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Av gets electric upgrade, maybe.. HELP

Wesmills24

New Member
Joined
Jan 13, 2021
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5
So I recently switched out the stock alternator for a high output one from mechman to be able to meet my stereos high demands about 6000 watts between replacing all the door speakers and adding an aftermarket subwoofer and amplifiers for both(I like my music real loud lol). I went with the 370 amp elite series plug and play from mechman. I followed their exact guide for my AV as far as how to wire it since it's slightly different due to this "battery current sensor" I've always had this issue where my voltage always sits at 13.9v. On start up, after it's warm, with nothing running, with the lights on, heated seats etc. What I'm getting at is it's ALWAYS 13.9 no matter how much current I draw. I've replaced this "battery current sensor" in hopes to fix my issue because I was told that if it's getting a bad signal etc that it puts it to a default of 13.8-13.9v. even when I unplug the sensor nothing changes...
 
Ignore the video that was when I was trying to run 2 batteries and removed it after I learned about that sensor
 
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What year do you have. ??
And how did you run the alternator ground wire, to the block then to the ground on the battery
 
It's an 07. Basically what I'm trying to do is bypass the RVC completely. A constant 14.4-14.7. unplugging it also makes it 13.9v
 
If the '07 has the "smart" alternator setup you will be unable to bypass it alarming without reprogramming the BCM. It looks for certain reactions to its adjustments and if it doesn't see them it will trip a code. Also, why are you trying to max out the voltage? If it bothers you THAT bad, add another alternator and battery. Run the second battery at max voltage and be done with it. I did this. All it costs is a bracket since you already have a second alternator, maybe a bracket and a second battery(I say maybe a second bracket because I believe you already have the bracket for the second battery from the factory). Would suggest staying away from Optima batteries and just get a good quality AGM. There are some characteristics of the Optima batteries that make them undesirable in a daily driven car or truck.

If you have a modern, high quality amplifier they don't care what the incoming voltage is. Only older or cheap amplifiers care what the incoming voltage is anymore. Modern amplifiers are designed with the smart alternators in mind and won't benefit from the higher voltages you are proposing. Running your voltage high will only cost you gas mileage and not benefit you at all. Modern Amplifiers use Pre amplifier capacitors to store energy for the high requirements of a sudden high output such as a heavy bass beat. These basically make a large Capacitor obsolete because they accomplish the same function. These also regulate the voltage down to match the capacitors so a higher voltage will do nothing for you. I would assume if you have a 6000 watt system that you are using good quality, modern amplifiers. If you are using cheap amplifiers, no way you are running 6000 watts.

If we consider: Volts * Amperage = Watts and to consider how many amps we need we switch this around to amperage = watts / volts. So we plug in your numbers at 12 volts: Amperage = 6000 / 12 = 500 amp. This will need a very large wire.
Same using 14 volts as an easier to use number would still be 6000 / 14 = 429 amps which still needs a huge wire.

What size is you alternator again? To output at 6000 watts you would need AT LEAST a 550 amp alternator if we assume you had a 120 amp alternator from the factory. This assumes a constant 6000 watt usage.

Please note that this does NOT take into account voltage drop in the wire which is about 5% per foot in a standard automotive wire. This number is not static however. The more amperage you put through the wire the more voltage drop you will get once you get past the thresh hold of the wire. So distance is a factor as well.

Lets assume you are using a high quality wire which is only a 2% drop and you are running 15 foot of wire to get from the battery to the back of the truck where you are splitting off your wire to different amps. Lets look at the size wiring you would need.

Using https://www.wirebarn.com/Wire-Calculator-_ep_41.html

At our 12 volts, 6000 watts equates to 500 amps. So if we look at the following gauges your drop in voltage would be:
4 = 1.25 volt drop
2 = .8 volt drop
1 = .72 volt drop
0 (1/0) = .5 volt drop
00 (2/0) = .4 volt drop

At our 13.8 "normal" voltage, we need 429 amps to get the same 6000 watts. So the change in wiring would be :
4 = 1.1 volt drop
2 = .7 volt drop
1 = .64 volt drop
0 = .43 volt drop
00 = .34 volt drop

These are significant drops and will likely heat up your wires and burn them. You can play with that calculator and see what you can do about increasing the number of wires to get your amperage going.

If you are running multiple amplifiers you will be able to get more wires to run them each on their own. But this is a massive under taking.

