Advice on alternator/battery sizing

[Tony Gao]

I have a 2004 I4 Honda Accord and upgraded my headunit, and swapped the fronts/rears and added a subwoofer to the car.

The relevant specs are :

OEM Alternator ( Old one went from old age, swapped a duralast a few years ago... believe it's 110A peak)

Front : 2 x 100W RMS/ 300W Peak @ 4ohms

Rear : 2x 100W RMS/ 300W Peak @ 4ohms

Sub : 300W RMS/600W Peak @ 4ohms

Amp 1 : 120W x 4 RMS @ 4ohms

Amp 2 : 300W x 1 RMS @ 4ohms

Batt : OEM Duralast, Group 51R

Headlamps : will be installing HID Xenons

Wiring was done well on my part, approx 8' 4ga into a 8ga distribution block for the two amps, 8ga ground leads to 4ga distribution block to bare chassis ground

For a while now I've experienced issues with depth of bass volume , symptomatic with some sort of electrical deficiency. I'm not 100% on what the issue(s) are, but the symptoms are :

• Low idle RPMS (supposed to settle around 900, if I play at volume for a few minutes can dip to 500-600, no stalling, though)
• Lack of low freq from sub, or at least the volume is overshadowed by the other speakers, which shouldn't be happening as I tried to make a pretty balanced system.
• Strange driving characteristics (the first 2500 rpms seem to just fly by much quicker than they used to)

My rough plan is:

1. BIG 3 (this kit : http://www.ceautoelectricsupply.com/big3kitstop.html)
2. v6 Battery Upgrade to a group 35 yellow top?
3. ~180A? H.O. Alternator?

Is it necessary to upgrade the alternator at 780W RMS? I know this particular model has the annoying ELD circuit where the alternator is two stage (12.4v low output mode, 14.4v high output mode) which doesn't account for accessory load, only essential electronics such as AC, etc. I'd PREFER not to deal with the ELD if I don't absolutely have to.

Same with battery, I don't know if it's necessary to upgrade the battery to a group 35 v6 battery with this small of a load.

Obviously the fact that honda uses a tiny 10ga lead from battery to chassis ground is likely one of the biggest reasons why I'm experiencing problems, and I will definitely start with the big 3, but I just wanted to make sure I have all the bases covered. I do not want to spend money or do work that I don't have to, but I definitely want to play my expensive system at the highest fidelity that it should be played at, which currently is not happening.

Any advice?

[Guest]

I have a 2004 I4 Honda Accord and upgraded my headunit, and swapped the fronts/rears and added a subwoofer to the car.

The relevant specs are :

OEM Alternator ( Old one went from old age, swapped a duralast a few years ago... believe it's 110A peak)

Front : 2 x 100W RMS/ 300W Peak @ 4ohms

Rear : 2x 100W RMS/ 300W Peak @ 4ohms

Sub : 300W RMS/600W Peak @ 4ohms

Amp 1 : 120W x 4 RMS @ 4ohms

Amp 2 : 300W x 1 RMS @ 4ohms

Batt : OEM Duralast, Group 51R

Headlamps : will be installing HID Xenons

Wiring was done well on my part, approx 8' 4ga into a 8ga distribution block for the two amps, 8ga ground leads to 4ga distribution block to bare chassis ground

For a while now I've experienced issues with depth of bass volume , symptomatic with some sort of electrical deficiency. I'm not 100% on what the issue(s) are, but the symptoms are :

• Low idle RPMS (supposed to settle around 900, if I play at volume for a few minutes can dip to 500-600, no stalling, though)
• Lack of low freq from sub, or at least the volume is overshadowed by the other speakers, which shouldn't be happening as I tried to make a pretty balanced system.
• Strange driving characteristics (the first 2500 rpms seem to just fly by much quicker than they used to)

My rough plan is:

1. BIG 3 (this kit : http://www.ceautoelectricsupply.com/big3kitstop.html)
2. v6 Battery Upgrade to a group 35 yellow top?
3. ~180A? H.O. Alternator?

Is it necessary to upgrade the alternator at 780W RMS? I know this particular model has the annoying ELD circuit where the alternator is two stage (12.4v low output mode, 14.4v high output mode) which doesn't account for accessory load, only essential electronics such as AC, etc. I'd PREFER not to deal with the ELD if I don't absolutely have to.

Same with battery, I don't know if it's necessary to upgrade the battery to a group 35 v6 battery with this small of a load.

Obviously the fact that honda uses a tiny 10ga lead from battery to chassis ground is likely one of the biggest reasons why I'm experiencing problems, and I will definitely start with the big 3, but I just wanted to make sure I have all the bases covered. I do not want to spend money or do work that I don't have to, but I definitely want to play my expensive system at the highest fidelity that it should be played at, which currently is not happening.

