Inverter /charger Voltage Readout

[Mark S]

Sitting at home, plugged in, my inverter panel almost always reads 13.4 volts and when driving 14.2 volts. While staying in the RV I noticed that at some times while in RV Park, plugged in, reading will go down to 12.6 and then up to 13-13.1.

While driving today I noticed voltage willl fluctuate from 14.2 to 12.7. I never noticed this before. Seems like it will drop and then the charger kicks in and it goes back up.

Shouldn’t charger/voltage be constant when running or plugged in?

[Grumpy]

No, the converter has 3 stage charging based on battery need. A car alternator also fluctuates.

[Mark S]

So when using the RV, are DC loads using the batteries or the converter?

[Grumpy]

They work in tandem when on shore power.

[Mark S]

Thanks Grumpy. I just never noticed the voltage dropping that much while on charger.

[Grumpy]

Remember many of the factory installed guages may not be real accurate or consistant either.

[RVermont]

When plugged in the converter is adjusting as it needs too. You might not have noticed this before with the old batteries as they might have required more charging due to starting to fail.
The 14 amps you see is from the truck alternator, this will come on as the battery isolation controller opens and closes as it test the house and chassis batteries. When it sees the house batteries low it close the circuit and the alternator charges the house batteries. The opposite occur when on shore power and it sees low voltage on the chassis batteries the converter charges the chassis.

[SloPoke]

Originally Posted by Mark S

Sitting at home, plugged in, my inverter panel almost always reads 13.4 volts and when driving 14.2 volts. While staying in the RV I noticed that at some times while in RV Park, plugged in, reading will go down to 12.6 and then up to 13-13.1.

While driving today I noticed voltage willl fluctuate from 14.2 to 12.7. I never noticed this before. Seems like it will drop and then the charger kicks in and it goes back up.

Shouldn’t charger/voltage be constant when running or plugged in?

We see this when we are first starting up... where the intake heater is operating.

[Mark S]

We have been stopped and plugged in for about 8 hours now and the inverter readout is 12.5 volts. I am suspecting that my charger is not working properly.

I am open to suggestions.

Thanks

[SloPoke]

Ours right now...
On utility power, Both AC running, No TV, Microwave, Coffee Pot loads on the inverter circuit. 13.1v

I have to say that I have seen ours at 12.5v in the past... with the unit plugged in.

Is'nt yours a different model inverter?

[Mark S]

After about 18 hours of being parked and plugged in, I am still going a reading of 12.5 volts. It would always read 13.4 at this point, so I believe the charger is not charging.

Time to start troubleshooting Where is the charger located?

[RVermont]

Charger is located in the fuse panel. [ATTACH]check the lights lower right these indicate the mode the unit is in. Good luck. If the unit is not working I would have expected lower voltage after 24 hours but it really would depend on how many lights you have on.

[Mark S]

Originally Posted by RVermont

Charger is located in the fuse panel. [ATTACH]check the lights lower right these indicate the mode the unit is in. Good luck. If the unit is not working I would have expected lower voltage after 24 hours but it really would depend on how many lights you have on.

Thanks Paul. I couldn’t check the fuse panel first because DW was still sleeping, so I went outside to battery compartment just moving wires to see if I found something loose, which I’d didn’t. When I came in the reading was 13.1 volts. The charge wizard is now flashing about every second indicating normal operation.

I am thinking I have a loose connection and will check tonight. I will keep an eye on the reading and let you know what I find.

Thank you all for the help. It is so reassuring knowing I have a group to rely on when issues arise.

[RVermont]

I think you found the general area now you just have to find the specific item.

If you haven’t done it yet. Check all your grounds where they attach to your chassis. I have reconnected several of these.

Sounds like your 6 volt batteries are standing up pretty well. I know that the original batteries on mine would have been down around 12.2-12.3 after 18 hours. The only issue I had installing the new batteries was the lack of terminal space for all the wires that need to be installed. I had a difficult task getting them secured. Hopefully you just have a loose nut.

Have a great trip out west and hope you don’t have to change any plans due to this horrible fire season out there.

[RoyBraddy]

Also check your battery for possible fluids being boiled out... The smart mode chargers are designed to keep changing the DC output voltages to prevent this from happening when charging.

I lost my first battery using a single output voltage converter/charger. It always just put out 13.6VDC. This eventually boiled out my battery fluids and I didn't catch it in time. Ruining my battery...

Roy Ken

[Mark S]

You got it Paul. The nut on the ground post came loose. Tightened and readout went from 12.4 to 13.2 volts.
I wish all issues were this easy.

[Mark S]

After sitting at a full hookup site (Tiger Run, Breckinridge Co) for a week we changed sites today. When I unplugged inverter read about 13 volts. After moving, putting slides out and leveling on battery power the reading dropped to 12.4. I didn’t think to meter that batteries before I plugged in.

I put in 4 new golf car 6 volt batteries before this trip. Seems like they drop to 12.4 pretty quick, just like my 12 volt Harris batteries did. We haven’t boondocked so I am not sure what they do after several hours of sitting.

What voltage readings are you getting on your inverter readout?

[SloPoke]

My readings are subjective - from Memory over the past 3 weeks.

Gen Running, Inverter on (a Xantrex unit that came stock on the 2015) 13.6v @1A

Gen just shut down in "auto mode" as batteries are charged. 13.1v @ 2-8A running 2 Televisions and the DirectTV box.

30 Minutes after the Gen Shut down - still running 2 TV and Direct box - 12.6v @ 3-8A

Next Morning... Electric Coffee maker running in brew mode, 1 UPS charging batteries 11.5v @ 90 - 95A

[Mark S]

Originally Posted by SloPoke

My readings are subjective - from Memory over the past 3 weeks.

Gen Running, Inverter on (a Xantrex unit that came stock on the 2015) 13.6v @1A

Gen just shut down in "auto mode" as batteries are charged. 13.1v @ 2-8A running 2 Televisions and the DirectTV box.

30 Minutes after the Gen Shut down - still running 2 TV and Direct box - 12.6v @ 3-8A

Next Morning... Electric Coffee maker running in brew mode, 1 UPS charging batteries 11.5v @ 90 - 95A

———————-
Looks like I may have some troubleshooting to do when I get home

Where are you getting your Amp readouts? Mine gives volts only.

As we head east we will probably do some Walmart’s and such so I will see how it does overnight.

And regards to Stacy and all your furry kids

[SloPoke]

Originally Posted by Mark S

—
Looks like I may have some troubleshooting to do when I get home

Where are you getting your Amp readouts? Mine gives volts only.

As we head east we will probably do some Walmart’s and such so I will see how it does overnight.

And regards to Stacy and all your furry kids

Mark, This is what our Inverter control switch/panel looks like. When turned on, it shows the battery voltage on the left, and the current draw on the right. It is usually within 0.1v of the voltage reading on the Onan battery monitor.

One thing you have to consider in your troubleshooting going forward, the battery voltages they use to determine the state of charge - are "No Charge and No Load, at rest for at least 2 hours" and have to be compensated for ambient temperature. It is essentially impossible to accomplish that measurement unless you physically disconnect your battery bank from the motorhome.

And we will miss youall this year.. we were really looking forward to you stopping by.