Dual battery alternator failure (1 Viewer)

[yngmrostrvile]

Looking to raise the topic of alternator failure with dual batteries.
1. What DC to DC charger are you using?
2. Do you know what failed on your alternator?
2. How many times has alternator failed in how long of period?
I'll start off, I have a Renogy DCC50S.
I had an aftermarket alternator failure in June '22. The rectifier was the failure.
I rebuilt a Denso with bearings, brushes, and voltage regulator. No rectifier.
July '25 that alternator failed. Replaced rectifier, voltage regulator, and brushes.
We could go into the weeds on other things that might cause failure. Background, I am an ASE master tech. I installed all systems. Did not cheap out or under size wires. All large gauge is crimped with marine heat shrink and smaller gauge is crimped, soldered, and has has marine heat shrink. Large gauge to DCDC and battery are fused on both ends.

 

[TLCPNW]

Looks like you can modify the amount of charge you add with that Renogy unit. Did you adjust the max amperage setting at all? If not, 50 amps is quite a bit for our stock 100 amp alternator (on your 2000).

 

[yngmrostrvile]

Looks like you can modify the amount of charge you add with that Renogy unit. Did you adjust the max amperage setting at all? If not, 50 amps is quite a bit for our stock 100 amp alternator (on your 2000).

Yes it is set to 30amps.

 

[excessive]

I have had dual batts for 4 years, a very simple setup with a Blue Sea ML-ACR. No alternator failure yet, but did replace the brushes in it as PM

 

[RKRUGER]

Been running Toyota reman alternator 2 years now powering a Victron 12/12-18 dc dc charger to a 100 ah LiFePo. No issues and knock on wood. One reason I went with the 18 amp dc/dc is I didn’t want to draw on the alternator too hard. After hearing some of the misadventures on this site, I went conservative.

 

[CORunner]

I'm running a RedArc BCDC 25A DC/DC charger for my X2 27F AGM 2nd battery for 4 years with no issues with the alternator. Wiring from the charger to battery is 8 guage.