Okay, I'm having a slight problem with my lights dimming (All of them, headlights, taillights, interior lights) whenever I have my system turned up and the bass hits hard. Now, I'm running a Kicker KX400x1 for the sub (400w rms, 800 max) and an MA Audio HK397 amp for my comps (75wx2 rms, 150x2 max) So when the system hits hard, I'm guessing I'm probably drawing about 900-1000 watts? Now, I don't have a capacitor, and my battery and alternator are still stock. The stock alternator in my Neon is a 75 amp. I'm not really sure how to fix the lights dimming. I've seen some conflicting opinions online. Do I need a capacitor, or would just an alternator that pumps out more amps and/or a new battery be sufficient?
Replies (6)
P0werLifter on 01/15/2005 15:54:56
Alrighty, lets go ahead and figure out the current draw as it stands right now of your system. To figure out current demands for your system, add up the total wattage of your system, divided by the efficiency of the amplifiers divided by the charging systems voltage (13.5 is a good average but todays charging systems do pump out 14.5). That will give the total current demand of your system if you plug in the max values of the components.
An average automobile takes 50-60amperes to run your stock electricals (Headlights, AC, Fan, Heater, etc). That leaves you ({since you stated that you have a 75amp alternator) with anywhere from 15-25amperes to play with.
now, lets do the math shall we?
800watts divided by .9 (class D are 90% efficient) = 888.88
300watts divided by .5 (class AB are 50-60% efficient) = 600
888+600= 1488/ 13.5 = 110.22 Max amperage draw for your alternator to keep up with.
for daily RMS usage your looking at
400/.9 = 444.44
150/.5= 300
444+300= 744/13.5= 55.11 amperes for daily usage not pushing the system to its extremes.
After crunching these numbers you start to realize how much of a struggle your current alternator is having tryin to keep everything up to par especially since you only have a 75ampere alternator.
Even at RMS usage your only giving the automobile 20amperes to run your electricals after your system takes its share.
If your only having minor problems with your lights dimming when the bass hits hard, upgrading your battery to a 800+ CCA, a Cap, might get you buy but i see some pretty major electrical upgrades in your fiture if this doesnt work.
You could also upgrade the Big 3 (Alt to bat, Bat to ground, Enging Block to Ground). If you upgrade all the wiring you should notice a difference in the charging efficiency of your automobile.
Again, if your only having minor problems with your lights as it stands (you might have the gains fairly low to keep the current draw down) then upgrade the Batt, add a Cap, and maybe upgrade the Big 3 as stated above. But if that doesnt work then you'll need to fork out the $$ for a Hight Output alternator to keep things running smoothly.
Descent on 01/15/2005 16:10:44
Whoa damn.
Okay. Well, after just a quick search, this is the only High-perf alternator I could find off the bat
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7947817517&category=33573&sspagename=WDVW
It says it puts out 75 amp at idle, I would imagine close to the 150 while driving...I really don't know much about how they rate these things.
I went to Pep Boys earlier, to see if I could find an Optima Yellow Cap battery, but I can't seem to find one small enough that I can fit in the current spot, without relocating it to my trunk, which I REALLY do not want to do. Can anyone reccommend another battry that would be sufficient? I believe the one in my Neon is a group 24? I'm not positive though. Now, if just upgrading my alternator would be sufficient, I really wouldn't mind spending the $250. Or would I need a cap, battery, and new wires along with that to make it right? I just don't want to spend unneccessary on going overkill with my electricals. Thanks for the help :)
uochronos on 01/15/2005 16:47:14
optimas well fit why do you need a yellow top? they are huge deep cycle batteries meant for trucks and other larger vehicles not for small cars... there should be an optima red top that well fit your car... i have a 850cca red top in my vehicle and it is very small and works well.
as for alternators 75amps at idle isnt bad at all... but make sure its a good quality product. if the guy hasnt sold other alternators before i may be ify about him... look for someone on ebay that has sold a some before... the guy i bought my alternator from sells a ton of alternators on ebay. got a 200amp alternator for only 220$ shipped. i well see if i can find his name for you...
i suggest searching for high output alternators on ebay and look for people that have tons of alternators listed then ask them if they can get one for your car chances are they can. it would be imposible for them to list every car at the same time and not very profitable:)
Chronos
Descent on 01/15/2005 17:37:51
Well, I just found your old post on the alternator you got before chronos, and it turns out the alternator I'm looking at is the same guy you got yours off of :)
As for Yellow Tops, well, I didn't really know much about them, I was just kinda poking around. I wasn't sure what was what. I just looked online and I might have found a red top that might fit under my hood. So, you think if I went with the 150 amp alt and the red top, that could possibly take care of this problem?
P0werLifter on 01/15/2005 23:34:39
If you upgrade your alt and your batt you will be fine for the time being. Sounds just about right actually 150amp alt will work perfectly for your application. Might see minor light dimming when your stopped but your not gonna have it cranked then alot anyway =),
swez on 01/16/2005 03:17:07
POwer Lifter is putting you in the right game plan. If you are having light dimming issues, it's going to make your electricals work a lot harder and ALT failure is a pending issue.
