Fusing mulitple batteries in parallel

[jco1385 5,000+ posts]

you missed the memo?

me = not argumentative today //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

but my "body" ground on my car in the trunk (uni-body car -> no battery up front) spins my starter like the bish is brand new, and it's 15y/o

 

[loopkiller 10+ year member]

you missed the memo?
me = not argumentative today //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

but my "body" ground on my car in the trunk (uni-body car -> no battery up front) spins my starter like the bish is brand new, and it's 15y/o

How much amperage does it take to start your car? Have you measured it?

 

[jco1385 5,000+ posts]

nope. and my amps are straight off the batt's in the back.

 

[loopkiller 10+ year member]

nope. and my amps are straight off the batt's in the back.

You said your starter spun like a beotch... //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

Your starter is pulling from the POS+ post of your battery and returning the NEG- through the chassis to the NEG- post of the battery. Depending on how much current you are pulling to start your car, you will see an increasing voltage drop due to the poor conductivity of the welded steel. But, since your start is less voltage dependent than your audio system, this is probably acceptable.

Now where you will have an issue with your grounds is when it comes to the alternator making the power to drive a given device, such as your amps. If your amps are receiving power on the POS+ wire from the alt, they have to give back those same electrons on the NEG- side to complete the circuit. If the NEG- path back to the alt is welded steel, guess what happens... Voltage drops. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[jco1385 5,000+ posts]

my starter do be spinning like said beotch. i haven't measured the draw of it though.

and it's pulling thru ~20ft of 1/0 for the pos, and the chassis for the neg (which it does anyway. it doesn't have a neg wire to it)

 

[loopkiller 10+ year member]

my starter do be spinning like said beotch. i haven't measured the draw of it though.
and it's pulling thru ~20ft of 1/0 for the pos, and the chassis for the neg (which it does anyway. it doesn't have a neg wire to it)

I was just wondering how many amps it took to start your car. I have a little Honda that only pulls about 100A when it is warm. I haven't checked in the cold because my car is garaged.

 

[jco1385 5,000+ posts]

tell me how to test (my mind = no-go today) and i will

 

[Buck 5,000+ posts]

yes. ~18" from each battery, between the batteries.
it should be front battery --> 18" wire --> fuse (300-350A) --> wire --> fuse (300-350a) --> 18" wire --> rear battery

I can't believe you changed your avatar...

 

[jco1385 5,000+ posts]

I can't believe you changed your avatar...

yeah //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

it took me a lot of thinking about it before i did. i had badass ava. but this one is cool.

hey buck, someone is staring at you //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[loopkiller 10+ year member]

tell me how to test (my mind = no-go today) and i will

Amp meter clamped around the POS+ wire //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[jco1385 5,000+ posts]

i don't have a clamp meter. oh wellz

 

[95Prober 10+ year member]

Well. I grounded my trunk batt. to my seatbelt bolt NOT to my hood batt..

Positive wire went like this:

it should be front battery --> 18" wire --> fuse (300-350A) --> wire --> fuse (300-350a) --> 18" wire --> rear battery