over charging alternator

I just got a new 220 Amp alternators in my truck and When i turn up the radio the voltage will drop to about 12v then spike sometimes up to 15.5v causing my subwoofer amp to cut off. But my Rockford Fosgate amp on my door speakers stay on. Is this spike due to not having a deep cycle battery? Do I need a Better ground on my subwoofer amp?

Thanks

Adam

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Some amplifiers will not work if it sees too much voltage on the remote wire.  

i am an idiot wrote:

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Some amplifiers will not work if it sees too much voltage on the remote wire.  

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So Should I lessen the gauge on the remote wire and give that a try? and does the remote wire fluctuate in voltage as the power wire does?

I noticed today when i turn the radio down or there's a pause and the alt is able to recharge everything in that fraction of a second the voltage spikes up to that 14.8-15.7v range if this information helps any.

Thanks

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A smaller wire will not do the trick.   You have a couple of options, first is to make that amp the last in line with the remote wire and inserting a resistor in series to drop the voltage a bit.  You will have to experiment with resistor values to see what your amp needs.  First try 100 ohms then 470 and then 1K ohms.  If that is not enough, measure the voltage drop across the 1K resistor and let me know what that reading is.  Second would be to purchase a 7812 voltage regulator from radioshack.com, and install that device before the remote terminal of that amp.

i am an idiot wrote:

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A smaller wire will not do the trick.   You have a couple of options, first is to make that amp the last in line with the remote wire and inserting a resistor in series to drop the voltage a bit.  You will have to experiment with resistor values to see what your amp needs.  First try 100 ohms then 470 and then 1K ohms.  If that is not enough, measure the voltage drop across the 1K resistor and let me know what that reading is.  Second would be to purchase a 7812 voltage regulator from radioshack.com, and install that device before the remote terminal of that amp.

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Alright ill get into that tomorrow. Do you think the second option of the regulator might be the best?

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yeah i see it on radio shack website. I'll try the resistors for the time being while the chip is coming in. If you think the chip is the most efficient.

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and no i dont have a electronics store close by what im seeing on google.

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Yeah I got the regulator they did have it in stock and its still doing it. There's only one way to hook it up right? You cant hook it up and it still work. I think I may have to get a capacitor to keep the stream smooth. The Alt is easily powering my system but it just spikes too high up. what do you think? is there a regulator for power cable?

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Did you ground the center leg of the regulator?

i am an idiot wrote:

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Did you ground the center leg of the regulator?

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I grounded the top hole. on the package it says that is also a ground.

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Found out my battery is good but is being over charged up to 840 amps instead of 700. So I dont think the Alt has a problem I think my battery is too small. They suggested a Second battery so the engine battery wouldn't be over charged past its capacity cause that could cause damage and what not. I cant afford a new huge engine battery so the Small Second will have to do.

what you guys think?

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The Battery was tested. at Advanced auto parts cause its free there.

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I got the Alternator tested at Advanced auto parts and Auto zone and the battery and Alternator are 100%.

I need to make sure you guys understand what the problem is. The alternator doesn't just randomly spike all the time. It charges at 14.1-14.4 volts all day long. When i turn the radio up the alternator is Perfect only dropping to about 12volts on the Low end notes. It is when the music stops playing from a loud volume when the spike occurs. So if its on a Bass note voltage drop at 12volts. if I pressed pause at that moment. then the voltage Spikes. Explain why a capacitor would not help to take that surge and keep the voltage regulated at a voltage lower at the amps. Or is there something i can buyy to keep the voltage below 14.4?

Thanks Adam.

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anything?

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It sounds like a classic ground problem - ie, bad engine to chassis.

Did you upgrade your ground wires? The extra engine to chassis strap needs to be rated to suit and be at least the size of the alternator output lead.

(Apologies for stating the obvious, but I haven't noted any mention of grounding upgrades.)

oldspark wrote:

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It sounds like a classic ground problem - ie, bad engine to chassis.

Did you upgrade your ground wires? The extra engine to chassis strap needs to be rated to suit and be at least the size of the alternator output lead.

(Apologies for stating the obvious, but I haven't noted any mention of grounding upgrades.)

