|
|
|
|||||||
|
#1
11-03-2002, 12:30 AM
|
||||
|
||||
alternator wiring idea: what do you think?
I'm getting ready to install the Denso 130A alternator in my 68 Charger.
Battery is mounted in the trunk, with a large-gauge lead running to the starter. There's also a 10-gauge feed wire running from the battery post up to the starter relay post, so the battery receives current from the alternator through this feed. This is the same basic method the factory used, except the battery is front-mounted. Now, here's the deal: Why couldn't I run a beefy 6 or 8 gauge lead from my alternator to the starter relay post (with some kind of fusible link), and from the relay down to the main battery cable lug on the starter? This would allow the alternator to charge the battery through the large main cable, instead of trying to stuff all that current through the smaller auxilliary wire. What do you guys think? 
|
|
#2
11-03-2002, 02:35 AM
|
||||
|
||||
|
We have to use a ford type 'noid on our circle track racer and we run a 10 ga. from the alt. straight to the 'noid where the batt. cabbles attached. Starter cables on the other lug and a wire from starter switch to the small lug.
You are basicly talking about doing the same thing we do except you're using the relay. It works great. 
|
|
#3
11-03-2002, 03:50 AM
|
||||
|
||||
dwc, thanks for the input.
Yeah, I'm thinking it should work pretty well, especially in my case where there's such a long distance between my alternator and battery. It just makes sense to use a larger "pipeline" between those two points for all that current. I'm just hoping somebody with good auto electrical knowledge can point out any potential pitfalls with this plan before I do it. As an aside, does anyone know why Chrysler originally did the two wire method from the battery? I'm just curious.
|
|
#4
11-03-2002, 05:37 AM
|
||||
|
||||
You asked a good question there. I have no idea, either.
My batt. is behind the seat, (inclosed of course) so I have a shorter run of cable than you have, but it charges nice with the one wire from the alt to the 'noid. The 'noid is on the engine hoop bar just across from the starter, just so you have an idea of how short a run of cable I use. I think a 10 ga. would be enough and yes, use that fuse link. Would hate to see a '68 or anyones car melt to the ground.
|
|
#5
11-03-2002, 02:47 PM
|
||||
|
||||
|
Okay, I did a little more digging and here's the scoop:
According to the book "Hot Rod Wiring" (page 9), a 125-150 amp load requires the following wire size for a given wire length: 125-150 amp load 0-13 ft. - 2 ga 13-19 ft. - 0 ga Looks like I'm going this route: - 2-4 ga from alt to starter relay - 2-4 ga from relay down to starter cable lug on starter - fusible link, 2 sizes smaller than main wire AWG, between relay and alt Thanks go out to Mopar Action tech editor Ehrenberg for his advice/help with some of the above information
|
|
#6
11-03-2002, 06:15 PM
|
||||
|
||||
|
Yeah, dan, I was thinking of telling you to drop him a line. I have gone to him several times and he always answers emails within a day or two.
a nice change to see one of the magazine guys who takes the time out for the little guy Kevin
|
|
#7
11-03-2002, 07:40 PM
|
||||
|
||||
|
2g - 4g from starter relay to starter motor (SOL lead) is a little overboard. Factory was only a 12g lead and that works perfect for the small load that it is passing.
If you are speaking the BATT lead, then 2g - 4g is right. Then from the starter to the rear mount battery, I would go with a 0g cable.
|
|
#8
11-03-2002, 09:06 PM
|
||||
|
||||
|
Ed,
I'm better visually than verbally; here's another way of stating what I plan to do:
|
|
#11
11-04-2002, 02:33 AM
|
||||
|
||||
|
Greg,
I'm not following what you mean by a cut-off switch. Ignition kill is accomplished via ignition switch position, which controls activation of the MSD box and voltage regulator. If I am understanding things correctly, this is basically the same set-up as factory, except the alternator is sending charging current to the battery through the large battery cable instead of a factory-style auxiliary lead. If I am misunderstanding or misinformed, please explain. Thanks, Dan
|
|
#12
11-04-2002, 04:02 PM
|
||||
|
||||
|
In a racing application, you would have a main power cutoff switch, between the battery and the main electricl system. This switch should also control a relay that will open the field leads on the alt.
If you wreck, during a run, this gives emergency crews a quick exterior control to shutdown ALL electronic in your vehicle, so they don't have to be concerned about your engine running or an electric fuel pump spraying fuel all over the place.
|
|
#13
11-05-2002, 01:37 AM
|
||||
|
||||
|
Ed,
I run a standard rotary-type kill switch for my battery when racing. In the event of an accident, would that cover me? Maybe I should upgrade to one of those that has the built-in alternator kill too...
|
|
#15
11-05-2002, 05:33 PM
|
||||
|
||||
|
Well I called my bro last night (he's an electrician) and ran my swap by him.
