Battery, Caps? which one for my setup?

[shredder1 10+ year member]

I've got 2 CAB amps strapped @ 4 ohms on my subs a RF 500s for the mid-hi's 2 group 75's under the hood with a 250a alt, dual 0 ga run to the rear /w/ all 0 ga on the amps except the 500s. My voltage stays at 14+ on the dashboard meter until really low notes... "32hz and under"... at really high volume take it to 12V or so. Does anyone think a basic 5 farad cap will make enough of a difference to buy one? I really want to avoid purchasing a AGM and putting it in the rear if possible. If I go with a cap, how big should I go or am I kinda stuck upgrading the group 75's up front? The charging system can almost keep up with the car running... the videos I've seen have these drawing 165A apiece at 2 ohm... will the caps have enough reserve and recharge fast enough to give a buffer while running? I don't park and pound.

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[Airman21 10+ year member]

Big 3?

 

[shredder1 10+ year member]

All done, all 0 ga , the current charging/ battery setup ALMOST keeps up. I've got to really get stupid with the volume to get it to 12v. I'm probably only getting 2000 watts on the subs or so after box rise etc...

 

[Lbetts818]

I have two strapped at .5 each(two d4s wired to 1 ohm) and dip pretty low if I get hard on it but running a 250a alt(tested at 290 on the bench) big three with 2/0 welding cable and two runs pos and neg to the back with a 55ah under the hood and two big agms in the back. Batteries in the back may have to be a option. Or lithium. Especially if you want to go with something bigger sub wise and get more power out of these amps. Mine have been installed for a few weeks now and have dipped into the high 11s low 12s a few times when setting it up and these take it like a champ no protect or anything at .5 per. They get a little warm but not hot. Overall for 200$ I'm impressed.

 

[Papermaker85 5,000+ posts]

i don't see how your getting any voltage sag you not drawing more than 200 amps.. two of those amps strapped realistically @ 4ohm after rise is around 2400 watts on a sinewave.. you should be at hte alts limits but it shouldn't be dipping past about 13.5.. i'm dropping to 12.8 full bast with a 3600@.5 and a 225x4 full blast(right below clipping) *on music* when i'm burping rev to 2k RPM i see 12.5 or so if i have a cap bank id probably see 13.8...

 

[shredder1 10+ year member]

Strapped @ 1 ohm... lol!.. I just had one of these replaced! I'm good at 4 ohm strapped for now it is a comfortable 2 ohm per amp... I know they are 1200 or so into this each so I figure 2000 after box rise and this is fine for my subs but the question was will an cap be enough to give it just a little help as it is only dropping to 12v at severe volumes/ low notes over 142 db. Don't want a battery in back or load the amps to the max but it seems to need just a hair more. If I need to upgrade the batteries I'll probably just lose the lead/acid 75's and go with Agm's under the hood... eventually. But I really don't believe they are drawing that much. I don't SPL constantly or play 0 db sine waves when this happens. It is not affecting the system hardly at all ... I'd just like to give my Alt/ battery a little reserve and see the volts stay high. I'm using regular group 75 lead acid batteries and I know that is the problem but I'm tryin' to get off cheap with a 5-10 farad cap if possible. The Alt is a large case GM "250" bought off ebay so it probably is not 250 amps but it has brought the voltage up considerably... it was dipping into the 10's before and the highs were cutting out.

 

[Papermaker85 5,000+ posts]

Strapped @ 1 ohm... lol!.. I just had one of these replaced! I'm good at 4 ohm strapped for now it is a comfortable 2 ohm per amp... I know they are 1200 or so into this each so I figure 2000 after box rise and this is fine for my subs but the question was will an cap be enough to give it just a little help as it is only dropping to 12v at severe volumes/ low notes over 142 db. Don't want a battery in back or load the amps to the max but it seems to need just a hair more. If I need to upgrade the batteries I'll probably just lose the lead/acid 75's and go with Agm's under the hood... eventually. But I really don't believe they are drawing that much. I don't SPL constantly or play 0 db sine waves when this happens. It is not affecting the system hardly at all ... I'd just like to give my Alt/ battery a little reserve and see the volts stay high. I'm using regular group 75 lead acid batteries and I know that is the problem but I'm tryin' to get off cheap with a 5-10 farad cap if possible. The Alt is a large case GM "250" bought off ebay so it probably is not 250 amps but it has brought the voltage up considerably... it was dipping into the 10's before and the highs were cutting out.

if you want to know if a cap will help burp it and watch the voltage. if the initial voltage lowers it but it comes back up to charing voltage a cap will help. if you burp it and it doesn't get a battery..

 

[shredder1 10+ year member]

Yes, the voltage will recover without touching the volume... a higher frequency is all it takes, Usually it only drops when I'm playing something that is 28 hz or less. A cap sounds like it will do the trick... not even a big one thankfully... thanks to all for your advice...

 

[Papermaker85 5,000+ posts]

i wouldn't use a typical 1 farad or 5 farad cap. the super caps are superior by a long shot. its like going from a lead acid to a lithium.

 

[shredder1 10+ year member]

i wouldn't use a typical 1 farad or 5 farad cap. the super caps are superior by a long shot. its like going from a lead acid to a lithium.

Sounds great! But the great things I've heard have made me think that these are very expensive... I wouldn't know where to look for an inexpensive one, if there are any!

 

[Mayhem]

If you're set on caps then you have to get super/ultracaps

Don't waste your time with these "car audio specific" caps.

Maxwell 2.7 3000F bank of six for about 250-300 used with hardware

XS Power bank of six caps is 350 new

XS Power "super bank" is 450. Its a bank of caps inside a battery similar case/

There are people who will say DON'T use a bank of caps for a daily driver.

I don't see a problem with it at all. They are great as a voltage stabilizer. If you actually look at how much power caps can actually do its ridiculous.

If weight is the problem then you can also go lithium. Or caps, neither weigh anything compared to agm.

 

[shredder1 10+ year member]

$$$... Wouldn't I be better off with a battery in the rear for that price? Are they that great of an upgrade? I'm running budget amps, alt,subs and CCA wire with maybe... MAYBE... 2500 WMRS overall, hey don't get me wrong, it sounds great but the whole system has less than $1500 invested. I'd like to say that it's in the budget but...

maybe someday if I load the amps 2 ohm strapped or lower.

 

[Mayhem]

i have two of these https://www.sonicelectronix.com/item_88298_Kinetik-HC2400-BLU.html

supporting 4k and 600 watts of mids, no big 3, stock alt, and an xs group 34 up front.

idle it physically wont drop past 12.6 and @ 1700 rpm+ i see 13.3+ all at full tilt

I found a used one locally for 100 and just ended up buying a new one to match. Don't know why I don't see more people running them. They are very stout.

they are budget friendly

 

[shredder1 10+ year member]

That same item has been on my Ebay watch list for a month only Audiosavings has the listing I saw... It should fit. Keep the 75's under the hood and 1 in the rear?

 

[Mayhem]

That same item has been on my Ebay watch list for a month only Audiosavings has the listing I saw... It should fit. Keep the 75's under the hood and 1 in the rear?

Correct

If the two group 75s are wetcell just consider getting a charger and putting it on them once a week. The resting voltage for agm and lead-acid is a bit different and they can "drag down" the agm battery over time if not proper charged. Although you have a good alt so you would be fine regardless.