harper7
Senior Member
I tested the batteries while at idle tonight and both are charging at 13.2 volts, and with 1200+/- RPMS the voltage never changed. As a benchmark, we checked the voltage on our 2500HD duramax, both batteries were charging at 14.2-14.4. What voltage are your batteries charging at? Also does anyone have and links for a high output alternator. Mean Green doesnt make one yet......
Thanks for the help
Well there was this one hearing impaired guy......... Yes, no, maybe so? First DIY 300amp H.O alternator install-details inside! - Toyota FJ Cruiser Forum
IMO.....I don't think the alternator charging output is your problem though.We have 130amp Nippondenso alternators that are really pretty good .They are the same ones used in FJ's,Tacos and 4Runners for years with dual battery set-ups running fridges,inverters and enough lights bright enough to shine to the moon without a problem.
I believe they have 14 volt regulators in them so you will never see it go over 14V. I have a dual battery set-up with gauges in my console and the highest I've seen it at is 13.9V and that's after running my aux battery half way down playing with my lights and stereo. I verified/calibrated the voltages on my gauges with a Fluke meter so it's pretty accurate.Normally the alternator puts out 13.4-13.7V at start up and drops to a constant 13.1V output about 5 mile down the road.
Bad battery,isolator, alternator or possibly something constantly drawing off it is more then likely your problem.Your dual battery set-up should still be under warranty thru Kodiak and I'd let them make the call.Either that or go back to your single battery oem set-up to troubleshoot/monitor it,to see if it is the alternator,which I doubt.
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