am i on the right track with power upgrades?

[blkvenm97]

Ok I'm wondering if I am on the right track as far as upgrading my electrical to sufficiently run what I plan to run. My plan is to run two rockford t1000-1bdcp amplifiers and a rockford t400-4 amplifier for mids and highs. What I did to ensure it would be enough is take what is on the birthsheets for the amps and multiplied that by .82 (because the amps are 82% efficient at 2 ohm which is where they will be running) and I came up with 2460 (started with 3000 total because the amps have approxiately 1500 watts rms)...that means I have to add the 540 watts to the 3000 and I came up with about 3500 watts or so is what it would cost me to run those two amps with efficiency factored in (approximately) then you take the 400 into account it'd probably cost around 500 to 600 si I'm right at or slightly above 4000 watts cost with efficiency factored in. If I get a 250 amp alt you multiply 250x14.4 and I came up with 3600 watts that I could power. I have an xs power s3400 under the hood and will get a second battery for the back...probably a d3100 xs. Would that be enough to sufficiently run this setup and keeps volts up well with no dimming? Even though the total cost to run the amps at their max birthsheet ratings would probably be.a.little over 4000 watts with efficiency factored in and a 250 amp alt would only supply enough for 3600? I assume the two big xs power batteries will take care of the rest easily...am I on the right track? Thanks for any help...also anyone know where I can get a 250 amp alt for a 2003 svt focus? A mechman rep told me the biggest they make for this car is 180 amp but I am sure I've seen older focus running 250 amp alts before. Thanks again

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[Roland 10+ year member]

It really depends how hard/loud you run your system, mainly your subs. And what kind of box your subs are in.

Most folks don't get anywhere near the rated power of there amps when laying music. If your a bass head and have sealed boxes then you might prep for worst case.

I run 3000 watts of class D amps but never pull over 80 amps. most of the time my system is only pulling 40amps.

 

[blkvenm97]

Well I want to be able to run at full tilt and power everything fine that way I'm set regaurdless of weather I'm full tilt or not. I realize that most never see the ratings on the birthsheets because they don't see 14.4 volts...but the point in upgrading my electrical is so I can get as close to 14.4 as possible. I also went by the birthsheet ratings when doing the math just to prep for the most my amps can possibly put out at 14.4 volts...that way I hopefully am able to power everything to run at full tilt without a whole lot of voltage drop.

 

[blkvenm97]

I am running rockford p3 12s in a ported box right now but will be changing subs and going with either sundown or rockford t1 (possibly others) and run a second t1000 I have in addition to the one I already running on my 12s so there will be one amp on each sub. I wanna prepare as if I'm going to always run full tilt and anything less will be covered. Would a 250 amp alt and two xs batteries be enough? I have the xs3400 will probably opt for the d3100 as the secondary.

 

[akillj 10+ year member]

You don't multiply by .82, you divide. Efficiency doesn't mean that they produce 82% of their rated power, it means it consumes 18% more power than it's rated for, to create rated power. We figure this by 3000 / .82 = 3658w. Your amps will consume 3658w to create "3000w rms" (If they both, do indeed produce 1500w rms each)

3658w / 14.4v = 254a.

You would need 254 amps of alternator amperage to supply just your monoblocks (on a solid tone). Not counting mids/car requirements. Since you won't be just listening to sine waves you will be fine with less, or around that mark. (I'd always recommend more though)

Alternator constantly supplies power, batteries are temporary. More batts can stabilize your voltage, but they still need to be recharged. So getting a bigger alt to supply everything should be a priority over multiple batts.

 

[blkvenm97]

Yea I know you devide I did the same thing you just did in a weird roundabout way....I multiplied it by .82 and came out with 2460 and subtracted that from 3000 and the number I got there added to 3000...which came out to just over 3500...this is all just estimates based on the birthsheets btw. My way is the same just the long way around I suppose lol. Yea it would take around a 250 amp alt just for the monoblocks and ill just be running a t400-4 on mids so it'll come out to a little over 4000 id say...this is assuming all 3 amps do the birthsheet rates. A 250 amp alt should do it I would think but its be close. I'm thinking about possibly selling the t1000s and going with a t1500 then my electrical upgrades would be more than enough...albiet with a little less power overall on the subs.

 

[blkvenm97]

I would go with an alt larger than 250 amp but I've never seen one larger than that on a first gen focus (I drove a 2003 svt focus which I think has the g6..or 6g or whatever its called)...I would love to have enough alternator to supply the system and let the battery(s) just stabalize the voltage to have as little voltage drop as possible. Id like to get as close to 14.4 as possible at full tilt (I know that isn't easily done)...that way I could actually pull those numbers that are on those fancy birthsheets. Thanks for the help...anyone else wanna chime in? Anyone know where I can get a 250 amp alt for an 03 svt focus or possibly an even larger one? Thanks again

 

[akillj 10+ year member]

Holding 14.4 at full tilt is just un-necessary. Attempting to hold that, you'll be spending way more money than you need to without any real-world advantage. Unless of course you're chasing tenths on the meter. If your voltage is above 13 there's no problem whatsoever. Do you listen to sine waves when you drive? I doubt it. Calculating amp draw is only applicable when running a sine wave (constant draw, no breaks).

You should be fine with a 250a alt. Check Mechman / DC Power sites. They make great alts. I'd also check out Singer alternators. He makes big alts for cheap, without sacrificing quality.

 

[juanmgarza26 10+ year member]

Wanting 14.4 is not hard to get. My vehicle charges at 14.2 cold and 13.8-13.9 hot. Doesnt affect much when you set up your amps right. Like said above that's really only useful when competing and chasing tenths in the meter...

 

[blkvenm97]

well lets put it this way...i want my voltage to remain as high as possible (as in 13+ at full tilt all the time) without spending tons and tons of cash. I believe a 250 amp alt and possibly a d3100 in the back would more than cover that. thanks a lot guys this helped me a lot. so basically if your volts are staying low to mid 13s or even higher at full tilt you shoudln't have any dimming or anything like that...correct? I saw an older focus somewhere on here with a 250 amp singer...i'll have to check those out

 

[blkvenm97]

On the rockford fosgate website it has the average amp draw and ax amp draw listed for each amplifier they have. The t1000s have a max amp draw of 140 each and 70 draw average on music at 13.8 volts. The t400 is like 60 amp max (sinewave) and 30 amp average on music at 13.8 volts. So the max amp draw from all 3 amps is 340 amps on a sinewave...average amp draw from all 3 together on music at 13.8 volts would be 170....so with that being said I believe the 250 ammp alt would be fine. It helps some that ill be running each t1000 at 2 ohm which averages 82% as compared to only 70% efficient at 1 ohm with very minimal benefit as far as more power...the constant power amps put out very close at 2 ohm to what they do at 1 ohm...both of my amps are about 50 watts less at 2 ohm then at 1 ohm while being over 12% more efficient on average which greatly helps ecspecially when running two.