Seni Posted August 18, 2015 Report Share Posted August 18, 2015 Hello, this is my first post but ive been reading these forums for awhile. I have a 2015 GMC sierra 1500 5.3L double cab. just put a system in "small system by what i see on these forums lol" The problem im having is that the computer controlled charging system constantly shuts the alternator off or way down which in turn reduces the input voltage my amps see. now it really hasn't caused a problem that i can tell but clearly it would be better if the system voltage was 13.8+ instead of 12.5. i reached out to mechman and got an email back right away that the currently do not have a solution for this. My system stock headunit 8" LCD JL cleansweep rockford 1farad cap pioneer D8604 for the doors/dash upgraded all 6 speakers pioneer D9601 for the subs 2x 10" SKAR VD10 D4 at 1ohm i have knu 1/0 run for everything including big 3 and i replaced the stock battery with a 31 group optima everything sounds fantastic and the only problem is that the headlights dim ever so slightly when the bass hits. ive measured the voltage with a multimeter and it never dips below 12.2v but clearly without the alt running there's enough juice flowing to the amps that the headlights dim. I have a DD1 coming tomorrow and after i set my gains and doing some tuning i have a feeling i'm gonna be sucking even more juice (everything is set very very conservatively atm) Thanks for you help/time in advance! Link to comment Share on other sites More sharing options...
ToNasty Posted August 18, 2015 Report Share Posted August 18, 2015 This is the battery current sensor. 2005 and up have this. If you want to charge higher, then turn your lights on. You'll charge at 14.6 with the lights on. When you don't need to , shit the lights off ***Super Sellers List***http://www.stevemeadedesigns.com/board/topic/25829-super-sellers-buyers Link to comment Share on other sites More sharing options...
Seni Posted August 18, 2015 Author Report Share Posted August 18, 2015 And thats what the Dealer told me they also printed me the Smart charging system specs/rule sheet that explains the different modes and what triggers the system to charge etc. the problem is i think (not sure) that the optima battery is just so much better than the stock battery that when you turn the headlights on or the blower or the wipers (all these should trigger 13.9v charge mode). That the computer doesn't see any voltage drop so it doesn't trigger charge mode like it should. i drive around with the headlights on the A/C blasting and the system pretty loud and it just sits at 12.5v which is basically alternator OFF mode. the optima holds up really well (i'm not sure how many amps in drawing) but i've run the system with the truck off for 20-30 minutes and the battery is still at 12.4v after i let it rest a bit. im fairly sure i'm not drawing more than a 150 amp alt can handle with this system. so if it's sitting at under 14v i assume its because the computer is telling it not to charge. Link to comment Share on other sites More sharing options...
ToNasty Posted August 18, 2015 Report Share Posted August 18, 2015 It's to get better gas mileage. I have the same thing on my silverado. It's normal ***Super Sellers List***http://www.stevemeadedesigns.com/board/topic/25829-super-sellers-buyers Link to comment Share on other sites More sharing options...
Seni Posted August 18, 2015 Author Report Share Posted August 18, 2015 what year is your truck and is that a DC270amp alt i see in your sig? Link to comment Share on other sites More sharing options...
ToNasty Posted August 18, 2015 Report Share Posted August 18, 2015 07 classic. Alts from 2005-2015 are the same ***Super Sellers List***http://www.stevemeadedesigns.com/board/topic/25829-super-sellers-buyers Link to comment Share on other sites More sharing options...
Seni Posted August 18, 2015 Author Report Share Posted August 18, 2015 ok... A. the alternators are not the same GM switched between Denso and Bosch year to year. they range from 145 to 160amp theres literally 10 different part numbers that the stock alts could be. but yes they do have the same mounting holes and are in fact basically the "same" B. the alternator is not the problem the computer telling the alternator what to do is the problem. C. The 5.3l has changed and all the acc. they have on the truck have changed don't you think its likely that they changed the computer charging system algorithm a bit from 2007 to 2015? i'm not trying to be a dick i appreciate you trying to help but i'm past "unplug the modem and plug it back in" tech support no offence. If anyone has a 2014/15 GMC (they are the same anything older has a different BCM) and has dealt with this issue i'd love to hear from them. Link to comment Share on other sites More sharing options...
ToNasty Posted August 18, 2015 Report Share Posted August 18, 2015 The alts are all same mounting and same plug. They are the same. The part you are referring ro is the battery current sensor. It "senses" current and tells the alt more or less. 05 and up have that ***Super Sellers List***http://www.stevemeadedesigns.com/board/topic/25829-super-sellers-buyers Link to comment Share on other sites More sharing options...
BassJunkie Posted August 18, 2015 Report Share Posted August 18, 2015 This is the battery current sensor. 2005 and up have this. If you want to charge higher, then turn your lights on. You'll charge at 14.6 with the lights on. When you don't need to , shit the lights off My 08 malibu has the same thing. Mine has a little clamp meter looking thing near the battery. Always wanted to try running my power wire to the rear through it to see if it would sense more current and keep the alternator on. Never did try it tho. 1986 C20 Suburban 9 American Bass XFL 15's B2 M1MKII 14v XS Power Batteries Maxwell Caps Acoustical energy is free. Electrical energy is not you havent lived until you've hit a screw with a router. Link to comment Share on other sites More sharing options...
Seni Posted August 18, 2015 Author Report Share Posted August 18, 2015 Are you reading my posts are do you just pick out key words and reply? let me start by telling you that i completely agree with everything you just said. i know what the battery current sensor is i know what it does and i know how it should work. Listen to what im telling you. the only time the alternator charges at 14v or higher is the 30 sec its supposed to after the truck starts. it then drops down to 12.5-13v and never comes back up. Now if you tell me that my amps seeing 12.5v input isnt a problem and i should be happy with that then fine. but seeing as how everything is rated at 14.4v and most cars run around 13.8v as a realistic number 12.5v is pretty low. You have completely skipped over my actual concern and keep telling me shit that A. is in fact wrong and B. DOESNT MATTER. Link to comment Share on other sites More sharing options...
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