Diagnosing Charging Issues Continued - 50DN and it's Charging Regulator

[neoneddy]

Thought I'd start a new thread with new information from this thread https://www.busconversionmagazine.com/forum/index.php?topic=33315.0

Recap - started seeing low / no amps from alternator during last trip.   Once the batteries got a full charge from being boon docked previously, I started seeing amps flowing into my house system.   I started to suspect the alternator didn't fail, but was operating at a reduced capacity.  I've all but confirmed that this morning.

After my bus being at the shop for 3-4 days , effectively boondocked (had a fridge full of stuff and whatnot) my system needed a good charge and didn't get all it wanted from solar / it spent a day indoors.

Anyway, I noticed only 1000 at most watts (measured via shunt)  coming in from the coach into the house system, I could only measure this while parked at high idle (1000 rpm or so).  I adjusted my voltage regulator last night and could hear the engine unload as I adjusted it down and say the voltage drop from 26.2 or so, to 25  or so.  As I adjusted it back up it would never get past 26.3 or so.  My batteries showed  at  50% charge or so... it will take some serious juice to show 27 or 28v, prior to this event it would jump up to there.

So this morning after it got a good charge again,  I started it up and I noticed it  got up to 29v or so with no load, so I know the voltage regulator wasn't inhibiting the proper voltage and thus amps coming in (high amp draws will make voltage sag).   Before I could run 2 ACs and the voltage would hang around 27-28 or so, now it's 26 showing a little draw from the house side, so my total output is down.

Now I stuck a stick under the pedal to raise the rpm to more like 1400-1500 rpm and the watts / amps went up, I'm thinking it's just a diode set or two (of the 3) , I'll need to take it easy until I get some replacements.  Or my windings are shorted someplace so I don't have full capacity there.

Anyone replaced these diodes?   I'm only finding a few entries on ebay for them, some air cooled, is there a difference?  Mine is a gear driven model.

[TomC]

I have a 12v 50DN and digital voltage regulator (size of a pack of cigs). When all batteries are fully charged and no charge is going out, the alternator light comes on. Hence, I run with my headlights on at all times. Good Luck, TomC