[formerly]

There are bits and pieces of info floating around but I haven't seen any definitive threads on the topic.

I'm looking to add at least 1 additional group 31 AGM battery that I plan to run pretty heavily/consistently most days.

Questions:

1. AGM batteries need ~14v to charge, but the 5th gen alternator outputs ~12.8, so people get those voltage boosters that seem to work. Will a HO alt that says it outputs 14.8v eliminate the need for the booster? I saw someone mention that the charging system needs to be tricked into accepting that output.

2. Do these alternators require additional/upgraded (thicker) wiring or bigger fuses? The websites either don't mention or say it's not necessary, but I've seen upgraded/additional wiring used in a few threads.

Options:

A. 270 Amp XP High Output Alternator (Toyota 4Runner 5th GEN 4.0L 1GR-FE)
– DC Power Inc.
B. 250A High Output Alternator for Toyota 4Runner, 2014 - 2022 4.0L V6 (241c.i.) - 11764-250-HD1-1 | PowerBastards.com | PowerBastards.com
C. '10-17 Toyota 4Runner 4.0L 270 AMP XP High Output Alternator

[Humble Leader]

check this thread

4Runner alternator upgrade (gen 5) - Toyota 4Runner Forum - Largest 4Runner Forum

[2021nightshade4x4]

Go all the way. There should be at least a 320A for 4Runners.


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[JaSC1]

Since I have dual AGM batteries, I did this after reading quite a bit. It works.

General Motors, DIODE, 12135037

[4RunnerAquasport]

Unless you plan on adding a powerful stereo, lights, fridge or other high amperage draw accessories, you can get by with a booster.
The GM diode has worked just fine for a lot of people, and there are some that do not want to eliminate the 7.5 amp fuse in the " Alt sense " circuit.
I have the arclight booster.

And there is also the Dirty Parts booster.

Both of these have the fuse. The novelty of the Arclight is you can turn it off so as not to be taxing your alternator all the time.

Get a smart charger also so you can keep your AGM topped off over night once in awhile. I've kept my AGMs healthy for years by doing this.

[formerly]

Originally Posted by Humble Leader

check this thread

4Runner alternator upgrade (gen 5) - Toyota 4Runner Forum - Largest 4Runner Forum

I did check that one out before. I guess I'll just get my choice of HO alt and add the secondary positive cable with fuse and call it a day. Thanks!

[formerly]

FYI for anyone in the future - SDHQ confirmed that their HO alt is direct plug and play, nothing additional needed.

[formerly]

DC Power replied and said it's direct bolt in, but they recommend doing the big three and keeping the factory wiring.