How much audio can I run off a 787 charging system?

[IDoSeaDoo]

Hey guys, I'm looking to upgrade my 97 Challenger with a decent sound system. The boat has the single 787 2-stroke engine, which has just a magneto to maintain the battery and fire the plugs. Do you guys think I could run a 400W amped system w/o frying the charging system? I plan on having two batteries, one for starting, and one isolated for the sound system. I plan on having a switch where I can connect the two and charge the audio one while I'm running, but disconnect it when I stop. Wouldn't want to gamble with my ride back. I know these old 2-stroke ECUs are delicate when it comes to voltage spikes so who's had experience in this realm and can offer a bit of guidance?

Thanks!

 

[Albysure]

I'm not sure about the charging system. But I do know u gotta be carefull with the ecu. I just avoided the whole thing and dropped in a big marine deep cycle battery by its self. Hooked the radio and lights to it along with a solar powered trickle charger. Never dies on me, so far. Not the answer your looking for just different idea.

 

[IDoSeaDoo]

Yea, my plan is to have the stereo system on its own battery, but I'm wondering if I could have that battery also attached to the other battery in parallel while the boat is running and the system is on. Would the drain of the sound system overwhelm the magneto? Would there be voltage drops when the speakers all try to hit at the same time? Mind you, I don't plan on putting in Subs, possibly 8", but most likely 6.5".

 

[Guest_User]

Yea, my plan is to have the stereo system on its own battery, but I'm wondering if I could have that battery also attached to the other battery in parallel while the boat is running and the system is on. Would the drain of the sound system overwhelm the magneto? Would there be voltage drops when the speakers all try to hit at the same time? Mind you, I don't plan on putting in Subs, possibly 8", but most likely 6.5".

the only thing I can add is this:

The PO had the wiring in place for an amp, parts to install a 2nd battery/dual battery switch etc., and huge sub woofers mounted in the foot well...

I did not want or need the extra loud tunes, the aftermarket head unit sounds very loud as it is, so all of that came out. The PO never did mount the amp, but his intention was to run the dual battery switch, and a battery of capacity for powering the Amps. I`m guessing he was going to run the stereo while anchored off the Amp battery and switch to dual while underway.

The problem with the ECU, so I`ve read and heard testimony, is that the charger used in maintaining the battery(s) while the battery is hooked up live without a cut off switch is what can fry the sensitive ECU. A high amp auto charger will fry the ecu if all is connected. A battery tender will be safe either way, but it is always recommended to install a cut off switch...

I really don`t foresee any issues as long as you install correctly and head these guidelines...

I don`t think it`s wise to power up on a single battery and crank the tunes while sitting for hours, a back up battery would def be beneficial!, good luck...

 

[Spimothy Leary]

out of curiosity, wouldn't a fully charged good battery hold up for a LONG time running just tunes by itself, you could ignore the switch part, just run all the audio off the separate battery and never have to worry about messing with the charging system itself, It seems to me that you easily could have 4-6 hours of audio on a separate battery, and more like 6-8 if you buy a really good one like maybe an Optima Yellow Top. just a thought.

 

[howie099]

On mine I turn the battery switch off before I charge the battery. I installed and AB-All switch don't trust any charger on a Seadoo with power going to MPEM. Right now I have dual batteries w/600 watt Sony AMP, 10" Sub with 2 - 7.7" speakers and I have no issues with batteries. I do switch batteries when I am beached so I don't kill the main starting one. I have ran on one battery for few hours beached and the boat still started on that battery I was listing to. Plan to add 2 more speakers and another 300 watt AMP. You can pull all the power you want from the batteries it just doesn't mean the system will charge them up enough without help. I change my batteries after every day trip I go on.