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More Wiring Questions: Hot Leads To Battery Or Starter Solenoid?

Discussion in 'Intermediate CJ-5/6/7/8' started by obarrett, Nov 1, 2019.

  1. Nov 1, 2019
    obarrett

    obarrett Member

    Lake County, CA
    Joined:
    Sep 8, 2010
    Messages:
    53
    Since I am knee deep in figuring out existing wiring the previous owner did (he replaced stock wiring with the 22 circuit Painless Pre 75 Jeep kit: Painless Wiring and used a fair amount of Home Depot THHN wire for some of the accessories... let alone never replacing the cold air intake box, thus just an open whole for rain to come down on the dash)

    Its been a good learning exercise on wiring in general, and how my jeep is setup, fix the bad stuff, add some good stuff and get the heating assemblies all squared away.. I feel like I know what every wire is... and the condition of that circuit.

    I will put all the pics on the bottom, but on to my questions.

    My plan is to going to:

    - Run 10awg from battery to fuse block (this is called out in the Painless manual, but my guy ran 12awg)
    - Run 8awg from alternator to battery
    - Fuse both[EDIT: fuse each circuit with their own fuse]

    Each wcircuits with a MaxiFuse (
    - 50 amp from battery to fuse block
    - unsure what size from alternator to battery


    - I have a what I believe to be stock, but rebuilt alternator... I had this done last year so I would assume < 60 amp
    - Upgrade some switches/relays and replace some bad wires/connectors
    - Add some good grounds throughout

    Question on the Battery / Alternator wires. Stock wires terminate on the starter solenoid on the firewall.

    If I am fusing both circuits, is there any point to run them to the starter solenoid mounted on the firewall?
    Are the stock wires terminated there out of simplicity?
    Any benefit / downfall to either way?
    The battery terminals I will be using are the military style, so adding a couple eye terminals should be easier, and figured they would be easier to use with winch cables, etc..


    Some pics of what my adventures looks like (the goal is to have running again by Sunday night):


    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    (not my pic, but what the military lugs look like)

    [​IMG]
     
    Last edited: Nov 2, 2019
  2. Nov 2, 2019
    tomasinator

    tomasinator Member

    Redmond, WA
    Joined:
    Aug 26, 2015
    Messages:
    415
    What's the purpose of the separate circuit breaker between the battery and the alternator? The Painless circuit diagram shows both the power going to the fuse block and the main charging wire from the alternator connecting together on the protected side of their big main fuse (or your circuit breaker). Suppose in your proposed setup, the circuit breaker powering the fuse panel trips, but the breaker to the alternator has not tripped. It seems like there's the possibility of back-feeding various circuits through the still-powered alternator and out through the two smaller wires to the alternator (the white alternator exciter and the red alternator B+). I'd go with the single main breaker to avoid this possibility.
     
  3. Nov 2, 2019
    obarrett

    obarrett Member

    Lake County, CA
    Joined:
    Sep 8, 2010
    Messages:
    53
    hmmmm felt like I understood everything 20 minutes ago, but now back to the drawing board after reading your questions

    The Alternator to Fuse Panel wire is screwed into the "ALT BATT POST" terminal in the fuse block...
    (and is currently a 12awg, and was going to rewire to 10awg as i was thinking anything from the alternator should be larger...)

    My understanding... (and I could very well be wrong) is that its a fused circuit, (a fuse in the actual panel), so i would "think" that would trip if there was a fault that was > than its fuse... but unsure.

    My manual doesn't say anything about "ALT BATT POST" , but the #30001 manual states:

    1. ATTACH THE WIRE FROM THE BATTERY POST ON THE BACK OF THE ALTERNATOR TO THE ALT BAT POST TERMINAL. (RED WIRE) (12GA)


    1. ATTACH THE WIRE GOING TO THE IGNITION SWITCHED TERMINAL OF THE ALTERNATOR REGULATOR (INTERNAL OR EXTERNAL) TO THE ALT IGN B+ TERMINAL. (WHITE WIRE) THIS WIRE TURNS ON THE REGULATOR WHEN THE IGNITION SWITCH IS TURNED ON. (14GA)
    So that would be the exciter wire which is the small orange wire in my alternator picture (maybe 18 gauge) and goes to the "ALT IGN B+" terminal on the fuse block.. and I believe provides a little power to the alternator to tell it to "charge".