Any advice?

I am not an expert on this stuff but. You might be able to get away without buying a high output alternator. You are only pushing about 800wrms.

I think a battery upgrade and the big three would likely fix your issue. Just do not buy yellow top, they are not all that great. Look into XS Power batteries they are amazing from what I hear. Also, those CE auto supply products seem awfully expensive for what you get. Maybe it is just me though idk. But, for the big three it is wayyyy cheaper to just buy like 15-18ft of zero gauge wire from Skyhighcaraudio with a fuse for between your alt and battery and ring terminals as needed.

However, these upgrades are for fixing voltage problems. I am not sure if they will fix issues with your cars rpm output.

Also, your issue with the subwoofer not being as low hitting as you would like could be due to the low pass crossover set too high or maybe your sub box is not tuned properly.

Help that was somewhat helpful.

[JeepAndBassXJ]

I ran about 900 watts off of the stock 60 amp alternator and a five year old battery that had been dead for a year in storage lol. Did that for over a year and really did not have that big of a problem. Yes, the voltage was kinda crappy but the neither the alternator or the amp ever had a problem. You should be able to run 800 watts on a 110 amp alternator and a decent battery, just do the big 3, it makes a big difference.

[Tony Gao]

-snip-

I am not an expert on this stuff but. You might be able to get away without buying a high output alternator. You are only pushing about 800wrms.

I think a battery upgrade and the big three would likely fix your issue. Just do not buy yellow top, they are not all that great. Look into XS Power batteries they are amazing from what I hear. Also, those CE auto supply products seem awfully expensive for what you get. Maybe it is just me though idk. But, for the big three it is wayyyy cheaper to just buy like 15-18ft of zero gauge wire from Skyhighcaraudio with a fuse for between your alt and battery and ring terminals as needed.

However, these upgrades are for fixing voltage problems. I am not sure if they will fix issues with your cars rpm output.

Also, your issue with the subwoofer not being as low hitting as you would like could be due to the low pass crossover set too high or maybe your sub box is not tuned properly.

Help that was somewhat helpful.

Thanks for the help!

The thing about the sub is before this alt went and I had the old(truly) OEM battery and OEM alt, I would be able to feel the bass in my bones and mirrors become completely useless. Over time it degraded, with the battery going first and the alternator next(tho I suspect alternator was due to the whole 11 year old car thing) I have a feeling the weird idle could be caused by the fact that so much energy is currently being lost to contact/wire resistance that the battery is not being charged as much as it needs to be on load. If I don't listen to music for a couple days, the idle goes back to normal.

I was being lazy with the CE kit, I'll take your advice and get off my ass and solder my own wires and buy my own terminals and ring connectors...

And I will definitely look into a XS Power battery. Do you think an AGM battery would be ok for starting/etc or should I buy a starting battery instead of deep cycle?

[Guest]

I have a 2004 I4 Honda Accord and upgraded my headunit, and swapped the fronts/rears and added a subwoofer to the car.

The relevant specs are :

OEM Alternator ( Old one went from old age, swapped a duralast a few years ago... believe it's 110A peak)

Front : 2 x 100W RMS/ 300W Peak @ 4ohms

Rear : 2x 100W RMS/ 300W Peak @ 4ohms

Sub : 300W RMS/600W Peak @ 4ohms

Amp 1 : 120W x 4 RMS @ 4ohms

Amp 2 : 300W x 1 RMS @ 4ohms

Batt : OEM Duralast, Group 51R

Headlamps : will be installing HID Xenons

Wiring was done well on my part, approx 8' 4ga into a 8ga distribution block for the two amps, 8ga ground leads to 4ga distribution block to bare chassis ground

For a while now I've experienced issues with depth of bass volume , symptomatic with some sort of electrical deficiency. I'm not 100% on what the issue(s) are, but the symptoms are :

• Low idle RPMS (supposed to settle around 900, if I play at volume for a few minutes can dip to 500-600, no stalling, though)
• Lack of low freq from sub, or at least the volume is overshadowed by the other speakers, which shouldn't be happening as I tried to make a pretty balanced system.
• Strange driving characteristics (the first 2500 rpms seem to just fly by much quicker than they used to)

My rough plan is:

1. BIG 3 (this kit : http://www.ceautoelectricsupply.com/big3kitstop.html)
2. v6 Battery Upgrade to a group 35 yellow top?
3. ~180A? H.O. Alternator?

