LifeLine on why ? 


good luck

[boogiethecat]

My guess, either a defective battery (rare) or severely overcharged (happens all the time), as in did you disable your charger/inverter's equalization function, and/or what voltage is your alternator set at?  Also are they located in a place that gets hot?  As compared to wet cells, AGM's can't handle heat at all.
Only overcharging or an internal defect can cause an AGM to blow.  Yes they still are lead acid batteries and yes they can make just as much of a mess as can a wet cell.  But they are MUCH
more forgiving to the sulphation effects, deep discharge effects, and maintainance issues that come with flooded cell batteries.  I'd be looking at what voltage your system presented to them.  Anything over 14.1 will kill 'em.  14.1 is the gassing point beyond which an AGM can't self-convert the gasses it makes back to electrolyte... above 14.1 they vent, and if severely above 14.1 they will get hot, they will vent, and can certainly blow...
  Hope you figure it out!!!

An interesting side note- evidently these things were popping for almost an hour!  I heard three booms, but my neighbor just called and said she counted 14 of them, and it started almost an hour before I woke up!  So I guess that says something about inherent safety designs of the batteries... made of materials that can actually explode and burn for an hour and not cause any major incident... and about me, I guess I sleep through a lot these days!  Wheeeee

[HB of CJ]

Gary...yep, the important thing is that you were not hurt, except for the knee.  What are you going to do at Burning Man?  Do they allow Crown Supercoaches?

I had a dream awhile back (have no idea why) that Burning man was held in a low lying dry lake bed and then the flash flood of the century happened.  AUGHHHH!

How long can one tread water?   Yikes!!  Glad it was only a dream.  Anyway, go and have fun, get naked, get stoned or drunk, and stay that way. Sunscreen?  CROWNS FOREVER!!  HB of CJ

[belfert]

The local battery warehouse may take batteries are no charge because they are forced to.  In Minnesota all battery retailers have to take any used lead acid batteries at no charge.  Then again, they might make a few bucks on the lead.

As far as flooding at Burning Man, I have heard that some years they get enough rain in the rainy season so the dry lake bed gets a foot or two of water on it.  The water actually creates enough wave action to smooth out the playa.