He remarked that a 2 to 4 gauge lead from alternator was about right, but it's unlikely that the charging circuit would ever see the high side of the alternator output for any extended period of time. Still, he said go with 2-4 gauge just to be sure. He also said he had done the same wiring modification as I'm suggesting; running the alternator hot wire down to the battery cable at the starter, and letting the fat starter cable carry charge current back to the battery in trunk. So, I'm having him score me some 2-gauge and some big terminal lugs, and we'll see if I can get this swap to become a reality. Can't wait to end my current-shortage blues... If/when I get a part # on the correct factory field wire pigtail for the Denso alternator (and if it fits), I'll post it here - maybe Kevin will add it to his cool parts list for the sticky. Thanks much to all who weighed in on this thread with their ideas, opinions, etc. I really appreciate it. Dan
|
|
#16
11-05-2002, 11:24 PM
|
||||
|
||||
|
The idea behind a kill switch that shuts down the alt is that NOT every accident stalls the engine. If you shut down the battery and the engine is still running, the alt is still pumping juice into the car and that will allow the engine to continue running.
|
|
#17
11-05-2002, 11:27 PM
|
||||
|
||||
|
I forogot to mentiona... Yes, it is very rare for that big of an ALT to ever reach max output. I don't think that the battery will accept anything above about a 60A charge rate. With that being the case, unless you have ALOT of other electronics, even recharging a dead battery wouldn't bring it up to max output.
|
|
#18
11-06-2002, 03:33 AM
|
||||
|
||||
|
Ed,
Aha, your explanation about the alt. kill makes sense to me now. I don't think I'll ever use the full capacity of this alternator, but it's good to know I've got reserve power rather than not enough (which has been a problem in the past). Come to think of it, I could probably get away with 4-6 gauge lead... Thanks for the info.
|
|
#19
11-06-2002, 12:22 PM
|
|||
|
|||
Hello,I'm just waiting on my alternator to come to do the same swap. Do you guys think it is necessary for me to put the same 2-4 guage wire from starter relay to the starter, like Charger-dan? My battery is in the original location. Also, does anyone know where I can find the proper size fusible link for the wire, from the alt., to the starter relay?
Thanks
|
|
#20
11-06-2002, 12:44 PM
|
||||
|
||||
|
OK, the 2g - 4g wire from the strater relay to the starter is NOT the SOL lead that you are thinking of. It is the BATT lead. If your battery is in the front, then you will NOT need this lead.
What you will need to do is run a 4g lead from the ALT to the BATT post on the relay. You can drop in a 6g lead between the 4g and the relay, as a fusible link.
|
|
#22
11-06-2002, 05:26 PM
|
||||
|
||||
|
Quote:
You mean a 6 gauge fusible link, right? Or straight wire? JoeMack, In addition to Ed's good advice, you'll also want to run a 4 gauge lead from the starter relay (we're talking about the large threaded stud, here) over to your battery. The stock wire will not handle the current produced by this alternator. Other things to consider when running the wire (pretty obvious, but bears repeating): - make sure when routing the wire through engine compartment that it avoids any sharp contact areas, and use plenty of clamps, zip ties, etc. to keep the wire neatly bundled and in place - consider running an outer protective plastic sleeve (or even rubber fuel line) to prevent chafing - use good quality, soldered and non-insulated lug connections, sealed with shrink tubing Best of luck
|
|
#23
11-06-2002, 07:19 PM
|
||||
|
||||
|
Quote:
Quote:
|
|
#24
11-06-2002, 09:07 PM
|
||||
|
||||
|
Ed,
A fusible link is a length of wire that is specially-designed to behave like a fuse (melt and cut the circuit) when current through the wire exceeds the designed-in, specified limit. Replacing a fusible link with a length of standard stranded copper wire provides no circuit protection whatsoever. On old Mopars, it's not uncommon to find the original fusible link (at the starter relay) nearly cooked, or corroded through, from years of service and, in the case of my Charger, a history of shorts in the wiring system. When I replaced mine, the charging system current was attempting to cram its way through less than a quarter of the strands of the original wire - the rest were brittle, broken and corroded! I was fortunate, that could have been real ugly. This is actually a simple but vitally important component in our Mopar wiring systems. As I understand it, most new cars today utilize actual heavy-duty blade-type fuses as primary battery-to-fuse box protection. A much better idea.
|
|
#25
11-06-2002, 11:08 PM
|
||||
|
||||
|
That's what I did to my '68 Charger. It had some electricla problems, when I bought it. So instead of a fusible link, I used a blade fusible link instead. I used 50A fuses. I went through 4 of them, before I had isolated all of the electricl problems. I'll tel ya what, it sure is alot easier, faster, and cheaper to replace a blade fuse, than it is to replace a fusible link.
|
|
#26
11-07-2002, 12:14 AM
|
||||
|
||||
|
Ed,
You know, that's not a bad idea. Tell me more about how you did this blade fuse arrangement. What brand of fuse holder? Was it anything heavy-duty, or just regular parts store quality stuff? Is the fuse receptacle just part of the regular wiring on firewall, or located elsewhere? Got pictures? What kinds of electrical problems did you encounter on your '68?
|
 |
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Alternator - Green wire | gthomas | Performance Talk | 4 | 11-27-2003 02:59 PM |
| Spark Plug Wire routing | brandywinelabs | Ram Truck Chat | 2 | 08-11-2002 11:15 AM |
| One Wire Alternator | bwlizard | Performance Talk | 11 | 07-13-2002 05:51 PM |
| Another Ram Recall, alternator wire | hemivaliant | Ram Truck Chat | 1 | 02-14-2002 03:42 AM |
| coil wire routing | moram | Ram Truck Chat | 3 | 05-20-2001 07:47 PM |
Linear Mode
