Thanks
-QFL
Is Bigger Really Better?
Moderator: Queue Moderator
Is Bigger Really Better?
My friend and I hare having a debate on how to get 150A feed to the trunk of a squad car and we need your input. I think we should pull one 4 AWG from the battery and through a 150A breaker. His idea is to pull six 10 AWG cables individually fused 25A each. His thinking is that if a wire should get nicked, the smaller wires with the smaller fuses will blow quicker than the larger cable with the breaker. Maybe you guys have a better idea.
Thanks
-QFL
Thanks
-QFL
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FFParamedic571
- Banned
- Posts: 467
- Joined: Tue Aug 27, 2002 7:57 pm
What could you possiby need 150A for in a trunk of a squad? Most cars I build have an 80A under the hood and a few fuses off the factory fuse drop in the passenger kick panel and that is over kill. A fully built 2003 PI with a all light streethog and full compliment of lights , video and MDT doesn't draw that much..
Re: Is Bigger Really Better?
If you want fuses to blow faster, paralleling them will work. I wouldn't do it over six 10 gauge wires though. One large cable should suffice and don't use the code for houses -- 5V drop is acceptable in house wiring at 115 Volts, but not at 12V. I-square-R is a mutha.QFL wrote:My friend and I hare having a debate on how to get 150A feed to the trunk of a squad car and we need your input. I think we should pull one 4 AWG from the battery and through a 150A breaker. His idea is to pull six 10 AWG cables individually fused 25A each. His thinking is that if a wire should get nicked, the smaller wires with the smaller fuses will blow quicker than the larger cable with the breaker. Maybe you guys have a better idea.
In response to the other, maybe he wants to key four 100W syntor X's at once
not to mention a but ugly instally of running the lightbar cable to the trunk either on the outside or inside...Cam22 wrote:Is this for a tanning bed or some kind of laser? That's a lot of power and the car may not be able to handle all that. If you have a lightbar, radios, MDT and all the other crap you could run in to problems.
Use the single #4 and you won't go wrong. Protect with a fast-blow fuse or a pair of paralelled #10 fusible link leads at 6" length.
Solder all connections under the hood.
As for using small multiple feeds: very unprofessional and amateur like.
If the single feed is "nicked", the installer obviously didn't install it properly and shouldn't be doing an install in the first place. Using a large power feed with a juntion/fuse block is the right way. As for the non-believers in the single feed with junction block, just as McCoy Miller, Pierce, Sutphen, Seagrave, Horton, AEV, Smeal, American LaFrance, KME, Spartan, Braun, Ford, GM, Chrysler, Kenworth, Freightliner, Peterbilt and many other commercial manufacturers who do this because it works flawless for them. SAE also specifies that equipment installed in this manner should be fed via a single master with matching sixe (or larger) ground.
150 amps is not out of reality. I have built cruisers that already measured 120 amps draw with all lights on. Yes- there were quite a few.
A car with a loaded MX7000, grille lights, deck lights and corner strobes is already at 80 amps. Add radios, video, MDT, wigwags, backflashers, side lights, dash light, map light and siren and you're over 100 amps like nothing. Better to have 150a feed. I explaing it like this to customers: putting a #4 feed into the console or into the truck is merely "relocating the positive battery terminal into the trunk or console."
GM, Ford and Chrysler give you 100A feed for radios. It might be overkill, but there's no voltage drop. Using 12 different feeds will guarantee you to have more failures and complicate installation.
Solder all connections under the hood.
As for using small multiple feeds: very unprofessional and amateur like.
If the single feed is "nicked", the installer obviously didn't install it properly and shouldn't be doing an install in the first place. Using a large power feed with a juntion/fuse block is the right way. As for the non-believers in the single feed with junction block, just as McCoy Miller, Pierce, Sutphen, Seagrave, Horton, AEV, Smeal, American LaFrance, KME, Spartan, Braun, Ford, GM, Chrysler, Kenworth, Freightliner, Peterbilt and many other commercial manufacturers who do this because it works flawless for them. SAE also specifies that equipment installed in this manner should be fed via a single master with matching sixe (or larger) ground.
150 amps is not out of reality. I have built cruisers that already measured 120 amps draw with all lights on. Yes- there were quite a few.
A car with a loaded MX7000, grille lights, deck lights and corner strobes is already at 80 amps. Add radios, video, MDT, wigwags, backflashers, side lights, dash light, map light and siren and you're over 100 amps like nothing. Better to have 150a feed. I explaing it like this to customers: putting a #4 feed into the console or into the truck is merely "relocating the positive battery terminal into the trunk or console."