You can do this in stages as the budget allows. A larger CCA rated BAT and wire upgrades are the cheapest things you can do initially. If that does not fill the bill, then your last resort, is to upgrade the ALT. This will either happen by doing it right the first time or waiting til the present stock ALT takes a dump and leaves you stranded.
Either way, if you want to run the bass system that hard, plan on the full electrical upgrades. Until then, consider using less bass power at night to give your electricals a fighting chance.
Swez
Replies (6)
P0werLifter on 01/15/2005 15:54:56
Alrighty, lets go ahead and figure out the current draw as it stands right now of your system. To figure out current demands for your system, add up the total wattage of your system, divided by the efficiency of the amplifiers divided by the charging systems voltage (13.5 is a good average but todays charging systems do pump out 14.5). That will give the total current demand of your system if you plug in the max values of the components.
An average automobile takes 50-60amperes to run your stock electricals (Headlights, AC, Fan, Heater, etc). That leaves you ({since you stated that you have a 75amp alternator) with anywhere from 15-25amperes to play with.
now, lets do the math shall we?
800watts divided by .9 (class D are 90% efficient) = 888.88
300watts divided by .5 (class AB are 50-60% efficient) = 600
888+600= 1488/ 13.5 = 110.22 Max amperage draw for your alternator to keep up with.
for daily RMS usage your looking at
400/.9 = 444.44
150/.5= 300
444+300= 744/13.5= 55.11 amperes for daily usage not pushing the system to its extremes.
After crunching these numbers you start to realize how much of a struggle your current alternator is having tryin to keep everything up to par especially since you only have a 75ampere alternator.
Even at RMS usage your only giving the automobile 20amperes to run your electricals after your system takes its share.
If your only having minor problems with your lights dimming when the bass hits hard, upgrading your battery to a 800+ CCA, a Cap, might get you buy but i see some pretty major electrical upgrades in your fiture if this doesnt work.
You could also upgrade the Big 3 (Alt to bat, Bat to ground, Enging Block to Ground). If you upgrade all the wiring you should notice a difference in the charging efficiency of your automobile.
Again, if your only having minor problems with your lights as it stands (you might have the gains fairly low to keep the current draw down) then upgrade the Batt, add a Cap, and maybe upgrade the Big 3 as stated above. But if that doesnt work then you'll need to fork out the $$ for a Hight Output alternator to keep things running smoothly.
Descent on 01/15/2005 16:10:44
Whoa damn.
Okay. Well, after just a quick search, this is the only High-perf alternator I could find off the bat
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7947817517&category=33573&sspagename=WDVW
It says it puts out 75 amp at idle, I would imagine close to the 150 while driving...I really don't know much about how they rate these things.
I went to Pep Boys earlier, to see if I could find an Optima Yellow Cap battery, but I can't seem to find one small enough that I can fit in the current spot, without relocating it to my trunk, which I REALLY do not want to do. Can anyone reccommend another battry that would be sufficient? I believe the one in my Neon is a group 24? I'm not positive though. Now, if just upgrading my alternator would be sufficient, I really wouldn't mind spending the $250. Or would I need a cap, battery, and new wires along with that to make it right? I just don't want to spend unneccessary on going overkill with my electricals. Thanks for the help :)
uochronos on 01/15/2005 16:47:14
optimas well fit why do you need a yellow top? they are huge deep cycle batteries meant for trucks and other larger vehicles not for small cars... there should be an optima red top that well fit your car... i have a 850cca red top in my vehicle and it is very small and works well.
as for alternators 75amps at idle isnt bad at all... but make sure its a good quality product. if the guy hasnt sold other alternators before i may be ify about him... look for someone on ebay that has sold a some before... the guy i bought my alternator from sells a ton of alternators on ebay. got a 200amp alternator for only 220$ shipped. i well see if i can find his name for you...
i suggest searching for high output alternators on ebay and look for people that have tons of alternators listed then ask them if they can get one for your car chances are they can. it would be imposible for them to list every car at the same time and not very profitable:)
Chronos
Descent on 01/15/2005 17:37:51
Well, I just found your old post on the alternator you got before chronos, and it turns out the alternator I'm looking at is the same guy you got yours off of :)
As for Yellow Tops, well, I didn't really know much about them, I was just kinda poking around. I wasn't sure what was what. I just looked online and I might have found a red top that might fit under my hood. So, you think if I went with the 150 amp alt and the red top, that could possibly take care of this problem?
P0werLifter on 01/15/2005 23:34:39
If you upgrade your alt and your batt you will be fine for the time being. Sounds just about right actually 150amp alt will work perfectly for your application. Might see minor light dimming when your stopped but your not gonna have it cranked then alot anyway =),
swez on 01/16/2005 03:17:07
POwer Lifter is putting you in the right game plan. If you are having light dimming issues, it's going to make your electricals work a lot harder and ALT failure is a pending issue.
You can do this in stages as the budget allows. A larger CCA rated BAT and wire upgrades are the cheapest things you can do initially. If that does not fill the bill, then your last resort, is to upgrade the ALT. This will either happen by doing it right the first time or waiting til the present stock ALT takes a dump and leaves you stranded.
Either way, if you want to run the bass system that hard, plan on the full electrical upgrades. Until then, consider using less bass power at night to give your electricals a fighting chance.
Swez
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