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daffydak
GenIII
 
5/05/2004
18:44:54
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 Subject: good place to ground amp and cap??
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I think i have my power problems tracked down to a bad ground point. I currently have my amp and cap grounded to a seat bolt (yuk) just scraped the paint off and put it there as i was in a hurry....
sad sad sad :-( i guess i'm still a newbie at the audio setup game, bear with me lol!!
Where is the best place to ground my system? (Gen 3 RC behind pass seat with factory jack relocated)
I was thinking about the hump where the jack was, but I’m not sure.... also will this be the correct way to prepare a ground point? (Scrape a 1-inch area around the ground screw/bolt and secure it this way.
I really appreciate the help, i can’t wait to get more power out of my system
Dan
MOPAR=More Power!!
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Justi
Dodge Dakota
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5/05/2004
21:41:53
|  RE: good place to ground amp and cap??
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If done properly the seat bolt is a very acceptable location for your ground. it goes straight into the chassis and with it's large threads offers a lot of surface contact area. So if you are having ground related problems with a seat bolt ground then I'd guess you aren't connected to it well. That or you have a short and it's leading you to believe it's a ground problem..
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daffydak
GenIII
5/05/2004
22:02:56
| RE: good place to ground amp and cap??
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Thanks!! The reason i think its a ground problem is that i tightened my ground cable on my battery and it got better. I have a 117-amp alternator, and a 1-farad cap. I dont think i should be getting the voltage drop i get when i crank it. If i have it up moderately, the voltmeter on the cap dips into the low 12 range. If i really crank it, it goes into the high 11 range and my rpms drop!!!! I think it’s just a wiring issue, but i may need a bigger alternator. My battery is less than a year old, so that shouldn’t be the problem.
Oh i forgot to mention my setup: mtx 6500d amp fed by a 4ga power wire to an 8-ga dist block to my power cap to the amp. The amp is pushing 1 kicker solo baric L7 10 at 1 ohm.
Thanks for the help! I’m going to look and see if i can get a better ground tomorrow.
Dan
MOPAR=More Power!!
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JMII
Dodge Dakota
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5/06/2004
19:40:10
|  RE: good place to ground amp and cap??
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How big is your ground wire? It needs to be 4 gauge. And run the 4 gauge directly to the cap AND amp, get rid of that tiny 8 gauge it's limiting your system. Seat bolts are normally very good grounds, provided you've scraped away the paint and have a good connection there (put some light grease around the area to prevent rust).
Also look into upgrading the ground wire on your battery itself. It can only carry so much juice and if your cap is pushing the limits you need to look at current flow as the problem. I doubt a bigger alternator will help you much.
- John
http://www.blueoceanpress.com/~storage/truck/index.html
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daffydak
GenIII
5/06/2004
20:14:11
| RE: good place to ground amp and cap??
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i was thinking about the 8ga wire being a factor. i have some 4ga somewhere around here. all i need to do is find it and buy a new dist block and terminals. i didnt think the 8ga was that big of a deal, because it only runs from the dist block to the cap to the amp... my main power wire is 4ga. everything else is 8ga.... thanks for the heads up on the bottleneck!!
i have the paint scraped off with a dremel. and after I attached the wires, I sprayed the area with battery anti corrode paint.
Dan
MOPAR=More Power!!
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DSW
Dodge Dakota
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5/06/2004
21:12:06
| RE: good place to ground amp and cap??
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If your grounding to the seatbelt bolts or seat bolts your relying on the stock chassis to frame grounding points. It's best to ground to the frame since the - battery cable connects to the frame.
I drilled a 5/8 hole through the floor and grounded everything (amps, cap, changer and stereo) to a common ground point which is the end of the inner frame rail below the drivers seat. Rockford Fosgate suggests to use frame ground instead of body ground since body ground can induce a ground loop (noise). I went overboard and connected the common frame ground point the the - battery terminal with an 4 ga wire to make sure I had a very low resistance ground. It might be over kill, but I don't have noise in the stereo.
