2nd Battery charging cable size

[F-137 Kong Ramch]

Hello all! I am installing a 5kW sub amp w/two 10s, w/an extra deep cycle battery. I have a concern...

If my sub amp requires two 0/2 positive leads and two 2/0 negative leads to my secondary battery, do I need two 2/0 positive leads between both batteries (and battery isolator) and two 2/0 ground/chassis connections on each battery, or can the charging cable for the secondary battery be just big enough to charge the battery? I don't want to bottleneck my system. Any and all help is greatly appreciated! Thank you!!! I don't want a car-B-q!

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[hispls 5,000+ posts]

I hope this isn't any kind of legit 5K amp as only 1 additional battery isn't going to cut it.

 

[djdilliodon!]

Would be way better off doing an alternator upgrade first. Which amp do you have?

 

[F-137 Kong Ramch]

I hope this isn't any kind of legit 5K amp as only 1 additional battery isn't going to cut it.

It is Mr. MusicMan new compact 5kW Amp. The builder said I wouldnt even need an additional battery.

 

[F-137 Kong Ramch]

Would be way better off doing an alternator upgrade first. Which amp do you have?

MrMusicMan mini 5kW

Would be way better off doing an alternator upgrade first. Which amp do you have?

Product Page | Mrmusicman Audio

www.mrmusicmanaudio.com

 

[F-137 Kong Ramch]

Would be way better off doing an alternator upgrade first. Which amp do you have?

I was looking at a SkyHigh 370A H/O alternator build for older Ford model. I guess that's where my next $1k is going!

 

[some dude]

Quick YouTube search showed a 3.8k doing 4200 watts at 1ohm. Looks like a legit amp. I've never heard of the brand.


What are you going to wire your subs at Ohm-wise?
That effects your electrical road map.

 

[djdilliodon!]

I was looking at a SkyHigh 370A H/O alternator build for older Ford model. I guess that's where my next $1k is going!

i have no experience with that amp but let’s say it’s a true 5k rms, you will 1000% need a new alternator cause the stock one won’t even be close to cutting it! An amp that does 5k rms with decent efficiency will pull around 450 amps plus by itself of current playing tones. With music it would pull around 350 ish amps all assuming you are playing it at high levels. You will need an upgraded alternator, upgraded battery in the factory location, and at least 1 extra battery added. The actual battery setup to go with will depend on how much run time you want them to have. Of course those of us with limited space can’t just be throwing 4 batteries in the back so we must come up with the best compromise. You will also want to run all 1/0ga ofc wire at the min.

 

[metalheadjoe 10+ year member]

Hello all! I am installing a 5kW sub amp w/two 10s, w/an extra deep cycle battery. I have a concern...

If my sub amp requires two 0/2 positive leads and two 2/0 negative leads to my secondary battery, do I need two 2/0 positive leads between both batteries (and battery isolator) and two 2/0 ground/chassis connections on each battery, or can the charging cable for the secondary battery be just big enough to charge the battery? I don't want to bottleneck my system. Any and all help is greatly appreciated! Thank you!!! I don't want a car-B-q!

Since no one else answered the question... The highest current flow is between the rear battery and the amp, so double runs there is a good idea. Sizing between the front and rear batteries depends on current capacity of each battery and alternator output. For a stock alternator and typical front battery, a single run will be fine. You can never have too much conductivity, so more wire is always better.

In my vehicle, I have two runs of 1/0 from the rear battery to the amp and one run of 1/0 from the front battery to the rear battery, and it works great. I would start with that. You can always add more if needed.

Don't bother with a battery isolator unless you plan on running it long with the vehicle off. They are meant to prevent you from draining your starting battery and being stranded.

 

[F-137 Kong Ramch]

Quick YouTube search showed a 3.8k doing 4200 watts at 1ohm. Looks like a legit amp. I've never heard of the brand.


What are you going to wire your subs at Ohm-wise?
That effects your electrical road map.

I'm wiring 4ohms.

 

[F-137 Kong Ramch]

i have no experience with that amp but let’s say it’s a true 5k rms, you will 1000% need a new alternator cause the stock one won’t even be close to cutting it! An amp that does 5k rms with decent efficiency will pull around 450 amps plus by itself of current playing tones. With music it would pull around 350 ish amps all assuming you are playing it at high levels. You will need an upgraded alternator, upgraded battery in the factory location, and at least 1 extra battery added. The actual battery setup to go with will depend on how much run time you want them to have. Of course those of us with limited space can’t just be throwing 4 batteries in the back so we must come up with the best compromise. You will also want to run all 1/0ga ofc wire at the min.

Thank you for your input. I seriously appreciate it!

 

[F-137 Kong Ramch]

Since no one else answered the question... The highest current flow is between the rear battery and the amp, so double runs there is a good idea. Sizing between the front and rear batteries depends on current capacity of each battery and alternator output. For a stock alternator and typical front battery, a single run will be fine. You can never have too much conductivity, so more wire is always better.

In my vehicle, I have two runs of 1/0 from the rear battery to the amp and one run of 1/0 from the front battery to the rear battery, and it works great. I would start with that. You can always add more if needed.

Don't bother with a battery isolator unless you plan on running it long with the vehicle off. They are meant to prevent you from draining your starting battery and being stranded.

This is what I was hoping. Thank you very much for your detailed response. I appreciate it!

 

[some dude]

So at 4 ohms your amp is putting out around 1200 watts?
I'm thinking 1 run of 1/0 gauge OFC would be more than enough. You can use 4 gauge OFC and be fine. Someone chime in to confirm.

 

[metalheadjoe 10+ year member]

I'm wiring 4ohms.

Why not wire to one ohm? You could achieve the same output with a smaller amp wired to one ohm. If you want the big amp for future planning, you can still wire your subs to one ohm and turn down the gain to a level your subs can handle. There are no drawbacks to wiring to the lowest load your amp can handle (others disagree, but I've yet to hear a valid counterargument).