    You say: I'd go with the single main breaker to avoid this possibility.

    Where would you place this?
     
    Last edited: Nov 2, 2019
  4. Nov 2, 2019
    obarrett

    obarrett Member

    Lake County, CA
    Joined:
    Sep 8, 2010
    Messages:
    53
    my wife's Volvo XC90 alternator had some type of fault and overcharged her battery... (was a great snowy night in Tahoe when that all went bad)..
    figured since I have everyhting torn apart, adding some simple proteciton would be easy... but I do understand where you are going with the rest of your questions..
     
  5. Nov 2, 2019
    obarrett

    obarrett Member

    Lake County, CA
    Joined:
    Sep 8, 2010
    Messages:
    53
    now I am wondering what the wire from the alternator to the fuse block actually does...

    I think I understand the exciter... its there to tell the alternator there is a load, and to start to work...
    but whats with the supply wire from the alternator to the fuse panel?

    previous owner had it wired... do you think there is a chance I dont need it.?


    I have power from

    - battery to fuse panel
    - panel to key to starter solenoid
    - panel to ballast resistor to coil
    - alternator to battery

    do you really need anything else?
     
  6. Nov 2, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
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    23,596
    Have you read the Painless instructions? https://static.speedwaymotors.com/pdf/10102.pdf I expect that will answer a lot of your questions.

    No about the exciter. An alternator makes 3-phase alternating current by spinning a rotor (armature) inside a set of field coils. Ith then rectifies the AC to DC that charges the battery. The moving rotor coils and the stationary field coils make opposing magnetic fields that induce a current in the field coils. Nothing happens until some small current flows to make the opposing fields, so the exciter wire is used to bootstrap or "excite" the alternator to start making electricity. Once current starts flowing, the exciter is not needed to maintain the field. This bootstrap happens regardless of whether there is a load.

    For a Delco alternator, you need four connections. You need the battery wire, to send the alternator current to the battery, you need the exciter wire, you need a sense wire, and you need ground through the alternator case. The sense wire looks at the battery voltage and tells the voltage regulator to send more or less current to the rotor coils. This changes the output voltage based on demand.

    Depending on whose diagram you are following, the sense wire could connect anywhere that's on the positive side of the collected loads. Jeep takes the sense wire and bends it right back to the battery wire, and that works fine. Likely Painless sends the sense wire to the fuse panel, to measure the load there. Not a big difference.

    You have some kind of wierdo hacked alternator with the regulator bolted to the back? I suggest you dump it and use a Delco 3-wire alternator. May as well do it now while you are sorting out the wiring. What year/model/equipment is your Jeep? You should put that in every post. If you add it to your signature file, it will automatically appear in every post.

    All this is basic automotive electrical knowledge that you can get from the Jeep shop manual, online on YouTube videos or whatever, or from books. The textbooks meant for trade schools are a great source of general knowledge like this, or there are aftermarket books meant for shade tree mechanics that may be worthwhile.
     
  7. Nov 2, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    I also suggest that you use fusible links instead of fuses or circuit breakers for the main power feed wires. This is what Jeep does. There are only two places that you need protection. First is between the battery and the fuse panel, and the second is between the alternator and the battery. These links are meant to protect the Jeep from the stored power in the battery, in case of catastrophe like a wreck. The links are very reliable and you won't be in a situation where you care about easy replacement, should the links be needed.
     
  8. Nov 2, 2019
    obarrett

    obarrett Member

    Lake County, CA
    Joined:
    Sep 8, 2010
    Messages:
    53
    thanks for the info...

    want to circle back to the original questions

    - any reason not to run power to the fuse panel directly from the battery and not starter solenoid? (there would be a fuse or fuseable link)
    - any reason not to run power from alternator directly to the battery and not the starter solenoid? (there would be a fuse or fuseable link)


    re: fuseable link vs fuse
    - I guess my thinking was fuses are easier to replace if the need arises...



    re: wires I am 99% confident where all the wires go...

