New alt but lights still dim

Hey guys its been awhile since i visted the forums, i guess thats a good sign that my sytems is still in one piece.  But my problem is that i got a new alternator from www.4alterstart.com (supposed to be real good....thanks haemphyst) its a 150amp alt but my lights are still dimming a little bit.  I got a stereo battery from lightning audio, upgraded the power cable off the alt to the battery to 4ga wire.  lights dim while driving not while idle so the alt is supposed to be putting out full power.  i dont have a volt meter or amp meter installed yet(on the to do list) so i really cant give any specifics on voltage and wheather my system is actually pulling full power.  thanks for any input.

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Memphis MC-1300
2 12" JLw6v2
Diamond audio M3 6x9
Diamond audio M3 5.25 components
Audio control Matrix
Carputer

Did you upgrade your ground wire from the battery to the chasis? 

I was told by both alterstart and a honda master tech that it was not necissary as the it is already grounded very heavily through the engine block

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Memphis MC-1300
2 12" JLw6v2
Diamond audio M3 6x9
Diamond audio M3 5.25 components
Audio control Matrix
Carputer

chassis ground upgrade is probably all you need... your motor is connected to the chassis by rubber mounts so not much help from that.. engine and chassis should see 4 ga wire for ground... should make those pesky dimming lights go away!!

did the alt help at all or is it the same?????

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owner of
Motion Marine & Car Audio
the florida keys

I'm glad you were able to get an alternator, finally! No, you need to do the ground cable from the engine block to the chassis, and the ground cable from the chassis to the battery as well. Ideally, they would be connected at the same point. Be certain you clean the paint from the connection point well... While it is true that the alternator itself is grounded right to the engine block, a physical connection that is, to be sure, capable of at least a couple thousand amps, the engine block connection to the chassis is run through a 12 or 10 gauge braid, and a similar connection to the battery. These braids are where your power is being lost. Upgrade these, and see if it fixes your problem. BTW, the best place to get your chassis to block ground point is right at the mounting bolt for the alternator itself. Leave the other cable as it is, it will hurt nothing.

One other thing, did you run the alternator output right from the post to the battery, making sure to bypass all of the Honda stock cabling? I know on the later Hondas they connect a 10 gauge to the alternator post, and then run it across the top of the enging to connect to the main fuse block under the hood. I bypassed this wire completely. It is shrink wrapped and taped at both ends. Check this as well. If you leave it, it will do nothing bad, but I just felt it a better solution to remove it.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

If you have an accord/civic the wire looks like 8 gauge at the battery.  Depending on the year of your car you can just remove the ground from the battery and replace the battery connector and cabling with some high quality 4 gauge or better wire.  This would help your cars electrical system out.

The stereo battery you bought.. Where did you mount it?

Did you mount it in place of the main battery (in the engine compartment?)

If you had kept your stock main battery, and put the stereo battery in the trunk (with a $29.95 battery isolator from AutoZone next to the battery in the trunk) I believe that would have solved the problem completely.

It did for me! I just did it a few days ago.

Because of this, I didn't need ANY electrical system upgrades. When the amps require their enormous amount of power (250 amps on paper), they drain it from the battery 2 feet from them, not from the front of the car, because the battery is closer.

And, when the amps stop draining all that power, the battery in the trunk will charge itself from the alternator.

///Leif

hehe, i think i found my problem....im retarded  .  When i was driving at night i would look closely at my lights, but at the same time i would let off the gas and my rpms would drop, so my alt wasnt putting out max power.  But do you guys i should get a cap or something since my engine is not always at 1500rpms so my alt puts out max power.

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Memphis MC-1300
2 12" JLw6v2
Diamond audio M3 6x9
Diamond audio M3 5.25 components
Audio control Matrix
Carputer

Aa cap will NOT make sure your alternator "puts out max power"... If your RPM's drop, your alternator WILL NEVER put out max power. A cap will not fix the issues you are describing. You have fixed it to the best of your ability. Just make certain you upgrade the wiring under your hood...

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

yeah i know that cap wont help put out the max power of my alt, only keeping the rpms above 1500 will do that. i was just saying would a cap help for the times when my rpms do fall below 1500 and my alt isnt putting out max amps.

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Memphis MC-1300
2 12" JLw6v2
Diamond audio M3 6x9
Diamond audio M3 5.25 components
Audio control Matrix
Carputer

Nope... If the alternator is not there for the demand, the battery voltage will continue to fall, and the amplifier output will suffer. Physics dictate this. A cap is for IMMEDIATE current needs only... (bass notes) It WILL NOT fix a low voltage condition, which is exactly what is happening when your engine falls below 1500 RPM. The same thing can and does happen in my system (which you have seen) when I am sitting there idling, and I have 2F worth of cap. You can put the cap in, but it will not fix the problem you are describing. Only a higher idle speed or a "readjusted" voltage regulator. This would cause overvoltage conditions at regular engine speeds, though, so you don't want to do that.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."