rear battery discharge first?

[Lil Poot 5,000+ posts]

so i got my 2 batteries load tested today, an optima yellow top g34 up front and a powermaster d3100 in the rear.

the yellow top is about a year older than the d3100, and was for a couple of months in parallel with a very worn out optima yellow top g31. i'm hard on my setup, and didnt have enough electrical for how i usually beat on it.

i figured the yellow top would be bad if either one was... but it tested great, and the xs power d3100 only showed 900cca.

the only thing i can think of, is that when my amp pulled current, the d3100 would supply most of it being that it was next to the amp and would offer less resistance?

i just want to make sure there are no underlying problems i may need to address before i put in my new battery bank

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[I Like Waffle]

How many cca is it supposed to have? Maybe it was low on charge when you had it tested. Yea i think the amp would pull most of its current from the rear batt, like you said current follows the path of least resistance

 

[Lil Poot 5,000+ posts]

more than 900 for sure... i think they're 1100 or 1200 cca batteries. i didnt charge it before taking it in, just left it installed in my truck, but i did the same thing with the front battery.

the load tester is supposed to be able to tell the amount of charge the battery has.

 

[jdawg 5,000+ posts]

was the d3100 new when you got it? The optima being older could have drawn down the d3100, this is why you should buy batteries together, also you are running a gel cell and an AGM battery, shouldnt run different types of batteries. Also if you get technical you should run all batteries the same size and the same date code.

 

[Lil Poot 5,000+ posts]

yeah the d3100 was brand new when i put it in.

i thought both the yellow tops and d3100s were agm??!!

my new c&d batteries are agm. picked up a 40/20/10/4 black and decker charger today, i have it charging the 3 new batteries in parallel right now. that is the proper way to charge a bank right?

would you recommend replacing the yellow top up front also, maybe with a g34 c&d?

i want to make certain i get it right this time. i'm planning to charge about every other weekend, i just disconnect any wires that dont lead to other batteries and charge the front and rear batteries as a whole, right?

 

[smoka 10+ year member]

Ditch the underhood batt and don't replace it. With 3 large batts in the back, they should have more than enough CA for your engine.

That way all batts will be the same.

 

[Lil Poot 5,000+ posts]

really? extending the stock engine wires to the rear is no problem, it's just that i've never heard of anyone not using an underhood battery.

 

[Lil Poot 5,000+ posts]

after reading a few posts in a thread on mixing group sizes by audiolife, this is starting to clear up some.

i think once my bank finishes charging i'm going to put c&ds in the rear with 3 runs of 1/0 from my alternator to the batts and extend my stock battery wires to the back.

i'm curious though, i shouldn't run into any issues leaving the stock alternator charging wire off right? i'm not sure i can fit it on there along with the 3 1/0 terminals.

 

[smoka 10+ year member]

I think 3 runs of 1/0 power is overkill since all that will be up front is a 240a alt. I would do 2 runs of power, and 1 run of ground. You don't need to extend any wires to the back except for the 1/0 powers and grounds. Just use one of these to couple your battery engine cables with with one of your power runs.

You should be fine leaving the alt wire off, as long as you are sure it the correct wire and not the starter wire. If you have doubts, then I would add it.

 

[Lil Poot 5,000+ posts]

the starter wire hooks up straight to the battery, seperate from the alt i though?

 

[dappa5 10+ year member]

just re hook you stock charging wire to up front batt and big charge wire to rear batts use front just as car batt not as part of system /seperate the two

 

[s1ctech 10+ year member]

so i got my 2 batteries load tested today, an optima yellow top g34 up front and a powermaster d3100 in the rear.
the yellow top is about a year older than the d3100, and was for a couple of months in parallel with a very worn out optima yellow top g31. i'm hard on my setup, and didnt have enough electrical for how i usually beat on it.

i figured the yellow top would be bad if either one was... but it tested great, and the xs power d3100 only showed 900cca.

the only thing i can think of, is that when my amp pulled current, the d3100 would supply most of it being that it was next to the amp and would offer less resistance?

i just want to make sure there are no underlying problems i may need to address before i put in my new battery bank

**** if your that hard on your stuff... Do you have an HOalt?

 

[Lil Poot 5,000+ posts]

yeah my electrical is in my sig and should be very beefy.

last night, i replaced the d3100 with my 3 c&d batts after giving them and my front batt a good charge. haven't put it on a multimeter, but going off my dash gauge i'd say i'm dropping to low-mid 13s while driving at full tilt, as long as i dont play an extended bass note and just let it drain way down.

it seems louder to the ear and body for sure, i've been able to turn my head unit up more than what i did before.