Electrical wizzards: Please help! 1986 toyota truck voltage / amp draw isuses

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
Dec 8, 2010
Threads
11
Messages
51
Location
Snellville, GA
Website
www.youtube.com
Ok guys, so I have been having some issues with draining my battery and weak winch line pulls, so I did a swap for a 120A Jaguar alternator from a 96 Jag XJ6, as I found that the wiring harness plugs right in to the Jag unit and doubles the amperage output. I also purchased a huge Deka Deep cycle / 1000 CCA battery. I was thinking this would solve EVERYthing, however I am running into a few problems. I know this is a lot of questions, so please bear with me...

As a precursor, I do have a LOT of electric accessories attached to / running from the battery. Electric radiator fan, high wattage headlights and a nice stereo with some percentage of 1100 watts are the most common running voltage draws. Also, for some reason, the turn signals (which are now small 55w fog lights) really kill the voltage when flashing left or right, but not at all when Hazard is selected?!? :meh:

The headlights flicker as the alternator turns faster, and I am not sure why. i can see the volts go up and down on the volt meter. from 'really high' to 'normal high', if that makes sense. This happens in rapid succession, as if the voltage is coming and going so fast it makes the needle bounce...and this is reflected in bouncing of the brightness in the headlights.

My impression is that maybe the ground wire is not big enough off the battery---could this be the case? Also as a side note, I ran the alternator power cable DIRECTLY to the battery, and then replaced the fusible link wire from the factory toyota fuse block with a 175A link and solid cable, and ran it directly to the battery separate from the alternator wire. Could this arise a problem with flickering lights, etc?

Also, my second guess would be that maybe the factory ground for the alternator (I'm assuming in the factory toyota wiring harness) may not be big enough for the new 120A alternator. Could this be the case? If so, which prong / wire in the wiring harness does the ground for the alternator, and would it be possible to splice in a much larger ground and just run it to the frame?

Also, does the battery need to be ground to the frame, or to the engine block? Mine is currently ground to the engine block. I am not against getting a second ground and going to the frame.

Any knowledgeable electrical guys got some input that could be of use?! I got a big wheeling trip this weekend, and could use some help FAST!!!
 
What is the maximum amp draw of the electric fan? Many are way over 50 amps. If so, then due to hot summer nights, you are possibly using more amps than the fan leaves from the max of 120. Any undersized wires and/or bad connections will just amplify the problems. John
 
What is the maximum amp draw of the electric fan? Many are way over 50 amps. If so, then due to hot summer nights, you are possibly using more amps than the fan leaves from the max of 120. Any undersized wires and/or bad connections will just amplify the problems. John

The fan draws a max of 25-30a, it runs just fine off of a 30a fuse, and has for years. The biggest event that happens is the flickering of the high beams with equally reflective bouncing of the volt meter in cab.

Also, the ground cable off the battery gets really hot...which leads me to think there may not be enough grounding capacity for all the new amperage coming in, or maybe it's supposed to get hot?
 
The fan draws a max of 25-30a, it runs just fine off of a 30a fuse, and has for years. The biggest event that happens is the flickering of the high beams with equally reflective bouncing of the volt meter in cab.

Also, the ground cable off the battery gets really hot...which leads me to think there may not be enough grounding capacity for all the new amperage coming in, or maybe it's supposed to get hot?
OK. You may not be exceeding the alternator output, but, using the 30 amp fan as a constant, add the other items and you may be exceeding the recommended amp load for the size of ground wire or connectors you have, especially if it gets warm/hot. Many rigs have a ground strap from engine to frame. If you don't, you could add one, or run an extra ground lead to the frame. Figure out the gauge and length of the smaller wires, especially the ones that get warm. You should be able to find/Google/ charts that show wiring volt/amp/limits per length to see if that is part of the problem. Even the bigger sires can fail. I had a problem years ago with a battery ground cable that looked good, but about 1/2 way down, it had collected water inside the insulation and it was corroded thru. It felt a little lumpy inside, so I jerked on it and it snapped in two, and the broken ends were nothing but cottage cheese! Good luck
 
okay, did some ground reworking, and i think that fixed the problem for the most part.

thanks for the help, I really appreciate it!
 
Back
Top Bottom