AMP bypass

-
68purpledart

68purpledart

Well-Known Member
Joined
Dec 19, 2011
Messages
50
Reaction score
1
Location
Lethbridge Alberta Canada
Want to do an amp bypass as per madd, battery in the trunk, in stead of going from the alt, can I go from the battery, pull the amp wires from the bulkhead, connect them, and run though a fuse not a fuseable link, all under the dash. Alt output is 65, and have Robs plug & play headlite kit, which works awesome!

Thanks in advance for any and all input!!
 
Not clear what you are proposing. There's no reason to run more than one "hot" wire from the battery to the front. Use a 4 terminal (DPST) disconnect, which has two large and two small terminals. String two no14's up front, and use those to fire a relay or continuous duty solenoid up front to control ignition loads, fuel pump, etc

Either get yourself a nice big insulated stud for a junction up front, or if you don't have much additiona wiring (fans, pumps, etc) just run the battery to the starter, and a jumper up to the starter relay, or vice versa.
 
Del, would you be so kind as to explain to me in layman's terms why fusible links are even used? Why not just a heavy fuse? Or maxi fuse? Can you use a maxi fuse instead of a fusible link?
 
I think the main thing is that maxi type fuses were not common when these cars were built. "Big" stereos weren't around. I can even remember older 2--way radio stuff typically had huge cartridge add-on fuse holders

And I'm sure some came down to cost. A big 50-70A fuse and fuse holder is a buck or two. A fuse link is cheap.

By 74, "Ma" had finally reworked SOME of the harness to be a little better protected. I've forgotten the earliest........I think some models in 72? were beginning to have external shunt ammeters.


Later stuff typically like this, but still not cheap

$%28KGrHqR,!jgFB93NWemSBQ%297Q+BQFQ~~60_35.JPG


early stuff used stuff like this
 

Attachments

  • GE Heavey Duty Fuse Holders.jpg
    58.9 KB · Views: 269
So then, the answer is you can use a maxi type fuse as long as it is the correct corresponding size?
 
It is my understanding (and I'm no expert) that the fuse link is a slower acting component than the maxi fuse. The fuse link will not "open circuit" as quickly as the maxi fuse. The maxi fuse is designed for immediate circuit protection, whereas the fuse link is kind of like a "slow blow" fuse.
 
I'm not sure what the characterics (time, etc) of large fuses and or maxi as opposed to fuse link. I would guess, frankly, that a large enough maxi would be OK. The size is going to depend on

The size of wire it protects

The output of the alternator, unless you have bypassed same

The projected loads in the car, IE are you running "big fans" or a "big pump" etc through that feed?

And "if you are" ya might consider providing SEPARATE breakers/ feeds for those large loads.

So I guess the answer is "yes" under certain conditions, you should be able to use such as Maxi fuses.

Let me repeat..........I've never had much confidence in a fuse link. This is opposed to properly designed, fused systems, which IMPLY that you should be able to blow a fuse / breaker numerous times without jeopardizing wiring.

(Hell some guys use fuses to troubleshoot with.....they just keep blowing fuses while they "easter egg" the problem)

But in my experience you won't get away with that "every time" with a fuse link. They seem to me more like a last last last ditch effort.
 
amp-ga27.jpg


Where are you going to connect the alt charge line, back on the starter relay or running it back to the battery?

Don't really even need to make the connection of the red wire that loops with existing black wire. If your bulkhead is in good shape. That line is no longer carrying the alt charge load. Quick and dirty, move the red wire on the engine side of harness to current location of black wire coming from alternator. Or move the black wire on the interior side over, whichever is easier. Make sure the wires are terminated and no loose bare wire exist.

You might think about installing a circuit breaker in the line going up front to feed your dash/interior. A type 1 auto reset may work, BUT, if you have an issue and it continues to reset, it may melt stuff... a manual reset style may be a better choice. More hassle when it pops, however, it won't keep resetting and feeding a compromised system.

Thanks for the good feedback on the headlight relay kit. Good to read you are happy. :thumbup:
 
crackedback said:
....You might think about installing a circuit breaker in the line going up front to feed your dash/interior. A type 1 auto reset may work, BUT, if you have an issue and it continues to reset, it may melt stuff... a manual reset style may be a better choice. More hassle when it pops, however, it won't keep resetting and feeding a compromised system. ....
Click to expand...

I like it! And I'll use a manual reset breaker, but what size breaker, please?

BC
 
If a fusible link is a slow blow, then I probably want to leave all that gheyness out. Having all the circuits properly fused will be plenty.
 
Can't argue your point, never really thought about it. With "all the circuits properly fused"would be the key, and call for several more fuses with their added wiring, fuse box, etc, etc.
Might be easier to use an aftermarket whole car harness and just pigtail off the MOPAR parts ya want to keep. The lights would be easy, variable speed windshield wiper/washers not so easy. There is a certain appeal to having no more crumbling insulation, hidden corrosion and so on.

BC
 
As long as you don't have any crazy loads inside the car, a 30 amp breaker should be fine.

If you have a vert, then the amp load goes WAY up with the actuator pump. If you wire around the standard wiring using relays, then the same 30 amp breaker should work OK. Fuseable link can work as well

I had a list somewhere of basic amp loads from accessories/lights/etc.
 
All MY inquiries are based on me using an aftermarket wiring harness on my rat truck. I didn't want to get this too far off track.
 
crackedback said:
As long as you don't have any crazy loads inside the car, a 30 amp breaker should be fine.

If you have a vert, then the amp load goes WAY up with the actuator pump. If you wire around the standard wiring using relays, then the same 30 amp breaker should work OK. Fuseable link can work as well

I had a list somewhere of basic amp loads from accessories/lights/etc.
Click to expand...

With the ammeter eliminated I tend to agree. No10 wire, in the 120/ 240 V world, is normally fused at 30A
 
I always to the amp gauge bypass it is a great upgrade.
I also do the big three upgrade..which is 4 gauge from battery to alt and 4 gauge from battery to ground and 4 gauge from engine block to ground.
As for the battery in the trunk what I did was I ran a 0/1 gauge wire from the battery to the starter motor off a Ford solinod then installed a juction block in the engine bay and ran a 4 gauge wire from the alt to it and another 4 gauge to the battery in the trunk to drive my stereo.
I like this type of juction block as it has 8 other terminals that you can grab power from.
I have also used a blade type 30amp fuse in place of the fuseable link in a couple cars without any issues.
AL
 

Attachments

  • februnner 003.jpg
    78.6 KB · Views: 243
  • februnner 010.jpg
    87.4 KB · Views: 237
You must log in or register to reply here.
-

Back
Top