Author Topic: Battery/charge issue?  (Read 4517 times)

Adam Hicklin

  • Guest
Battery/charge issue?
« on: December 15, 2019, 09:51:16 PM »
Went out to the coach to check a couple things out. Tried to start the generator; completely dead.  No clicks.  Completely dead.  Thought I’d try to start the Aqua hot diesel, same thing.  Nothing.  Coach has been plugged in to 50amp since October.

Checked batteries with a multimeter.  House 13.4V. Chassis 13.2V

Started the coach. Started fine.  At 1000 rpm. House 13.6V  Chassis 13.4

With engine on, generator stared right up.  Engine and generator on. House 13.6. Chassis 13.4. Aqua hot also fired up with no problem.

Turned coach engine off.  Kept generator on.  House 14.45V. Chassis 14.56. Held those number now for about hour, running just the generator. 

Other info.  Charger/inverter has been acting weird for the last year, including dead control panel.   Last time I used the generator, in October, I did notice it started slowly, but I didn’t think much of it at the time.  Chassis batteries about 3 years old.  House batteries 1.5 years old. All house lights were normal (ie, no indication batteries were low or dead. 

Question:  1. What are your thoughts.  2. Does the generator charge the batteries through the inverter/Charger or does it charge the batteries directly?

Thanks in advance. 

Adam Hicklin

  • Guest
Re: Battery/charge issue?
« Reply #1 on: December 15, 2019, 10:03:25 PM »
Addition.  After turning off generator, coach plugged in to 50 amp:  House 14.3V Chassis 13.9V. Charger is on because I checked just afeter I turned the generator off, before the transfer switch switched to shore power and the readings were House 13.6V. Chassis 13.5V. Those reading were after the generator had run for a little over an hour. 

David T. Richelderfer

  • David, Leslie, Jasper, & JoJo
  • BAC Member
  • *
  • Posts: 1676
  • Thanked: 497 times
  • OSU, Class of 1971, RVing nearly 50 years
Re: Battery/charge issue?
« Reply #2 on: December 16, 2019, 02:40:02 AM »
My suggestion is to start the whole process over.  Shut down the generator and leave the 50 amp shore power plugged in.  Pretend you again returned to the coach and just repeat the process.  I don't know your coach; only know ours in a half-assed way... but after 7+ years it's making more sense every year.

Our coach has three generator starter switches - one switch at the dash near the pilot's seat, one switch in the bedroom beside the bed, and one switch on the generator.  Additionally, the generator can be started by the inverter and by the Silverleaf.  I'm curious to know how you tried to start the generator when you first went to the coach (when it did not start).  I'm wondering if the starter switch you used may be getting tired... but that doesn't explain why the Aquahot didn't fire up.
2004 Beaver Marquis Sapphire

I had a dream... then I lived it!

Joel Ashley

  • BAC Member
  • *
  • Posts: 2341
  • Thanked: 801 times
  • OSU Class of '73, Oregon Native. RVing 39 years
Re: Battery/charge issue?
« Reply #3 on: December 16, 2019, 03:32:05 AM »
Sounds like a poor chassis ground somewhere, or at the battery negative post.  Just enough looseness or corrosion and only the additional alternator oomph can overcome the resistance in the hydronic and genset circuitry, which at furthest from the batteries and both having high start current draw are most susceptible to voltage drop.

Joel
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat

Adam Hicklin

  • Guest
Re: Battery/charge issue?
« Reply #4 on: December 16, 2019, 06:34:39 AM »
David, I tried both the dash gen start and the mid-ship switch over the table.  I did not try the bedroom switch. 

Joel, I’ll check the grounds and neg battery cable. 

Do either of you know if the gen set charges the batteries directly, or does it charge through the inverter/charger?

David T. Richelderfer

  • David, Leslie, Jasper, & JoJo
  • BAC Member
  • *
  • Posts: 1676
  • Thanked: 497 times
  • OSU, Class of 1971, RVing nearly 50 years
Re: Battery/charge issue?
« Reply #5 on: December 16, 2019, 11:46:25 AM »
Our coach's generator, an Onan 12.5kw Quiet Diesel, produces 120/240v 50 amp and does not have its own starter battery.  Thus, its power must be converted from 120v to 12v in order to charge the house and chassis batteries.  The only converter in our coach that I'm aware of is the Xantrex 3000w Freedom Inverter-Charger.  Since shore power and generator power both enter the working part of the coach through the Transfer Switch, both sources' 120v power must be converted by the inverter-charger to 12v to enable battery charging.
« Last Edit: December 16, 2019, 11:51:29 AM by David T. Richelderfer »
2004 Beaver Marquis Sapphire

I had a dream... then I lived it!

Gerald Farris

  • Guest
Re: Battery/charge issue?
« Reply #6 on: December 16, 2019, 02:23:11 PM »
Adam,
Some Onan generators do actually have a 12 volt alternator that can produce enough power to recharge a small battery. The 12.5 Onan in my coach does have an 12 volt alternator, but most Onan generators use an idler pulley in place of the alternator. I have seen only one 10K Onan with an alternator, but I have never seen a 7.5 Onan like yours with one. So I would assume that the only battery charging capability that you have is either from the inverter/charger or the engine alternator. Even on the few Onan generators that have an alternator, it is so small that it does not make a difference in recharging the batteries.

Gerald   

Larry Dedrick

  • BAC Member
  • *
  • Posts: 172
  • Thanked: 51 times
Re: Battery/charge issue?
« Reply #7 on: December 16, 2019, 05:11:33 PM »
Adam
            Just to pass on some knowledge I gained from my Generator, which is 12.5. It would have an intermittent start problem in which it would not crank when I would hit the start switch. I don't recall if there was any clicking noise from the fuel pump which is normal when it primes before the starer is engaged. After about a year and a half of dealing with this, I decided to replace all three relays that are located inside the generator housing by the air cleaner. The reason I replaced all three is that I wasn't positive which one could be the culprit. So after all three  were replaced, the generator would start without any problems, But, about a year later, same problem. The relays I installed were not a Sealed relay, and considering the Generator not only produces electricity it is also a large Vacuum Cleaner sucking up dust and that dust can enter the relays and foul the contacts inside. This time I had a tech fix the problem and I supplied him with a Sealed relay. End of problem. I opened the old relay and could not believe the amount of dirt (dust) the was inside. This was three years ago and no problems since. The key here is use Sealed Relays. This may not be your problem, but wanted to pass my experience along for the memory bank.
   Good Luck
Laura/Larry Dedrick
Ormond Beach, FL
2008 Beaver Marq. Amethyst
Cat C15
The following users thanked this post: Joel Ashley

Mike Humble

  • BAC Member
  • *
  • Posts: 118
  • Thanked: 54 times
  • BAC Past President 2014-2018
Re: Battery/charge issue?
« Reply #8 on: December 16, 2019, 06:12:47 PM »
Larry,
Please send info on the relays.  Last time we used gen we had to start the engine to start the gen.
Mike
2008 Marquis 45' Cat C-15 600hp

Adam Hicklin

  • Guest
Re: Battery/charge issue?
« Reply #9 on: December 17, 2019, 06:30:06 AM »
Thanks. Give me some directions to look. 

Gerald, this is a 10kw generator, not the 7.5.  Do those battery voltages look acceptable? 

I can’t figure out why, with the engine running, the batteries are getting a slight charge, but with generator running, they’re getting a full 14+ volts. If the charge is coming from the inverter, why would it appear to be floating (for lack of a better term) while plugged in, but getting 14+ volts with generator running?