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Alternator problems again

I recently installed a sense wire directly from the alternator to the positive terminal of the start battery. When I fired up the coach charging was solid at 14V. Had to take the coach to the water treatment plant to dump the tanks voltage all over the place (rough roads) and settled at 12 volts. Voltage at start battery agrees with the dash meter. All connections that I checked are tight, obviously something is loose. Alternator is three years old. Will be checking the integrity of the ignition wire and the battery corrections again tomorrow. Any other ideas? Is it possible that there is something loose inside the alternator? Oh and sense voltage reflects the start battery voltage. Started the coach yesterday and alternator was at 14v.l :thumbsdown: if I had hair on my head I would be pulling it.

Roland
1993 U280 4341
2010 Jeep Liberty
The Pied Pipers

Re: Alternator problems again

Reply #1 –
are all power wire connections clean and tight as well?

if voltages all over based on vibration, connections would be my first look. maybe one of your sense wire crimps is on the jacket and not actual conductor? ive seen that cause major headaches. incredibly hard to find as well.
Matt
95 U300, 78k miles
Cat 3176 Jake Brake, HD4060.

Re: Alternator problems again

Reply #2 –
Check for power from the excitation circuit breaker. I had similar symptoms for a year until the circuit breaker failed completely.

Re: Alternator problems again

Reply #3 –
Quote from: Bob McGee –
Check for power from the excitation circuit breaker. I had similar symptoms for a year until the circuit breaker failed completely.
Is the excitation circuit breaker an issue with a direct wire from the alternator straight to the start battery?

Roland
1993 U280 4341
2010 Jeep Liberty
The Pied Pipers

Re: Alternator problems again

Reply #4 –
I assume your alternator has four lugs: one large positive, one large negative, one small lug for the sensing wire, and one small lug for the excitation wire that energizes the alternator field when the ignition is turned on and allows the alternator to charge the batteries when the engine is running. Think most if not all Foretravels use this externally exited alternator in conjunction with the isolator to maintain two separate battery banks. Hopefully one of the forum experts will chime in to explain this better.

Re: Alternator problems again

Reply #5 –
Rotor on ours had a loose connection internally and acted like yours. Had a new OEM rotor installed and that was that ^.^d
Larry
1996 U295 36'
Build # 4805
Actually we sold it but just like to lurk

Re: Alternator problems again

Reply #6 –
Most likely Roland's is like mine. Has only the sense wire, no exciter. I think Roland, that if you have an isolator (unless you removed it) you need to bypass it and join the cable coming from the + on the alternator to the start battery cable directly and see if the voltage stabilizes. If so, it is the isolator causing your problem.
1994 U280, Build 4490
Deming, NM.

Re: Alternator problems again

Reply #7 –
When you say that the voltage "settled at 12 volts" I'm assuming that is the voltage on the dashboard which measures the start battery bank. This makes me think that you are not getting sense voltage to the alternator. As Twig says, you should connect another wire - a jumper if you will - directly to the start bank and see what happens then.

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: Alternator problems again

Reply #8 –
Quote from: wa_desert_rat –
When you say that the voltage "settled at 12 volts" I'm assuming that is the voltage on the dashboard which measures the start battery bank. This makes me think that you are not getting sense voltage to the alternator. As Twig says, you should connect another wire - a jumper if you will - directly to the start bank and see what happens then.

Craig
I installed a 6gauge wire from the sense post on the alternator directly to the positive post of the start battery as stated in my original post. It was after this installation that I continued to experience erratic alternator charging.

Roland
1993 U280 4341
2010 Jeep Liberty
The Pied Pipers

Re: Alternator problems again

Reply #9 –
Quote from: Roland Begin –
I installed a 6gauge wire from the sense post on the alternator directly to the positive post of the start battery as stated in my original post. It was after this installation that I continued to experience erratic alternator charging.

I know. That's why I suggested a "jumper" just to see if that wire is making good connections. 6gauge wire is a little overkill for that, by the way. The sense doesn't draw much current.

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."
 

Re: Alternator problems again

Reply #10 –
Quote from: lgshoup –
Rotor on ours had a loose connection internally and acted like yours. Had a new OEM rotor installed and that was that ^.^d
Where did you have that done?

Roland
1993 U280 4341
2010 Jeep Liberty
The Pied Pipers