Wiring gurus, please advise.

[Yo]

I recently installed a pair of 13" Derale electric fans in my 91 K5. I did a lot of research and had a few discussions with the folks at Painless, as well as with a lot of guys in the alternator business, and we've concluded that in order to run my accessories as efficiently as possible, I'll need a 200amp alternator, and ideally, an upgrade in wiring.

So I've decided to upgrade the alternator to a Delco CS-144 200 amp as well as the wiring to 4g from the alt to the battery. Currently I have the factory Delco CS-130 105 amp alternator, and it's working to cover all accessories, but just barely. I've found that when both fans are running, flicking on the headlights or the dome lights will restart my radio, presumably because those accessories are demanding a load the alternator simply can't keep up, thus, the radio falls off. What's weird is the radio doesn't reset, it simply turns on and then comes back on.

However, today I noticed my #1 fan quit, so I checked the fuseable link, and the fuse is melted beyond recognition. Fan #2 exhibited a similar condition but is still intact. The relays are grounded to the radiator core, and the fans are grounded to the frame. The motor is a zz4 carbed crate engine, so additional electrical accessories only include fuel pumps, wipers, windows, 1000w radio, headlights, and an MSD 6a. There's no off road lights or winches etc. FYI, the fans pull 24.8 amps a piece.

My question is, if my accessories are working in an environment that isn't able to support the load, why would the fuses melt as opposed to just pop? Moreover, why aren't the fans simply dropping off like my radio? Will the 200 amp upgraded alternator solve my electrical woes?

 

[boz42]

They melted because that is how fusable links work.

The fans aren't dropping out because they are fed from a larger wire that is closer to the supply. They are drawing power first which causes the radio to drop out.

I am sure the larger alt would help, but I am leaning towards something else. It is not like you are using every acc at the same time. I am thinking you could possibly have a bad ground, either from the frame to the battery of the engine to the frame. I would start by double checking all the grounds before I shelled out for an alt.

I could be wrong, might just be the alt.

 

[JDNobodi]

The relays are grounded to the radiator core, and the fans are grounded to the frame.

I don't know about the later model blazers, but I know 73, 74 blazers' frames aren't really grounded well. There only one 16 gauge maybe 14 gauge wire that goes from core support down to the frame. The core support SHOULD have a wire that goes direct to the battery. The main ground cable goes to the motor which is isolated by the motor and transmissions mounts. The body then should have two paths to ground, one though a ground strap from the motor to firewall and the second is though the core support mention earlier.

I say move your fan grounds to the motor.

 

[496truck]

I don't know about the later model blazers, but I know 73, 74 blazers' frames aren't really grounded well. There only one 16 gauge maybe 14 gauge wire that goes from core support down to the frame. The core support SHOULD have a wire that goes direct to the battery. The main ground cable goes to the motor which is isolated by the motor and transmissions mounts. The body then should have two paths to ground, one though a ground strap from the motor to firewall and the second is though the core support mention earlier.

I say move your fan grounds to the motor.

I concur.

 

[Yo]

Hmm. I'll upgrade the ground wiring this weekend and see if the problem persists, but unfortunately, I'm not sure if this is the culprit, as a bad ground would cause erratic behavior and not a problem with resistance, which seems to be the case.

I spoke to another guy at Painless today and he said he doesn't feel like it's a ground issue either; I also spoke to a dude on the summit tech line and he agreed. They're telling me my fuseable links aren't big enough to support the load of the fans or that one of the wires somewhere has big time resistance.

I guess I'll also upgrade the fuseable links to larger unit. Does anyone have any other suggestions?

 

[496truck]

Hmm. I'll upgrade the ground wiring this weekend and see if the problem persists, but unfortunately, I'm not sure if this is the culprit, as a bad ground would cause erratic behavior and not a problem with resistance, which seems to be the case.

A bad ground can also be a high resistance ground. IIRC a bad ground (high resistance) can pull too many amps through the circuit and melt fusible links or blow fuses depending on the application. A loose ground, often also called bad, can be erratic, opening and closing the circuit. I'm not saying this is definitely your problem, just something to check.

 

[Yo]

Nice, I think I'll soup up the grounds to 0g anyway for good measure.

I called Derale and even those dudes don't have an answer for me.

Simplest solution I've found? Replace fuseable links from AGU type to ANL, although this solution seems a bit pricey as well as overkill, not to mention my relays are only rated for 25 amps a piece.

