JL Audio 250/1 sub amp pushing 2 JL 10" free air subs
JL 300/4 pushing 4 Babbs speakers: 5 1/4" and 6x9"

With the power off (remote trigger wire switched off with dedicated switch) Fluke DMM hooked in series on the (+) amp lead.

the 250/1 amp is pulling 32mA
the 300/4 amp is drawing 2.6mA

Why such a difference? Enough to drain a battery in 1 week?


With power on, playing Gwen Stef???? Hollerback Girl for some hard hitting using a DC current clamp meter on the amps (+) power leads separetly:

250/1
10% volume, 1.4A
90% volume, averaging 2A-2.5A, with spikes to 5A.

300/4
10% vol. 2.2A
90% vol. meter all over the place with spikes up to 30A


Is it normal for a mono amp to not draw much current and the 4 channel to draw alot?

Any insight is greatly appreciated.
Thanks

I don't know about readings, but I can tell you that my head unit wiired direct to the battery ould draw enough power to drain the battery down in about 3 weeks. Unplug the fuse to the head unit and it would stay charged all winter. This is with a RF 500 watt amp also hooked up.

Your problem is obvious. You're playing Gwen Stefani on an offshore boat. Try some Zeppelin. Maybe Black Dog or Rock & Roll. Problem should clear right up.


Serously- you're not getting real info on current draw with the setup you have. If they work and smoke isn't coming out, they're OK. As far as the system-off current draws, those seem to be in line. The big question is why they're not on disconnects. That solves your main problem plus prevents your boat from burning up while you're not around. If you want to save memory, wire a small gel cell on an isolator.

All sounds about right.

Chris is 200% correct, Amps should be on disconnects.

D class, 1 channel amplifier are very efficient. Close to 90% efficient. This comes at a sacrafice to sound quality, but on the base end you don't notice. Look up amplifier classing to see why/how it works. That is why the sub amp draws much less current.

The four channel is probably a B class, or AB class, which is much less efficient, but a lot more musical.

Besides those loads on it, a battery will loose about 5% a month just sitting disconnected. Once you leave a battery low, it sulfates, and its harder to get back to the full charge. A battery disconnect switch is a must in a boat.

Now here is why you need a good battery charger. A 12 volt battery needs to be charged at 12.6 volts max. The only time the voltage should be raised to 14.7 is to equalize the cells. The alternator at 14.7 is ok because it isn't always on. Now, 12.6 is based on room temperature, and needs to be raised or lowered if its colder, or hotter. Any significant ripple effect (from turning AC 120v into DC will kill the battery too). This is why a good high quality battery charger/floater is necessary, with temperature compensation. Cheap ones have a lot of ripple in the out put and are harmful to your battery.

Ok for the amp readings. I'll take that as they are fine then. Was ready to pull out and send them back for a looky see.

So you guys are suggesting running the power leads for the 2 amps thru a switch like the battery ON-OFF switches?
Guess I never really heard of doing that, just going directly to the battery.

The on-board charger I have is a Guest dual bank 3 step charger, but only 5/5A output. PLanning to replace with a 30A
(20/10) output, also 3 step one. It might not be fully up to keeping up with the amps when cranking hard, but will should give me more play time do to the 20A vs 5A charging rate I have been using. Any size larger charger than the 20/10, the physical size is too big, such as the likes of the Charles Chargers.

Thanks!

I've seen lots of boats burn up. Electrical is often the cause. water, sometimes salt, poor maintenance- they all lead to corrosion which adds circuit resistance which can cause excessive heaing in the wiring and then you have fire. If you've never seen it, fiberglass burns VERY well.

I believe it's a CG reg that everything is on a disconnect.

The only thing directly tied to the batterys on the positive side should be the selector switch. Everything else should be wired after the switch, even the amps. You want every single load in the boat to be isolated and disconnected with the battery switch.

The only exception would be the auto bilge pump if kept in water, and memory wires for the stereo and gps if they need it. The memory lines should also be fused at the battery the same as the pump with accurately sized fuses.

Do the in-line fuses on each of the amps power act as a disconnect? Be the same concept as the radio memory and bilge pump leads. Just outta curiosty. Will go the switch though, not a hard install.
Was going by the instructions, of direct wiring to the battery with the fuses right at the battery. But these are automotive amps, not the marine version. Possibly the reason of no mention of a disconnect??

Thanks again!

I didn't know that about a disconnect on the amps either. I always just had the amp fuse less than a foot from the battery.