Amps Over Heating

[rdlangston13]

a legit 100 degrees or 100 heat index?

[DOCDRS]

100 external. 86 lake. Temps as registered on my seadoo and the 86 confirmed on boat lake temp

[EarmarkMarine]

Here in the DFW area, as of today, we have had over 20 days straight of 100 degree plus temperatures. We have yet to have a boat owner call or bring his boat by with thermal shutdown issues where we installed Class D amplifiers.

David
Earmark Marine

[rdlangston13]

Here in the DFW area, as of today, we have had over 20 days straight of 100 degree plus temperatures. We have yet to have a boat owner call or bring his boat by with thermal shutdown issues where we installed Class D amplifiers.

David
Earmark Marine

so can low battery power cause the amps to over heat even if the voltage is ok due to the alternator charging?

[EarmarkMarine]

rd,
Low voltage is hard on all electronics including boat electronics, starters, etc.
Let's look at a particular scenerio...
You've been at rest and run two group 29 or 31s down to 10.5 volts (considered empty) and the audio system shuts down due to low voltage. So you start up the boat which has a 90 amp alternator (pretty good size) and are running at a moderate rpm. The alternator is only rated and intended to deliver its full rated output while at high rpms and for short durations. So you're not getting the full 90 amps. The boat operations, ignition etc, take 15 to 20 amps without any DC lighting or accessories. You are continuing to play your stereo at half power which is drawing 67 amps. The two depleted stereo batteries are discharged and a serious liability rather than an asset to your charging system at this point, thus are pulling 25 amps each initially until they get a charge. Collectively we have a 137 potential total amperage draw from an alternator that is realistically putting out 70 amps under the present conditions. Since the total draw is exceeding the alternator capacity, right now we are pulling down the starting battery as it levels with the stereo bank since the battery switch is in the 'Both' position. If its an ACR there is no way its combining under these conditions and the stereo bank is off-line entirely from the alternator. In either case you won't begin to charge the stereo bank until you shut down the stereo. As the current draw increases a voltage drop is simultaneous. If your reserves are depleted then the issue is greatly compounded. Its unavoidable. Something else to consider is, if the voltage is down to just 12.5 volts you may have lost up to 20 percent of your amplifier rated output power with a continued loss of power as voltage drops farther. By the time the system shuts down due to low voltage your amplifiers are generating just a fraction of their rated power.
You can upgrade your alternator. Past 120 amps you are going to have to get away from the conventional V belts and pulleys which is very expensive. Really large alternators when under serious load also impact HP and may even be noticeable.
While this is an extreme scenerio for some its the norm for others and even more complex for those with systems twice the size.
First, battery reserves are important.
Second, get a serious AC shore charger rather than a trickle/tender/minder variety.
Third, give the stereo a rest sometimes so the charging system can catch its breath so to speak and has the opportunity to charge the batteries after a long period at rest.
Fourth, the above issues are why I so strongly recommend designing an audio system from the beginning for maximum efficiency including sub, sub enclosure, tuning and especially amplifier efficiency. Increased efficiency will go a long way towards eliminating thermal problems also.

David
Earmark Marine

[rdlangston13]

ok new batteries installed. Two interstate SRM-29s for the stereo and one interstae group 24 marine cranking for starting. Also now have a permantently mounted prosport 20 plus. the first test of the new set up will be this weekend on lake belton. lets hope the amps will play for more than a half hour!

question on adding water to batteries, do you fill them till they over flow or what?

[Razzman]

ok new batteries installed. Two interstate SRM-29s for the stereo and one interstae group 24 marine cranking for starting. Also now have a permantently mounted prosport 20 plus. the first test of the new set up will be this weekend on lake belton. lets hope the amps will play for more than a half hour!

question on adding water to batteries, do you fill them till they over flow or what?

I always fill mine to the bottom of the top plate

[EarmarkMarine]

Fill to a level that is above the top of the plates.
Never, ever overfill and spill. You are releasing important chemicals from the battery that are needed and also the chemicals happen to be very destructive when exterior to the battery.
Only use distilled water and never tap water.
Check 3 to 4 times per season. When you are adding moderate amounts of water more than several times per year that is an indication of over-charging or failing batteries and it would be time for a load test.

David
Earmark Marine

[rdlangston13]

thanks, i saw a little battery watering kit at bass pro that fits on top of the battery, looks like it is supposed to make filling them easier. any thoughts on products like these?

[rdlangston13]

Went to the lake this weekend and th stereo performed flawlessly. We never really party coved at all but we did use the harpoon at a low to moderate volume for hours. Very pleased so far