Running power wire direct off alt?

[Julian 10+ year member]

When going from my front battery to big 3 to rear to stright off the alt I noticed .3 volt difference... but granted I have a huge battery bank in the rear so I dont rely on my front battery

 

[bubbagumper6 5,000+ posts]

Guys, guys....
The alt and battery are connected. It's the same point electrically. The alt supplies power when the engine is running, not the battery. It's totally OK to run the amp power off the alternator terminal. I have an install like that for 10 years without issues. Of course the "big 3" becomes even more important if you run the system without the engine running. Need to make sure the batt to alt wire is fat enough.

haha thank you...I was reading this thread thinking "surely SOMEONE has to have some sense"

 

[bubbagumper6 5,000+ posts]

[quote name='jolly_26']A lot of different opinions/theories on this and I'm still pretty lost, although @maylar is thinking exactly the same way as me now that I look at it more. It is not as if the battery will be excluded, it will just be a bit far away, and the positive and ground wire will have to be stepped up quite a bit.[/QUOTE]

The only person you need to listen to is Maylar...

 

[Boomsday 10+ year member]

Bunch of dumba$$ in this thread..smh ughh

 

[winkychevelle 10+ year member]

The only person you need to listen to is Maylar...

really i shouldve cleared this up before but it depends on the current draw if you will be drawing under 80amps u should be fine as the factory wires on the factory batt will suffice for the buffer anything more than that and you really should either a put the amps up front by the batts or b run a smaller batt by that amps. but reading you other post i was pretty confident that you were going to be running a small system. i have ran an arc audio se2300 at 2ohm mono off of my chevy silverados 145amp alt for about 3 years and the alt is still going fine even with the factory 8 gauge being the only thing connecting the alt to the batt.

i have had some good voltage drop when i get on it but i never really dog my system but its just two 12 inch morel ultimos why would i try and get loud they are barely even noticeable till u turn them off.

it really depends on the amount of current you are trying to draw

and yea ive noticed that i end up posting in everyone of your thread as well guess you are just one of the guys i think have valid questions or is active enough for me to post for

 

[NFrazier 10+ year member]

Do not run your power wire from the alternator directly.

 

[wenn_du_weinst 10+ year member]

alts are to float your batteries not provide a constant charge, you want to burn it up go a head and run it off the alt.

 

[Boomsday 10+ year member]

Do not run your power wire from the alternator directly.

They are already connected

 

[winkychevelle 10+ year member]

They are already connected

exactly **** people the alts on most new cars run continuously anyway. my 2011 cruze charged to 13.8 all the time and up to 15.4 under heavy load. same thing with my 07 silverado classic, and my 2012 versa is charging a continuous 14.2 volts so whats the difference

 

[NFrazier 10+ year member]

exactly **** people the alts on most new cars run continuously anyway. my 2011 cruze charged to 13.8 all the time and up to 15.4 under heavy load. same thing with my 07 silverado classic, and my 2012 versa is charging a continuous 14.2 volts so whats the difference

Whenever the car is running, the car's charging system is going to be 13.6-14.4, your car doesn't just run at 12.6v if the alternator is not outputting the bulk of its current output. The battery itself acts as a load on the charging system until the alternator cannot adequately supply the current draw of the vehicle and its accessories. You want the battery there to be able to handle the flux in current demand not the alternator itself.

Running the power wire to the alternator itself will subject the alternator and voltage regulator to voltage spikes that will harm and drastically diminish the life of the alternator. The battery, as stated before, can actually act as a crutch for the alternator during those voltage spikes.

Factory alternators rarely, if ever, supply meaningful current at idle. Factory alternators are 1. designed to run at about 80% of its charging capacity (i.e. if you have a 100a alternator, it was designed to have 20 amps of buffer after running ALL accessories in the car), and 2. don't produce meaningful current til => 2kRPM. Yes, the voltage will be ~14v but voltage is only part of the equation and not necessarily the important part.

Please read how alternators, batteries, and the overall charging system in your car works first.

To me it sounds like you don't have enough current supply and you're looking for an easy way to take a short cut.

 

[winkychevelle 10+ year member]

Whenever the car is running, the car's charging system is going to be 13.6-14.4, your car doesn't just run at 12.6v if the alternator is not outputting the bulk of its current output. The battery itself acts as a load on the charging system until the alternator cannot adequately supply the current draw of the vehicle and its accessories. You want the battery there to be able to handle the flux in current demand not the alternator itself.
Running the power wire to the alternator itself will subject the alternator and voltage regulator to voltage spikes that will harm and drastically diminish the life of the alternator. The battery, as stated before, can actually act as a crutch for the alternator during those voltage spikes.

Factory alternators rarely, if ever, supply meaningful current at idle. Factory alternators are 1. designed to run at about 80% of its charging capacity (i.e. if you have a 100a alternator, it was designed to have 20 amps of buffer after running ALL accessories in the car), and 2. don't produce meaningful current til => 2kRPM. Yes, the voltage will be ~14v but voltage is only part of the equation and not necessarily the important part.

Please read how alternators, batteries, and the overall charging system in your car works first.

To me it sounds like you don't have enough current supply and you're looking for an easy way to take a short cut.

yada yada i have yet to ever replace an alt so you can say one thing and i can say another what you arent seeing is that his battery is still connected to the alt and the amp its just more out of the way and yes electricity takes the path of least resistance but consider this

if you alt produces say 100amps and you car uses 60amp that leaves you with 40amps of extra current that you can use for what ever this is headroom left at the factory for upgrades like snowplows and warning lights and so on. now what you are saying is that while the car is on all the vehicles electrical draws power of the batt but really the batt with the vehicle on is above resting voltage so it cannot supply current until the voltage is below resting voltage. so what supplies the current? the alt!!! you are correct that the battery buffers voltage peaks but only a bit until you start dropping large amounts of voltage. and since his battery is still going to be inline with the amp and alt he shouldnt have any problems. its not like he is trying to run his system with no battery in the car.

and yea you can be snyde but idc this is the internet and we are all entitled to our on opinion. im talking out of experience i cannot speak for you im guessing you are as well

 

[NFrazier 10+ year member]

That's fine, you are entitled to your opinion. Also keep in mind that the battery acts as a "filter" in most cases to reduce any (if any) ac ripple that may be left from the rectification process. I just don't get the purpose. Why not go to the battery, upgrade your big three and call it a day.

 

[winkychevelle 10+ year member]

That's fine, you are entitled to your opinion. Also keep in mind that the battery acts as a "filter" in most cases to reduce any (if any) ac ripple that may be left from the rectification process. I just don't get the purpose. Why not go to the battery, upgrade your big three and call it a day.

his batt is in the front of the car which is mid engined the factory wire for the batt is probably 2 gauge and his fuses are probably in the back of the car running from the alt to the amp will prolly take 10-12ft of wire where running to his batt will be like 30+ft of wire running all the way to the batt and all the way back the the amp. which would be the best way but for a 600w system it isnt necessary

 

[NFrazier 10+ year member]

his batt is in the front of the car which is mid engined the factory wire for the batt is probably 2 gauge and his fuses are probably in the back of the car running from the alt to the amp will prolly take 10-12ft of wire where running to his batt will be like 30+ft of wire running all the way to the batt and all the way back the the amp. which would be the best way but for a 600w system it isnt necessary

I missed the mid-engined part. my bad.

 

[Worlddre 5,000+ posts]

how about we find out what the car in question is?