help with voltage drop on a ms2250

Need help with your car stereo system? Have a technical question? Post here.
Post Reply
dwobert
Posts: 14
Joined: Sat Jan 05, 2008 6:10 am

help with voltage drop on a ms2250

Post by dwobert »

I have two kicker cvx 12's they are wire at 2@ohm. They powered by a ms2250. Running in stereo mode. Amp is feed from 5 farad cap. Cap is a voodo. I also have a 1000cca bat and 225amp alt. Bat is a dry cell. Wire from bat is 1/0 to dis block and #4 to cap and amps. I also have a Zx450v2 powering my mids and Highs. That amp is wired @ 4ohms x 4 should be pushing about 75watts by 4.
I cant turn ms2250 up high do to voltage drop. When bass drops to low notes voltage drops to about 11.9. I have ms tune down so clip lights only flash on low low notes. I my subs can handle lost more. Gain is about 3rd same with bass boost. I just ordered a phoenix gold line driver for ms2250. Alex and Phil @ Phoenix Gold said that will help amp make more power. But will not help voltage problem.
What should I do to help this out. Should I change cap to a name brand or should I add 2nd batt. Or should I do both.
User avatar
KHPower
Posts: 878
Joined: Wed Apr 23, 2008 2:18 am
Location: In the Phoenix Phorum's boiler room , east of the janitors closet
Contact:

Post by KHPower »

Have you checked the voltage at the battery with a multimeter or from the alternator?
I would add a second battery or make sure yours checks out ok
dwobert
Posts: 14
Joined: Sat Jan 05, 2008 6:10 am

Post by dwobert »

I did chck voltage drop at alt and bat. Voltage at bat and alt are the same when bass drops 12.13volts @ 1500rpms voltage is 12.92
yesterdaysyouth
Posts: 29
Joined: Sun May 04, 2008 7:23 pm

Post by yesterdaysyouth »

high output alternators put out less current at idle, than a stock alternator. that's just how it works....

if you want more power you're gonna need to get the rpm's up, another battery will just load down the alternator more, but it will help with voltage drop below 12.8V.

when I had my ms2250 wired just like yours, in my car, with a 180amp alt. i could hold the rpms @1500 turn on a 35hz. tone and shut the engine off.

it's also possible that you've burnt out a diode or even burnt windings inside the alt. I did it 3 times, in one year...

the ms2250 makes lots of dynamic power, but it takes alot to feed it!
User avatar
stipud
Voltage Ohms
Posts: 14719
Joined: Sat Nov 26, 1983 4:00 am
Location: Burnaby, BC
Contact:

Post by stipud »

Less current than stock alternators? That's not necessarily true at all... My externally regulated 190 amp alternator makes more amperage than my stock alternator does at max RPMs (130).

Not all alternators are created equally. Some produce 200 amps at max RPM, but only 85 at idle (still approximately equal to what you would get with a ~130 amp stock alternator, if you're lucky). Some produce 200 amps, but 135 or more at idle. It all depends on how they were constructed. Of course, higher idle current usually means more expensive, since you need to do things like external regulation to reliably produce this! (External regulation keeps the regulator cooler at idle, so that it has an easier time keeping your current solid).

Check out http://www.wranglernw.com/. They used to make the alternators for PG. I bought one from them, and it was a literal work of art, especially compared to the other cheaper "high output" alternators I have bought in the past. Compared to my old "250 amp" alternator, this 190 amp one has never had a hiccup, powers my stereo far more reliably, and my voltage never sags.

With an aftermarket alternator, you get what you pay for. Same goes for batteries -- the ones better suited for your stereo (like Kinetik) are quite expensive compared to typical batteries.

It sounds like your battery (1000cca dry cell) is a decent one, so I wouldn't necessarily add a second one. As yesterdaysyouth pointed out, this will just load your charging system down more, and it would only really let you play longer when your car is off. However, if your alternator cannot provide sufficient amperage and you load your battery down with every bass hit, a second battery would help keep your voltage at around 12v at the very least (though this would only be a kludge fix, at this point you would really need more alternator).

First and foremost what I would recommend is CHECKING YOUR AMP GAINS!!! If you clip an MS2250, no charging system out there will avoid voltage sag. The easiest way to clip is by using bass boost! Please turn that off, and use your amp gains to increase/decrease the volume instead. Read this FAQ and set your gains at the correct level:
http://phoenixphorum.com/gain-setting-w ... vt280.html

Second thing to do is upgrade your big 3! Make sure you create a ground from the battery to the frame and battery to engine/alt in 0 gauge. Upgrade your alternator to battery wire to 0 gauge as well, considering your 225 amp alternator. I personally run 0 gauge power and ground directly to my alternator, with a 0 gauge ground to my frame from the battery. This has proven to be an extremely reliable setup.
User avatar
KHPower
Posts: 878
Joined: Wed Apr 23, 2008 2:18 am
Location: In the Phoenix Phorum's boiler room , east of the janitors closet
Contact:

Post by KHPower »

wow thats some good info and saves me from posting more questions 8)
dwobert
Posts: 14
Joined: Sat Jan 05, 2008 6:10 am

Post by dwobert »

my alt puts out 105amps @ idl and 225amps a @ 1500 rpms. I starting to think I need 2nd batt to help would like to know for shore..
User avatar
fuzzysnuggleduck
Soy Milquetoast
Posts: 4423
Joined: Wed Dec 06, 2006 1:08 pm
Location: The best place on earth
Contact:

Post by fuzzysnuggleduck »

Continuous power draw for an MS2250 is rated at 90A. Peak is 130A.

Just throwing that out there.
SOLD: '91 PG 4Runner
Post Reply