GM, Ford and Chrysler give you 100A feed for radios. It might be overkill, but there's no voltage drop. Using 12 different feeds will guarantee you to have more failures and complicate installation.
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c17loadsmasher
- Posts: 200
- Joined: Mon Jul 21, 2003 7:26 pm
My background being Automotive audio more than radio (power requirements are the same).... Proper fuse's, quality cable, grommets, split loom and a good ground.
I agree, #4 all the way, multiple runs just complicates things, install it properly and "nicks" are not even a thought. Althought, ensure it's fused at BOTH ends. I watched a kid burn his car to the ground because the #4 wire he installed (Right to the battery, NO fuse) got "nicked" about half way through and turned into a nice big heating element.
150A doesn't seem too much for a fully loaded vehicle depending on lighting / equipment
I agree, #4 all the way, multiple runs just complicates things, install it properly and "nicks" are not even a thought. Althought, ensure it's fused at BOTH ends. I watched a kid burn his car to the ground because the #4 wire he installed (Right to the battery, NO fuse) got "nicked" about half way through and turned into a nice big heating element.
150A doesn't seem too much for a fully loaded vehicle depending on lighting / equipment
It's amazing just how many car stereos were installed with a #4 or #2 cable utilizing NO fuse! These ones also run through the firewall with no grommet, have no loom or any other protection. These ones usually have the cable under the carpet instead of in the rocker wire run track that was placed there for running wiring.
I've seen these same size cables run into the cab through the fender into the door jamb, through the weatherstrip and into the car between the weatherstrip and the closed door!
One local PD has a cop do the installs. He uses #4 welding cable into the console, but doesn't fuse it under the hood. He also doesn't use a grommet. It's nice to see that some people have a little clue about what they're doing, but are dangerous enough to cause these problems. Speaking of welding cable...I'm not a big fan of this. It's no more reliable than autmotive rated cable and carries no more current. It also can be cut through much easier if it DOES find a sharp edge- and it's twice as much $$$ as automotive SAE designated battery cable. One note is that it does flex easier and last longer when flexing alot, but why do you need this quality? Maybe for a slide-out generator or winch.
I've also seen #2 stereo feeds laying on exhaust and belts and laying on A/C tubes rubbing through. It's amazing that more kids don't burn their cars down with this much current capability.
Our local FD had a car fire a while back in a fullsize GM where the kid just got his license that day and installed a stereo. The power feed was flopped down over the inner fender and was laying on the upper control arm and it got sawed through in no time at all. It was a #8 looking cable that was jammed in between the battery and the positive terminal with no fuse. Ouch!
I've seen these same size cables run into the cab through the fender into the door jamb, through the weatherstrip and into the car between the weatherstrip and the closed door!
One local PD has a cop do the installs. He uses #4 welding cable into the console, but doesn't fuse it under the hood. He also doesn't use a grommet. It's nice to see that some people have a little clue about what they're doing, but are dangerous enough to cause these problems. Speaking of welding cable...I'm not a big fan of this. It's no more reliable than autmotive rated cable and carries no more current. It also can be cut through much easier if it DOES find a sharp edge- and it's twice as much $$$ as automotive SAE designated battery cable. One note is that it does flex easier and last longer when flexing alot, but why do you need this quality? Maybe for a slide-out generator or winch.
I've also seen #2 stereo feeds laying on exhaust and belts and laying on A/C tubes rubbing through. It's amazing that more kids don't burn their cars down with this much current capability.
Our local FD had a car fire a while back in a fullsize GM where the kid just got his license that day and installed a stereo. The power feed was flopped down over the inner fender and was laying on the upper control arm and it got sawed through in no time at all. It was a #8 looking cable that was jammed in between the battery and the positive terminal with no fuse. Ouch!
I ran a #4 welding cable to the rear of my truck for a winch, jumper cables, and aux. power for my shop trailer. I used welding type because it is a little bigger and a lot more flexible than regular #4. In the places where chafing was even a remote possibility, I ran it through a piece of garden hose, the heavy rubber type. It is working out great. Something else to remember in addition to fuse protection, is make sure you have a big enough ground from battery to chassis. If you have 150amps going out, it has to get back in somewhere.
I was leaning to the #4 cable anyway, and this definately put an end to the debate. Thanks everyone! As for the Lazer & tanning bed we are installing in the back - they are for off-duty use only. the cars are fully loaded, and its just a matter of time until they want to add something new. this way we wont need to pull new power when the day comes. And it WILL come! Good point about beefing up the ground side to the battery. We have done the same, but I think it needs to be said again for the newer installers out there. im not so sure about the garden hose grommet. I think I can find something a little more professional out there.
Thanks everyone!
-QFL
Thanks everyone!
-QFL