    The 1% issue is the wire from the alternator post back to the fuse panel... Is this even needed?
    The manuals seem to flip flop on this, as I describe below.

    The problem I am having with the Painless manual is depending on what revision you read, some of the wording / routing is different, even for the same Part #

    My fuse block is at least 12 years old, and the names of the fuse block terminal connections in the CJ manuals are different that what my fuse block says.

    My fuse block is labeled:
    ALT IGN B+
    ALT BAT POST



    Manual #90504
    #10105 Classic Customizable Jeep CJ (’74-back)
    #10106 Classic Customizable Jeep CJ (75-later)

    I have been referencing my local copy on my laptop published Jan of 2014 and it shows the 715 wire (12 awg) going to the fuse block, to the "Alternator B+" terminal

    The fuse block labels for this version is
    714 Alternator Exciter (14 awg)
    715 Alternator B+ (12 awg)

    [​IMG]

    Their November 2018 version of the manual shows that wire going to a midi fuse then on to the battery, and NOT back to the fuse panel

    The fuse block labels for this version is
    714 Alternator Exciter (14 awg)
    795 Alternator Regulator (12 awg)

    [​IMG]

    Which circles this conversation back to tomasinator's message about back feeding the fuse panel from the alternator?

    A completely different manual, which seems more inline with age of my fuse block and the naming convention used:
    ALT IGN B+
    ALT BAT POST

    30001
    12 CIRCUIT ATO FUSE CENTER
    May 2005

    [​IMG]



    And the manual that Tim referenced has:

    The fuse block labels for this version is
    914 Alternator Exciter (14 awg)
    915 Alternator B+ (10 awg)


    Maybe I start with removing the Alternator Post to Fuse Block wire and go from there?






    re: Alternator regulator / wiring
    The regulator & rebuild work was done by a reputable shop that my Dad (ran his own auto shop for 35 years) had done business with for years, so I trust it...
    Might not be the optimal alternator, but its new and got a lot of wires off the fender/regulator and I will run it for now.
    (At the time I had a broken alternator mount and non functioning alternator, so just wanted to get that back working...)

    - Sense Wire: on my alternator, appears to be bent back red wire to the battery post as Tim describes in his post above

    - Power to Battery: the blackish (its actually blue THHN home depot wire with flaky skin) wire in my picture, that I plan to replace

    - Exciter: Orange wire from Alternator to Fuse panel is the exciter

    - Power to Fuse Panel: Red wire going to the fuse panel to the ALT BAT POST terminal
    DO I NEED THIS WIRE seems to be the biggest question



    [​IMG]
     
    Last edited: Nov 2, 2019
  9. Nov 2, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    If you have the fender mounted solenoid, it's just a convenient place to connect to the battery. Connections on top of the battery tend to corrode, and I'd think the smaller gauge wiring connected to the battery terminal would be easier to damage. It's hard enough keeping the battery cables in good shape without adding extra wires.

    Again, it's just a convenient place to attach wires. The battery connection on the solenoid and the battery itself are electrically identical. The battery cable adds negligible resistance, and IMO the top of the battery is a bad place to attach wires.

    I prefer the fusible links because you onl;y need them in case of something really bad, like a wreck. Anything electrical with mechanical connections (fuses) or moving parts (circuit breakers) is way way way more likely to fail than a piece of wire you crimp and solder in to the harness. I use uninsulated crimp connectors, a proper crimping tool, solder, and adhesive-lined heat shrink to make splices. This should be as reliable and weatherproof as the wire itself.

