Firearms and Ammuni Forum banner
1 - 3 of 3 Posts

·
Registered
Joined
·
145 Posts
Disclaimer: it is many, many, many years since I learned this and I could be horribly confused. But I'm pretty sure I'm not. Check everything with a test harness and a multimeter first.

OK, so first you need to establish something: were the AAA batteries in parallel, or in serial? If in parallel, then you had 4.5 volts , and triple the life of one 4.5 battery (or more likely, cel). If in serial, you had about 13.5 volts going through there. If you want to know, digital multimeters are cheap and as long as you do it right, boringly reliable.

If it was 4.5V, your LED might fry under 9V (unlikely) or burn bright (likely) but perhaps not efficiently or maybe not even very long. There are a lot of ifs, ands and buts involved.

If you had 4.5V, then if you put two LEDs in parallel over your 9V battery each one should get (assuming equally resistant wiring) about 4.5V of electrical tension across it.

If it was 13.5V, then your 9V would get you a dim light. If you then put three 9V batteries in serial, and two LEDs in parallel over it, you should work out at 13.5V per LED.

But first test everything with a multimeter. Then test it again the other way around.
 

·
Registered
Joined
·
145 Posts
The principle behind serially connected batteries:

the batteries are daisychained, with the positive terminal of one connected to the negative of the next. You get (minus internal resistance and a few other factor of relatively minor importance) an addition of the voltage across them. Thus 5 * 9V batteries in serial gives you 45V of tension. If you have 45V running over a circuit offering 1 ohm of resistance, it should give you 45A of current flowing, because V/R=I.

The principle behind batteries connected in parallel:

the batteries are all linked with like terminals together. Between the positive side and the negative side each battery can only push at 9V, thus they collectively push at 9V but each one takes a lot less of the load, producing a much smaller amount of current per battery. This means that each battery lasts a lot longer before being exhausted.

The easy way to tell whether they're in serial or parallel, if the connection doesn't make it obvious, is a multimeter.
 
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top