View Full Version : Electrical question?

04-20-2009, 06:42 PM
Does anyone know how many watts your boat uses when running and how much your alternator is cranking? I only run my stereo when the boat is running so I am trying to see if I need to buy another battery or not.

04-20-2009, 07:05 PM
Start by telling us about the stereo? Stock stereo? Amps? Speakers? It all matters when asking a question like this one. ;)

04-20-2009, 07:47 PM
well i'm just going to use a 600 watt amp powering a sub and no amp for stock stereo, and want to make sure when my boat is running that I am not going to be draining my battery. I don't plan on sitting idle and listening to tunes since there is no time to be wasted when its sweet butta on the lake. I was reading on wakeworld that mostly outboard boats/older boats need an extra battery since their alternator's don't put out as many watts since they are only powering just small electronics via lights and fish finders.

04-20-2009, 08:39 PM
My req on that then would be to downgrade that 600W amp for the sub or keep the gain down as it'll over power the stock Kenwood stereo. You have a 70amp alt which is more than sifficient for what you want. BUT i always recommend a second batt if nothing more than for safety, that starting batt goes dead and your hosed.

As to your original question, it's the same as your car when running or idling.

04-20-2009, 08:46 PM
get a second battery. Lights eat juice too!

04-20-2009, 08:48 PM
to start with your altanator puts out amp not watts. you could run a extra battery, or a large cap on your amp this will cut down the drain on your battery

04-20-2009, 11:15 PM
Thanks razzman. I am just trying to keep the price down since i already have a 600w amp thats collecting dust since my subs in my truck were stolen. I was just planning on buying a 10 kicker comp since the bump pretty good for what i need and they are like 50 60 bucks online. I guess I look into buying a second battery then. If only money grew on trees.

04-21-2009, 12:16 AM
If only money grew on trees.

Amen! LOL! Yeah the Kicker Comp 10's put out some real nice bass for the bucks, had one in my Tigé. Just keep the gain down so it doesn't drown your stereo! :p

Because the battery is in the forward compartment you can add a second batt without breaking the bank as it doesn't take much wire.
Add a Stinger 80 amp isolator ($20 online) to do your switching automatically
use cables from your auto parts store cheap as well for around $20
Get a deep cycle batt from Costco for around $75

and there you have a budget second batt solution on the cheap for a little over $100. The Stinger will automatically disconnect the batts at rest and connect/charge them when running. Also ran that for two years on the Tigé without issue. The pic below shows you the Stinger on the top of the board, nothing to it and easy to install.