    All those plastic-insulated crimp connectors look very amateurish to me and are not nearly as weatherproof as they could be. I would pull them off and use uninsulated terminals, crimped with a proper tool, soldered and covered with adhesive-lined heat shrink. I'd also lay out the routing of all the wires before I terminated anything. A few hundred cheap sacrificial zip ties could be used to bundle it all, then when your circuits are finalized, terminate and add black wrap or plastic loom, as you prefer.

    Use the Motorola alternator if you want. Up to you. Back in the day they were a lot more unreliable than the Delcos or even the later Motorcrafts are now. As I recall, their main issue is that they tend to pop diodes, and this makes the voltage output drop so they slowly drain your battery. The Jeep mechanics would take them apart, solder in new diodes, and the alternator was repaired. Repair parts are likely unavailable today, so you'll have to take whatever cheap parts the reman company uses, if it ever fails. The shop may have done a fine job, but my experience says the design itself lacks something. Dunno, maybe the diodes are better today, and this makes the Motorola alternators as good as any others.

    I suspect your problem is you don't understand circuits that well. Technically you can connect the charge wire to anywhere on the battery side of the total load. All of that wiring is at the same potential, and the only difference is in the resistance between tha alternator output and the battery. Usually you make as short and direct a connection to the battery positive as possible, minimizing any heating due to the wire resistance between the source (the alternator) and its sink (the battery). As I mentioned above, for everything but the starter motor, connection to the battery terminal of the solenoid is electrically equivalent to connection directly to the battery post. Similarly, connection of the alternator to the solenoid or to the big midi fuse terminal that Painless added later should be essentially equivalent.

    I don't have time to research this for you now, but I expect you can read about the charging circuit in the Jeep TSM and learn enough to understand how it needs to be wired. Off the top of my head, I don't know how the separate alternator and regulator are supposed to be wired. What year, model, and equipment is this Jeep? Likley I would look at how Jeep wired the charging system and copy that. I'd trace out the circuit on a piece of paper and read the section in the TSM. The Painless instructions seem not to want to explain the wiring, instead to tell you how to wire it up without learning why it's wired that way (Painless!?). The TSM will tell you more.
     
    Last edited: Nov 2, 2019
  10. Nov 2, 2019
    obarrett

    obarrett Member

    Lake County, CA
    Joined:
    Sep 8, 2010
    Messages:
    53
    Always room to understand more, but the question pointed to why everything is run to/from the solenoid was best answered by the corrosion comment on the battery terminals, not that i was wondering how electricity moves form the battery to the solenoid to the fuse or from the alternator to the solenoid to the fuse.
    I guess in my mind I was thinking you run a winch directly from the battery, not the solenoid (even though they would be electrically equivalent), why wouldn't you do the same for the fust panel / alternator.


    1972 - 1973 TSM shows a single wire off the alternator battery post, to the starter solenoid.

    Nothing from alternator battery post to fuse panel, so I will follow that.

    Thanks Tim, always appreciate all the input

    [​IMG]
     
  11. Nov 3, 2019
    53A1

    53A1 Member

    Kern Co. Ca.
    Joined:
    Jun 17, 2008
    Messages:
    447
    The only thing I can add to what timgr has already explained is alternators normally run a little hotter than you would expect. I would consider relocating the regulator asap. The wiring on them is very simple usually just four wires. Also you may be blocking some of the vent on the alternator (hard to tell) which will add to the problem.

    Just on a side note and not related to your setup, I went with a 10si internally regulated alternator because I had a new one already available for free and it makes for a very clean installation but I can't comment on the pros and cons. I haven't had any problems yet. I run all of my hot wires to a one terminal block on the firewall and then one wire to the battery. I have one heavy gauge wire going from the alternator to the terminal block (about 1.5 foot span) and only one wire to the battery (1/2 foot span). I use the engine as a ground for the alternator.
     
  12. Nov 3, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Glad you are making progress, and weren't put off by my lengthy reply ... and possibly dismissive tone. Not how it was intended.

