I doubt there is a difference when looking at power requirements, but sometimes, noise can be addressed this way. Also, the tap may be another failure point to keep an eye on.

 

you can probably just run a single 4 gauge and split it to both amps. What amps are they?

 

I bought everything cheap but new from ebay. I'm not going for competition, super wattage or vibrating the neighborhood, just good sound inside the car.

Alpine PDX-F4 (400 total watts) under the passenger seat, Alpine says 4 gauge recommended but it seems overkill to me, but to be safe I'll go with the recommended 4 gauge power and ground.

Infinity Basslink (200 watts) in the trunk, rear left corner. I had a Basslink in another car in the past and it sounded great inside the car. I could probably run a 10 gauge but I'll go ahead and run an 8.

I've also just installed 4 new Polk speakers and a Pioneer head unit. Most of it's done already except both amp powers and grounds, and all the Basslink wiring (RCAs, control knob for dash, etc). I'm just about there.

 

There is no disadvantage (or advantage) to running two separate power cables - one for each amp. Go ahead and do it.

 

This is what I always thought, but why do the SPL guys run multiple power lines to amps? I guess at the wattage I run and the wattage they are at, they are trying to eek out the very last drop they can? In some cases, you see these guys run those metal bars off the positive and will have 4 or 5 positive runs back to each individual amp.

 

I need a 4 gauge for one amp and an 8 gauge for another. Other than looks is there any disadvantage to running two separate power wires, one 4 gauge and one 8 gauge, instead of running one 1/0 gauge and splitting it into one 4 and one 8 with a distribution block?

Any pros or cons either way?

In terms of power supply to the amps, it doesn't really make any difference (assuming the wiring in question is capable of handling the amps' current draw).

Instead, the issues here are more practical. How will u connect 2 power wires to the battery, and is that approach easier, cheaper, or otherwise better than a distro block? 2 power wires will also require separate fuses or circuit breakers, so don't forget to factor in that. Is it easier to run 1 big wire or 2 smaller wires thru the firewall of your car?

My thinking is that a single 0ga to a distro block is the more practical solution.

 

This ^^^^^

 

I just ran into this with my current install due to changing my mind. I already had OFC 4 awg and OFC 8 awg on hand so I ran two wires.

If you haven’t bought anything yet, just buy the 0 awg and run it to a fuse/distribution block. It allows for future expansion, its easier to work with just one wire while your back is aching leaning over the engine bay, and when all is considered (cost of both wires, waste x 2, connectors x2, etc.) the single 0 awg is probably cheaper.

 

I have 2, 1 1/0 and 1 4 ga

 

I have a smaller agm battery in the trunk that acts as my distribution block. Single run of 1/0 from the main battery (which is actually the same agm) - two amps each with their own 1/0.

In my last setup, my amps were all 4g input, i ran a single 0g from the front to a $60 kinetic hc800 agm battery and used it as a distribution block.

The advantage in this case is the added battery for surge requirements and negates the real need for heavier charging cable since the amps actually run off the local battery. Plus it’s cheap and easy to do relatively speaking.


Sent from my iPhone using Tapatalk

 

Unless you're planning on running some big wattage amps, like competition type stuff, you'd likely be fine running just one good quality 4 AWG wire from the battery back to wherever your amp is. And even then if you needed to add a junction and provide another (split off) 4 AWG wire to a second amp, I can almost guarantee you'd be fine.

That being said, you may get more peace of mind using a 0 AWG. There are so many options for junction blocks that having the larger 0 AWG as your feed might help you sleep at night. As to whether or not you really need it as opposed to a good quality 4 AWG, probably not.

Just get quality wire, make good quality clean connections, and you're gold.

But I certainly wouldn't run 2 separate wires from the battery, only for the reason that it would be more complicated, bigger pain in the ass than just the one.

 

Thank you to everyone that replied. I believe I am going to try and run the 1/0 and split it with a distribution block.

I am currently down as I cracked a rib last week so will not continue with my install until I heal up in a few weeks. I already worked on it once and got worse, so not again. Not having a garage or a place to work complicates things as I have to work wherever I can, keeping tools, wires, etc in the trunk until I'm finished. It's a pain just having a place to work on it.

Sure wish I had a garage.

I have a few more questions I will probably be posting and appreciate all information, opinions and advice.

 

I also just run one large cable from the front battery to the trunk where I have a second and sometimes third battery.

I like this approach because it's only one penetration through the firewall, preferably through and existing rubber boot.

The single larger cable is more likely to be of better quality/fire resistance/abrasion resistance. I use neoprene/fiberglass jacketed welding cable, usually 1/0.

I find it easier to neatly run/hide one large cable.

Also you get surge ability with a battery in the trunk. I use a deep cycle so if I leave my system on my car will still start. I went three days(like 200 miles) with a bad alternator when I had three batteries. Then I upgraded to a high output alternator.

Use the second battery as the distribution point. Usually deep cycles have nice threaded connections.

