front battery voltage no matching to battery bank

[knockinthastreetzof608 1]

well my batterys i have is 1d4300 in the front and 2 3100 in the trunk i have aso a mechman 270 alt for my car my voltage reads in the front 14.1-14.2 but since my voltmeter in the back and off my amp it shows at the highest 13volts why could that be i just charged the batterys as well so idk any help

[stevemead08 752]

is your volt meter calibrated?

[Dangrebel 89]

most likely an uncalibrated volt meter. i myself had to calibrate mine. good luck!!

[jonbearsmt 919]

the back will always be lower... more runs of wire normaly help

[shizzzon 461]

this is why it's almost necessary to run a ground cable from the alt's casing or from the ground of the batt up front to the rear ground post on battery bank.

IF you run from batt to batt, the alt needs to be grounded directly to starting battery for best effectiveness.

[Ohjay 116]

this is why it's almost necessary to run a ground cable from the alt's casing or from the ground of the batt up front to the rear ground post on battery bank.

IF you run from batt to batt, the alt needs to be grounded directly to starting battery for best effectiveness.

Why would the alternator ever need to be grounded to the battery directly?

[jonbearsmt 919]

i have a full frame car, so for me, the big three..plus a alt ground to frame in front then i just go right off the frame in the rear to my battery banks..

shizzon runs unibody frame, and i think its best to run a ground front to back .. less resistance ... a uni body has welds upon welds that add resistance,

[Ohjay 116]

The battery is grounded to the body/unibody which is bolted to the frame/subframe, the frame/subframe is bolted to the block and the block is obviously bolted to the alternator which creates a large ground area and you could wire to any of the above mentioned components successfully.

[Ohjay 116]

In reality, you already have a ground from the battery to the alternator.

[jonbearsmt 919]

im not going to go on and on ..

a cars electrical system is designed to support the needs of the fuctions the car .. with in reason plus a little more.,but IMO when you add a tremendous load then you need to upgrade the back bone....

if you add HUGE wheels then you would get better breaks, and lower gears,

if you went hiking you would wear boots,

if you were going to sleep with a prostitute you would wear a condom.

if your having problems just keeping needs in mind that may help you along your adventure.

[steveo50 3]

Oooo big jon impresses me 2thumbs up

[steveo50 3]

-the hooker thing your still guna get aids

[Ohjay 116]

There's no need to go on and on, from the little information we have to go on, it's pretty tough to even take a stab in the dark. Who knows what could be the problem.

On a positive note, I saw several wild today so there should be plenty of food next weekend.

[knockinthastreetzof608 1]

is your volt meter calibrated?

yes it has been calibrated the 1st time i got it, with my fluke 115

most likely an uncalibrated volt meter. i myself had to calibrate mine. good luck!!

answered above

this is why it's almost necessary to run a ground cable from the alt's casing or from the ground of the batt up front to the rear ground post on battery bank.

IF you run from batt to batt, the alt needs to be grounded directly to starting battery for best effectiveness.

well in my mechman alt there a ground stud that matthew already made on it , so you think if i use that ground and run it all the way to the back batterys i should see an increase?

all i have now is the big 3 and one full run(meaning one postive and negative post of my d3400 straight to one of my 3100)

i have a full frame car, so for me, the big three..plus a alt ground to frame in front then i just go right off the frame in the rear to my battery banks..

shizzon runs unibody frame, and i think its best to run a ground front to back .. less resistance ... a uni body has welds upon welds that add resistance,

how do i determine my car from being a unibody frame to a full frame car? the car im having trouble with is a 05 ford mustang coupe

[shizzzon 461]

this is no question about it man.. It's the ground, trust me.

Think about it..

IF you had a bank of batteries in the back and you wanted to make a buss bar for them, what material would you choose-

Copper

Aluminum

or...

Steel...

Sure as hell wouldn't choose steel.. But that's what you and everyone else is using for conductive grounds in their vehicles.

[knockinthastreetzof608 1]

this is no question about it man.. It's the ground, trust me.

Think about it..

IF you had a bank of batteries in the back and you wanted to make a buss bar for them, what material would you choose-

Copper

Aluminum

or...

Steel...

Sure as hell wouldn't choose steel.. But that's what you and everyone else is using for conductive grounds in their vehicles.

my answer is steel lol jk copper will be best but you think if i do a single run from my alternator ground to the one of my rear d3100 i will be fine? or should i do 2 runs and place one ground on each battery?

[shizzzon 461]

all you need is ONE run and that's it.

The ground we all use "works" already, it just needs a helper to keep the voltage up, that's what the cable is for.

If you have a long run of wire already or a set of jumper cables, u can temporarily connect it to the alt and battery bank and see for yourself.

[knockinthastreetzof608 1]

all you need is ONE run and that's it.

The ground we all use "works" already, it just needs a helper to keep the voltage up, that's what the cable is for.

If you have a long run of wire already or a set of jumper cables, u can temporarily connect it to the alt and battery bank and see for yourself.

aww i understand the same concept on the big 3 when you want to add on the cable and not replace it with the 0 gauge correct? but thanks shizzon i will do it now you think also a another run of postive will help as well? or am i just wasting wire?

also i plan on walling my mustang and getting a bigger amp (atomic 7k) and 2more d3100's you think i will have to do anything different in the wiring?

[shizzzon 461]

just add that one run of ground right now and see how that goes.

You don't need imo 4 d3100s for 7kw, 2 is plenty.

[Dictator 39]

Every spare battery you hook up takes 10amps of current away from the alternator....the batteries are their to keep you from going below 12volts!!!!

[knockinthastreetzof608 1]

Every spare battery you hook up takes 10amps of current away from the alternator....the batteries are their to keep you from going below 12volts!!!!

full tilt on 3500watts i do drop below 12volts

[shizzzon 461]

if u currently drop below 12v with 2 d3100s, then you are about to kill them...

They need to be charged separately.

[Dictator 39]

if u currently drop below 12v with 2 d3100s, then you are about to kill them...

They need to be charged separately.

Yup.

[knockinthastreetzof608 1]

okay i will do that, now im trying the run from alt ground and doing another run of postive from my d3400 to my d3100 as well

[knockinthastreetzof608 1]

well now its werid i started my car up and it climbed up to 13.8 and after i went full tilt on music and then turned it down it stayed at 14.0 but im still going to do everything that was mentioned here thanks