We didn't even consider the efficiency of the amplifiers here. Older amplifiers were only 50% efficient so if you were putting out 6000 watts you had to send them 12000 watts worth of power. They would put off 6000 watts of heat and 6000 watts of audio energy. I believe even if you get the very expensive, very efficient amplifiers they are still only 90% efficient which means your still up closer to 7000 watts.

If you are truly putting out 6000 watts with the most efficient amplifiers out there you need to be running somewhere around 3 alternators with one for your truck and the other two running your audio system. And each would require 2 2/0 wires to properly power up your amplifier. Assuming 300 amp alternators. And they won't use the 13.8 voltage so your 12 volt figures would be the correct ones to use.

If you are running a single alternator and the truck is dialing down its voltage then you have no where near 6000 watts in your truck and your alternator is doing its job properly.

I am running around 2000 watts in my truck. With high quality amps. I have 1/0 wires running to them and have it engineered for a minimal voltage drop. I have a cheap 350 amp alternator in as the second alternator and a second battery. This second alternator is running at full speed all of the time. My main alternator and battery run the rest of the truck and will operate as intended. The bracket cost me $300. I took out the power tap that was there and install my ground wires to the block that held it. The power tap I am talking about was where the Alternator was connected to the original power wire. I have replaced the alternator wire with a 1/0 wire directly to the battery. A bit of overkill but you can never have too big a wire. My amplifiers are 25 years old and are not regulated so they will benefit from the higher voltage. They also don't have the large capacitors in the prestage but with the large wiring and a good quality AGM battery my subs still hit hard as heck. Enough that change won't stay on the hood for long.

Good luck.
 
Modern yes, high quality I wouldn't say so at least for the mono. It's a taramps bass 5k and they're known to have issues when they don't get their 14v but they do put out their rated power and then some (feel free to look them up). My 4 channel is digital designs so I'm not worried about that. Running a pair of sundown NSV4 18s. Wire is quality over sized 1/0 ofc from sky high. Dual 1/0 to the amp dual 1/0 for the charge wire. My main reason for trying to figure this out is because I'd like to ditch the agms and switch to cmax or headway cells. I've been looking into running a dedicated electric system for my audio only but I'm not really sure to go about it. How do you set the voltage for the second alt if it's not running through the bcm? Pretty sure it's max voltage is 20v off the alt +could be wrong here) but I'm pretty sure smashing 20v constantly is not a great idea. And finding an external regulator for it seems damn near impossible. I've contacted mechman, xs power and a few other companies that make voltage regulators but they all said they don't have one that is compatible with my vehicle.
 
You are correct in that Mech, XS and SMD, the three go tos for this type of application don't make a regualtor specifficaly for this vehicle or anything in a DR44 2 wire case (stock AV configuration) for that matter. The only way that I know of to achieve a constant 14.4+ on a single alt setup is by swapping to a D/AD case 4 pin alternator or DR44 case 4 pin alt and using a separate ignition triggered relay and external manual regulator (like the XS Power XPS 313 or 320 harness kits). That's what I did but in a dual alt setup. I upgraded the factory alt to a Nations 260 (DR44 2 pin case) and ran all of the existing vehicle electronics from it as well as powered my 4 channel pushing my rear door 6.5s and tweets on the A-Pillar and a small 2 channel running the front door 6.5s from the 13.9v supply from alt 1 and it's associated battery.
I used a 2nd alt bracket and ran a second alt and battery, a Nations 350 (DR44 case but 4pin D/AD wiring) controlled by the external relay and harness/regulator to push the 4 channel powering my 6.5s and tweets I installed in custom kick panels, and a pair of monos for the subs at 14.8v from Alt and Battery 2
The harness mentioned above allows you to regulate the output between 11.7 and 15.5v. I know WARR Performance makes a 4-pin to 2-pin adapter that lets you run a DR44 case 2 pin alternator off of a vehicle with D/AD wiring however I've never seen the inverse. If you wanted to keep the alt you have it might be possible to achieve a 14.4+v output but at the very least you would need an ignition controlled relay like the Beuler BU-5088 to trigger the alt, then externally regulate the alt via the available D/AD harness and then plug that into the D/AD to DR44 2 pin adapter.
In short, without a BCM reprogram there is no way to defeat the existing auto-regualtion of the output of a factory wired DR44 case 2 wire alt if retaining the factory trigger. The attached photo is following the initial mock-up of the Nations 350 install (prior to swapping the stock out for the 260 and final wiring). alt.jpg
 
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