noobslayer77 Posted September 23, 2014 Report Share Posted September 23, 2014 resistance in parallel drops? 2004 Jeep Liberty Limited 2 13w7s skar 3500 cnf mids (soon) xs batteries Link to comment Share on other sites More sharing options...
SLYentist Posted September 23, 2014 Report Share Posted September 23, 2014 haha yeah, so if the ground run was put in, it would be in parallel with the chassis ground. the resistance is 1/r + 1/r = 1/R, instead of series with is r+r=R example: two 10 ohm resistors in parallel breaks down as (10x10)/(10+10) = 5 Ohms two 10 ohm resistors in series breaks down as 10ohms+10ohms = 20ohms Cables and wires almost never fail; the terminations do. Link to comment Share on other sites More sharing options...
MrSkippyJ Posted September 23, 2014 Report Share Posted September 23, 2014 How does adding a ground wire change any of that? F150: Stock 2019 Harley Road Glide: Amp: TM400Xad - 4 channel 400 watt Processor: DSR1 Fairing (Front) 6.5s -MMats PA601cx Lid (Rear) 6x9s - TMS69 Link to comment Share on other sites More sharing options...
Karkov Posted September 23, 2014 Report Share Posted September 23, 2014 Maybe I missed it but what is your voltage drop like? What alt you got? Batteries? how many and what ya got? That amp has dual inputs. Maybe I am over thinking this You running the amp at 1 ohm or lower? I mean, without knowing what your voltage is like or your setup it's hard to say if you should add another run. If you got a beast alt and one 8' run to the back of a Geo Metro and 10 batteries in back running your amp at 2 or 4 ohms I doubt you would need another run front to back... 2007 Chevy Tahoe (SOLD) 12 ~ FI Audio X series 10" w/BP option 2 ~ DC Audio 5.0K @0.67 3 ~ DC Audio 5.0K @1.0 2 ~ PPI 3 way sets (not installed yet) 1 ~ RF T400-4, 1 ~ RF T600-2, 1 ~ RF T600-4 4 ~ CT Sounds 5.25" Strato comps (rear fill only) 1 ~ XS Power D4800 1 ~ XS Power D3400 8 ~ XS Power XP3000 160 stock alt, Mechman 370 Elite, 185 DC Power 320+ Sq. Ft. Sound Deadener Pioneer AVH-X5500BHS Youtube: https://www.youtube.com/user/knfjdkghjudfhsgkjdhf/videos?sort=dd&view=0&shelf_id=0 Link to comment Share on other sites More sharing options...
gckless Posted September 23, 2014 Report Share Posted September 23, 2014 ^This. No one can say for sure until we know what's up front. The only current that's going to be running across that wire is whatever is being supplied from the front, i.e. your alternator and front battery (unless you have something more). Rear bank doesn't really matter here. I would say it's unnecessary unless you have a 270A+ alt and a large battery up front, but it's not like it's going to hurt. Just some extra money that might be better spent elsewhere. Do you notice different voltage readings in the front versus the rear? "Clipping" is the biggest forum boner now. It's like witchcraft... it automatically explains just about everything people don't understand. My build log: http://www.stevemeadedesigns.com/board/topic/200295-gckless-2011-chevrolet-impala/ High resolution photos: Gilbert Kless Photography Link to comment Share on other sites More sharing options...
SLYentist Posted September 23, 2014 Report Share Posted September 23, 2014 How does adding a ground wire change any of that? Adding an additional ground wire instead of an additional power wire sets up a lower resistance to ground between the rear bank and the alternator up front. adding another power run reduces resistance on the power, but the ground is still restricted by the chassis. Cables and wires almost never fail; the terminations do. Link to comment Share on other sites More sharing options...
MrSkippyJ Posted September 23, 2014 Report Share Posted September 23, 2014 I understand your thinking, although there was a test done that shows up to a certain wattage (I want to say it was 5k) that the chassis was actually better. My question though is how adding a second ground wire changes the parallel/series wiring in anyway. F150: Stock 2019 Harley Road Glide: Amp: TM400Xad - 4 channel 400 watt Processor: DSR1 Fairing (Front) 6.5s -MMats PA601cx Lid (Rear) 6x9s - TMS69 Link to comment Share on other sites More sharing options...
SLYentist Posted September 23, 2014 Report Share Posted September 23, 2014 I understand your thinking, although there was a test done that shows up to a certain wattage (I want to say it was 5k) that the chassis was actually better. My question though is how adding a second ground wire changes the parallel/series wiring in anyway. The second ground wire would run from the rear battery distribution block ground directly to the front battery ground, and the chassis ground gets left alone. That creates two connections to ground from the distribution block, making a parallel connection. I wouldn't trust a chassis ground up above 300A MAX, but that really depends on the car or truck. Steel is much less conductive than aluminum or copper. Cables and wires almost never fail; the terminations do. Link to comment Share on other sites More sharing options...
MrSkippyJ Posted September 23, 2014 Report Share Posted September 23, 2014 I understand your thinking, although there was a test done that shows up to a certain wattage (I want to say it was 5k) that the chassis was actually better. My question though is how adding a second ground wire changes the parallel/series wiring in anyway. The second ground wire would run from the rear battery distribution block ground directly to the front battery ground, and the chassis ground gets left alone. That creates two connections to ground from the distribution block, making a parallel connection. I wouldn't trust a chassis ground up above 300A MAX, but that really depends on the car or truck. Steel is much less conductive than aluminum or copper. OOOH. I see what you mean now. Not sure why that didn't sink in before. That was the point of the test though, because people always assumed since frames are steel that it is just always better to run a dedicated ground. The thing the test showed was the amount of steel in the frame more than makes up for the conductivity loss. Of course the type of car makes a huge difference (I believe the test was in an Altima) and I do not remember what the max amperage was. F150: Stock 2019 Harley Road Glide: Amp: TM400Xad - 4 channel 400 watt Processor: DSR1 Fairing (Front) 6.5s -MMats PA601cx Lid (Rear) 6x9s - TMS69 Link to comment Share on other sites More sharing options...
soundstream15 Posted September 23, 2014 Author Report Share Posted September 23, 2014 170a mechman alt Xs power d3400 under hood Kitneik hc2400 and shuriken bt35 in trunk Big 3 All 1/0 sky high OFC I drop to 12.8v and wired at 1ohm Link to comment Share on other sites More sharing options...
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