Generator Question

[Larry Dedrick]

Does the generators alternator charge the coach and chassis batteries directly?

Thanks,
Laura and Larry

[Edward Buker]

Larry,

It does but it is a small alternator and it is a long cable run back to the batteries. If your generator is on the chassis battery for starting you would not have a path to the house batteries with an echo charger which only connects the banks when the house batteries are being charged. The house charger that runs on 120V would do most of the charging work with the genset on.

Later Ed

[Gerald Farris]

Larry,
Your coach has a 10K generator, and none of the 10K Onan generators that I have worked on have a 12 volt alternator. So if your generator is so equipped, the generator only produces 120 volt current. Therefore, it can not charge any batteries without the use of your inverter.

Gerald    

[Edward Buker]

Gerald,

The 10K HDCAA that I have has an alternator and it swings to tension the belt. Check page 42 of this manual.

http://www.cumminsonan.com/www/pdf/manuals/981-0526D.pdf

Must be when you changed your belt you were going so fast with the wrenches like the "Six Million Dollar" man would that you had no time to see the alternator....the other explanation is there are 10kw Onans without alternators. I can assure you I had time to see the alternator at the rate I spin some bolts :-)

Later Ed

[Joel Ashley]

Looks like it's figure 9-1 on page 9-2 of your cited manual, Ed.  I couldn't find normal pagination, except by section.

Joel

[Gerald Farris]

Ed,
I have seen 2 Onan 10K units disassembled, including my own that I replaced the belt on, and neither of them had a battery charging alternator. The belt adjustment pulley is just an idler pulley because a battery charging alternator is not necessary since the Onan does not have a battery.

The question can be answered by starting the generator and letting it run with the charging function of the inverter turned off. If the generator has a battery charging alternator, the battery bank that starts the generator will have charging level voltage present at the battery post.  

Gerald

[Steve Huber Co-Admin]

Ed, Gerald,
Looks like it's a time period issue. The HDCCA units in the 2000 Marquis clearly do not have a 12v charging system. Nothing in the manual about one either. Ed, your document for 10K genis was published in Feb 04 shows and refers to a battery charging alternator. An Onan generator handbook published in Aug of 2012 clearly states the genis (10K included)are only capable of charging batteries via an external battery charger. Looks like Cummins added one sometime between 00 and 04 and discontinued it prior to 2012.
Steve

[Edward Buker]

Gerald,

I will measure the voltage when we get to VT and I have a few minutes. None of these 10kw Onans have a battery internally but they all require a battery to start them and it would make sense in most applications to have an alternator. According to this ad it mentions battery charging is a standard feature and not an option. This is a current ad so things may have changed over the years.

It is a very small alternator as alternators go but mine was significantly bigger than just an idler pulley and a set of bearings as I remember it. My guess here is that maybe Beaver/Monaco may have saved some money and special ordered some without an alternator, not sure.

http://www.generatorjoe.net/html/onan/ONRV-010D603.pdf

This is a 20amp stator part for the alternator, as you can see it is not very big. I have the HDCAA 10KW parts manual and it shows two 20 amp alternators, one with the 65mm pulley and one with the 74.5mm so they have been around awhile given they did away with the 65mm belt system. I could not find a listing or drawing for an idler pulley arrangement as an alternative but that does not mean that they did not make one.

http://onanparts.com/index.php?main_page=popup_image&pID=389

Like you say if you want to know if you have an alternator measure the voltage before and after starting the genset with the inverter charger off.

Later Ed

[Larry Dedrick]

Gentlemen:
             Thanks for the replies. Our gen set was removed for noise and also, when they were running the gen, before removal to diagnose the noise, the gen set auto shut down due to an overheat detection.
              I feel good about them removing the gen. The inspection showed nothing serious except some foam strips were in the fan area creating the ticking noise I mentioned in my previous post " gen goes tic tic tic". Further inspection by them showed the fan belt was in very bad condition and then I noticed the alternator and asked a few questions. I have an Isuzu engine on this gen set and seeing the alternator, I was wondering if it is functional.
               While the gen set was removed, I wanted all hoses changed out and they will do that plus thermostat, temp sensor, fan belt, remove and clean the radiator (which was restricting air flow) and they felt it best to replace the front bearing on the generator.
                Their mechanics were very knowledgable with onan gen sets and the business is an onan dealer, so I feel very confident it is being repaired properly.
                 Fortunately, the problems we have discovered besides the gen are being discovered before our first real adventure coming in two weeks. If it wasn't for our upcoming trip, I was thinking about the belt change myself after Gerald's comment on the maintenance he did on his gen. Oh well, maybe next time I will rip into it.
                They assured me these gens are good for many many hours of operation.

      Thanks for the info.         Larry D.

[Steve Huber Co-Admin]

Larry
I've got the same generator and was apparently mistaken last night when I noted it did not have a DC alternator. While I could find nothing in the documentation noting an alternator, the spec sheet does refer to a 20A max 12vdc charging capability. Missed it last night.
Steve

[Larry Dedrick]

Thanks Steve . No problem
     Larry D