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Powertech Gen Alternator No Workie
The alternator on our 17.5kw gen isn’t charging the gen battery. Anybody have a part# and source besides Powertech? Or a suitable replacement?
Thanks
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12 Replies
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Take it off and go to a NAPA store, they can most likely find one.
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Interesting. My gen battery is maintained by the house battery bank with an isolator to keep from draining the house. I did not realize some had their own alternator.
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My gen battery can be charged 4 different ways:
1) It’s own little 12v alternator
2) The inverter/chargers charge house batts which charge gen bat thru isolator
3) The Liberty installed 12v alternator driven by 90* gear box, which charges house batts, which charges gen bat thru isolator
4) With a portable battery charge -
Cool. I guess i have 3 ways .
1984 96" with 8V92TA
(remodeled Liberty Coach)
Greenwood, MO -
Hi Don… have 100% confidence you will get it done!!! That’s a tiny job for YOU!!! Hope all is well your way!
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On a 1998 Power tech 17-5 I had a dynamo instead of alternator and got new one on line either ebay or amazon for $70 bucks 2 years ago.
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yours should have a part number on it . Power tech wanted about $700 and I got on line for $70.
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DANSS, does your DYNAMO look like what I’m calling my gen alternator?(see pic above)
When I researched “DYNAMO” they appear to be a generator, not a alternator, that produces the proper voltage output when the gen is at operating rpm(1800).
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Not sure as I no longer have bus. I would pull your alternator/Dynamo off and it should have a part or brand name on it. I got mine off Ebay. If you cannot dertermine the kind I would call Power tech for info. Hope this helps.
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It’s a Nippon Denso alternator and it does workie! I determined that the generator alternator is good. But, it’s not coming to life and charging the gen battery because the excitation wire is not getting any voltage? The gen battery is good. There are only 2 wires connected to the gen alternator. The bigger one connected to the gen battery, and a smaller one (excitation wire) that plugs into the back of the alt. Where it comes from I haven’t a clue?
I hooked the alternator up to another 12v battery I had sitting around, fired up the gen, and the alternator charges just fine.
I’ve looked in the little black watchdog box for a fuse or something and couldn’t find anything? Under it is the gen control box. I see 2 good fuses in there but nothing else?
I left a message for Bill Darby @ Liberty asking where the excitation wire and protection comes from.
Suggestions? -
See if this is like yours.
This is off the Power Tech web site.
Bill Darby returned my call and told me the alternator excitation comes from either the gen fuel pump circuit or the gen diesel fuel shutoff solenoid circuit. I went digging and found that the gen alternator excitation wire had been cut, probably intentionally by a previous owner. WHY? The gen alternator regulator charges at 14.9 volts, enough to boil the acid/water out of the wet cell battery in no time. I fixed the wire but have left it unplugged from the alternator. I can easily plug it back in if for some reason I ever need to charge the gen battery with the gen alternator. There is 3 other ways to charge the gen battery: 1) inverter/chargers; 2) 12v DD engine driven house battery alternator; 3) portable battery charger.
In the 6+ yrs that I’ve owned this bus, the gen alternator has never charged its battery for the above stated reason. My DuraLast marine wet cell group 27 gen battery was new in Dec of 2013. I’ve tested it twice lately and its condition and state of charge are good. It has never needed any water added.
I know how to take care of batteries. My 4 NAPA commercial chassis batteries are 7 yrs old and are still good. My 3 Lifeline 8D house batteries are only 3 yrs old. I expect to get at least 8 yrs out of them.Thanks Buddy, I believe the wire I found cut was the 10 Gray wire in the diagram downstream from where it Ts off of the hobbs and fuel pump circuit.
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