battery specs

[pimpnyou204 10+ year member]

Alright im kind of confused on the batter options.

1) i understand normal and cold amps but how much does like maybe 100 of a difference make on a battery?

2) i saw amp hours on one of them, whats this mean?

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[AlterEgo99 5,000+ posts]

1. CCA (Cold Cranking Amps)

Cold Cranking Amps is a rating used in the battery industry to define a battery's ability to start an engine in cold temperatures. The rating is the number of amps a new, fully charged battery can deliver at 0° Farenheit for 30 seconds, while maintaining a voltage of at least 7.2 volts, for a 12 volt battery. The higher the CCA rating, the greater the starting power of the battery.

2. Amp Hours

The Amp Hour rating tells you how much amperage is available when discharged evenly over a 20 hour period. The amp hour rating is cumulative, so in order to know how many constant amps the battery will output for 20 hours, you have to divide the amp hour rating by 20. Example: If a battery has an amp hour rating of 75, dividing by 20 = 3.75. Such a battery can carry a 3.75 amp load for 20 hours before dropping to 10.5 volts. (10.5 volts is the fully discharged level, at which point the battery needs to be recharged.) A battery with an amp hour rating of 55 will carry a 2.75 amp load for 20 hours before dropping to 10.5 volts.

How did I find this information????

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[pimpnyou204 10+ year member]

So basically saying. Since i live in south fla the CCA rating means little to nothing correct since it will never get under 40F? Also since it will just be a battery in the back I wont really need it to start persay and it'll eventually heat its self up if it ever was too cold some how right?

Now for the amr hours thats basically the power of the amp correct? Higher the hours the better and is mostly what your looking for in a battery outside brand yes?

 

[AlterEgo99 5,000+ posts]

Yeah, CCA shouldn't be that critical in Florida, although recently is has gotten pretty darn cold down there...another feather in the cap for global warming. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Amp hours doesn't tell you too much about a battery. When I was in the market to swap out my OEM AC Delco with an aftermarket battery suited to car audio, I discovered that most "car audio" batts will specify the max wattage they are designed for. Typically you can determine the max wattage of your vehicle based on the max output of your alternator, add in your aftermarket audio gear wattage and then determine the size battery you need. If you are using this battery as a secondary and it will be powering your car audio only, then all you need to know is the max wattage of your car audio amps.

I have a Kinetik HC2000, which is rated at a max of 2000W and amp hours of 102. As I only have a 1000W RMS system and don't even push it to that limit very much, this was the largest single battery I could get that would fit under the hood of my '08 Silverado. Plus the OEM AC Delco was about 78 Ah, so stepping up to 102Ah has proved more than enough.

If you are going with a multiple battery setup and not using an isolator, your batteries should be the same size and series if at all possible. Otherwise you will shorten the life of your batteries. Check out this link for more information:

http://www.caraudio.com/forum/showthread.php?t=398527&highlight=battery

 

[smoka 10+ year member]

Amp hours doesn't tell you too much about a battery.

You are right Ah can be misleading and easily manipulated by manufacturing. But using Watts to choose a batt is a terrible way to pick a batt. Watts is a pure marketing scam designed to help people that have no clue about batts and is not based on real measurements.

Around here Ah is the choice spec when picking out a batt. But the people that know better go by Reserve Capacity.

 

[MakeshiftAudio 10+ year member]

You are right Ah can be misleading and easily manipulated by manufacturing. But using Watts to choose a batt is a terrible way to pick a batt. Watts is a pure marketing scam designed to help people that have no clue about batts and is not based on real measurements.
Around here Ah is the choice spec when picking out a batt. But the people that know better go by Reserve Capacity.

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Explain.

 

[smoka 10+ year member]

//content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif
Explain.

Thats easy, its the Ah vs RC that can get complicated.

So you have a 2000W battery? So thats P(watts) = I(amps) x E(volts). So that means a 2000W batt puts out exactly 166amps@12v or 181amps@11v? That sounds nice and dandy but unfortunately thats not how batts work.

In reality a batts output is based on the load. So if your load demands 100a, your batt will output it first at 12v. After your batt starts draining, you will still be pulling 100a but now the voltage will start dropping.

A batteries capacity degrades as you pull power from it. This creates a curving sloped trend that can be difficult to put into numbers, thats why Ah and RC are based over a uniform period of time. If you want to use watts, you at least need to have a time based attached to it i.e (x)watts/per(x)mins

I know, its hard to believe that Kinetik came up with this marketing scheme. Especially since they are solely a marketing company who does not design or manufacture their own batt cells. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[slim2fattycake 10+ year member]

What ever happened to powermaster suing kinetiks for their misleading info on their batteries?

 

[AlterEgo99 5,000+ posts]

Thats easy, its the Ah vs RC that can get complicated.
So you have a 2000W battery? So thats P(watts) = I(amps) x E(volts). So that means a 2000W batt puts out exactly 166amps@12v or 181amps@11v? That sounds nice and dandy but unfortunately thats not how batts work.

