I want to use a small battery pack to power a strip of LEDs from Radioshack. They didn't have the power supply but list the requirements as 12VDC/1.5A. I know 8 AA batteries will provide 12 volts but I'm less certain how they will react to the 1.5 amp draw. We put 8 new alkaline batteries into a battery holder and did a quick non-solder test and the strip did light up nicely but the battery pack started to get warm even though we only had it connected for less than a minute or so. The plan is to solder a 9-volt type connector to the strip so it will be easy to connect/disconnect the battery pack instead of some type of switch. I know that I can add a current-limiting resistor inline with the wiring but I'm not sure what value to use. The strip looks like it has built in resistors so I'm at a loss as to what size resistor to try. The project is really just a short-term way to decorate a french horn for a school concert. My 15-year-old daughter can just connect the pack when the performance starts and then disconnect it when it is over. My concern is I don't want her to have the battery pack overheat during the performance. I don't care about how long the batteries last, this is a one-time use.
Maybe another way to ask this is, what is causing the battery pack to heat up, the LED strip drawing excessive current or some other reason?
I'm not trying to use rechargable batteries or build a charging circuit, just simply light up the instrument during a concert but safely.
[EDIT] We did a test using the battery pack and after 30 minutes we couldn't detect any noticable dimming and the battery pack was still around 90-92 degrees F, tested with an IR thermometer. I told her she can just leave the pack in her lap and if it gets too hot to unhook the connector or remove a battery. She plans on taking an extra set of batteries with her as replacements for when the first set run down. My guess is that we previously had shorted the battery pack accidently which caused the temp to spike but now that the wiring has been connected properly we are seeing more typical behavior heat-wise.