Upgrade alternator??

[Jeffkurtz]

I have a 1991 supra impulse with a 351 in I'm looking to add an amp and subwoofer to my stereo system, I was told to get a 100 amp alternator to keep up with the stereo draining the battery, having trouble trying to figure all this out,
Any help or input would be great....Thanks on advance.

Jeff

[James Evans]

I put in a pretty hefty size amp (5ch) to run 8 speakers and a sub in my 92 conbrio/impulse. Didn't upgrade alternator and have had no problems, but have noticed that my volt gauge sets lower than it did prior. I will be upgrading mine over the winter, as I also plan to add another amp and 2nd battery dedicated to the stereo.

DB electrical has the best prices I have seen so far on upgrades.

[Jeffkurtz]

Thanks for the reply that's what I was thinking I'm going to be running 2 tower speakers and the sub off of the amp.....

[wotan2525]

Alternator is probably secondary to adding another battery. I'm a fan of the blue-sea add-a-battery kit, but there are other options. You want to make sure you can crank your stereo for a while and not worry about killing your starting battery. An isolator will take care of that for you.

I'd also add an on-board charger/maintainer (but I got sick of being stranded or having battery problems a LONG time ago.)

[Wylietunes]

Jeff,

Simply adding "an amp" is far from needing to upgrade the alternator in order to keep pace. Let me ask a few questions:

Whats the makeup of the existing audio system
What amp are you adding
does the boat have 1 or 2 battery banks?
Do you use an onboard charger or other shore charging used
Do you spend a lot of time at anchor playing the system

[Jeffkurtz]

Current system is head unit and 6 speakers, speakers are run right off the head unit. 2 tower 8"speakers and 4 internal 6.5", I'm adding a 4 channel 1600 watt amp and a 12" 250watt rms sub.
Boat currently has a singal battery, mostly listen to the stereo while riding but will listen to it on the beach also at times.........charge battery as needed when boat is on the trailer....

[Wylietunes]

Do you by chance know the amp model? 1600W (which is in in AC) is a marketing number and means little when calculating what the average DC current draw will be. I presume you will be leaving the 4 in-boats on the head-unit and relocating the 2 tower speakers to the new 4 chnl amp along with the sub?

I would put my money into a Blue Sea battery switch, a group-24 deep-cycle battery rather then an upgraded alternator.

[Jeffkurtz]

Amp is a BOSS 1600.4, yes I will be putting the 4speakers in the boat on the head unit and the 2 tower speakers and sub on the amp, I will also be putting a group 27 deep cycle in.....

[Wylietunes]

Realistically, I dont think that amp is going to draw more than 25A DC. Id say about 200W rms to the woofer bridged and about 50W rms for each tower speaker.

[Jeffkurtz]

Good to get a second opinion, I appreciate it, I think I'll try as is and see what happens...Thanks again!!