In reality a batts output is based on the load. So if your load demands 100a, your batt will output it first at 12v. After your batt starts draining, you will still be pulling 100a but now the voltage will start dropping.

A batteries capacity degrades as you pull power from it. This creates a curving sloped trend that can be difficult to put into numbers, thats why Ah and RC are based over a uniform period of time. If you want to use watts, you at least need to have a time based attached to it i.e (x)watts/per(x)mins

I know, its hard to believe that Kinetik came up with this marketing scheme. Especially since they are solely a marketing company who does not design or manufacture their own batt cells. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

OK, then using your approach, how does one determine what size battery they need based on the vehicle's electrical load and the added aftermarket car audio equipment? Using Ah that is. I mean, I didn't purchase my Kinetik so I could run my system with the engine off...I rarely if ever do that...so with the alternator cranking, the ECM/PCM regulating voltage and the electrical drawing, how does one calculate the correct size battery????

Reason I ask is I pressed this very issue when I was looking for a replacement battery and never got a clear answer. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[smoka 10+ year member]

OK, then using your approach, how does one determine what size battery they need based on the vehicle's electrical load and the added aftermarket car audio equipment? Using Ah that is. I mean, I didn't purchase my Kinetik so I could run my system with the engine off...I rarely if ever do that...so with the alternator cranking, the ECM/PCM regulating voltage and the electrical drawing, how does one calculate the correct size battery????
Reason I ask is I pressed this very issue when I was looking for a replacement battery and never got a clear answer. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

There are too many variables to give a easy answer. Just by listening to Rock or Rap you make a big difference in your power requirements. Its hard to say how much battery capacity you need, but its easy to just get more than you need then you don't have to worry. I've never heard of any drawbacks of having too much capacity.

I'm not trying to bash Kinetik. Sounds like you made a good choice for your system.

 

[audiolife 5,000+ posts]

You are right Ah can be misleading and easily manipulated by manufacturing. But using Watts to choose a batt is a terrible way to pick a batt. Watts is a pure marketing scam designed to help people that have no clue about batts and is not based on real measurements.
Around here Ah is the choice spec when picking out a batt. But the people that know better go by Reserve Capacity.

a constant 25 amp trolling motor spec tells you what is best for audio? I also know for a fact there is more to kinetik specs than just drawing numbers out of a hat. Also know they have input how their power cells are.

 

[MakeshiftAudio 10+ year member]

Oh. By you referencing the "Watts" rating, I thought you meant the "Watts per cell/WPC@15" rating.

I know what you're talking about, but I thought you were calling the WPC rating a load of it. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif (Pun not intended)

 

[smoka 10+ year member]

Because of Peukerts law, both numbers are hard to interpret in terms of car audio.

Peukerts law: expresses the capacity of a lead-acid battery in terms of the rate at which it is discharged. As the rate increases, the battery's available capacity decreases.

http://en.wikipedia.org/wiki/Peukert%27s_law

Lets look at Ah first:

So if you have a 100ah batt that means it can do 5a for 20hrs. What happens when you pull 10a? You would think the same batt can do 10a for 10hrs but thats not true due to Peukerts law.

What people don't realize, is that peukerts law does not have an equal effect on all batts. The quality of internal components and technical construction within the battery will generate different characteristics that will change the way Peukerts law effects the capacity. That is probably why a C&D batt costs less than a (insert expensive brand here) even though they have the same Ah.

For instance, say you buy a 100ah batt from brand A, and a 100ah batt from brand B. Most people would see these as being equal. But when you pull 10a from brand A it may only last 6hrs where brand B might at 10a may last 8hrs.

So for car audio where you are pulling 100+a, you can see why this "5a" measurement doesn't really apply.

You are right the RC is based off a trolling motor spec, but because its based off of a 25a load, and not a 5-7a load found in Ah, it makes more sense to apply the RC spec for car audio.

Car audio batt companies should really come out with a spec that better defines their batts. Having a RC spec at a 100 or 200a load would be great.

I'm not doubting Kinetiks CA or Ah specs, but I am curious to know the formula they use to determine Watts.

 

[McIntosh 10+ year member]

I'm not doubting Kinetiks CA or Ah specs, but I am curious to know the formula they use to determine Watts.

P=IE?, JK I know what you mean but I couldn't resist.

 

[audiolife 5,000+ posts]

So for car audio where you are pulling 100+a, you can see why this "5a" measurement doesn't really apply.

You are right the RC is based off a trolling motor spec, but because its based off of a 25a load, and not a 5-7a load found in Ah, it makes more sense to apply the RC spec for car audio.

Car audio batt companies should really come out with a spec that better defines their batts. Having a RC spec at a 100 or 200a load would be great.

I'm not doubting Kinetiks CA or Ah specs, but I am curious to know the formula they use to determine Watts.

I think many companies copy the kinetik numbers and say "they are the same as kinetik but only cheaper".