I heard this statement from a "How To" video. He was connecting to a battery.
"You'll have sparks. Sparks is good. It's not a bad thing. It means the battery is alive"
Any truth to the statement??
Depends on what’s happening.
In most cases sparks are bad.
But sometimes they are part of the process.
Most UPSs will spark when a battery is connected. This is with the UPS off.
Big inverters will have a huge and possibly damaging spark when connected. So a resistor should be used to bring the system up. Then connect the battery, then power it on.
All the Best,
Jeff
That is interesting… That would indicate that there is a reasonable amount of current flowing at time of connection. For example… in a car I could see that happening due to the immediate power up of systems that are always powered plus any lights that are on due to doors being open. The downside… battery off gassing will burn very violently, so one could run into trouble with a bad battery in place. Now if connecting to something that should have no residual power draw and sparks are present… it would suggest some sort of short in the system.
Sounds like he was a graduate of the university of redneck.
Sparks are not a good thing—it means metal is melting because current is flowing in the system. If the currents are large then molten metal will be created and can be explosively expelled by the arcing. My main worry would be eye damage followed by skin burns, hence wear eye protection and gloves when messing with batteries. Think about what arc welding is all about.
+1 on what jeff said, to avoid the sparking, use a pre-charge resistor to bleed off the inrush current as capacitors in the system charge up, then make the terminal connection. Use a power resistor of 1 to 10 Watts rating with a value about 4 or 5 times the voltage, e.g. if 12V battery use a 50 or 60 Ohm 1W resistor for the pre-charge, hold it in place for 5 seconds then connect the terminal—no sparks.
The video was about connecting 2 E-scooter battery packs in parallel so one can have more capacity. It's the battery packs that go into E-scooters. They are connecting it using X60 connectors. The X60 connectors made a pop/spark as they were closing the X60s.
Sparks when connecting a pair in parallel is bad news.
That means there is a significant difference in the two voltages.
One is dumping energy into the other.
Lots of potential for problems in that case.
All the Best,
Jeff
Surely you do not do that when jump starting a car, do you? Sparks are not good, but sometimes they have to happen. EV, I would never touch any thing under the hood short of washer fluid and changing lights… The capacity in those things really do worry me.
Yes, you are correct and the video actually emphasized making sure to charge both packs to match the same voltage before connecting the parallel way. Usually using a smart charger or charging to 100% using a standard charger. Mind you charging 100% is not the best way but that’s another topic.
I was reminded of a time long ago when I fried my car’s CPU by accidentally shorting the car battery with a screwdriver.! :money_mouth_face:
That’s not a spark -
This is a spark!
You want sparks, you got it! }) Just ask ElectroBOOM!
Amazing that he still can see considering the lack of safety glasses… 
This is only true on a car battery. Some minor sparks are ok, its inevitable.
You should NEVER see a spark coming from a Lithium Ion Battery.
I’ve seen this demo in person. They set off an arc at the beginning of the show using the glass panel in the foreground that is very loud.
The museum is worth a visit any science and technical nerd who finds themselves in Munich. Very old school, though.
Don’t forget to go through the mining exhibit in the basement, which is done up like a mine.
That’s some good stuff!
Can’t start a fire without a spark.