My battery blew up on a tender charger

Alberto, is the battery an Interstate? What's the brand of tender, and was it truly just trickling along, or did it have an adjustable setting and it was charging at a higher amperage?

Normally tenders are current limited to keep what happened from happening....... I'm not a battery expert, but I'm guessing that several internal plates shorted, which allowed the amperage to peak, which then caused overheating/boiling of the electrolyte, and then a runaway situation.

Not the first time this has happened with a tender.......

 

Batteries charging give off hydrogen gas, which is volatile.

 

Whether it a battery tender or charger, I'd never leave any of them plugged in if I leave the house. Minor inconvenience opposed to burning my house down.
Main reason I've never owned a battery tender BTW .

 

Not likely. You didn't mention how old the charger was. The older charges used to trickle charge wet cell batteries if they needed it or not. In some cases the charge would boil off the water over time and cause the battery to heat up and fail.

An older charger or a charger with an issue can overcharge a battery and cause it to heat up. Since the battery in your case is effectively sealed (some wet cells advertise that they are sealed)...the pressure will cause the case to fail as yours did.

In my opinion, Deltran Battery Tenders are very reliable. The latest models have safety features built in to accommodate wet cell, AGM and Lithium. I have owned them for years without a single issue. I have three cars that stay connected to them when they are not being driven.

 

Did your charger have an in-line fuse?

 

Surely the 6 screw-in caps should be removed during charging to prevent the build up of hydrogen? Too much pressure inside could lead to the battery splitting in this way.

A battery with flip-out caps on the cells does not tend to be so well sealed up and so would allow the gas to escape, although these should be removed during charging too.

 

The Ferrari charger is a CTEK, Alberto. They’re usually quite reliable. I’m glad no damage was done

Andres

 

My read is an internal battery fault, as the ONLY time I have had a battery blow to pieces, it was shorted out.

You have to keep the "="......................................away from the "-"!!!

 

Any battery charger can fail. I had a Deltran charger malfunction and it overcharged a sealed battery to the point where it was hot to the touch and getting ready to explode. I have seen batteries explode before from overcharging/battery defects. During charging hydrogen gas is created. On vented batteries it just goes out the vent. On sealed batteries, the case must contain the pressure from the gas, during normal use this is not an issue. The plates and all of the connections between the cells are usually below the level of the acid/electrolyte in the battery.
When the battery is overcharged, too much hydrogen gas is created and the level of the electrolyte drops below the connections between the cells. Sometimes there will be a poor connection between cells, which will cause a spark to be created and this ignites the hydrogen gas inside the battery. The resulting explosion
blows the top off of the battery.
You can monitor the charging voltage of the battery to make sure that it is not too high (above 14.5v or so). On batteries with removable caps you should check the electrolyte level every six months to make sure that doesn't go below the lower level.

 

As stated previously, the battery appears to have severely sulfated and shorted internally across the plates. While a battery tender should detect the short and shut off, I am unsure if that is possible to do in all cases of a battery internal short. It would be interesting to hear from a battery tender manufacturer and ask what their claim is for protection.

Also my understanding is even sealed AGM batteries have a vent...it has to, in order to release gas. They don't leak electrolyte because instead of liquid, the plates are covered in a paste or damp membrane.

 

Caps need to come off during higher amperage charging, as there is a higher likelihood of boiling the electrolyte from over charging. But not with a battery tender, the charging is low amperage, usually 1 to 3 amps. Much, much lower than the car's own charging system

 

Had that happen once, using a Deltran "supersmart battery tender." My only guesses were that a component outright failed, or humidity condensed inside the tender case & dripped onto circuitry, causing it to malfunction. Either way? Still use one of them on a regular basis & also use a CTEK.

 

Multiple battery tenders used for the last 20 years on multiple vehicles. Only failure I ever had was a CTEK unit. It quit while I was overseas for 3 months. Tripped the circuit breaker in the garage, which turned off the freezer. What a mess when I returned.
Avoid the cheapo tenders (harbor freight) as they tend to over charge. I have Schumacher and Deltran tenders.... never a problem.
A worn out/sulfated battery cannot be charged with a tender..... perhaps that is why the OP had the battery rupture.

 

Am I right to assume this was on some "modern" vehicle requiring continues power source for some "computer"(?) they all now seem to feature ?
I've never seen any real need for these on "vintage" ((pre-computer/ECU ?) vehicles, but it seems I'm in the minority.
In my experience, if all "vintage" vehicle electrical system components are in proper working order and no clocks, etc are drawing amperage, battery charge should last months, during which it should be driven periodically anyway to prevent other component ailments or failures.

 

I agree. I have never used one on my 328 and have never had a battery issue (other than a nine year old battery finally giving up the ghost). I do, however, keep my 360 on one most of the time.

 

Yes, it won't hurt, but if everything else is OK, it shouldn't make much of a difference. If the clock doesn't work anyway and you want to make sure it don't draw any amperage, you might consider disconnecting its power source (fuse?). Better to drive it more often

I have and know of some 6Volt era vehicles that have been known to sit few months battery connected in between drives with no starting problems.
Same with 12V and just like tires, I recommend replacing a battery as part of scheduled maintenance and usually before it gives you problems, no later than every 5-6 years.

 

Hi Alberto,

For what it's worth, I've been using Battery Tender brand trickle chargers for the past 10 years on 80s Alfas, 80s Porsches, and 70s, 80s, 90s, & 2000s Ferraris with no problems. I use Interstate batteries on all of them and leave them constantly connected when not in use. I've had batteries fail while connected due to faulty batteries, but nothing has ever been hurt on the cars or blown up !


Skipp