The guy at Painless said the interference type blade fuse and holder is probably creating resistance that's melting the unit?

I'm having a lot of issues getting my fans straightened out

 

[Thunder]

1000Watt stereo??? You need 2 batterys + 200 amps
Your stereo is eating around 85 amps when working hard. Fans = 50 amps when running + they will pull quite a bit more on start up. So you are at least 135 amps draw with fans and radio.. Then throw lights and other accessories in the mix
Just right there you have way more than maxed out your 105 amps. Electric motors dont like low current. That is why your fuses may be blowing.
With that kind of power draw you definatly need the 200 amp alt + 2 batterys to even out the load and not cause a premature death to the alternator.

 

[chulisohombre]

1000Watt stereo??? You need 2 batterys + 200 amps
Your stereo is eating around 85 amps when working hard. Fans = 50 amps when running + they will pull quite a bit more on start up. So you are at least 135 amps draw with fans and radio.. Then throw lights and other accessories in the mix
Just right there you have way more than maxed out your 105 amps. Electric motors dont like low current. That is why your fuses may be blowing.
With that kind of power draw you definatly need the 200 amp alt + 2 batterys to even out the load and not cause a premature death to the alternator.

x2.you are overloading the system with the sterio already.it would be hard to compensate for just the amps running when you hve the sterio up high volume.then you add the fans and other accessories and headlights at night and your charging system would have to try to comp and would not do well,as you have seen.a high amp deep cycle battery and a better alternator would definitely help a lot i would say.as far as melting the fueable link,you can put a higher guage wire in with a inline fuse and it may help that problem.

 

[Yo]

Right right.

I realize the 105amp alt is a weak link; as I stated I'll be upgrading to a 200amp here in like a week.

The stereo is pretty basic; 6 speakers powered off a 350watt Kenwood, and a 350 watt mono Kicker for a 10" polk sub. Very simple, and not a window shaker by any means. I have actually been running the truck without the headunit faceplate attached so that I can minimize the load demanded from it, and I really don't think a second battery is necessary.

Last night a tech from Derale called me back and suggested I remove the fuse holders, because he says "we use realllly cheap fuse holders that, frankly, aren't able to support a continues 25 amp current". He suggested I upgrade to a breaker system, so I guess I'll be doing that, but really it's a pain in my ass to have to fix something that's brand new.

Does anybody have a suggestion as to where I could find a 50amp automotive breaker for 10gauge wire? Perhaps someplace I might be able to pick one up locally as opposed to ordering?

 

[chulisohombre]

those two amps are probably pulling more than you think.350 watts peak and max are different and a lot of amps are underrated for their full cap ratings.bridged to the one sub it is bridging the amp up in power also uses a lot of power.does the amp have different outputs for the 6 different speakers or are you hooking them in series together on the same output?if more than one speaker is attached to the same output it will add more resistense and also require more output from the amps which drives the input power needed to run the amp up also.breakers are a great idea for you.then they would have solid wiring and no fuses to replace.if it pops just take power away and reset the breaker..should help along with the bigger alt.bigger battery may be needed also depending on what you got now.650 to 800 cc amp you should be fine.

 

[blazin_blazer]

are you hooking them in series together on the same output?if more than one speaker is attached to the same output it will add more resistense and also require more output from the amps

this depends upon how the speakers are wired together..if they are in series/1 speaker + to other speaker - then yes, you add the resistance of the drivers & if they are wired in parallel/+_+ & -to - it cuts the resistance in 1/2...in parallel, you actually add up all the speakers resistance & divide by the # of drivers..iirc....2 4 ohm drivers in parallel=2 ohms, but 2 4 ohm speakers in series= 8 ohms....4 4 ohm speakers in parallel =1 ohm, but 4 4 ohm speakers in series would be 16 ohms

 

[blazin_blazer]

i have a 96 tahoe and i'm curious if i find a 200A alt thats self exciting & 1 wire charge like this adjustable 12-16v alt..will this be a direct bolt up case?

http://www.batteriesareus.com/index.php?main_page=product_info&cPath=65_149&products_id=9248

something like that, you could set it at 14-14.5v w/heavy gauge wire straight to b+ and it have good ''overhead'' power..

but what do i do with the stock alt wires when i put the 1 wire high output alt in charging 2 batteries through an isolator so it can jump start itself or make that final winch pull w/a hot b+..?

anyone ever used a solar powered trickle charger /battery tenders..which ones work, if any?