TL;DR - I've upgraded the wiring (Big 7) and alternator under the hood so that I can more quickly charge the new LiFePO4 electrical system that I recently installed.
Mo powa baby!
One of the most critical components in our Tacomas is the alternator. This little workhorse generates all the electricity needed to keep our cylinders firing, radios running, and gizmos charged up. Working as hard as it does, it's downright amazing how robust the stock alternators are, even if they only generated 60A-80A when they were new from the factory!
In fact, the most common failure I've seen (and experienced) is that the brushes - a wear component - get worn down and stop making contact with the spindle. When this happens, the alternator stops working and the battery light on the dash turns on. Luckily, this is an easy - and inexpensive - part to replace.
In other cases, especially when there are additional loads on the alternator - aftermarket lighting, winching, charging/running of a house electrical system - it can be a good idea to upgrade the stock alternator to one that outputs more current. This too is relatively easy, and there are several options that bolt right in. I've had a new 105A Denso collecting dust in the shop for about 5 years, and with the new LiFePO4 electrical system - which has the ability to draw up to 50A when charging - I figured it was finally time to get it installed.
Of course, when installing an alternator that will output more juice than the stock alternator, it's critical to think about the pathways in which all those little electrons will run around in the engine bay. The factory wiring can handle a few more amps than the stock alternator could supply, but Toyota isn't in the business of installing tons of extra, expensive copper if it's not necessary, so it's a good idea to upgrade the wiring as well. For those unfamiliar, this is known as the Big 3, Big 5, or even Big 7 upgrade, depending on who you talk to and how many wires will be replaced in order to enable the additional loads.
- Big 3 - this is the "basic" upgrade; all three of these need to be done first, and at the same time.
- Alternator to Battery (+)
- Engine Block Ground to Battery (-)
- Battery (-) to Fender Ground
- Big "More" - depending on who is describing it - adds
- Battery (+) to Fuse Box
- Frame Ground to Battery (-)
- Starter to Battery (+)
- Cylinder Head Ground to Firewall Ground
Naturally, increasing wire size should be done at the same time as - if not before - the alternator.
If you're looking to replace your alternator and upgrade your wiring and replace your alternator, these guides outline the process and provide links to all the parts and tools needed to do the job (at varying price points).
Given that my first order of business - purchasing and then long-term storage of the alternator in the shop - was already complete, I set about finding a good option for upgraded wiring. This was something I could have fabricated myself, but I knew that Zane @Speedytech7 over at Outlier Motorsports had already done all the research into wire gauge and length, so I picked up a Big 7 Wiring Kit that would cover all the bases. No point in replacing half the wires if I was going to have the entire wiring harness out of the truck anyway.
Wires. Exciting.
The biggest part of the job was removing the factory wiring harness from the fuse box, battery, alternator, and starter, but with a bit of patience I was able to get everything unclipped and unbolted which left me with the wiring harness laid out across the shop floor.
A dusty mess.
A few minutes later, I had several of the Outlier Motorsport wires swapped into the wiring harness and it was ready to go back into the Tacoma.
Pulling the wiring harness had also necessitated pulling the alternator - if only to get better access to the connector on the back - so as I reassembled everything, it was the perfect time to install the new MOAR POWAFUL Denso.
The new alternator looked very similar to the original. Only placement of the control plug and positive post were a little different (but not a problem).
The usual application of this alternator - in a Suzuki - uses a threaded hole for tensioning the alternator belt. On a Tacoma, this threaded hole isn't necessary, and the threads are easy to drill out in order to make room for the tensioner.
Soon enough, the alternator and all 7 wires were installed, their bolts, nuts, and belts torqued to the proper tightness. Climbing into the cab, I fired up the engine, happy to see that everything seemed to work just as it had before - the alternator supplying a crisp 14.1-14.3V just as the factory alternator had, but doing it while pushing out 50A to my Victron Orion XS DC-DC charger, without breaking a sweat.
With this sort of power, I can charge the 280Ah battery from empty in just over 5 hours.
D, where is you find your military-style battery terminal connector?
Hey Bill, those terminals are made by GP Audio, and are targetted at folks who listen to music with a lot larger sound systems than I have, lol. They aren't cheap, but I've never had an issue with them loosening. You can pick them up here: GP Audio Aluminum Battery Terminals
Good morning!
Yep...I did this upgrade as well. The difference was immediately apparent when I turned the key to start the truck. The starter just seemed...mmmm.....lets just say a bit more "perky". One thing I did since my plastic shielding and wire trays or guides around the truck are getting older now is to wrap these wire looms using Tesa fabric tape.(can be found in the Amazon) It is incredibly durable and will not leave a sticky, gummy mess like traditional e-tape. I also fused the lead to the alternator (120A) just for safety. If you ever say switch the leads when trying to jump the vehicle, in the dark, when its raining at 2am in the middle of Washington, this will save you. (Ask me how I know....oh and be sure to carry extra fuses) The other thing I did was to add pos/neg distro blocks to keep these leads from piling up on top of the battery. With all the accessories we run...winch, lights, compressor etc...its nice to have all that tucked safely out of the way. Anyway man...as always I enjoy these articles. I miss it out there!!!! Take care...drive safe!
Morning Matt! Sounds like you did some nice work there! I'll check out that Tesa fabric; sounds nice. Does it hold up over time? (how long ago did you do the upgrade?)
For the pos/neg bus bars - I totally get where you're coming from there, but I figured that I could either try to find a spot to put them in my already-overstuffed-engine bay, or just have them sitting on my terminals, so on the terminals it was, lol!
Glad as always that you're enjoying. Nice to get comments from folks who've done similar work!
I did the Big 7 upgrade about three years ago as well as a couple of other projects where the wire keepers and plastic was just shot and the Tesa tape has held up well. Is there something better? Oh I"m sure... but its reasonably priced and easy to remove. Note: There is a high heat Tesa tape option which I used on the fuel injector harness & plastic cover which was literally crumbling and then the felt type tape for interior use which is really nice to keep the rattling of wires and connectors to a minimum on the road. Granted your truck has been around the world, back again, to Mars and then some compared to mine so my disclaimer is that "results will vary". 🙂 Safe Travels
Awesome, I'll definitely look at getting some of that stuff. Three years is a lot longer than most stuff lasts in an engine bay! 👍