Multiple batteries w/stock alternator?

I've seen several posts on different message boards where people are running 3-4 batteries with a stock alternator. In most, there is no mention of isolators or any kind of switching being used. How are they not constantly going through alternators?

Also, back in the day, you would never see different battery types/sizes used in the same vehicle (including the one under the hood). Now, I'm seeing installs with two or three different battery sizes in them. Has battery technology changed that much in the last 10 years to allow this kind of flexiblility or are people just installing them and "getting away with it" for a little while?

In the agm side of things, technology has changed quite a bit over the last ten years, optima's now suck, so do deka's and kinetik, xs power is the leader in the battery market other then cactus or batcap.

So are you saying that isolators and high output alternators are not necessary for two and three battery installs due to changes in agm battery technology?

not necessary, but highly recommended.

You want to match your demand!!! IF you system requires 800 amps of current then you need 1000+ of charging amperage plus a battery backup of 800 amps RC capacity. Otherwise you will drop below the setpoint of the alternator charging output (14.1-14.9) or even worse down to resting voltage of the battery bank, (12.6-13.1)

Reason you want more charging amperage then your demand is simple, you don't want to run any electrical component at 100%, you lower the lifespan.

ALL OF THIS IS FOR A DAILY SETUP, something that will have a wide range of frequency in bass output and current pull.

Isolators are not ever needed in a daily setup.

i'm mcdriunk

So is it ok to run a 14 volt battery without charging system upgrades? This route would include swapping the starting battery to 14V as well.

The 120 amp alternator I have puts out 14.5 at idle with no demand on it. With the cheap amps, I have never seen voltage drop past 13 at idle.

No, you need to charge around 1.5 to 2 volts higher than resting voltage, so you would need around 16.5 volts to charge

You would need some sort of external or internal regulation on the alt to charge at 16+ volts.

resistors work for gettin the voltage up but idk if they do any longterm damage to the alts, me n a friend did it to his car just to test a theory and were surprised to see the output at like 16.7v iirc

Back to Andrew's first response, I can't believe no one has commented on his statement about Kinetik batteries (considering how many I see currently being used). I knew that Optima was no longer worth anything from racing and never felt that Deka was a "front runner" in batteries. I have no personal experience with XS Power or Kinetik so I'd like to see some posts from other people as well.

I know ya'll are probably getting tired of questions, but I'm getting closer to start making some purchases to rework my truck. I just need to sell a race quad, an enclosed trailer and the current sub/amp set up and I'll be making some HUGE changes, hence all the recent questions.

My own personal real world test of kinetik vs xs power showed the same the xs power battery recovered faster and with more voltage after drop. I compared a hc2000 to a D6500 with a real 180 amp 30 second tone pull on a memphis mojo 2500.

i too will go with xs power. it will be awhile though.

so the "fake kinetik" beat the real kinetik, haha

Andrew, thanks for the clarification on your "they suck" post.

I've been reading and researching and have come up with another battery question. Does anyone know of a XS dealer anywhere in central Arkansas?

Street Sounds can get them, but i bet you can get them online as cheap or cheaper.

Just get them direct from XS on Team pricing, they are located in Knoxville, TN so shipping is like 2 days on ground.

I'm ready to make a purchase on batteries and have been leaning heavily toward the XS Power, until I saw some NSB 90s. By comparing Ah and CCA ratings, it appears that the NSBs are about 1/2 the cost of XS.

I wouldn't expect them to be the same as XS, but when you can buy twice as many for the same dollar, you have to at least consider it an option. Plus, I have seen them tested (on message boards) against Kinetik and winning so reason would say that they fall, at the very least, somewhere between the performance of the Kinetik and an XS.

So let's hear the opinions out there on NSB.

from what i hear nsb 90 are the best.