 

Also you get surge ability with a battery in the trunk. I use a deep cycle so if I leave my system on my car will still start. I went three days(like 200 miles) with a bad alternator when I had three batteries. Then I upgraded to a high output alternator.

G'day all...I forgot I was a member here until I received a random email from DIY! Anyway I noticed this query and was interested...

Apologies to the OP as this query is not related to your question (FWIW I think it has been well answered by others and I agree with what's already stated!).

However this comment has me intrigued in a number of ways...could I ask if you use a regulator/solenoid between the front battery and rear battery(s)? That would help. 'Surge ability from a battery in the trunk' is an interesting concept I have not heard of before either...always looking to learn new things!

Cheers

 

is there a problem if the trunk battery is different from the car battery?

 

If they were the same it would be a saturn ion.

Just kidding, I couldn't resist. As long as they are both lead acid batteries with a nominal 12volts you should be fine. I usually put a marine deep cycle in the trunk. They have a lot more capacity. In the case of my old car the capacity of the deep cycle was more than twice as much as the starter battery even though it was only one and a half times the size. Generally marine deep cycles don't output as much surge current but will run much longer. You can start a four cylinder reliably with a marine deep cycle if your starter battery goes.

If you have multiple batteries I would reccomend testing them individually every couple months. In my case I would disconnect the deep cycle for a couple days and run just the starter. Then I would disconnect the starter and run just the deep cycle for a couple days. Even with 12' of 1/0 the deep cycle would spin the starter audibly faster than the starter battery.

My current vehicle doesnt have a deep cycle and I only got my subs in it a couple months ago. Twice now I forgot the amp on all work week and the battery went dead. I think when I put in a deep cycle it will be hooked up with a diode and only recieve power from the charging circuit when the vehicle is running. The amp will be connected to the deep cycle. This way the amp can run the deep cycle dead but not the starter.

 

with a diode your amp will still be able to run them both dead.

 

If I point it the wrong way yes. In my setup the diode would allow the deep cycle to always send power to the starter battery. Once the vehicle is running the solenoid would connect the deepcycle to the starter bypassing the diode to allow it to charge.

As far as mixing deep cycles and starter batteries being bad, I'm not saying its ideal. Im just saying that with several 4 cylinder cars and my ssref500/2-infinity kappa perfect 12s it worked fine for years. Different chemistries yes but they both have the same nominal working voltage. The deep cycle can be drawn a good bit lower repeatedly more reliably but that didnt happen more than a handful of times. Yeah the best would be a second starter in the trunk which matches the front battery but I didnt want to buy two identical batteries, just one.

Again, not saying this setup is 100% "correct". I am just saying it stopped me from having a dead battery and needing a jump while also making wiring easy and helped provide surge current.

I will say you need to cover the battery terminals properly though. In my last car I had my golf clubs in the trunk......

 

:snacks:

 

^This...

I have a decent enough knowledge of car audio (I have run a dual battery many times before); and I could see a few flawed/ambiguous statements and was after some clarification. Off we go....

I tried to comment previously thanking you (Grinder) for the links but it apparently was deleted immediately by mod's. No idea why...don't know if this will get through either...

Peace everyone.

 

in no order:

-it doesn't matter how you run your wire as long as the entire length from source to load is adequately sized and fused appropriately.

-don't mix batteries. Just don't. It will technically work, but you reduce the life of the bank and you probably won't see any gain from just running the battery with the higher resting voltage by itself. Also stop running deep cycles if anyone is doing this. Audio demands large spikes in current for brief periods.

-some caps work, and they work very well. None of the ones branded for car audio do. You can completely remove your battery and replace it with a bank of supercaps if you want, although it will be quite a bit more expensive to get the equivalent peak discharge current. Making a lithium battery bank would likely be comparable in cost and provide much higher discharge capability though. Supercaps were all the rage maybe 8-10 years ago but have been replaced as lithium tech prices go down.

-caps can help filter a/c ripple on your power lines. You already have some in your alternator to do this, however they don't completely eliminate it. Noise should not be a concern though, as you also have a bunch of capacitance inside your amp to act as a filter. Inductors can be used to filter high-frequency noise, but they need to be inserted in series as opposed to a cap which is run in parallel to get a similar effect, and you don't want a large inductor on your power/ground line.

-I admittedly skipped over some of the discussion on solenoids/isolators/diodes, but there's never really a good reason to use any of them.

 

Not sure if it helps any but just some food for thought...

In regards to using a trunk battery as the distributor block. I decided to swap out my trunk secondary battery (XS Power) for the FluxCap (power supply not a capacitor) from Harrison Labs.

Alternator and primary battery are upfront with a single 0 guage cable ran to the trunk/FluxCap and then connect amplifiers/gear straight to FluxCap (which has screw post terminals).

*if you want to maintain a secondary battery bank or banks, the FluxCap can also function an isolator relay.