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Yeah the Grounds have all been upgraded to 0 Gauge wire by doing the BIG 3.

the Chassis is the Same as the Firewall right?

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Yeah - chassis equals car metal (assuming the metal is all grounded to the battery -ve etc).

Well if you have solid grounds from alternator to engine to chassis to battery -ve.....
And a solid connection from your alternator's (regulator's) sense wire to battery +ve (without any voltage drops caused by other loads), then it should be charging ok.


It sounds like you need the full system checked out.
Maybe the regulator is reacting to injected AC etc, or it's a poor regulator.
Or the alternator is underdamped etc.
(And I assume you only have the one alternator!)


BTW - a battery acts like a huge capacitor itself so additional capacitors are unlikely to prevent any spikes.

I think I might need to Hook my grounds to my battery Better. Im gonna try that before sending the Alternator back.

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Except for battery charging and alternator dips, there should be negligible current flowing to/from the battery.

But there should be no major voltage drops between alt body, engine, chassis & battery -ve.
And the battery terminals and all contacts should be clean to ensure "clamping" of any spikes.

Normally I wouldn't expect huge spikes from an alternator unless it has an external regulator (especially mechanical if such things still exist!), but these are large output alts with about 2 to 3 times normal capacities.

oldspark wrote:

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Except for battery charging and alternator dips, there should be negligible current flowing to/from the battery.

But there should be no major voltage drops between alt body, engine, chassis & battery -ve.
And the battery terminals and all contacts should be clean to ensure "clamping" of any spikes.

Normally I wouldn't expect huge spikes from an alternator unless it has an external regulator (especially mechanical if such things still exist!), but these are large output alts with about 2 to 3 times normal capacities.

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Yeah I just went to walmart and got a more efficient terminal for my battery. It was much needed anyway. But i hope this could be the reason. My battery is already charging better with the truck turned on. But i couldnt test it because its 4am in a apartment complex.

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Just my 2 cents. There are very few "frames,chassis" today. Almost everything is uni-body.What this means is poor welds,"goop" between the body parts ect. GM vehicles are the worst. The only thing to do in my opinion, is to ground EVERYTHING back to the battery.This can be a pain in some cases, but it eliminates a lot of those mysterious head scratchin',wrench throwin, dog kickin' problems. Not to memtion buying a lot of gadgets that don't work.

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"That'll get ya 10 in Leavenworth,11 in Twelveworth, or 5 & 10 in Woolworth". Groucho Marx                                                      

MrArff - are you saying that modern vehicles are a collection of non-welded (electrically bonded) metal panels?

I thought Uni-body & monocoque construction meant better electrical bonding - ie, NO insulation between body and chassis/frame (whether unintended corrosion or rubber/noise insulation etc).
I also thought welds or fusion to still be the only feasible panel joining method (for most of the vehicle's construction).   

I'm not saying that bonding isn't an issue. A common mistake for those with separate chassis and body was not bonding the two (ie, hi-power alternator and battery grounded to chassis with amps grounded to body with insufficient body/chassis connection).

Similar bonding issues contribute to electrical noise - eg, bonnets needing a grounding strap etc.


My reason for asking is that a few years back - in reply to someone's similar statement about a chassis/body - I commented that I found it incredible that panel work and welds etc would NOT exceed the conductivity of large cables, and if it did, I would be somewhat worried about the vehicle's structural integrity!!
If your experience is different, I'd like to know more. (The older statement above was made by a reality-challenged graduate working in the industry.)

I have often stated that a dedicated ground strap back to the alternator and (engine) battery may be worthwhile as it avoids cable/chassis connection breakdowns, but that such cables should not be required. (Better instead to duplicate cable bolts/joins to save weight & cost.)


I use chassis as a generic term for body/chassis. (I tend to use earth or chassis, not "ground". I'd rather use 0V.)
Whilst it does mean chassis for separate frame/body vehicles (trucks, bikes, my ute etc), it implies "chassis rails" in monocoque vehicles (as per all my sedans) - the latter mainly for physical reasons when bonding/bolting 4G, 0G etc panel sections.
If that terminology is different on this site, I should know so I can avoid confusion.   

Thanks in anticipation!