shadowm891

when running a car audio battery in the back of your car without a isolator and having the car running does the amp run off both battery's or just the one in the back ?

VO...

iTrader: (25)

when the car is running the audio system will always run off the alternator...

dcains

iTrader: (15)

Well, unless you're pulling more current (along with all the other accessories) than the alternator can output. Not likely.

Since the batteries are not isolated from one another, it's all just one big system, as if the two batteries were side-by-side and wired in parallel.

92K1500

iTrader: (1)

They work together.

I have a batcap 800 in the back and funny thing is my front ground worked it's way off the post when I got a new battery (too small of a negative post) and I noticed every day my car seemed to crank a little slower. After about a week it didn't want to crank very well so I decided to yank the new front battery and take it back. That's when I found out I was only using my rear battery.

shadowm891

so in order for my amp's to run off just the battery in the back and ignore the one up front i would i need a battery isloator then

VO...

iTrader: (25)

Thanks for the clarification. This is what I meant to say, just not as detailed.

The OP's question is a bit vague though IMO. I'm not sure exactly what he intends to do with his system or misconceptions of how it works. If the OP believes he can can have a dedicated battery to power his system without a source to recharge it, then that dedicated battery (rear) will die after running his system a few times. Of course this is dependent on current draw...

92K1500

iTrader: (1)

Why would you want to do that?

I have a 1000w sub amp and a 100x4 mid/highs amp and I can easily play for an hour with the car off and have no problems starting up.

Unless you plan on running a big rear batt I would just link them in parallel.

92K1500

iTrader: (1)

The isolator will disconnect the two batteries while the car is off and when you start it off the front battery it will reconnect the two to recharge the rear battery.

That puts a lot of strain on the rear battery and if you play too long with just the one battery or have a larger system the volt drops will make it easy to burn stuff up.

VO...

iTrader: (25)

Agreed. ..

VO...

iTrader: (25)

+1...

VO...

iTrader: (25)

Make sure you buy a deep cycle battery for the rear one if you do this, or you'll find yourself ruining many batteries if they run down multiple times...

Spike100

If you want to install two batteries but not have an isolator, you wire them in parallel. There is no additional function beyond this. You have more power, but both batteries drain together.

If you are looking for a more sophisticated setup, you need an isolator and dual battery controller. This is the setup popular with off-road vehicles and marine installations.

Here are some features of a dual battery controller:

• Isolating both batteries (preventing charging from one another), yet charge simultaneously all the time
• Switch between battery A only and battery B only, and A+B (in parallel for high load)

The idea is you can control which battery(s) supplies power, and never have both batteries deplete themselves. This is a feature essential to an off-roader who never want to have a dead battery when he’s miles from a road.

92K1500

iTrader: (1)

Shadow, go to CarToys on Memorial on a Thursday night around 7ish. There is usually a group of people there who would be more than willing to answer your questions/help you out.

I've been there a couple times to check out everyone's setups and BS with them. Sometimes they even get their termlab out so people can meter their cars.

shadowm891

thanks for the info 92k1500. i just went and bought me a kinetik khc1200 today for my car. do you think i could run this as a starter / system battery. all i am running right now is a single sundown audio sa-10 off a jl audio 300/2 and a polk audio 300.2 for my kenwood kfc-p709ps component's up front.

92K1500

iTrader: (1)

I'm running a Napa factory size battery under the hood and a batcap 800 in the rear with 1000w to the subs and a 100x4 for the comp set in the doors.

As I said I can play for an hour and still easily start the car.

Unless you're going to be drag racing I would run both batteries.

chaseAD21

hey op i doubt w.e. set up you have needs a dedicated/secondary battery, if you are noticing significant drain under load, i.e. lights dimming. you might want to spring for a high output alternator in place of a 2nd battery. i only have a single 1200 watt kenwood 12" powered by a 2000 watt bridged amp (only because i have to get a custom box in order to fit both my 12"s) running right now and with the AC on plus lights and amp it does drain it right down to 12.3 volts under heavy load then the alternator kicks it back up to 15~ so i find myself charging my battery every weekend just to be on the safe side it only gets down to ~80% but if you have a battery charger that could be a stop gap solution for you as well. just my 2 cents

92K1500

iTrader: (1)

12.3v?

Sounds to me like you have another problem....

With my 1400w RMS and everything on my dome lights barely dim and I have a tiny secondary batt.

With OP's ~500-600w he will be fine.

jdmfetish

iTrader: (3)

not sure exactly what that kinetic specs out at , but to give you an idea
I use the spp1200 stinger only with quite a bit more power than you are using

I do have a upgraded alternator with a lot of 0 awg wire

but 1 battery no issues at all , you should do the big 3 in 0 awg if you have not , and use the largest + & - power & ground wire your amps can house

Description:

◦SPP1200 includes removable brass battery posts for installation flexibility.
◦12v Dry Cell Valve Regulated Lead Acid Battery (AGM)
◦SPP Series Batteries are good for over 400 full discharge cycles.
◦Internal resistance: <4.0 mOhms = Ability to quickly deliver power. The lower the number the faster the delivery.
◦20 hour rate: 2.20A/44Ah
◦5 hour rate: 7.48A/37.4Ah
◦1/2 hour rate:55A/27.5Ah
◦5 Second Cranking Amps: 1200A
◦CCA: 560A
◦Watts: 2400
◦Peak Discharge: >2600 A
◦Weight: 44.86 lbs.
◦Dimensions: (6.75”H x 7.75”W x6.5”D)

92K1500

iTrader: (1)

I have the Napa legend battery under the hood which is probably 2 years old now when my factory battery crapped out after 8 years.

Attributes:
Battery BCI # : BCI #35
Battery Cold Cranking Amps @ 0 Degrees F : 625
Battery Posts Type : Top Post
Battery Voltage : 12 Volt
Wet or Dry : Wet
Battery Cranking Amps @ 32 Degrees F : 775
Battery Reserve Capacity (Minutes) : 95
Battery Weight : 35 lbs

Then I have a single run of 4707 strand OFC 1/0 to the Batcap 800 in the back which is really old.... I bought it used like 4-5 years ago.

Meet our new and improved tough guy...Model 800.

Dimensions:

H-6.5"/W-7"/D-3"

The Model 800 weighs 14 lbs. and gives you an unbelievable 800 peak amps!

Auto racing enthusiasts and audio competitors alike have come up with some pretty creative ideas for this battery.


I have it grounded to the child car seat latch point, then short runs OFC 4awg to each amp.

I also have an AC Epicenter and an AC DQT but those don't use much power.

I thought about doing the big 3 but I haven't gotten around to it yet. My voltage is fine the way it is.

chaseAD21

other problems such as? Cuz thats the voltage the battery puts out no matter what the charge on it is the only reason its usually up around 15 is because of the alternator. The only problem I think I have right now related to that is the battery is ****ing old!!! But for me right now charging it every week back up to 100% in 10 minutes is fine with me I have other things my Z is sucking money out of my pocket for, you know