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Hahndol Samba Member
Joined: October 17, 2021 Posts: 11 Location: San Diego California
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Posted: Sun Oct 17, 2021 7:33 am Post subject: charging system |
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Hi, I have a custom sand rail and the charging wire from the alternator is getting very hot and eventually blows the inline fuse. I've replaced the the neg and positive battery cables. Bypassed to fuse block. Replaced the ignition switch and push button starter. The alternator is new. The starter is new as well. The battery voltage will the motor is idling is around 13.8 vdc. Its not over charging. It seems like there is a short but I don't know where else to check. Any ideas? |
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Dale M. Samba Member
Joined: April 12, 2006 Posts: 20377 Location: Just a tiny bit west of Yosemite Valley
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Posted: Sun Oct 17, 2021 7:41 am Post subject: Re: charging system |
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Hahndol wrote: |
Hi, I have a custom sand rail and the charging wire from the alternator is getting very hot and eventually blows the inline fuse. I've replaced the the neg and positive battery cables. Bypassed to fuse block. Replaced the ignition switch and push button starter. The alternator is new. The starter is new as well. The battery voltage will the motor is idling is around 13.8 vdc. Its not over charging. It seems like there is a short but I don't know where else to check. Any ideas? |
Sort of sounds like your new alternator may be a dud..... Disconnect the lead from the B+ terminal and see what system voltage does....
Does voltage at battery change?
Does output voltage of alternator change?
Did you have a problem with alternator requiring it to be changed?
What is size of wire from B+ wire from alternator to battery (charge cable)?
What size fuse in line? _________________ “Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
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All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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Hahndol Samba Member
Joined: October 17, 2021 Posts: 11 Location: San Diego California
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Posted: Sun Oct 17, 2021 8:05 am Post subject: Re: charging system |
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The voltage after I disconnect the alternator goes up to 14.5 vdc to 14.8 vdc at the alternator post.
The battery doesn't charge after I disconnect the wire. It starts to discharge.
The old alternator was charging but not great I thought that there could have been a problem with the voltage regulator. I was running out of options. So, I decided to replace the alternator.
The wire is 12 gauge with a 30amp inline fuse. |
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Dale M. Samba Member
Joined: April 12, 2006 Posts: 20377 Location: Just a tiny bit west of Yosemite Valley
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Posted: Sun Oct 17, 2021 8:23 am Post subject: Re: charging system |
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Umm... #12 gauge wire is kind of small, should be more like a #8 or #10.... And a 30 amp fuse is kind of small if it is really a alternator. Most alternators are capable of about 55 amp outputs...
You mentioned a "regulator" you sure you have alternator (there was only 1 year that used alternator with external regulator), all later alternators only have B+ lead to battery for charging and D+ to ALT/GEN light... _________________ “Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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Hahndol Samba Member
Joined: October 17, 2021 Posts: 11 Location: San Diego California
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Posted: Sun Oct 17, 2021 8:43 am Post subject: Re: charging system |
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I'll switch the wire and fuse block to 10 gauge. I've never had a problem before.
Yes, this is an alternator. It has has an internal voltage regulator. Its a 75 amp out put.
The only draw on the alternator/battery is the ignition system. I've taken the lights and all of the gauges out of the system. There should be very little amp draw but the charging wire is getting hot to the touch. |
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Dale M. Samba Member
Joined: April 12, 2006 Posts: 20377 Location: Just a tiny bit west of Yosemite Valley
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Posted: Sun Oct 17, 2021 12:18 pm Post subject: Re: charging system |
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Hahndol wrote: |
I'll switch the wire and fuse block to 10 gauge. I've never had a problem before.
Yes, this is an alternator. It has has an internal voltage regulator. Its a 75 amp out put.
