Dedicated/Isolated Battery for Stereo - question

[WickedPorter]

Howdy everyone, hopefully a rather quick question here ...

I have a dedicated and completely isolated, i.e. standalone, battery for my amps. The head unit is still powered off the primary / main battery. This set up works great for me; as if I completely drain the stereo battery, my primary is untouched, I can still start the engines and head back (hasn't happened yet, but I bet it will).

With this, the remote turn on wire from the head unit doesn't work to power on the amps (assuming it's a problem with having the headunit on a separate battery). So, in order to turn the amps on, I use fused switches and a small jumper wire from the 12v input to the amp's remote turn on. This works fine, BUT ... when powering on the headunit, I get a rather disturbing and startling POP from the sub/speakers.

I can deal with the popping sound, although it is a bit annoying. The system works perfectly fine aside from this, sounds fantastic and has no noise. My concern is: will the pop/thump hurt the speakers at all?

Sub is a bazooka tube with built in amp (not too concerned about this thing)

In-boat speakers are MX650s powered by a JL Audio XD400/4v2 and (4) JL Audio MX650s (this is what I'm concerned about)

I can run the headunit power to my isolated battery if necessary, which I think will solve the problem with the remote wire, allowing the head unit to power up the amps with proper timing so there are no pops.

 

[subysti]

So do you have 3 batteries? By main battery do you mean the standard house battery used for the stereo and not the starting battery? The way it's worded it sounds like you're using 3 batteries. My question is why don't you use the normal 2/3 battery setups that everyone uses? This would solve all the problems and you don't have to worry about killing your starting battery or your amps.

 

[WickedPorter]

So do you have 3 batteries? By main battery do you mean the standard house battery used for the stereo and not the starting battery? The way it's worded it sounds like you're using 3 batteries. My question is why don't you use the normal 2/3 battery setups that everyone uses? This would solve all the problems and you don't have to worry about killing your starting battery or your amps.

Sorry for the confusion ... the boat came with one battery for everything (2013 AR240), I added another single/standalone battery specifically/only for the JL amp and the Bazooka amp, so now I have two batteries total in the boat.

 

[Chuckbig]

You don't have a common ground, this causes your remote cable to be ineffective. You really want the electronics all on one power source. They really aren't made to handle this type of setup. Dissimilar grounding is bad and could be a fire hazard, given the right (or wrong for that matter) conditions.
Edit: all of the electronics that are tied together on the same power source.

 

[WickedPorter]

You don't have a common ground, this causes your remote cable to be ineffective. You really want the electronics all on one power source. They really aren't made to handle this type of setup. Dissimilar grounding is bad and could be a fire hazard, given the right (or wrong for that matter) conditions.
Edit: all of the electronics that are tied together on the same power source.

You are correct in that the head unit does not have common grounds to the amps... and I believe this is causing the popping sound. My original question was: could the popping sound harm the speakers? I don't think it can, it's not that loud, but just want to make sure.

There shouldn't be a fire hazard here ... the runs to the amps from the battery are all less than 2ft 8ga wire. I have (2) WetSounds (WW-CB60) 60amp fused switches which are powered off when the system is not in use.

If the speakers could be harmed, I will simply run new switched/fused power and ground from the head unit to the amp battery, so the entire stereo system is served by my "stereo" battery. I don't want to fish anymore wire through the boat though... my back hates this idea and since I have to live with my back, I do too.

 

[subysti]

Why not just add the charging relay to be safe. I guess its hard to say if it will be damaged without hearing it but it cant be good.
https://www.amazon.com/Blue-Sea-Systems-Add-A-Battery-Kit/dp/B000RZNP5K?th=1

 

[Jgorm]

Why not just add the charging relay to be safe. I guess its hard to say if it will be damaged without hearing it but it cant be good.
https://www.amazon.com/Blue-Sea-Systems-Add-A-Battery-Kit/dp/B000RZNP5K?th=1

That's an expensive solution! I use a $10 50a bosch relay with a switch for always connected, connected when engine on (default), and off. I have my rv setup like this, but with a larger contact relay.

 

[tdonoughue]

But to get to the OP question: Yes, the popping can damage your speakers. The worse the pop, the more the damage. The more frequent the pop, the more the damage. This is not instant or anything (not like one pop blows your speakers), but in a pop you are usually bottoming out the cone, which over time will crack it and the fine wires in the electromagnets driving the speakers. After years running sound in the theatre, hearing those pops always makes me cringe...

 

[Julian]

If the batteries don't have a common ground, I would add that first and see if that solves the problem....its cheap and no harm from it at all.

 

[WickedPorter]

Hi all, thanks for the info!

I went ahead and plumbed new power/ground to the head unit, it's now powered off the dedicated stereo/amp battery, so the entire system is now ran from my trusty Optima D34m.

No more popping, remote turn on works, and stereo stays running during engine start. All is awesome now. And this is my first experience with JL Audio... all I can say is, OMG. Sounds amazing!!!

 

[addisonm06]

Why did you choose the D34M as a house battery to power the accessories? That seems to me to be more so a starting battery and not a house battery. Just curious.

 

[Jgorm]

Why did you choose the D34M as a house battery to power the accessories? That seems to me to be more so a starting battery and not a house battery. Just curious.

I think that the deference between deep cycle and staying is blown way out of proportion. I ran my rv on the Wal-Mart car batteries it came with for 5 years. I switched to high end Trojan deep cycle and hardly noticed an improvement. This is based on my meter that records amp hour use and voltage. The number one rule is don't ever run it less that half capacity. Ideally keep them over 12v all the time. 11.5v is dangerous. Get down to 10v 5-15 times, or get to 8 a couple times and three battery is shot. I understand the theory on thicker plates, bla bla,, I've read hundreds of pages on 12v battery technology. I have dual or triple stage chargers on anything I don't use weekly.

 

[WickedPorter]

The Optima D34M is a dual purpose deep cycle with a manageable weight/size and excellent reserve capacity that I was able to purchase new for just under $200. I don't plan on ever discharging it "too far"; using it solely for a moderate sound system with a JL XD 400/4 and 600/1, and is charged with an on-board Minnkota 315D digital charger after every outing (and sits on charger in my house all winter). Hoping to get a few years out of it at least.