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daffydak
GenIII
5/06/2004
21:59:14
| RE: good place to ground amp and cap??
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how hard is the frame to drill?? that sounds like a killer idea!!!i'm going to get all 4 ga wires instead of 4ga to 8ga dist block. then i will go from there....
btw, my fuse looks like its been stressed pretty good (element looks a lil distorted,, not melted) its 80 amps, so i know im pullin alot of juice (or have too much resistance)
many thanks!
Dan
MOPAR=More Power!!
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DSW
Dodge Dakota
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5/07/2004
00:58:19
| RE: good place to ground amp and cap??
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The drivers side inner frame rail has a 1/4-5/16 hole close to the edge, I just drilled it to 3/8 so I could use a bigger bolt. The frame was a pain to drill, wonder if my dull bit had anything to do with it?
Your fuse might look hot because of the poor ground and dipping voltage. 800w of power at 14V equals a 57 amp draw, but 800w of power at 11v equals a 73 amp draw. Could be why the fuse looks discolored.
Even if you get the ground problem straightened away, you might still have a problem with the voltage dipping, especially when the truck is off and the alternator isn't providing power. I could see your battery voltage dipping down to the 11v range after an hour of drawing 50-80 amps with the truck off. A bigger alternator will give you more charging potential and power when the truck is running, but a bigger battery or second battery will provide more reserve power when the truck is off or at low RPM. Alternaotrs don't put out thier rated power until they are spooled up, 2-4K RPM I would guess.
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daffydak
GenIII
5/07/2004
10:36:08
| RE: good place to ground amp and cap??
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There’s no way i would dream of running my stereo with the engine off! lol.
The amperage draw is a good point, i didn’t think of that (watts/volts=amp draw, right?).
I just ordered 4ga terminals so i can redo all my amp wires in 4ga. that should help a little bit at least. Next will be the whole truck ground cable, I may make that 1/0ga!!
Thanks for the help!!
Dan
MOPAR=More Power!!
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daffydak
GenIII
5/12/2004
15:18:34
|  RE: good place to ground amp and cap??
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ok, I now have all my amp and cap wires in 4 ga. it didnt help, if anything it made it worse! now the voltage really drops when its cranked (at idle) I dont know about driving down the road, but I dont like having such low voltage!! (sometimes high 11s on the cap's meter. battery is only about 6 mos old)
I think I have reached the limit that my alternator can produce (117 amp stocker) thats the problem. my old amp never did this (cheap legacy la590 "800" watt amp) but my much more powerful mtx thunder 6500D (running solobaric s10L7 @1 ohm) draws a LOT of power!!
I thought class D amps were supposed to be better on power? oh well, time to save up for a bigger alternator.........
Dan
MOPAR=More Power!!
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Levey
Dodge Dakota
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5/12/2004
16:57:14
| RE: good place to ground amp and cap??
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What kind of battery do you have?? It doesnt really matter how old it is,if you bought a cheapo. I never put anything less than about 900-1000 CCA (cold cranking amps) A lot of batteries they try to sell you are closer to 500-600. And they arent much cheaper either.
For almost 2yrs ive had a MAXX Yellow battery from Wal*Mart..ran me $70 rated for 950 CCA. When i go camping i run my stereo with the car off for several hours and it still starts right up!
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DSW
Dodge Dakota
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5/12/2004
17:06:29
| RE: good place to ground amp and cap??
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If you ran 4 ga wires to the amp and grounded everything realy well, your problems should be better or maybe the same, but I wouldn't see how it could get worse. Upgrading to a larger alternator might produce the same problem since the alternator won't deliver full power until the engine is off idle and spinning the alternator faster.
It seems like the battery you have doesn't have enough reserve capacity to provide sufficient power for your amp. Is your battery the stock size? Why not try putting in the largest battery that will fit in the tray? I looked at mine the other night and there's extra room in the tray to put in a bigger battery, like a group 29 or 31.