The only draw on the alternator/battery is the ignition system. I've taken the lights and all of the gauges out of the system. There should be very little amp draw but the charging wire is getting hot to the touch. |
How good is battery?.... Sound like alternator is trying to charge into a battery that maybe weak or has bad cell....OR a short in electrical system... _________________ “Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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Hahndol Samba Member
Joined: October 17, 2021 Posts: 11 Location: San Diego California
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Posted: Sun Oct 17, 2021 3:05 pm Post subject: Re: charging system |
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The battery is brand new. I'm leaning towards a short in the electrical system. But, I've gone through everything. Running out of ideas. |
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Wulfthang Samba Member
Joined: August 25, 2018 Posts: 719 Location: Tucson
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Posted: Mon Oct 18, 2021 8:25 am Post subject: Re: charging system |
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Electrical problems can be difficult to diagnose because you can't "see" the problem like a hole in a piston or a bent rod. First, fix the problems you know about and then test for the ones you don't know about.
Pull the alternator and battery and have them both tested. "New" can still be defective.
The alternator sounds like a "one wire" unit. Did the car have that kind of alternator to start with or is it a conversion? Sometimes, that kind of conversion requires a kit to make it work. I had to get a plug in regulator conversion to make mine work. (Ford 135 amp)
Absolutely replace the 12 gauge feed wire for the alternator. A 12 gauge wire is rated 20 amps max. It may be ok if the battery is fully charged and there's no drain like headlights, etc. but a couple of starts and stop and go traffic will discharge the battery. Then the alternator will charge at a higher rate and the 12 gauge wire will overheat and melt. It should be 6 gauge minimum. 4 gauge is better. You can get 100 amp fuse blocks on Fleabay for under 10 bucks.
If you had a short in the system, it would have to be only a partial short. A true short circuit would burn the wiring and/or blow the fuses. Feel the fuse block and wiring harness. Any hot spots? No hot spots then probably no partial short.
Honestly, what you're describing....."charging wire from the alternator is getting very hot and eventually blows the inline fuse"....... combined with .........."The wire is 12 gauge with a 30amp inline fuse"......sounds like it's under-wired and under-fused. Replace it with a larger wire and fuse. |
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liquidrush Samba Member
Joined: July 18, 2018 Posts: 588 Location: MO
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Posted: Mon Oct 18, 2021 11:10 am Post subject: Re: charging system |
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Can you post some pics of your setup? Might be helpful. On mine I ran the charge wire to the B+ on the starter and that cable goes to the battery + terminal. It's 10ga wire too and all of my wire ends are soldered, no crimps. Make sure those connections are clean and tight meaning disconnect them, clean the terminals and reassemble them and if any of your wires are crimped check them carefully and I'd solder them. Make sure you have a solid ground from the battery to the block and again, take them apart, clean and reassemble. I also got rid of every incandescent bulb on it and replaced them with LEDs, much less current draw.Trust nothing, verify everything. |
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Aerindel Samba Member
Joined: May 30, 2015 Posts: 459 Location: Western Montana
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Posted: Mon Oct 18, 2021 4:40 pm Post subject: Re: charging system |
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Quote: |
If you had a short in the system, it would have to be only a partial short. A true short circuit would burn the wiring and/or blow the fuses. Feel the fuse block and wiring harness. Any hot spots? No hot spots then probably no partial short.
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Yep. I had a true short on my truck once. Opened the hood and saw three feet of white hot wire glowing, before it melted and broke. A car battery has enough juice to weld with if direct shorted. _________________ Homemade woods/street, bug out rail. IRS, Balljoint front end. 1967 1600cc DP, Weber 32/36 progressive, tri-mil quiet pack. Rear only cutting brakes.
http://www.thesamba.com/vw/forum/viewtopic.php?t=630046 |
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stevebaz Samba Member
Joined: March 14, 2008 Posts: 189 Location: El Monte CA
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Posted: Tue Oct 19, 2021 9:44 am Post subject: Re: charging system |
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check the battery connections and the wire up to the starter. everything want to connect at the starter. if the wires and connection then power is going to draw from someplace else. I am surprised you could draw everything through a 12 gauge wire at the alternator. grounds are just as important as positive wiring. |
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