# Cable length and amperage

My brother-in-law is buying an underwater camera for use with his marine biology studies.

Here are the electrical specs for the camera. Input voltage 12 VDC Power Consumption: 1.4 W Cable: 30, 50, 100m (basically a really long cable with an RCA connection) 21 LED lights Image Sensor: Color CCD

He's trying to understand the options that he has available for the Battery Kit. He can choose from:

• 4.5 A Battery + charger
• 7 A Battery + charger

Why would he get one over the other? Is it actually paired up with the length of cable that is connected to the camera?

Doing some quick Math: P = VI => I = P/V I = 1.4 W / 12 V = .12 A.

So the camera doesn't really require that much amperage. So why would he choose the 7A Battery over the 4.5 A Battery b/c that seems more than adequate.

• Will this battery be used for all components on the platform? May 2, 2012 at 6:03
• I'm in no way endorsing this product...but here's the link. theimportsworld.com/nauncasytide.html This bundle comes with the camera and a USB connection Kit...assuming that you will connect your computer. Perhaps @sptrks is hitting the nail on the head that the Battery Kit is also used for other devices. May 2, 2012 at 6:10