Lets talk capacitors
Registered User
Joined: Oct 2002
Posts: 7,584
Likes: 1
From: Baton Rouge, LA
i have too much experience w/ draining my battery. 
my system is rated at approximately 750 Wrms. i think i figured out my current draw at one point, but don't remember where... it's quite agressive actually... but the first time i ran my system close to wide open (w/o the engine running) with a fully charged stock battery - it lasted just under 7- 8 minutes (almost 2 songs). i was fiddling with something in the trunk when this happened, so i didn't immediately recognize i was so low until both amps cycled off (from low voltage) and turned back on whenever a bass note hit...
(once i did that, i realized the battery was dead, so i didn't spend a whole lot of time worrying about it... having to replace it was already a certainty.
)
in intervals that followed over the next few months -- i would roughly get 3 - 4 minutes of full volume play time before the battery would dip below 11 V. and after draining it completely a few more times (it was dead afterall), i wasn't able to get more than a minute or so of loud play before i wasn't able to start the car...
with my current Optima, i get much closer to 30-45 minutes of almost full volume play before voltage starts to get low. since it's a deep cycle battery, i just pop it on the charger and... good as new.
my system is rated at approximately 750 Wrms. i think i figured out my current draw at one point, but don't remember where... it's quite agressive actually... but the first time i ran my system close to wide open (w/o the engine running) with a fully charged stock battery - it lasted just under 7- 8 minutes (almost 2 songs). i was fiddling with something in the trunk when this happened, so i didn't immediately recognize i was so low until both amps cycled off (from low voltage) and turned back on whenever a bass note hit...
(once i did that, i realized the battery was dead, so i didn't spend a whole lot of time worrying about it... having to replace it was already a certainty.
)in intervals that followed over the next few months -- i would roughly get 3 - 4 minutes of full volume play time before the battery would dip below 11 V. and after draining it completely a few more times (it was dead afterall), i wasn't able to get more than a minute or so of loud play before i wasn't able to start the car...
with my current Optima, i get much closer to 30-45 minutes of almost full volume play before voltage starts to get low. since it's a deep cycle battery, i just pop it on the charger and... good as new.
Registered User
Joined: Oct 2002
Posts: 7,584
Likes: 1
From: Baton Rouge, LA
well, i know it's a model 51. optima batteries doesn't even list that model on their site.
i found info about it here: http://www.1st-optima-batteries.com/yellow...top_battery.asp
but i don't know anything about that company (ie. i'm not recommending buying there...)
they list it for 26 lbs.
hrm...
according to this in the S2ki marketplace, the stock battery is 28 lbs. so, i actually saved weight AND got a better battery? SWEET!
i found info about it here: http://www.1st-optima-batteries.com/yellow...top_battery.asp
but i don't know anything about that company (ie. i'm not recommending buying there...)
they list it for 26 lbs.
hrm...
according to this in the S2ki marketplace, the stock battery is 28 lbs. so, i actually saved weight AND got a better battery? SWEET!
Joined: Jun 2001
Posts: 88,444
Likes: 21
From: Pt. A to Pt. B via VTEC!!
Having you girlfriend sit in the car be-bopping away draining your battery at Kitty Hawk while the S2k nuts freeze at the top of the hill 
Having your S2k pals roll your S so you can get a good clutch start at Kitty Hawk.....priceless and memorable
2 batteries( 1 hidden) a toggle switch, a 5 farad cap and an iso relay later = insurance
I can jam all day with the S keys in my pocket
Having your S2k pals roll your S so you can get a good clutch start at Kitty Hawk.....priceless and memorable
2 batteries( 1 hidden) a toggle switch, a 5 farad cap and an iso relay later = insurance
I can jam all day with the S keys in my pocket
You ain't kidding. I'm off to buy a can of fix a flat and get my AAA card laminated...
Registered User
Joined: Aug 2003
Posts: 8
Likes: 0
From: San Pedro
Guess I need an education! Please debunk the following:
I thought dimming lights are caused by a voltage fluctuation. Unless we've somehow elected to break Ohm's Law, when we have a constant load and need more amps, the volts have to give.
Isn't a cap employed to smooth out voltage fluctuations by acting as a fast-acting reserve power source? Obviously, if your charging system is inadequate, the cap would be called upon too often to handle the voltage fluctuations, and would mostly be discharged and therefore ineffective. So like it's been said, if the charging system is undersized, a capacitor wouldn't fix the flickering lights.
I noticed that my interior lights were dimming with a 1 farad capacitor. My lights are no longer dimming with a 2.4 farad capacitor. Since nothing else changed, can I not deduce that the charging system was generally adequate, but I just needed to provide a bit more reserve with a bigger cap? Consider that when I turn off my audio system while playing at elevated listening levels, the steady state intensity of the lights doesn't change.
Concerning the HIDs, I didn't notice if they were fluctuating. But if the input on an HID ballast designed for DC is fluctuating fairly radically, wouldn't the output fluctuate too? I know that a ballast's purpose is to provide constant output voltage based on a wide range on input voltages, but isn't that just saying that it will operate as well at 18v as it will at 12v? It doesn't necessarily follow that it provides a steady output if the input is fluctuating wildly from 9 to 14v. This isn't a loaded question. I really don't know the answer, as I'm not familiar enough with HID ballast control circuits.
Regardless of the answers to my misunderstandings, I guess the upshot is this: my lights were flickering with my audio setup and a 1 farad capacitor. They don't flicker with a 2.4 farad capacitor.
I thought dimming lights are caused by a voltage fluctuation. Unless we've somehow elected to break Ohm's Law, when we have a constant load and need more amps, the volts have to give.
Isn't a cap employed to smooth out voltage fluctuations by acting as a fast-acting reserve power source? Obviously, if your charging system is inadequate, the cap would be called upon too often to handle the voltage fluctuations, and would mostly be discharged and therefore ineffective. So like it's been said, if the charging system is undersized, a capacitor wouldn't fix the flickering lights.
I noticed that my interior lights were dimming with a 1 farad capacitor. My lights are no longer dimming with a 2.4 farad capacitor. Since nothing else changed, can I not deduce that the charging system was generally adequate, but I just needed to provide a bit more reserve with a bigger cap? Consider that when I turn off my audio system while playing at elevated listening levels, the steady state intensity of the lights doesn't change.
Concerning the HIDs, I didn't notice if they were fluctuating. But if the input on an HID ballast designed for DC is fluctuating fairly radically, wouldn't the output fluctuate too? I know that a ballast's purpose is to provide constant output voltage based on a wide range on input voltages, but isn't that just saying that it will operate as well at 18v as it will at 12v? It doesn't necessarily follow that it provides a steady output if the input is fluctuating wildly from 9 to 14v. This isn't a loaded question. I really don't know the answer, as I'm not familiar enough with HID ballast control circuits.
Regardless of the answers to my misunderstandings, I guess the upshot is this: my lights were flickering with my audio setup and a 1 farad capacitor. They don't flicker with a 2.4 farad capacitor.