    A couple of comments if I may. Do you have the TSM? I'd guess that diagram is from a Haynes or Chilton's manual. The diagram in the TSM for 1972 is completely different, and Jeep would not have merged the years. Also, the ammeter was a factory option in 1973, and that diagram would not work with an ammeter. If you look at the '74 TSM wiring diagram, there is an inset that modifies the harness if the optional oil pressure and ammeter are present. http://oljeep.com/gw/74_tsm/22-7-CJWiringDiagram.pdf A '74 is basically the same CJ as a '73, except for maybe some emissions changes, different badges, and likely other minor stuff that I am not aware of. Major changes to the rest of the Jeep line for '74, but the CJs were effectively unchanged that year.

    If you are looking at a Haynes or Chilton's manual, don't trust it too much - experience shows they include a lot of errors. It would be a pain to follow that diagram closely, route a bunch of wires and discover an error.

    The winch on my J20 was connected to the solenoid post, just for comparison. I have no experience with winches other than that one, but I'd guess how it's connected would depend on the installer.
     
    Last edited: Nov 3, 2019
  13. Nov 3, 2019
    53A1

    53A1 Member

    Kern Co. Ca.
    Joined:
    Jun 17, 2008
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    447
    Oh ya, forgot to mention TAKE OFF THE WEDDING RING. Seems stupid but you will eventually get bit and depending on what your doing your results will vary. I worked in machine shops in my early days so I NEVER wore mine in the in the garage. But... the one night my wife and I were going out I was fooling around with the timing while she was getting ready and BAM my ring was welded to the the hot post on the starter. Third degree the size of a pea down to the muscle. If it's the size of a quarter then it's a different situation but why even go there.
     
  14. Nov 3, 2019
    obarrett

    obarrett Member

    Lake County, CA
    Joined:
    Sep 8, 2010
    Messages:
    53
    re: ring... great advice, right now the battery isn't even in the jeep

    re: alternator... bigger back story is the mopar injected 258 sitting in the garage... I think its a 10si on it, and I probably coulda/shoulda took it off that in hindsight.
    I want to get this in some day, but it has power steering, but the jeep doesn't...
    so there is a laundry list of to do's aside from the electrical to get ready for this.

    [​IMG]

    the bigger, bigger back story is also in the garage is a rebuilt Dana 300 w/ 4:1 kit, rebuilt T18 with the 6.32 1st gear, Scout Dana 44 rear with the Warn full floater / disk brake kit, and a narrowed Chevy Dana 44 for the front... it was fun tearing down and rebuilding / fabricating all of it with my Dad and my two boys, and things moved along pretty good till he retired and closed up shop a few years back.

    Not having dedicated space where I can leave stuff out, let alone all the tools laid out ready to go, really slowed down everything (I have a 1/2 car garage at home).

    The wiring has been like this for damn near a year (the 13 and 8 year old boys keep me busy), so at this point want to get it safe and reliable and think I made some decent progress today.

    This was one of my favorite finds...

    [​IMG]

    Was able to get rid of and replace this stuff..

    [​IMG]

    And the fuse panel is starting to look a little better... heat shrink terminals, and heatshrink on top of that. unsure if there is a protocol for the heat shrink coloring, but I wasn't following the factory wire colors, so just make unique combinations to make them easier to identify... and wrote everything down.

    [​IMG]


    re: TSM, I used that image in the post above I found on the internet, as it was cleaner... here is a pic of my TSM wiring diagram, its the same

    [​IMG]

    [​IMG]


    re: alternator -> battery run... previous guy had it run from the alternator on the driver side through the firewall, through the cab, back out the passenger side firewall to the solenoid
    Is it safer to keep it in the engine bay? or if its sized / fused correctly, shouldn't be an issue?


    thx again, appreciate the knowledge...
     
  15. Nov 4, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    The only reason you'd want a loop through the dash is if you had an ammeter. In that case, the charging current must be routed through the ammeter so the charging status can be seen by the operator. An ammeter was included in the optional gauge package for these Jeeps - you would have holes in the dash to receive the ammeter and OP gauge. You can see this wiring in the added diagram at the top of the page in your FSM. Without the ammeter, the charge wire goes directly to the battery, and yes that's the safer arrangement.
     
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