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too much draw or a incorrect ground on a cap? [Archive] - Toyota MR2 Message Board

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too much draw or a incorrect ground on a cap? [Archive] - Toyota MR2 Message Board Toyota MR2 Message Board > Toyota MR2 Generations > MK 1 MR2 - AW11 > MK1 Interior and Stereo Modifications > too much draw or a incorrect ground on a cap? PDA

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prgwarren04-29-2011, 01:19 PMtheres alot of power running through my kenwood system. it includes a Tsunami 5 Farad Capacator rated for 5000w and im at about 3500w.

When i signal the electical guage jumps. the base fades the dash lights each time it beats.
Ive been around so i know that this is a common problem with a large draw from the battery, my question is should i have grounded the capacitor to the frame or the battery post like i did, could that be the prob?

the neg battery post is the brass one with all the red wires.http://i1028.photobucket.com/albums/y344/prgwarren/P1010172.jpg ToyotaTechGeek04-30-2011, 05:31 AM1st: how many watts and how many amps TOTAL are you running? remember that a capacitor is only used for transient moments in the music or signal that goes through your system. if you are running only your stock alternator, then you need to think about a higher amp alternator. also, i see you are trying to use a star ground sort of set up. you need to probably address the actual main battery ground when doing a star ground as such.
on a side note, i find it interesting that you've properly terminated your ground wires with heat shrink, but have exposed +12v wires going into that battery terminal. prgwarren04-30-2011, 02:10 PMI've found 130 amp alternators for sale, I think stock is 90 amp, upgrading is a "to do" on a list somewhere. Sooner than later i guess. A larger battery as well?

Has anyone had a short cause this?

ya the +12v is poorly connected. good eye. Kerry Phillips04-30-2011, 10:09 PM3500 watts/12 volts/75% efficiency~400 amps

The stereo system is taking far more current (at peak) then the engine's starter!

This is my recommendation:

Add an additional battery-your best choice is probably a large capacity marine battery-dual purpose deep cycle/engine start.

Add an additional large capacity alternator, my 1989 Ford Taurus came with a 130 amp unit!


And the most important part...... Keep the amps and the car's electrical systems isolated!!!!!!! So, only the amps, marine battery, and second alternator are interconnected and INDEPENDANT from the rest of the vehicle.

This will prevent electrical gremlins from developing, ease electrical troubleshooting, and by completely isolating the electrical systems, your car will have ZERO problems starting due to the stereo discharging the starting battery.

kerry MANDALAY04-30-2011, 11:43 PMTo answer your question the cap should be grounded with the shortest earth cable possible straight to the body.
The cap Tsunami 5 Farad i dont know this one. Does it have a very low ESR ?
Or is it just one of those big caps that are used on Russian Tanks ? prgwarren05-02-2011, 02:27 AMall very helpful and ill put to use. i allways thought i knew alot about stereo systems, humble this guy.
http://i1028.photobucket.com/albums/y344/prgwarren/my%20Dues/P1010216.jpg
i was told its too much but whatever you only live once.
http://i1028.photobucket.com/albums/y344/prgwarren/my%20Dues/P1010215.jpg
6x9 mod to the door. i dont think i shoulda done that but again, its all good.
thing is i had to make a template and cut a hole. eew cut a hole. eewww. scottohno05-02-2011, 02:55 AMhmmm left hand drive and JDM/euro cluster..... where are you located? i thought only americans drove on the left, and we dont read speeds in KM/H

on another note, get a deep cycle battery, mount it in the frunk or trunk, and connect it in parallel to your current battery. should be problem solved.

i must ask, why so many ground wires? the WHOLE body is ground. if your engine and chassis grounds are good, youre fine. i grounded my system (it was smaller though) to the seat bolt with 4G wire. worked fine. prgwarren05-02-2011, 03:15 AMim in canada. km/h, LHD. the star ground was a gift. i like it. guaranteed ground though. ha. ya Deep cycle, i hate to add any more weight but its no spacecraft so ill weld a old tray in the frunk. haha last owner took out the spare and removed the mount for the tire bolt retraint. SMRT. scottohno05-02-2011, 01:10 PMhmmmm, i may leave mine, just cause i dont want the front end to slide, i want the rear end to slide.

i actually usually put a sub in the frunk usually to weigh it down for rainy days. Luni05-02-2011, 02:06 PMI have a real hard time believing youre really using 3500 watts of power. Thats ALOT.

Either way, if your amp pulls down more than 90 amps of power youre overdrawing your electrical system. No matter what you got to "help" it cant "help" beyond the scop of the original charging system.

It doesnt take much to exceed what the alternator can put out. Right around 1000 watts will do it. At 1000 watts, you have a few amps left over for the vehicle to run, but it wont be enough if you have the hvac blower running, headlights on, turn signals, etc. It all uses juice.

You need a rewound alternator. Even having another battery is going to be a double edged sword. The alternator can only recharge so much. So, if youre using the stereo, you arent recharging anything. The alternator is focused on keeping everything charged, it will HELP a little bit, but the problem on the flip side is the second battery may never get fully recharged unless you drive around with the stereo down.

You cant make power from nothing. You need more amps available at all times. That means a bigger alternator. Like a Startach rewound one. If you really are pulling down 3500 watts (I seriously doubt it, just based off your amps), but lets say you are. Youd need a ~300a alternator to run all that.

Post specs on all the stuff you got. Amplifier model numbers, what speakers you are running, etc. Lets see realisticially how much you have.

Another good way to tell what you cant go past is looking at the fuses in the amplifiers themselves. Voltage x Amperage = Wattage. Under normal circumstances your voltage is 14.4 volts in a car, with the engine running, but some amps have regulated power supplies that dont let more than 12 in. So do the math at 12. Look at the fuses for your amplifiers and see what their amperage is and times that by 12 and see how many watts you are capable of using (you can never overdraw the fuse without popping it, so if you arent popping it, you arent overdrawing it, and thus not using even THAT much power).

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