Lazy Daze Owners' Group

Lazy Daze Forums => Lazy Daze General Info & Discussions => Topic started by: John DaCrema on October 17, 2025, 05:00:14 pm

Title: Quick Question, RE house batteries and driving
Post by: John DaCrema on October 17, 2025, 05:00:14 pm
I use to know this.   
Once the engine generator provides the truck battery and engine requirements.  Does the generator provide current to the house batteries while driving?
Title: Re: Quick Question, RE house batteries and driving
Post by: Larry W on October 17, 2025, 05:27:00 pm
I assume that you are refering to the engine's alternator and not the coach generator.
Yes it does charge the coach battery if the isolator is still functioning.

Larry
Title: Re: Quick Question, RE house batteries and driving
Post by: John DaCrema on October 17, 2025, 06:00:44 pm
Thanks Larry that is what I thought.  Yes I was thinking of the engine's alternator.   The coach's generator's carb needed to be deep cleaned on my Daughter's (formally our's) mid bath.   It was all gummed up.  I remember a discussion that driving would charge the onboard house batteries quicker than trying to charge with the Onan generator.   The tech recommended we drive the gas tank down before running the Onan.  So fresh gas goes through. 
Title: Re: Quick Question, RE house batteries and driving
Post by: Dave Katleman on October 17, 2025, 11:15:18 pm
I remember a discussion that driving would charge the onboard house batteries quicker than trying to charge with the Onan generator.   The tech recommended we drive the gas tank down before running the Onan.  So fresh gas goes through.

Not so sure about quicker, it’s all about the size of the alternator.  It’s pretty uncommon for an alternator to out charge a generator.

As for running down the gas tank, I assume you’d then fill up with some fresh gas and maybe some Seafoam in the hopes it cleans out a bit of gum.  Reminder, generators don’t run on less than a quarter tank of gas.
Title: Re: Quick Question, RE house batteries and driving
Post by: John DaCrema on October 18, 2025, 12:53:13 am
Not so sure about quicker, it’s all about the size of the alternator.  It’s pretty uncommon for an alternator to out charge a generator.

As for running down the gas tank, I assume you’d then fill up with some fresh gas and maybe some Seafoam in the hopes it cleans out a bit of gum.  Reminder, generators don’t run on less than a quarter tank of gas.

Dave, thanks for the reply. She was about 75% full. The tech put the carb in a sonic bath, then rebuilt it. The carb has never been off the RV (2007 build). I did run the RV in the spring but after Tucson hit triple digits in June I did not do much. So it is my fault. The RV drives fine, so I think the hot dry desert air did a nomber on the gas in the carb. Like I said that is my fault. It starts fine now and will start and run fine again after it cools down. We will drive the MB around town some and refil the tank when it is below a half and near a quarter full. Then when my daughter drives up to the Grand Canyon NP she will run the generator while driving. 
I was impressed with the mobile RV service.  They knew the kid was heading east this weekend and bent over backwards to get the generator running.  If you need help in the Tucson area they are precision RV,(520) 500-6692.  This spring the auto step bit the dust and they installed a new step. It works great. Their price is reasonable, not great, but reasonable and they do good work. 
Title: Re: Quick Question, RE house batteries and driving
Post by: RonB on October 18, 2025, 01:56:04 pm
Hi John; Your daughter only needs to run the 2007 LD's generator for the roof top air conditioner.  The dash air should be all that is needed most of the time. Very high outside temperatures might require that the genset run also.
   Normally the engine alternator, if you are running the engine anyway, can charge the house batteries, (and the chassis battery) all together just fine.  I remember pretty discharged lead acid batteries took about 5 hours driving time to be totally topped off. Your 2007 MB may have a bigger alternator than my 130A 1999 E350 chassis has.  RonB
Title: Re: Quick Question, RE house batteries and driving
Post by: John DaCrema on October 20, 2025, 01:40:34 am
Hi John; Your daughter only needs to run the 2007 LD's generator for the roof top air conditioner.  The dash air should be all that is needed most of the time. Very high outside temperatures might require that the genset run also.
  Normally the engine alternator, if you are running the engine anyway, can charge the house batteries, (and the chassis battery) all together just fine.  I remember pretty discharged lead acid batteries took about 5 hours driving time to be totally topped off. Your 2007 MB may have a bigger alternator than my 130A 1999 E350 chassis has.  RonB
A day later. After a fill up (half tank) the gen starts and runs as it should. They are in Grand Canyon NP, Mather CG for a few days. It was a six hour drive. All is good with the RV. Many thanks RonB.
John