Selecting and installing the marine stereo that is right for your boat.

Selecting and installing the marine stereo that is right for your boat.

Ok we have all had those wonderful days when we went down to WalMart, bought a marine stereo and plopped it in only to have never ending relationships with our battery charger every time we came in. This it turns out is directly related to the small amperage put out by the stators and even alternators in our beloved outboards.
On Larger vessels with inboards or (UGH) I/O's, you generally can get away with about the level of stereo you would be willing to put in a car with a stock alternator (yup I am one of these guys who is not averse to adding say a 175 amp Leece Neville or a 500 amp Bosch Alternator in the interest of better sound). On outboard engines with stators, 30 amps is considered a lot of juice and something along the lines of 10 or 15 is more the norm so here are some tips to help you get a nice sounding stereo on your boat without burning out your stator or having to re-charge your batteries every time you come in from a day on the water.

   First off determine how many amps you have available - look it up in your service manual or ask your favorite parts guy what your stator/alternator is putting out. Pretty low number was it not?

 OK now to both make the math easy and compensate for overhead count every amp as you can throw 10 watts out of your new stereo. In other words, take the number of amps you have coming out and multiply by 10 and that  is the number of available stereo watts you should be running.

   There are other factors to take into account as well. Look at your gauges - count each one as able to pull 1/4 amp with the lights on. Now look at your lights - reverse the formula from the step above to calculate the number of amps (or fraction thereof) each light draws. Go through and look at the amp draw of each of your other devices on the vessel - count everything - GPS, Baitwell/livewell pump, sounder/fishfinder and anything else you have on board that you may need to run home with at night. Now add all these together and you have your amp consumption take off 10 watts from your stereo output for every amp drawn. [ Old Boombox oughta be looking good about here if you are running a small outboard eh? ] Don't forget to leave at very minimum an amp or 2 to charge your batteries with!

   Ok Outboard folks are mostly looking at this, scratching their chins or some other part of their head thinking maybe that stereo aint such a good idea - ok I can help just a little bit towards fixing the situation........

  Here are some simple things you can do to get a little more available amperage:

First:

Dump those ancient old filament bulbs in the nearest trash receptacle and get LED replacements. They are available for most automotive (and hence boat) socket types and use way way less wattage. Another alternative would be to go to xeon bulbs but these are generally not as efficient as LED's and are a bit of the proverbial "overpriced poodle" when it comes to longevity.

 Second:

   Look at your instruments, replace All those bulbs with LED's. Now focus on your GPS/fishfinder. Is it newer and energy efficient or some amp drawing hulk you bought 30 years ago? Newer units that are efficient are getting priced down to where we can all afford them. Garmin across the board is the most efficient but Raymarine runs a really tight second when it comes to the bigger screens. Lowrance units readily die when tied into an electrical system with much more than a boombox on it.

Third:

 Look at your Stator - can you get a bigger one? Is it like some of the older ones where you have an 18 amp stator and a 10 amp rectifier - if so replace the rectifier with one rated a couple amps under what your stator is supposed to throw.

Next:

 Pick out your stereo.

Hmmmm stuck with a lower watt unit eh? You can compensate easily with larger speakers. Go for diameter and always go with speakers rated at least twice the watts your new stereo is able to throw. Make sure you match your Ohms when buying speakers - watts dont really matter except that you do not want to buy speakers rated less than what your stereo is going to throw.

Mount dat puppy and all the speakers too. Then run your wires - solder all your connctions (forget those speed connect crappy things do it right and do it once) make sure you use good aircraft or marine shrink wrap with the epoxy on the inside and use 2 or 3 overlapping layers.

   Go out and enjoy the tunes..