A/C Inverter Fault on 2023 Micro Minnie FLX

[dfw62]

I have a 2023 Micro Minnie 2108DS FLX. When I try to run my Truma air conditioner on battery power (all other loads off) my Xantrex 3000W inverter shuts down and displays an 03 error code for an overload. Battery state of charge does not seem to matter as this has occurred with 98% to 100%. This problem occurs the vast majority of the time when trying to run the AC as soon as the compressor tries to come on. It will do this for 20 plus attempts (resetting the inverter after each shut down) and then for no apparent reason eventually run as it should.

Anyone having this problem?

I have had my trailer in to two different dealers and in each case demonstrated the problem to the service manager. Both service managers agreed there was a problem but in both cases I was told the battery just needed to be fully charged and that it then worked fine for them. When I picked the trailer up I must admit the AC would run, however, once back home the next time I'd try to run the AC off the battery the inverter would trip with the 03 error code.

I have spoken with Truma Tech Support and they asked me to talk to Xantrex Tech Support first to confirm the inverter was set properly. I spoke to Xantrex Tech Support and they said it sounded like a wiring problem, possibly a loose connection. While talking with Xantrex we realized my battery to inverter cables were size 2/0 where Xantrex requires the cables to be 4/0 and a max length of 5 feet. My 2/0 cables are less than 5 feet long. Not sure if undersized cables are my problem and asked in another thread for others to let me know the cable size in their FLXs.

According to Xantrex Tech Support if the inverter sees it's supply voltage drop to 10.0 volts or less it will instantaneously trip the inverter and the error code will the 03 for an overload and not a low battery error code. With the problem being intermittent Xantrex suspects a loose connection which with the undersized 2/0 cables is more likely to cause a problem. I have not found any connections that appear loose and am still in the process of trouble shooting.

I was able to get the AC to run with the compressor cycling on and off for several hours all the way down to a 10% state of charge on one occasion but this was a rare occurrence. However, this has me wondering if the Truma AC has an intermittent issue with how it soft starts.

Unfortunately, my volt meter is not capable of capturing the instantaneous voltage drop when the AC compressor cycles on or the starting current.

Posting this thread on the off chance that another FLX owner has had the same issue and can direct me to the cause.

Thanks in advance for any help.

[creativepart]

Have you read this post on FLX setup? Seems many come from the dealer setup in correctly and dealers are really ignorant of the system operation.

https://www.winnieowners.com/forums/...ml#post3929376

Also one of our members is an electrical engineer with Lithionics, your battery’s manufacturer. He may be able to point you in the right direction. His username is “electric” so you may look for his posts or contact him here.

https://www.winnieowners.com/forums/...es-366502.html

You are correct, if the battery is properly charged and nothing else is using a lot of 110v power then the A/C should run fine. Perhaps the system is not setup properly and showing full charge when it’s not? And yes your issue could mean a proble with the A/C unit itself.

[Marine359]

Xantrex specs cables on the heavy side to be sure, as they recommend cable size to match max current specs. In your case, cable size is definitely not the issue. The load created by your A/C is nowhere near the max amperage capacity of 2/0 wire. The cables would not be overtaxed unless you were running the A/C and microwave simultaneously, and even then, I don’t think you would exceed 2/0 ampacity rating. If taxed, the cables would get hot. For years, I ran my soft-start equipped 13.5K Dometic Brisk on my Xantrex XC2000w inverter/charger over 1/0 cables. I would agree with the Xantrex rep who suggested that maybe your cables are loose. An actual load great enough to tax the Xantrex input circuit would trip the fuse or breaker protecting the circuit (if you have one). If you can replicate the scenario, try putting a clamp ammeter around the positive Xantrex dc input cable. If dc current input fluctuates during this test, there’s a problem with your battery connection.