With your truck idling, turn up the stereo and check the cap voltage with a multimeter, then check the voltage of your battery with a multimeter. If they are the same (let's say 11.8V) then your wiring is good, but your battery can't handle the load. If you have an extra (fully charged) battery hook it up to your truck with jumper cables and see if the cap and battery voltage readings change. Hooking up the second battery will add the reserve capacity of the second battery, even though the jumper cables are not the best conductor to hook the batteries together. A second battery is an option, but you would have to find a place to mount the additional battery and run battery cables.
If you get another battery make sure it's fresh, new batteries that have been sitting on the shelf for a long time (6-12 months) can sulfate. I buy 1 or 2 batteries a year for my boat and try to get batteries that are current or a month old. There should be a sticker noting the date of the battery in the format of month/year, E/4 or 5/4, which means May/2004.
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daffydak
GenIII
5/12/2004
20:43:04
| RE: good place to ground amp and cap??
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My current battery is a duralast gold from AutoZone 62.99 + tax (730 cca 906 cranking amps) the problem isn’t really that much worse, maybe i just expected it to get a whole lot better...
The cap has its own digital power meter (accuracy unknown) and during really crazy bass it sometimes drops into the 11.90V range momentarily.
It comes right back up to around 13.80 or so when I turn the volume down or the stereo off.
I dont really have a second battery (riding mower may suffice??) i just dont get it.... i mean even the rpms drop with the bass sometimes, and the volt mater on the dash goes below the 14V middle mark.
Maybe I should try an optima battery, they sure are expensive though.
Thanks
Dan
MOPAR=More Power!!
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DSW
Dodge Dakota
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5/13/2004
00:10:33
| RE: good place to ground amp and cap??
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Reason the RPM's are dropping is because the alternator is kicking in and putting a load on the engine in the process, either that or the voltage fluctuation is messing with the engine electronics.
It sounds like you just need a bigger battery or a second battery so when the amp wants to draw 50 amps, the battery(s) can deliver the 50 amps of power. Your cap should be bridging the gap when the battery can't provide enough power instantaneously, but then again the cap can only charge to the voltage of the battery and/or alternator.
What group size is your battery? You need the biggest battery that you can fit in the battery tray to start off with and then add a second battery from there if needed. I don't think the type of battery has anything to do with the problem, AZ Gold compared to Optima, rather it's the amount of battery that you have.
In my boat I can troll around for 4-5 hours on one brand new battery, or 7-8 hours on 2 old slighlty run down batteries. I get more out of 2 older batteries because there is more "battery reserve power", even though they are not providing optimal power, they still work better than one perfect battery. Same thing with your situation, one big battery is going to work better than one small battery since the bigger battery can provide more power, or 2 batteries are going to work better than your single battery.
The lawn mower battery won't wory for the test since it has very littlt reserve power. One bass hit from you amp would probably melt the terminals, explode the case and send acid spewing forth, just kidding ;)
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daffydak
GenIII
5/13/2004
09:40:41
| RE: good place to ground amp and cap??
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how do i find out the group size? it it on top of the battery somewhere? its a pretty big battery, it takes up the space under the heat shield nicely (gen 3) its aout the same demensions as the oem one.
I figured the rpm drops were from the alternator, or the coil losing voltage. its not a really bad drop (about one little mark on the tach) but it sprngs right back up when the bass lets up.
maybe I should just wire my speaker back up for 4 ohms, it didnt put out near as good though :-(
thanks again
Dan
MOPAR=More Power!!
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DSW
Dodge Dakota
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5/13/2004
18:38:51
| RE: good place to ground amp and cap??
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Group size should be listed on the battery. I have an OEM sized replacement battery and it has about a 1" gap between the battery and tray on each side. I have plenty of room to put a bigger battery in my Gen III and thought you might as well. Wished I had bought a larger battery, but the amps weren't thought of when the battery went dead last year.
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