Firing Batteries

Battery Ratings
Batteries generally come with two different values. Voltage and Amp-Hours. Voltage is exactly what it says. It is the nominal operating voltage of your batteries. If interested, read a further explanation of voltage. Amp-Hours is the manufactures way of telling you how long your batteries will last. What the heck is an Amp-Hour? An Amp-Hour (Ah) is a unit used to give you the duration of a consistent current output. So for example, we may have a 12V 7A-h battery. This means your 12 Volt battery will put out seven amps (across an appropriate load) for 1 hour before it starts to degrade. Or it will put out 1A for 7 hours. Or it will put out 1mA (1 milliamp = 0.001 Amps) for 7000 hours. Get it?

Additional Firing Battery FAQ's

Most Firing Systems run off of 24 volts, but they only sell up to 12 volt batteries. How is this possible?
Quite simple actually. Any two batteries (of the same type, otherwise you will have issues) can be tied together in series to "add" their voltages. For example, if you had two 12 volt batteries and you tied them in series, you would get 24 volts across them. Make sure you tie them in series and not parallel. If you tie the batteries in parallel, you are adding the overall charge, and not the voltage. In other words, you would still have 12 volts. If your still confused about the whole series-parallel thing, read our electricity 101 tutorial.

So how big of a battery should I buy?
This depends on the demand of your system. Assuming we are talking about a typical 24 volt firing system that will be used to shoot a show with anywhere from a couple hundred to a a couple thousand different shots, you want to go with something that will handle anything. So I would recommend at a minimum a 5A-h lead-acid (lead-acid = same type as your car battery but smaller) battery. Personally, I use a 7A-h, that way I can go a few shows in between charging them. Remember, you might be putting out a couple amps per shot, but your only producing that current in bursts for very short intervals. Your 7A-h batteries should last you a large number of shows before they would be considered dead. You could probably get away with shooting 15 or more shows on a single charge, but I wouldn't push your luck. I try to keep my batteries topped off for each show.

                        
                                                Lead-Acid Batteries Commonly Used for Firing Systems. Two on the left: 12V 5A-h, Two on the right: 12V 7A-h

What happens if I touch the black side of the battery to the red side of the battery?
You will probably have to change your underpants. This is know as "shorting" the battery. This is BAD!!! Don't do that. You are dealing with a large battery with a significant charge. If you were take a short piece of wire and touch the two sides of the battery together, you would get a blinding flash, a loud crack, and when the smoke clears, the end of your wire or the battery terminal itself would be melted. Yes I said the metal would be melted. This would happen almost instantaneously! Hopefully you can imagine the amount of energy that would take. You can read our electricity 101 tutorial for better understanding of why this happens. In the worst case scenario, the battery explodes, throwing acid all over the place including you. Needless to say, you could get hurt. Don't do it. Be careful when ever handling the batteries. Try to avoid having wires connected to the batteries just waving around unconnected. Your just asking for trouble. Because of this, it's a good general rule of thumb to first attach the battery cables to the firing board, then the batteries, so you avoid this possibility all together.