JOHNSON 125HP - ALTERNATOR

[LOSTBOATER72]

DOES ANYONE KNOW WHAT A SAFE STEREO SYSTEM WOULD BE TO PUT IN MY BOAT WITH THE ABOVE MOTOR? IT IS A 1972 AS WELL AS THE BOAT SO THIS WILL BE A MAJOR UPGRADE. I AM MERELY LOOKING INTO A DECENT STEREO WITH 4 DECENT SPEAKERS BUT WANT TO BE SURE BEFORE I INSTALL IT ALL THAT IT WILL NOT END UP DRAINING MY BATTERY AND CAUSING FUTURE PROBLEMS...<br /> SINCERELY, LOST72

 

[JB]

Re: JOHNSON 125HP - ALTERNATOR

Howdy, Lost. What is the power usage of a "decent" stereo? No, not power output, power usage, which will be much higher than power output. For example, an Audio-Vox MS-100 has 120 watts of output, but uses more like 240 watts. That is 20 Amps at 12 volts. Your engine probably has the 10-35amp alternator which could only keep up with that stereo well above idle speed and then with very little other drain.<br /><br />You would probably be safe with a stereo that uses under 100 watts, with a typical output of 40 to 60 watts.<br /><br />Another option is to install a second, deep cycle battery to run your stereo. Isolate it and charge it as you would a troller battery.<br /><br />Red sky at night. . .<br />JB