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Nightcrawler

Inverter question

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Nightcrawler,

Welcome to the FMCA Forum.

Your alternator charges your chassis and house batteries while driving.

As long as alternator output exceeds the draw on the batteries  (and any charging if the batteries are discharged) you are good to go.

You could drive as long as you desire as long as the above is true. 

If batteries are deeply discharged (like when dry camping) you may want to run the generator to bulk charge the batteries before relying on the alternator to supply all your needs.

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Okay thanks, just wondering because we were driving for about 7plus hours last week (something we don't normally do) and well into the 7th hour the inverter started going on and off and the fridge would beep.

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What coach/chassis?

Do you know the alternator rating (in amps)?

What did the house battery voltage read when the inverter turned off (from inverter remote panel or other means of determining voltage? What did the chassis battery (dash gauge) read?

Any other high amp loads-- either 120 VAC from the inverter or high amp 12 VDC loads (like driving lights plus dash A/C and fan on high, etc at the same time)?

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Nightcrawler,

The Freightliner chassis build sheet shows a 160 amp alternator.

https://cdn.fccchq.com/specsheets/5b7abfafcf1da258f28db094/2010-Tiffin-Phaeton.pdf

As long as you don't start with deeply discharged batteries, that should be just fine for running the loads you describe.

If you see voltage dropping below 13.0 on either battery bank while driving at highway speeds, I would suggest having the alternator checked out.

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5 minutes ago, wolfe10 said:

Nightcrawler,

The Freightliner chassis build sheet shows a 160 amp alternator.

https://cdn.fccchq.com/specsheets/5b7abfafcf1da258f28db094/2010-Tiffin-Phaeton.pdf

As long as you don't start with deeply discharged batteries, that should be just fine for running the loads you describe.

If you see voltage dropping below 13.0 on either battery bank while driving at highway speeds, I would suggest having the alternator checked out.

Both on the same thread  and your thoughts are equal to mine. found the same size alternator, but he should use the last 7 characters of the Vin and give  then a call and ask who supplied the alternator they used on his chassis.

Freightliner service in Gaffney S.C. 1-800-384-4357.

Rich.

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What make and model # is the residential fridge? Look inside the door of the fridge and let us know what the maximum load in amps is the fridge. This will help in determining how much load is on the inverter. Maximum load is not what determines the actual load of the fridge but will give a baseline for load purposes.

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On 9/25/2019 at 2:43 PM, wolfe10 said:

Nightcrawler,

Welcome to the FMCA Forum.

Your alternator charges your chassis and house batteries while driving.

As long as alternator output exceeds the draw on the batteries  (and any charging if the batteries are discharged) you are good to go.

You could drive as long as you desire as long as the above is true. 

If batteries are deeply discharged (like when dry camping) you may want to run the generator to bulk charge the batteries before relying on the alternator to supply all your needs.

If you have a large bank of batteries and they are deeply discharged it is possible the alternator output is exceeded and the alternator will overheat and fail.  I lost 2 alternators before I figured it out.  The solution is to install a larger output alternator, I went from a 160 amp to a 260 amp.  First 2 lasted about 1 1/2 years and the larger one was still working when I sold the coach 15 years later.

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Hopefully you have resolved the issue.  If not, suggest you check out the battery (house to chassis) solenoid.  This device connects the engine alternator to the house batteries after the ignition switch is turned on.    Had a problem a bit like yours in my 08 Phaeton.  Assuming your coach uses a mechanical solenoid, the contacts in the solenoid become pitted over time and develop high resistance.  If your 2010 Phaeton is wired like mine,  you also have the same type of solenoid supplying power to your mechanical slides.  These  can be found on the internet for about $30. Just Google the part number written on the side of the device.   Also check the house  battery voltage monitor with the engine off, no shore power, and generator not running,  lets say its around 12.4 VDC.  Now start the coach engine, wait a few minutes.  The engine alternator voltage gauge (instrument panel) will climb to normal charge.  Now check the house battery voltage. It should jump up about a volt or more (depending on charge state of chassis and house batteries) now connected in parallel.

I like to keep a spare solenoid just in case.  They are used for several different things in these coaches and tend to fail over time.  You will find them in the electrical bay near the engine.

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We had a similar issue. Freightliner indicated we had a 160 amp alternator.  The Electrical expert at Lazy Days in a forum discussion we attended some years ago, stated the standard 160 amp alternator installed at the factory might not contribute a significant amount to house batteries due to the load of modern Diesel setups in today's motor homes.  After installing an 18 cf Samsung Fridge running off the inverter, we noticed voltage was becoming an issue on a frequent basis.  We likely also had an issue with the existing alternator in addition to the load from the new Samsung.  One day we actually had to run the Onan Generator to help recharge chassis batteries as we were driving on I-75 in Florida.  The chassis battery voltage had dropped to 11 volts on the dash indicator.  I went to TRS Starter/Alternator repair in Orlando and had them rebuild the Alternator to 200 amp.  Money well spent.  No more problems.  TRS is a splendid outfit with very experienced and competent folks.  We had read about them previously in these forums and found them to be the place to go in Florida for Alternator/Starter service on big rigs.  

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In the bus conversion world it's common to mount a second alternator on the main engine which is dedicated to charging the house batteries while underway. Usually this is done because many bus chassis are 24v and the second alternator installed is 12v for the house system, but it seems like this might be a solution for coaches where the chassis alternator is being overtaxed by house systems. Every engine setup will be different, but I'd guess that most engines have options for adding additional accessories like a second alternator.

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