Is it necessary to upgrade the alternator at 780W RMS? I know this particular model has the annoying ELD circuit where the alternator is two stage (12.4v low output mode, 14.4v high output mode) which doesn't account for accessory load, only essential electronics such as AC, etc. I'd PREFER not to deal with the ELD if I don't absolutely have to.

Same with battery, I don't know if it's necessary to upgrade the battery to a group 35 v6 battery with this small of a load.

Obviously the fact that honda uses a tiny 10ga lead from battery to chassis ground is likely one of the biggest reasons why I'm experiencing problems, and I will definitely start with the big 3, but I just wanted to make sure I have all the bases covered. I do not want to spend money or do work that I don't have to, but I definitely want to play my expensive system at the highest fidelity that it should be played at, which currently is not happening.

Any advice?

I am not an expert on this stuff but. You might be able to get away without buying a high output alternator. You are only pushing about 800wrms.

I think a battery upgrade and the big three would likely fix your issue. Just do not buy yellow top, they are not all that great. Look into XS Power batteries they are amazing from what I hear. Also, those CE auto supply products seem awfully expensive for what you get. Maybe it is just me though idk. But, for the big three it is wayyyy cheaper to just buy like 15-18ft of zero gauge wire from Skyhighcaraudio with a fuse for between your alt and battery and ring terminals as needed.

However, these upgrades are for fixing voltage problems. I am not sure if they will fix issues with your cars rpm output.

Also, your issue with the subwoofer not being as low hitting as you would like could be due to the low pass crossover set too high or maybe your sub box is not tuned properly.

Help that was somewhat helpful.

Thanks for the help!

The thing about the sub is before this alt went and I had the old(truly) OEM battery and OEM alt, I would be able to feel the bass in my bones and mirrors become completely useless. Over time it degraded, with the battery going first and the alternator next(tho I suspect alternator was due to the whole 11 year old car thing) I have a feeling the weird idle could be caused by the fact that so much energy is currently being lost to contact/wire resistance that the battery is not being charged as much as it needs to be on load. If I don't listen to music for a couple days, the idle goes back to normal.

I was being lazy with the CE kit, I'll take your advice and get off my ass and solder my own wires and buy my own terminals and ring connectors...

And I will definitely look into a XS Power battery. Do you think an AGM battery would be ok for starting/etc or should I buy a starting battery instead of deep cycle?

Most AGM batteries are fine as a starting battery. With the XS Power batteries, make sure you get one of the "D" series and NOT the "XP" series. The D series is meant to replace the OEM battery under the hood while the XP series is designed as a supplemental battery. The Logic line of AGM batteries from Crescendo are also pretty good too!

And about your idle problem, if a good battery and the big 3 doesn't fix it, your problem might not be related to voltage.

[aculous]

In my experience wiring hondas have been awful. In the 2000s they started putting rubberized coatings and other stupid things on those cars which can cause dirty grounds and a lot of other issues. I ended having to wire things back to the battery and other stupid things like setting up a grounding block for my grounds. GIGANTIC pain in the ass. In full disclosure a buddy of mine had the same car no rubberized coating on the chassis...no problems...so grain of salt but it sounds like there may be other issues in the car.

For your setup I doubt you would need different alternator but I bet your ground and battery situation is not great. Also with the big three go big, it never hurts to do that and then you don't have to worry about it later on.

Also look into battery isolators. Doubt you would need one but it allows you a little more flexibility.

[Tony Gao]

Alright, just went and placed my order for parts.

Went with the XS Power D1200 and ordered 12 ft of 1/0 from skyhighcaraudio + fuses etc for the big 3.

Also went ahead and purchased a voltage monitor, more cable to fix some short amp wiring and parts for the ELD bypass. I figure since I am going to tear the dash apart again I might as well go ahead and bypass the ELD while I'm at it so I don't find out the ELD is the issue after spending hours putting everything back together. Parts were $12 on parts express so even less reason for my laziness

Oh and I also went and splurged on some projector halo CCFL LED headlamps, the OEMs must go.

Fun times await!

[Guest]

Alright, just went and placed my order for parts.

Went with the XS Power D1200 and ordered 12 ft of 1/0 from skyhighcaraudio + fuses etc for the big 3.

Also went ahead and purchased a voltage monitor, more cable to fix some short amp wiring and parts for the ELD bypass. I figure since I am going to tear the dash apart again I might as well go ahead and bypass the ELD while I'm at it so I don't find out the ELD is the issue after spending hours putting everything back together. Parts were $12 on parts express so even less reason for my laziness

Oh and I also went and splurged on some projector halo CCFL LED headlamps, the OEMs must go.

Fun times await!

Sick!! Good luck my man!!

[knowledge]

there is a ELD bypass thread here for hondas.