Skip to main content ↑ ↓
Topic: Charge to batteries (Read 423 times) previous topic - next topic

Charge to batteries

On 1995 U300 - what is the normal charge to batteries from the alternator?  Gauge indicates between 12 and 13

Should this be higher?  Fix?
Jim Wallace
1995 Unihome U300SE

Re: Charge to batteries

Reply #1 –
Start by measuring voltage with a voltmeter at chassis batteries at idle and 1,000 rpm. Then check same on the center terminal of isolator if equipped. Need two people. Lights off, dash AC off.
1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.

Re: Charge to batteries

Reply #2 –
Quote from: Gem Wallace –
Gauge indicates between 12 and 13
Should this be higher?
Fix?
"Between 12 and 13" is too low.
With engine at idle, headlights off, A/C off, you would normally expect to see the dash voltmeter above 14 volts.
Do not trust the dash gauge until you verify it is accurate by doing the checks suggested in the post above.
Let us know the results.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Charge to batteries

Reply #3 –
Mine reads 13.2 sometimes , never over 13.4      Clean all of the batta connections and behind the dash grounds.  The gauge may be reading low  or the isolator may be weak ,. leaky . 
  Get a second opinion, Read with a meter at the battery and poke around behind the  dash with a meter. 

Re: Charge to batteries

Reply #4 –
My dash voltmeter reads low and my Silver Leaf reads high which used to read low and when
I adjusted it I got it high which I will readjust sometime. My cigarette dash plugs are accurate. 
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Charge to batteries

Reply #5 –
Thanks to all for suggestions.  I bought a meter -- batteries at 'resting state' = 12.68

Started coach with load on batteries (lights, fan, etc...) Alternator charging at 14.12V !!!

All is good in the neighborhood!

Thanks again.

Jim Wallace
1995 Grand Villa U300




Jim Wallace
1995 Unihome U300SE

Re: Charge to batteries

Reply #6 –
Jim,

With dash voltmeter reading low, be sure to tighten the under-dash (raise dash to access) ground connections.  Another symptom of poor ground is a change in gauge readings when the headlights are turned on.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020