Whats the effect on Voltage and Amps when 244 9v batteries are connected in a series?

Question

There are many opinions about a stunt a guy did on youtube, where he connected 244 9v batteries together in series.

Can someone clarify the magnitude of

• Current being limited by the chemical reaction within the batteries
• The affect of above on Voltage (is it the same thing)
• Are there any current or voltage maximums in this configuration? How many more batteries are needed? What are they and how would I figure that out?

From what I read, he was doing something very reckless, and could could severe injury or death.

Answer 1

Assuming the batteries are identical, the current won't be more than one battery could supply into a short circuit (probably several amperes for a fresh 9V alkaline battery- I've measured 5A briefly from a Costco 9V battery) no matter the number of batteries. The voltage increases with each added cell, but so does the internal resistance, and by the same factor.

That said, there's potential for explosion if the internal resistance of one started to increase greatly (which it might from such abuse). Also, a couple amperes at 2.2kV is a lot of power, liberating a lot of heat even if the batteries stay balanced and they're closely packed so there's nowhere for the heat to go.

It is also easily a lethal shock hazard.

And putting that kind of voltage with that much available current into a Radio Shack handheld meter is reckless.

NiCd 9V batteries can supply 90A briefly which could well lead to a fairly substantial explosion- 90A at 2.2kV is going to create a stubbornly persistent arc, so it might not be just a single battery going up.

I remember reading some speculation (in an old issue of Analog, if I recall correctly) about an office-desk-size arrangement of AA batteries producing something like 1MV. The author speculated that it would be next to impossible to extinguish the arc once initiated.

The only limit on this insanity would be the geometry of the arrangement- if the voltage per cm gets high enough between any two points to break the air down you're going to have instant issues. But you could make a linear arrangement of 150,000 batteries and get 1.35MV (peak available output power about 3MW) if you could round up that many batteries- 4500 HP- almost 7 metric tons of batteries and still not quite what you can get from an internal combustion engine in a drag racer.

Answer 2

1. Current being limited by the chemical reaction within the batteries: When batteries are put together in series, the maximum current is the maximum current of the weakest battery in the series. The current is not added when cells are put together in series. I believe that the maximum current that any type of battery can provide is related to its internal resistance, assuming that there are no added electronics limiting the currents that a battery can supply.

2. The affect of the above on voltage: when cells or batteries are added together in series, the voltage of each battery is added to the next. So if in the video all of the batteries were at exactly 9 volts, then the voltage of his creation would be 244 * 9 = 2196 volts.

3. Are there any voltage or current maximums in this configuration? I don't quite understand what you are asking at this point. The voltage is as stated above, and the maximum current is the maximum current that a single 9 volt can provide, minus the added internal resistance of the 244 in series.

Answer 3

I've seen someone do something similar to this in person and go around setting fire to pencils, spot-welding paperclips together, and leaving arc burns on metal furniture.

You say "Are there any current or voltage maximums in this configuration? How many more batteries are needed?"

The limit on voltage is battery terminal voltage times number of batteries. As others have said, you can just keep adding batteries to get higher and higher voltage. The limit on current while all the batteries still have some charge is the total internal resistance, so you won't be able to draw more current than you would from a shorted individual battery.

Once a battery in the stack is fully discharged, you're limited to conducting through its electrolyte, which will probably be a fairly good resistor. Either that limits the overall current flow or it will heat up dramatically.