Battery Longevity

[cqaigy2]

I know you can overcharge a working battery with an arc welder.

I was in metal shop where someone was welding something on a motorcycle, when the battery went bang, and hot steaming battery acid/water drained out, onto the ground. Not sure if it was pressure buildup from water boiling or ignition of hydrogen gas.

 

[fried1765]

Not just an "I heard" but hard fact. One bad cell causes others to overcharge because the only practical means of limiting charge is voltage. The charging algorithm says, "I need to see 13.8V and I'm going to hammer it until I do."

This is a Mercedes-Benz Original Equipment Bosch AGM with a bad cell which M-B's much touted bad battery algorithm missed. Battery is under front passenger seat and is installed before the carpet. Carpet must be cut to access battery for the first time, has perforation, owner's manual says as much.

View attachment 679702

The Germans do get some things wrong.
My mother, and dad, got it right though.....Mother 1/2 German, 1/2 Swedish, father 100% imported Kraut.

My E-350 has TWO batteries (not diesel)
One in the trunk, under spare tire, to power some accessories.

One under hood is primary battery, but if disconnected for replacement, will require dealer to reset computer functions.
Must connect an external 12V standby source before replacing primary battery.

Nice car,.... but too expensive to dealer maintain, and too complicated!
I do not use dealer maintenance!

 

[Industrial Toys]

I guess the motorcycle battery was discharging hydrogen and ignited. How does welding on a bike or anything else overcharge the battery?

I think its mostly a myth that you can damage an electrical system provided you ground well to the area you are working on. In fact, I feel it safe to say you are probably better to leave the (low impedance) battery connected for protection. Better 13.8 volts DC there than who knows what inductive noise.

 

[cqaigy2]

I guess the motorcycle battery was discharging hydrogen and ignited. How does welding on a bike or anything else overcharge the battery?

I think its mostly a myth that you can damage an electrical system provided you ground well to the area you are working on. In fact, I feel it safe to say you are probably better to leave the (low impedance) battery connected for protection. Better 13.8 volts DC there than who knows what inductive noise.

I expect hydrogen ignited but that wouldn't cause electrolyte to be steaming unless it had been carrying a large current prior to it exploding. I'm not sure how something could be mostly a myth. Until it's not? I wouldn't and don't weld on something, unless i've disconnected the battery. I cleaned the grounding area well, placing it as close to where im welding and not just because of possible electrical issues, but also don't want bearings and whatnot arcing.

 

[goeduck]

Drove my old Mercedes 240D diesel up to my remote property on Sunday (hour+ each way). Dark day so I had the headlights on most of the way. About the time I got off the highway coming home I noticed the turn signals did not work and the windshield wipers were slowing to a crawl... got the rest of the way home (not dusk yet, but close) and looked at my headlights.... just a glow. Grabbed the multimeter... about 10.5 Volts. Charged up the battery with a NOCO and need to check out the alternator this weekend.

 

[Beaver Cove Deere]

That's the first time I've seen an AGM battery with corrosion on the terminals.

Not sure that's an AGM battery with the vent hose so close.

 

[Grumpycat]

That's the first time I've seen an AGM battery with corrosion on the terminals.

Not sure that's an AGM battery with the vent hose so close.

Most certainly is an AGM. Was the original factory battery. Had to cut the carpet on provided perforations to get to it. AGM batteries have vents too. Look up Group 49.

 

[Beaver Cove Deere]

Most certainly is an AGM. Was the original factory battery. Had to cut the carpet on provided perforations to get to it. AGM batteries have vents too. Look up Group 49.

Never once seen a vent on any AGM battery. Have bought and installed many including the 3 on my boat.

 

[goeduck]

The other 5 cells are forced up to 13.8V before the charging algorithm backs off. They get overcharged.

Okay that makes sense but the reduced amps does not make sense to me. If one cell is shorted then I would expect that the other 5 would still put out their amperage. So I would think a 600 CCA battery with one shorted cell would then put out 500 CCA. Assuming that a shorted cell is just that, a short circuit.

A stratified or sulphated battery would act with reduced ampacity but correct voltage as I understand it. But then I have not attended Battery University nor did I sleep in a Holiday Inn Express last night.

Oariginal Post:

(removed), Yes my battery is just dead, even though it shows on multimeter and my big charger that it's fully charged. Put a load to it and nada, zip. I ordered a replacement today. Will get it in tomorrow. I just hope with these new high winds we're getting today that power won't be shut off before tomorrow. Doesn't bother me so much, but it irks the wife!

 

[Grumpycat]

Never once seen a vent on any AGM battery. Have bought and installed many including the 3 on my boat.

Well, you learned something today.