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Inverters switching off and on repeatedly
1998 Trace SW Inverters – Rev 4.01 Option 2.2
Last week I woke up one morning to find a random set of devices with no power – Refrigerator, ceiling fan, microwave, aux air pump, etc. One of the inverter displays had just the Error light lit. I powered that inverter off and on, and everything seemed to return to normal.
Last night, I was awakened by the sound of my CPAP and ceiling fan cycling on and off every few minutes. I watched the inverter displays. Every few minutes they seemed to go dead for maybe half a second, then go to bulk charge, then return to normal operation – all within a couple of seconds. This was all happening a bit irregularly. The time between the events varied, and the inverters did not seem to by cycling in synch. I turned off the devices that seemed to be affected, and that I could do without, and I went back to sleep. This morning there was evidence that the power cycling had continued, but it has not happened at all this morning. The only thing that appeared a bit abnormal was that the current draw on one leg was 25 amps with no AC or heaters running. I hardly ever see draws above 20 amps with everything running.
Does anyone have any thoughts about what might be causing this?
Thanks,
Thom
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23 Replies
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Where are you right now…
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Are you hooked up to shore power? If so, could it be that the shore power is cycling off and on confusing the inverters? What is your house battery voltage when the inverters turn off?
Gerald
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I am near Pensacola at the moment.
Yes, I am on shore power, and the voltage seems to hold steady around 221-225 volts. I did not think to check the voltage during one of the outages. I will definitely check that the next time this happens. I have previously seen low voltage (around 100 V or less) cause the inverters to switch to batteries. Maybe these are really brief shore power fluctuations.
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You can set those inverters to monitor the actual voltage of your batteries? put them on that screen. When the inverters begin to cycle watch the actual battery voltages and see if there is a correlation between the battery voltage climbing and the inverters cycling.
The inverters will cycle off when the battery voltage stays above 30 volts for 30 seconds or so. Once the inverters kick off, the actual battery voltage will go down and the inverters will cycle back on. I can not tell you why the battery volts might be going up but I am curious to see if that is the case.
Another question. Does it always happen at night?
Davy
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Are your inverters 4024’s? You’re also giving us 220 voltages, are you just doubling the actual two legs?
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Tom – Yes, these are 4024s, and yes, I typed 220 volts when I meant to type 120 volts. Sorry for the confusion.
Davy – I think you are on to something. I was checking a lot of stuff last night during the cycling storm, but I am not sure that I was watching the battery voltage at just the right time. At one point, one of the inverters went into error mode and stuck there. This gave me a chance to see the error. The error was High Battery Voltage. The HBCO is set to the factory default of 30 V.
I was watching the shore power voltage during the events, and it never varied from about 123V.
Last night, I was awoken by the first event at 1:14am. There was a string of closely spaced events over a period of about 10 minutes, then nothing for maybe 20 minutes, then another string, and so on. I disconnected from shore power, and everything worked properly on battery power for about an hour. I restored shore power and got hit with another series of events. Sometime after 4 am, the cycling stopped. As with previous days, there are no events other than during that 1 am to 4 am period.
I will monitor battery voltage during the events tonight.
I need to take a nap now.
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I also have the 4024’s and they’re great inverters and highly adjustable. I’m reluctant to suggest settings unless your really familiar with all the parameters. There are many things that could be wrong, but check to be sure you are not in Equalize Charging.
Suggest you contact our Sponsor, Inverter Service, tell them your a PC guy and they’ll help you through troubleshooting.
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Thanks Tom. I will contact them today.
Last night I watched the battery voltage during the outages. The voltage is usually around 27.5, but it jumps to over 30 during the events. I raised the HBCO from 30 to 32 volts, which happens to be the default on units that do not have the RV options that mine has. Needless to say, the problems stopped immediately, and they have not returned.
My questions for the inverter guys are, what is causing the high voltage, what is the fix, and is there any danger in leaving the HBCO to 32?
Thanks!
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The reason I knew about the high battery voltage and it only happening at night is because I have been dealing with this for quite a while. If you disconnect shore power until morning, all is well when you hook back up. If you run the generator, all is well too.
Set one of your inverters to show you the actual battery voltage before you go to bed. Once you hear the inverters cycling, watch the voltage climb above 30, kick the inverter off, the voltage drop and the inverter cycle back on.
Jeff Rowe and I and several others have been trying to solve this for many moons. I travel nearly every week and most years I plug into 40-70 different 50 amp power services. The kicker is, this only happens in one place, my barn.
There is some 120 voltage variance at my barn but it does not track with the high battery voltage. Some nights my 120 voltage is rock steady and the actual battery voltage starts cycling the inverters off and on.
I would have to write a book to cover all the “ands, ifs and buts) that Jeff and I have considered but we are no closer to solving it.
I can only know your symptoms and feel your pain. I do not have the answer.
Take it from here, Jeff.
Davy
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The danger, even at 30 volts is your batteries are going to be damaged.
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Thanks.
Next question: Is there any risk in taking one inverter off-line, and just running one while connected to shore power? I have a hunch I want to test.
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Thom: I’m doing that right now on our 24volt Liberty, with guidance for that from Jeff Rowe.
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Do you know how to look at battery temp pad compensation values? Being that this only happens at night I would be interested to see what info the temp sensors are giving the inverters. Also, I always suggest everyone have shore power protection for low AND high line voltage like a surge guard or progressive industries unit WITH a disconnect contractor.
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I had same problem at Rudys place in Houston chacked voltage at power pole it would go beyond 130 volts on one leg would kick of inverter Leon at Marathon said inverters are designed to kick of at high voltage they would come back on in few minuets I unhooked all was fine next time I hooked to another Power pole
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I had an inverter that would switch between pedestal power and inverting from the house batteries. It would do this all the time. The cause was a bad neutral from the power company, prior to my pedestal. The bad neutral caused one side of the line to be quite high and the other side to be quite low.
The power company came out and fixed it. They said it was very common in Florida because all the connections were below ground and often under wet.
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