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Inverter pulsating sound

Is it normal for the inverter to have a pulsating sound instead of a steady sounding buzz.
Rick & MJ Berry
1998 U320 40'
Ohio

Re: Inverter pulsating sound

Reply #1 –
To help us answer, you might need to give more specific info on what inverter you have.  Make?  Model?

If you still have the original Freedom 25 Heart Interface, are you seeing any fault codes on the control panel?

Link to manual below, in case you don't have a copy.  Contains a trouble shooting section.

http://www.xantrex.com/documents/Discontinued-Products/Freedom_combie_Owner_manual.pdf
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: Inverter pulsating sound

Reply #2 –
It's a heart interface freedom 25 inverter.
Rick & MJ Berry
1998 U320 40'
Ohio

Re: Inverter pulsating sound

Reply #3 –
Lobat is flashing on the screen.
Rick & MJ Berry
1998 U320 40'
Ohio

Re: Inverter pulsating sound

Reply #4 –
The batteries are low,you need to get batteries charged to troubleshoot the inverter,if you don't have the manual,go to their site,it
should be there.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Inverter pulsating sound

Reply #5 –
I had 2 lithium batteries put in. When I pulled in the campground they were at 97 percent.  And probably at 13 volts.
And it was doing that not too soon after we got there.
I have a separate charger for the lithium batteries which is plugged into an outlet underneath.
Would that have anything to do with it.

Rick & MJ Berry
1998 U320 40'
Ohio

Re: Inverter pulsating sound

Reply #6 –
So here is the story.
I had the lithium charger plugged into a plug down below. 
And this time the GFCI switch kept popping out.
Originally the campground owner didn't want me plugging it into their box because they base their rates on an average of using 50 amps.
So it's Sunday and everyone left so I asked them if I could use the 110 hook-up also.
They said yes.
So when I took the charger cord off the coach and into a shore source the fluctuating buzz in the inverter and the tripped switch problem disappeared.
This is literally our first time out.

Rick & MJ Berry
1998 U320 40'
Ohio

Re: Inverter pulsating sound

Reply #7 –
So here is the story.
I had the lithium charger plugged into a plug down below. 
And this time the GFCI switch kept popping out.
Originally the campground owner didn't want me plugging it into their box because they base their rates on an average of using 50 amps.
So it's Sunday and everyone left so I asked them if I could use the 110 hook-up also.
They said yes.
So when I took the charger cord off the coach and into a shore source the fluctuating buzz in the inverter and the tripped switch problem disappeared.
This is literally our first time out.

Rick & MJ Berry
1998 U320 40'
Ohio

Re: Inverter pulsating sound

Reply #8 –
Rick,

I'm trying to figure out how your charging system is set up.

You said you "had two lithium batteries put in".

Are these lithium batteries used for coach power, or are they chassis (starting) batteries?

The inverter/charger in your coach should keep the coach batteries charged when you are plugged in to shore power.

You said "I have a separate charger for the lithium batteries".

Is this separate charger connected to your chassis (starting) batteries or to your coach batteries?

Which battery bank is showing LOBAT on the inverter control panel?  The inverter should be connected to your coach batteries.

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: Inverter pulsating sound

Reply #9 –
Yes I didn't want to buy a special inverter charger for my lithium "coach" batteries so I got a separate charger for them. Only because they are lithium and the inverter would overcharge them and burn them up. Likewise I had to get a special battery isolator that the alternator can steadily charge the engine batteries and 15 min on and 20 min off for the lithium batteries.
Also I have to flip the inverter breaker off on the panel in the bedroom. That way the inverter charger (heart freedom 25) cannot charge the battery.
Lithium in that respect are a pain but it takes very little time to charge them back.
Rick & MJ Berry
1998 U320 40'
Ohio

Re: Inverter pulsating sound

Reply #10 –
Yes I didn't want to buy a special inverter charger for my lithium "coach" batteries so I got a separate charger for them. Only because they are lithium and the inverter would overcharge them and burn them up. Likewise I had to get a special battery isolator that the alternator can steadily charge the engine batteries and 15 min on and 20 min off for the lithium batteries.
Also I have to flip the inverter breaker off on the panel in the bedroom. That way the inverter charger (heart freedom 25) cannot charge the battery.
Lithium in that respect are a pain but it takes very little time to charge them back.
Rick & MJ Berry
1998 U320 40'
Ohio

Re: Inverter pulsating sound

Reply #11 –
Inverting and charging are two different functions (in simple terms the reverse of each other) and are usually controlled by separate switches (or selections) on the inverter control panel.  In other words, you should be able to leave the inverter breaker on and just have the "charger" function turned off.  At least, that's how my Magnum inverter works.

If your coach (lithium) batteries are showing LOBAT on the control panel, then it would seem the stand-alone charger is not functioning properly.  A problem with the charger might also explain why it was tripping the GFCI.  Perhaps it is not grounded properly?  I would try a different charger and see if your weird symptoms go away.

I have never heard of a isolator that has timed "on" and "off" charging routines for lithium batteries.  Do you know what brand and model it is?  Just curious to read about how it works.

I think you have a rather complicate situation when mixing conventional lead/acid batteries and lithium cells.  I am hoping one of our members with "lithium" experience will step in and perhaps make some more educated comments.  Lithium charging technology is above my pay grade.
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: Inverter pulsating sound

Reply #12 –
Chuck, This is probably the Battle Born Alternator Isolation Manager unit he is referring to charging for 15 min, shutting down for 20 min.

Not knowing all his equip, additional battery charger, etc., most difficult to answer his issue.  Is his new battery charger for lifepo4 and is it designed for his total lifepo4 ah?

LiFePO4 Battery Isolation Manager - Battle Born Batteries
97 U295 40, Build #5040, 6C8.3 325 HP
Oregon Continuous Traveler
Samsung Residential #RF20HFENBSR,
Xantrex SW2012, (3)AGM8D Hse, (2)AGM Grp24 Eng, Victron BMV-712, 1800w Solar 4 LG & 2 Sunpower
Extreme Full Body Pt w/hdlmps, new furn/floor, 4 down Lexus 2004 GX470 AWD curb weight 4,740 lbs
Prev: 1990 Barth, 10L 300 2 yrs; 91&92 Monaco Signature, 10 yrs, 10L C 300 &  6C8.3 300; 1997 ForeT 6C8.3 325 since May 2017.  Employed by Guaranty RV 14+ yrs.  Former VW New Car Dlr/Service Dlr, Sales Mgr, Rv Sales, and Service Adviser from 1968-2017
"Don't criticize what you can't understand" Bob Dylan

Re: Inverter pulsating sound

Reply #13 –
I had put in two Briter batteries.
I forgot the name of the charger.
But it's one they recommend and installed.
So I plug that in shore power.
I will check on the inverter charger to see if I can turn the charger part off.
Rick & MJ Berry
1998 U320 40'
Ohio

Re: Inverter pulsating sound

Reply #14 –
Is it possible the charger is pulling a Huge load off the inverter while you are not plugged in? Let the Alternator do its thing while you drive.. maybe just overloading the system?

Re: Inverter pulsating sound

Reply #15 –
Quote from: DavidS –
Is it possible the charger is pulling a Huge load off the inverter while you are not plugged in? Let the Alternator do its thing while you drive.. maybe just overloading the system?

Indeed, if the charger is on an inverter-powered circuit, it is MIS-WIRED! Ain't no perpetual motion machines out there.

Said another way, your new charger should only receive 120 VAC from shore power or generator (from main 120 VAC breaker box).
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