Will I need to run two batts with 1700 watts?

(typhoon) · (typhoon) **Join Date: Jul 2001** 05-31-2007, 8:29 PM

I have a ski boat that I am installing 1 12" tc9 being run by a soundstream 900 watt amp and a 720 watt 4 channel amp runn four 6.5" and a pair of evid 6.2 tower speakers. Will I need a second battery?

(jpshaff01) · (jpshaff01) **Join Date: Jun 2005** 05-31-2007, 8:31 PM

I would get s second battery regardless. Best to be safe, and im not one of those people with scuba gear and two extra props in their boat haha(no offense).

(fuller313) · (fuller313) **Join Date: Oct 2006** 05-31-2007, 8:35 PM

I had that much running off of one optima battery but I don't recomend it.

(tanner) · (tanner) **Join Date: Oct 2005** 05-31-2007, 9:17 PM

Just grab you two Trojan T-105's. Wire then in Series, and it should hold you no problem's.

(wakecat) · (wakecat) **Join Date: Jan 2002** 06-01-2007, 5:30 AM

Hey Tanner, whats a good price to pay for those T-105's? I have 4 used ones that were given to me but they only have about 50% of life left in them according to my charger.
Thanks

(nbeihl) · (nbeihl) **Join Date: Mar 2004** 06-01-2007, 1:03 PM

Just like any answer... It depends. If you are planning on parking and running the stereo at high volumes or for long periods of time, then yes, you will need an extra battery, or at least a paddle to get home. If you are only going to be cranking it up when you are skiing, then you will be getting your juice off the alternator. To make things simple, when you are running the boat, the battery is being charged by the alternator, and the alternator is providing the power. With a setup like that, I would check how strong your alternator is!

(riverdave) · (riverdave) **Join Date: May 2007** 06-01-2007, 1:48 PM

With that much power, I'd bet at full volume it'd be overcoming the alternator and still draining the battery.

I'd definately stick another battery in your boat.

I used to run two Optima Blue Tops.
2 12's (Kicker L5's) powered by a 700 or 800 watt kicker sub amp. 6 pioneer 6x9's and a pair of kicker seperates powered by a large 5 channel amp.

With two blue tops, with the battery switch on "all" (running both batteries to power the stereo) it would last about an 1hour before the sub amp started clipping when they were new, and about 45 minutes after a season. I could still start the boat, after the sub amp clipped, so I'd just shut it off when that happened.

RD

(saroberts70) · (saroberts70) **Join Date: Aug 2006** 06-01-2007, 1:54 PM

Hey Tanner. I thought I came up with the Trojans in series. Once I did that I've never had a problem.

(masterxstar) · (masterxstar) **Join Date: Jun 2005** 06-01-2007, 2:00 PM

what i would do is get a bunch a aaa batterys you should be just fine ...

(Message edited by masterxstar on June 01, 2007)

(mikeski) · (mikeski) **Join Date: Aug 2003** 06-01-2007, 11:55 PM

There is a common misconception in this thread.

Extra batteries will give you more playing time. If you alternator is not keeping up the extra batteries will just delay the time until they go dead.

1700 watts is really not that much. I ran 1500 off my old boat with a 60A alternator and one starting battery and it never went dead. However, I never played it unless the motor was running.

Most boats require about 20-30amps to run the ignition and boat electronics. The remainder of your alternator amperage is available to power the stereo. Assume that you will average 50% power draw at a 50% duty cycle -> 425 watts average draw. At 14.2 volts that 29 amps. If your boat has a 60 amp or better alternator you should be fine with no additional batteries. If you want to listen to music while parked add an additional battery(s) to run the stereo.

I would also suggest you add one of these for cheap insurance, it's like an accurage gas gauge for your battery: http://www.lascarelectronics.com/PRODUCTS.CFM?STOCKNO=EMV%201200&CFID=22736882&CFTO KEN=49933503

Don't get lights, be careful with impeller pumps too, both are big current drains.

(chaus21) · (chaus21) **Join Date: Sep 2006** 06-05-2007, 6:05 PM

Mikeski - Good idea - Do you know of a U.S. website that you can buy that kind of product from?