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HO alternator or extra battery


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Hey everyone, I have a 2011 Silverado 5.3 and I’m either wanting to add a HO alternator or an extra battery. I was originally going to run a bigger alternator but I’m here for advice. 
 

My system consist of a 400x4 rms for mids and highs and a 1200x1 rms for my subs. I recently did the big 3 as well. Prior to the big 3 my interior lights would  dim when the bass hit. But I’ve never noticed my headlights dimming. Also if I’m pushing my system loud I can watch my voltage gauge fluctuate. After the big three it seems a little louder but the lights are still dimming. 
 

Problem is my truck has that rvc charging system that is controlled by the computer. The only two ways to work around the rvc is by turning the headlights on, or putting it in tow haul mode. Supposedly there is a plug for that rvc sensor you can unplug and it will allow the charging system to put out consistent voltage instead of fluctuating. My battery is about 2-1/2 years old and it’s just a stock replacement. Recently my voltage has been fluctuating quite a bit on the gauge without the radio playing. It’s never acted this crazy and I’m wondering if my alternator isn’t getting weak. Any help is appreciated. 

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I have the same truck. 

When I had a 1000 watt mono block, and a 400.4, I just upgraded the battery, did the big 3 in....I think it was 4 awg.... upgrade to a deep cycle AGM battery and never had a problem. 

Upgraded to 4 1000 watt mono blocks, and 2 400.4's, I went with a mechman 370 (not bypassing the RVC) and 2 80 ah deep cycle batteries under the hood with the big 3 now done in 1/0. Held up well (aside from corners cut by the car audio shop, but that's another story). A little bit of headlight dimming, but that's mostly because of the stock halogen lights. If/ when I upgrade to LED's, they shouldn't dim any anymore. Because LED's don't use as much energy, they're not as prone to dimming because of quick changes in voltage. 

Now, I'm in the process of upgrading again. Let's just say.....a decent amount more power. To bypass the RVC, I bought a Mechman 400 with a 4 pin plug instead of a 2 pin, then just tapped into a switched 12v source to power the alternator on. Mechman also has a bypass plug that uses a certain impedance to "fool" the stock 2 pin plug into thinking it's still controlling the trucks charging. 

As far as the voltage meter (in the dash in assuming) fluctuating, how did you do your big 3? On those trucks, it's more like a big 2, because you don't want to bypass the RVC ring with any grounding. So, basically, adding upgraded wire from alt positive to battery positive, then adding upgraded wire from battery negative, through the ring, to the engine block. Then also, from the battery negative to the vehicle chassis if that's how you grounded your amplifiers, though best practice is actually grounding to the chassis and all the way up to the batteries negative post. 

Pain in the ass....I know! 🤣

2011 Chevy Silverado under construction

My build log here. Check it out! 

 

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Posted (edited)

I have led headlights and they don’t dim. You’re right in saying it’s actually the big 2 lol. When I got the 2 wires installed I was scratching my head on the third one. So my big 3 I did, positive battery to alternator, negative battery to engine block, and the third I searched online about it and ended up running it to the chassis. The voltage fluctuation in the afternoon when I get out work had been so bad, today I unplugged the rvc sensor and it ran a flawless tick over 14 on the gauge the whole way home. When I had my system turned up I didn’t notice the gauge moving like before either. It moved a tiny bit but wasn’t like before. Supposedly by unplugging that sensor it will just charge like a normal alternator. I read a whole thread online about it and it was 8 pages long and no one had any issues with it unplugged so fingers crossed there. My big 3 is 1/0 wire. I was going to do 4 gauge, but you know how it is with car audio, always upgrading lol. 
 

So would it be a good idea for me to just upgrade my current battery then? I see you said you went with a deep cycle battery, any in particular you recommend? I’ve read most guys saying to go with an agm battery. I’ll be honest I have no idea that’s why I’m here. Thanks bro I appreciate your help!

Edited by Pak713
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9 minutes ago, Pak713 said:

I have led headlights and they don’t dim. You’re right in saying it’s actually the big 2 lol. When I got the 2 wires installed I was scratching my head on the third one. So my big 3 I did, positive battery to alternator, negative battery to engine block, and the third I searched online about it and ended up running it to the chassis. The voltage fluctuation in the afternoon when I get out work had been so bad, today I unplugged the rvc sensor and it ran a flawless tick over 14 on the gauge the whole way home. When I had my system turned up I didn’t notice the gauge moving like before either. It moved a tiny bit but wasn’t like before. Supposedly by unplugging that sensor it will just charge like a normal alternator. I read a whole thread online about it and it was 8 pages long and no one had any issues with it unplugged so fingers crossed there. My big 3 is 1/0 wire. I was going to do 4 gauge, but you know how it is with car audio, always upgrading lol. 
 

So would it be a good idea for me to just upgrade my current battery then? I see you said you went with a deep cycle battery, any in particular you recommend? I’ve read most guys saying to go with an agm battery. I’ll be honest I have no idea that’s why I’m here. Thanks bro I appreciate your help!

Going from the battery negative to the engine block, you went through the RVC ring, correct? 

I had Stinger sp1500dc batteries. But others like XS and full Throttle are great batteries as well. 

I've read that same thing about just unplugging the alternator. The only thing is you have to look at a battery light. Some black electrical tape can take care of that 🤣 here in California though, we have to get our cars smogged, so any dashboard lights, it'll fail. I had to go about actually bypassing and fooling the system

2011 Chevy Silverado under construction

My build log here. Check it out! 

 

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Posted (edited)

I hooked the ring terminal right on top of the negative post with the small nut on top and straight to the block. I wasn’t talking about unplugging the alternator. Right below the battery tray there is a plug. That’s the rvc sensor. You can unplug it and get no dash lights and it will charge like a normal charging system. No fluctuations. So if I’ll be good with just a single upgraded battery then I’m going that route. But I don’t want to spend money on the battery and still need the alternator later on. I guess I could do the battery and if the alternator was needed down the road I could go with the 160a stock alternator since mine is a 145a. I was originally going to go with a 250a HO alternator. 
 

Here is a pic of that plug. That’s not my truck in the pic. I saved it off the internet. The plug on my truck was in the same area though. 

0671F3CC-F9FA-402A-AEBC-B2B49A5B4AA5.jpeg

Edited by Pak713
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Yeah, that plug is plugged into a plastic ring that goes around the ground wire from the battery negative and the block right? 

When you upgraded the wire going from the battery negative to the block, did you pass that wire through the ring? 

2011 Chevy Silverado under construction

My build log here. Check it out! 

 

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That's why your voltage is fluctuating so much and acting crazy. But, if you've found a work around that will work, then go for it. I can't tell you if it'll cause problems or not, I haven't tried it ever. But if it works, great! 

2011 Chevy Silverado under construction

My build log here. Check it out! 

 

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That can’t be why it fluctuates. I just installed the big 3 over last weekend and it was fluctuating last week before the big 3. The fluctuations were also happening with no radio or subs playing either. Ac was on high and my front parking lights were on as they are wired to be drl’s during the day. 

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