http://www.1st-optima-batteries.com/...eepyellowspecs has the run down on yellow tops. You can also look at kinetik(overpriced IMO) and odyssey for batteries.

 

Well I called around today, and the cheapest yellow top I could find was 170. But couldn't find what size fits the crossfire. I'm probably going to go back to the place that installed my system, hopefully, they will give me a deal, since it has only been one week, and they were the cheapest. Does anybody know what size yellow top I need? I don't want to destroy something, so for now the amp is down super low. Thanks, chris

 

You really don't need to go so overboard with the battery, honestly you're not running much power at all. I've ran 1400W of class D power combined with another 500'ish of A/B on a stock 90amp alt with a $64 Everstart MAXX from wal-mart with zero troubles. Yellow Tops are great, but they serve a very specific purpose.

 

I was thinking of trying a cheaper battery, but Every thing i have heard, says yellow top. I don't know enough about batteries, to understand what the bonus's of deep cell batteries are. I didn't think I was going to draw this much drop in voltage either, but it is happening. I'll measure it with my meter monday at work. What is the specific purpose of yellow tops? chris

 

Yellow top = more amp hours + better life

look at amp hours of the yellow tops, and discharge rate and compare to equal cranking amp batteries.

 

The Yellow top is a deep cycle battery. It is designed to survive being drained until nearly dead and then recharged. The manufacturer says it will take that abuse about 300 times without losing it's ability to take and hold a charge.

They're used for applications where the battery will be used without being charged - like on race cars where the alternator is deleted; Jeeps where it is used as a secondary battery for winches; I have seen them used to power lights in National Forest bathrooms (they're charged during the day with solar panels).

The Red Top is the same battery design but made for cranking amps not deep cycling. Both are gel-cell maintenance free batteries that withstand vibration and jarring. I run them in my Jeeps. Wouldn't have anything else. The Crossfire will get one when the SubPAR battery takes a dump...

Don't know how you got to wanting a Yellow Top. Read the Optima web site for the best battery for your application and for the size you need for your car - probably need to look at the SLK entry if Crossfire isn't there. And my experience with trying to get Optima batteries for Import cars was rough - could not get my hands on one for my Volvo V90. It broke my heart...

 

so what would you guys suggest. Regular battery, or something more expensive? I don't want to buy a 90 dollar battery, just to have to turn around and get an optima. I guess either comes with a warranty. I just don't want to screw up something, due to power drain. thanks, chris

 

I still suggest a high-quality battery. You will never regret a good battery. As for the stereo, do the numbers:

To calculate how many amps your stereo is going to need you do:
watts = amps x volts

Your JLHD750/1 amp at continuous full power output (unlikely) takes a maximum of 750 watts. Your battery at rest is about 12 volts.

750 = amps x 12
750/12 = (amps x 12)/12
62.5 = amps

If you were continuously pushing 750 watts out of the amp, you'd need 62.5 amps to keep up. That's roughly half the capacity of the Crossfire alternator. That still leaves half the capacity of the alternator to serve other electrical components and charge the battery. That will work - just don't leave the stereo on with the car turned off and don't go getting any CIBIE World Ralley Championship light bars for your car...

You won't be doing 750 watts all the time - maybe not even for peaks. Say you only ran 400 amps (the minimum required to drive that woofer) it looks like this:

watts = amps x volts
400 = amps x 12
400/12 = (amps x 12) / 12
33.3 = amps

You are only using ~1/4 the capacity of a 120-amp alternator (Crossfire), which leaves a margin for it to charge the battery.

The battery is not the issue if your charging system can't keep up with your power needs - It's the alternator that is going to be the issue.

The math says your power needs are not substantially going to outpace your alternator. You might find that you're OK. Just don't pile too much in there or you will need to address the charging capacity of the system with a heavy-duty alternator.

For example, I knew that my other vehicle would have troubles because the 117 amp alternator was not going to do a good job keeping up with one of my attachments (a winch that draws 400 amps) so I went to a 200 amp alternator to reduce the recovery time of the battery. The winch will still sucks down the battery fast, (which is what the yellow top is for - being able to sustain repeated drains and charges).

You're not going to draw anything like that kind of power with your amp.

 

I have never replaced an alternator, I would assume you can get them checked, at autozone or similiar place. If it was in my cobra, That wouldn't be a big deal, it is stareing you in the face. Are they hard to get to on our crossfires? So you think it is the alternator, not the battery? which should I look into first. thanks, chris

 

Not TOTALLY an urban legend Tulsa, you have to take into account the kind of glass being used, because in most vehicles in high-end competition (Bass Race, dB Drag, etc.) the windows are replaced with plexi/safety glass for JUST that reason. I used to be a dB Drag and MECA guy myself (IASCA was just too restrictive.). The shop I worked at during that time had a patron with an Olds Bravada we sponsored, he broke out his rear panel...

To break glass with speakers you need a couple conditions to be met:

- Good "seals" on everything (which any vechicle with a system should have)
- Low tuned subs (In order to break glass you have to match the "resonant frequency" of the glass, which for back hatches/windshields is usually very low, 30-40 hz range
- around 163 dB and high SPL's...they're two different things.


A Famous quote: "You're born when you turn the key, Life starts at 163 dB"



Hope this helps someone thinking about trying to blow out their vehicle.

 

Do this first, It'll be cheaper than a battery OR cap, will most likely work just as well, and if it doesn't it's still a great upgrade.

 

At idle your alternator isn't putting out it's full charge. The 120 amps is at or above 2200 RPM. At idle your pretty much just on the battery. (That's the way the car is designed)

There's probably nothing wrong with the alternator if your car battery is staying charged and the car starts without problems.

You could turn down the stereo when you're at idle and probably not have any problems...

The "Big Three" article is interesting - putting 1 gauge wire will certainly assure the most power reaches the components but if you haven't replaced an alternator before, don't do this - if you don't get it right you'll burn your car down.

 

actually, driving down the road going 40, 50, or 60mph, the headlights dim on the pavement. as well as any other light in the car for that matter. I expect that the lights would dim at idle. But the car starts like it should.

 

That sounds like something you'd want to look into. It means that something (the amp) is pulling really hard on your power supply. Could just be an old battery, poor connection, bad ground, but you should have it diagnosed.

 

Is the big three upgrade, somewhat easy to do? Should I have the installers do it? Or can I do it myself? Either way,I'll have to pay for the wires. I can get 12 gauge at work, but it sounds like I need something bigger. Can I use something like THHN wire? I'll look at the big three again. thanks, chris

 

1 Gauge wire is quite large diameter. The connectors are harder to properly attach. The wire needs to be routed to prevent chafing and contact with components. If you have done lots of wiring this is an easy job. If you understand the operating principles of the electric system you are modifying it's easy. If you have the tools it's easy.

The best advice I can give is to make up all the replacement wires without taking apart your existing wiring and then replace them one by one. The article referenced does not recommend a fuse between the alternator and battery but I would suggest you consider it. Lots of these wires have a fusible link. It's pretty important. If the wire shorts against the body, it will burn down the car without a fuse.

 

I'm just going to get a yellow top, from the place that installed my system. I can probably get a break on the battery price. Does it really need to be that gauge of wire? What size are the stock wires? And I assume a stero shop would have that kind of wire on hand.