Flickering AC lights on battery

[wfeffer]

I have a 96' Tourmaster that we bought about a year ago. When be purchased it, it had 4 new house batteries (lead acid) 2 new engine batteries, a Xantrex Freedom SW 2012 inverter charger and 4 solar panels that are so old they do little more than keep the house batteries topped off. Since we purchased it I've never run any AC appliances or lights off of the batteries till recently and I noticed that the lights flicker and any AC device powers on and off. All of the DC lights work fine. I have a decent understanding of home electrical systems but there are so many components in an RV that I'm not sure what the most likely culprit is here. My guess is the inverter/charger, but it's also one of the newer items in the RV so I'm not sure I should blame that.

Does anybody have any suggestions on what might be the cause or how best to trace the issue? The RV has a battery tender full time and has been plugged into shore power for a year with no issues while plugged in.

[wfeffer]

any thoughts on this?

[Chuck v]

On my 2007 Tour Master none of the lights were AC...all were run on the DC house battery system. Of course when connected shore power, the house system was continually charged and batteries maintained from the shore power connection. This was true if the generator was running instead of the shore power as well. Even the florescent fixtures were run off the house DC system, so they were easy to convert to LED which I did.



The Inverter that ran the AC appliances like the residential refrigerator is another matter...it ran off a separate stack of golf cart batteries connected to give a high current 12 volt bank (4 cart batteries in series/parallel...) When I first got my coach, it had the Xantrex Freedom inverter that was originally supplied by GulfStream, but I upgraded to the pure sine wave Magnum unit. Both of these inverters have control panels that give a lot of information on the battery condition and the state of operation, and you should be able to view the pane when your symptom is occurring to get more about what may be happening. Does the input voltage sag well below 11 volts when the flashing is happening? Is the inverter input current high or low? If it pulses to low or near off, perhaps the battery connections are not capable of providing the high currents needed by the inverter to make the AC power. Battery connections can appear clean but have a coating of lead oxide on them that is an insulator -- I scrape with a blade to expose clean metal since the battery terminal brushes often do not remove this oxide very well.


Since your symptom is only present when supplying AC from the inverter, the root cause must be in the batteries, their connections, the inverter itself or the wiring from the inverter's transfer switch to the AC loads.


Let us know what you find...


Chuck

[wfeffer]

Thanks for your response. I have two light fixtures in my slide that are AC, they are the most noticeable thing that flashes. I currently have no other AC items plugged in but even the light on the GFCI outlet flashes when on battery. I've checked the control panel and it doesn't seem to see any issues. All the voltages are stable and it's showing no AC draw. I'll try testing the battery bank voltage when on the inverter, I haven't tried that yet just made sure it was correct when on shore power.

[DolceFarNiente]

Thanks for your response. I have two light fixtures in my slide that are AC, they are the most noticeable thing that flashes. I currently have no other AC items plugged in but even the light on the GFCI outlet flashes when on battery. I've checked the control panel and it doesn't seem to see any issues. All the voltages are stable and it's showing no AC draw. I'll try testing the battery bank voltage when on the inverter, I haven't tried that yet just made sure it was correct when on shore power.

If you are having flickering AC lights or on/off issues with AC appliances when on battery only, but not on shore power, then the problem lies in your inverter.

The first thing to check is the GROUND wire from the inverter; next, AC output cables from the inverter; make sure they are clean and tight. Third, check the battery connections, at the battery bank, at the big inline fuse and at the converter. Ffourth, check the connections where the AC cable from the inverter goes to your power center.

If the flickering is not caused by a bad connection somewhere, then what I imagine is happening is that your inverter is not making stable output AC voltage when drawing from the batteries. Google how to check receptacle voltage with a meter, but I think you'll find if connections are all good that replacing the inverter is the next step. Not hard to do but a mite expensive.

[wfeffer]

You're right! Just not in the way you thought... Looks like it was some setting in the SCP. I reset the whole thing to factory defaults and now it is not switching on and off. My guess after reading the entire manual is that the undercurrent setting was set too high and it thought the battery was about to die so it was freaking out. thanks for the help!