Alternator Oil Leak

[rrueckwald]

The 300 amp alternator is leaking a little oil around the shaft seal. How much is too much? Is this a nuisance, or warning of an imminent bearing failure? I fear this could get expensive.

[Randy Dupree]

mine has started leaking on this trip,i have been online looking for info.
something besides the shaft seal is leaking on mine.
I did find a place to get a seal kit.
If will be a few weeks before i fix mine.
Let me know what you find out.

[fxdwg]

Ron,

The only real way to tell if the bearing is fainling is to remove the alt belt and try moving the alt pulley sideways and also spinning it slowly by hand. If it moves much sideways, not good. If it's slowly self destructing, you can feel the rough wear spots in the bearing by slowing turning it by hand. It's sometimes tough to tell whether it's the front or rear bearing causing the roughness, but it can be done.

The oil connection is a bad source of leaking, most I've seen have this leak/seepage. Also the case junctions leak and I understand there is an o-ring at each case split.

[warbucks13477]

Randy/John what do you have in the coach that requires a 300A alternator? They take a tremendous amount of HP to run them. I have a 160A Leece-Neville alternator and have never seen it go over 130-140A on my link 2000 even after dry camping for a couple of days. Do you guys have an all electric coach and several large battery banks.

Tom,

My coach is wired such that the Xantrex inverter/charger load doesn't show up on the alternator ammeter gauge. I have two 3000 Watt inverters. That's over a hundred amps tapped off the alternator before the ammeter gauge shunt. I think many if not all Wanderlodge's are wired this way. Please correct me if I am wrong.

[fxdwg]

Tom,
We've got the 95 (Ron) and 96 (mine) 42' with the S60 engine. When they went to this engine, they combined the two 160A alternators found on the 8V92 engines into one 300A unit. If I've been parked over night, run a few lites, the radio and only one inverter; when I start I can clip 200A pretty routinely for a moment or two, then she comes back down to the 125 range for a little while until she drops way off. This is all at 12V. I looked at one this weekend with a 400A 24V unit. It was huge!

I haven't yet traced out my inverter setup (other than knowing I've got 2 Freedom 2500's. But it's on my list to do. One inverter will go to an equalization mode, when ever it's turned on. I've tried the old whack the right front corner with a rubber mallet to seat the board a little better without any success.

[Turbokitty]

As a point of clarity, A 300 amp alternator will only put out as much power that is needed up to... 300 amps. It certainly is not putting out 300 amps all of the time otherwise there would be a lot of boiled out batteries out there. Basic math says that 300 amps @ 24 volts is only using about 15HP if you figure 2HP/Kw which is a very generous formula. It is probably less than a 10HP pull at 300 amps. Anyway, keep the big alternator!

That's right Ryan. Just want to add that our systems are 12V which equates to around 5hp, but nothing is 100% efficient, so bump that up to around 8hp (mechanical and electrical loss, etc).

My 6000 Watts of inverters can bring my 300 amp alternator to it's knees, and the ammeter gauge won't budge!

[diesel bill]

I just had to remove my 300 amp Delco because it stoped charging. I was told that the stator wires were broken. Make sure you have a good back or some help when you decide to remove the unit from the coach. I had mine repaired at a local auto electric shop. The alternator worked fine after the repair, but developed an oil leak between the case's. There are o-rings between the sections and if not carefully assembled they can be damaged during assembly.

[dwjones75]

300a alternator full output 5hp.

Not much compared to 470 or 500 hp.

The power hog is the hydraulic fan ~45hp

Don