Overheating again. - little help

[69 Elim]

Well over the weekend, I managed to cook my amps again.
We were floating and playing at 1/2 volume for about 4 hours.
batteries - 2 optima yellow tops for stereo only
amps - 500/1 JL and (2) 300/4 JL with barrel fans on them. mounted in engine compartment
after about 4 hours of playing, all of a sudden from the subs comes a sound that sounds like a speaker is blown - the fluttering buzzing sound. well, it was coming from both 12's (W3) and we were'nt playing loud at all - just chillin in the boat talking.
ok, so I figured the amps were hot again (all mounted in engine compartment) and shut the whole stereo off. outside temp was 103 probably. and hadn't ran the engine like I said for 4 hours.
turned the stereo back on about an hour latter - no sound from the subs.
the next morning, went out to see if I could find something wrong. nope - fuses are fine, there is power to the sub amp, the power light is on, but it doesn't play.
I guess I smoked it.
so, I'm thinking on buying another 500/1 JL and moving all the amps under a seat base (is a 21 footer shockwave) with a push pull fan system to exhaust the hot air and get fresh air across the amps. I'll lose all my storage under my seats, but something has to be done.
any suggestions? I open for anything. :frown:

[Chubby4Life]

Do you have spacers installed to lift the bottom of the amp from the mounting surface?

[69 Elim]

no spacers - Shockwave did the install when the boat was built, now just trying to fix. never had a problem when outside temp was in the 90's. Now that its tripple digits its another story.

[Chubby4Life]

Add the spacers. 1" spacers cost about .50 cents each and will solve your problem. Also, I think you said you had squirrel fans right? Make sure the fan is blowing under the amp in the area the spacers created. Most people set the fan to blow onto the heatsink and this doesn't do anything to cool down as the amp draws it's intake air from the bottom and expells the heat through the heatsinks. You shouldn't have to move amps from their present location either.

[69 Elim]

my fans blow across the tops of the amps. JL's don't really have heat sinks. does this make since ?

[phebus]

I'd charge my batteries full before I went any further. If you were sitting for four hours, and I assume you played it before that, it's possible the amp just switched into protect mode from low voltage. You say it has power to the amps, but did you meter it to see what voltage it was?

[Chubby4Life]

Yes it does. the entire cast acts as the heatsink, by redirecting the fan to blow under the bottom your feeding it cool air to begin with.

[riverbound]

Did you also say they are in th engine compartment?? That right there will kill amps.

[69 Elim]

I have an onboard battery charger that I plug in every night. my batteries were topped off before we went to the lake.
I also have a digital voltage guage. I didn't check it at the time of failure, but based on prior times at the lake, I'd say voltage was probably 11.8
actually, 11.5 is the lowest its ever been.
oh, failure was Sat afternoon. then put back on the charge Sat night. played w/ just the 6x9's and no subs on sunday and monday (put on the charger each night.)
don't think it was a low voltage thing - but guess it could be.
most of the time we sit and float is by our selves in a quiet cove, so stereo doesn't have to be super loud. no other boats to compete against.
- Oh, I like the idea of the spacers -
any more suggestions - all are welcome.

[69 Elim]

riverbound - I know you've done lots of boats - please advise on what to do.
I really don't want to drive all the way down to LA to have a shop down there fix it. we have several very good stereo shops here in town. but, they don't have alot of boat experience. I can give them detailed instructions on what I want done and they'll do it. I'll try take some pics tonight and post them.

[ADAM GARCIA]

that is the worst place for amps , heat ,water,gas , try and relocate amps and make sure all high amps are at 4 ohms and have plenty of venting

[Havasu Hangin']

The engine compartment gets hot just from sitting, let alone when the engine is running.
When I put a low-ohm load on my amps (that are going to be subjected to 120 degree weather), the only long-term success I've had on cooling them down is to get cool air in, and the warm air out.

[h2oski2fast]

Add the spacers. 1" spacers cost about .50 cents each and will solve your problem. Also, I think you said you had squirrel fans right? Make sure the fan is blowing under the amp in the area the spacers created. Most people set the fan to blow onto the heatsink and this doesn't do anything to cool down as the amp draws it's intake air from the bottom and expells the heat through the heatsinks. You shouldn't have to move amps from their present location either.
OK, Ive heard it all now. The ouput rails (mosfets, transisters) and thermal sensors are mounted directly to the heatsink. The heatsink shape is designed to pull the heat away from the rails. The bottom plate has nothing to do with the cooling of the amp. The only way what you are proposing will work, would be to completely remove the bottom plate. This is not a good idea for the simple reasoning that it would be cooling the thermal sensors (which are there to protect the amp from getting hot enough to melt all of the componets off the circuit board) there letting the amp overheat. As for not moving the amps, that definately should be done. Cast iron engine blocks can hold heat for hours, thus bring up the ambient air temp under the engine hatch. I would move the amps under the bow somewhere. Under the bench seat leaves them susceptible to water. I would not put the amps in an small enclosure as there is not enough air to cool them (even with fans). I would leave then open and blow air over the tops of them, prefferably from a cooler source rather than blowing the same hot air over them continuously.

[ROZ]

OK, Ive heard it all now. The ouput rails (mosfets, transisters) and thermal sensors are mounted directly to the heatsink. The heatsink shape is designed to pull the heat away from the rails. The bottom plate has nothing to do with the cooling of the amp.
You sir have no idea what you're talking about.. The mosfets are tac welded directly to the amp cover, and the powersupply(made of a space age polymer,ofcourse) is directly connnected to the heatsink.. I usually reccomend hosing it off when it gets too hot... :supp: ;) :D

[h2oski2fast]

I usually reccomend hosing it off when it gets too hot... :supp: ;) :D
I ussually just pour the icechest water on them. I heard it was non-conductive after having at least a 30 pack (cans not bottles) in it.
Damn smart asses!

[ROZ]

I ussually just pour the icechest water on them. I heard it was non-conductive after having at least a 30 pack (cans not bottles) in it.
Damn smart asses!
You rock, dude! :D
You've forgotten more about 12v than I know :)

[riverbound]

riverbound - I know you've done lots of boats - please advise on what to do.
I really don't want to drive all the way down to LA to have a shop down there fix it. we have several very good stereo shops here in town. but, they don't have alot of boat experience. I can give them detailed instructions on what I want done and they'll do it. I'll try take some pics tonight and post them.
First thing I would do is get the amps out of the engine compartment. As others ahve said that is one of the worst places to put an amp (the swim step is another bad place).