How to Stop Your MaxxFan From Beeping & Shutting Down When Using Solar Power

How to Stop Your MaxxFan From Beeping & Shutting Down When Using Solar Power

Our 2020 Scamp 13’ was delivered from the Scamp factory with a Maxxair MaxxFan, an incredible fan which can either blow or suck air into the trailer (depending on the setting).  Since we don’t have air conditioning in our camper and use it off grid quite a bit, we really depend on this fan to keep us cool during warm weather (as well as blowing out smoke when cooking and also clearing humidity from the trailer when showering and sleeping to prevent detector alarms).

We soon discovered that our MaxxFan doesn’t like voltage variations beyond 12 volts.  When boondocking (without shore power), we usually use our solar panel briefcase to provide power to our Scamp 13’.  Voltage in our trailer can vary quite a bit when on solar power and is usually higher than 12V, sometimes reaching just over 15 volts (based on our internal voltmeter).  It’s common for our MaxxFan to complain (beep and stop) when we are running solar.  It especially doesn’t like it when our Scamp 13’ is running on solar and simultaneously running another appliance (like a water pump to provide water pressure to our sink when boondocking).  It generally will beep and stop in this situation.  We’ve learned that we can often keep it running as long as we don’t exceed the 30% speed setting.  On one occasion, our fan stopped altogether and wouldn’t restart.  To get it to run again, we had to pull the fuse (fuse labeled “rear of trailer”) to reset the fan.  Ughh!

It was warm on our recent trip to Big Bear Lake and we really wanted to use our fan at a high speed setting, but it wouldn’t cooperate.  Our MaxxFan just kept turning off when turned up higher than 30%.  With our solar panels soaking up the bright mountain sunlight at Big Bear, the voltage coming into the trailer reached 15.6 volts.  At this point, we needed a better solution.  Upon doing considerable research, we found that, indeed, voltage intolerance is a known problem for MaxxFans.  When the voltage is too low or too high the fan will often beep and stop.  It seems this fan has “Goldilocks Syndrome” as the voltage has to be “just right”.  A call to MaxxAir, maker of the MaxxFan, confirmed that there have been considerable issues with voltage affecting fan operation which have prompted the company to update the motherboard to accept voltages up to 15 volts.  The MaxxFan tech I spoke to said the motherboard used to have a voltage range between 10.8 volts – 13.8 volts (our model), but once more people started using solar panels and lithium batteries (leading to higher voltages within their rvs) the company came out with a new motherboard (sometime after 2020) to accept a wider voltage range (10.3 volts – 15 volts).  The tech told me that even with the new motherboard, the fan will still have problems with voltages outside the new voltage range.  Although some people have gone as far as replacing their motherboards in the hope that the more recent circuit boards will fix this issue, others have taken matters into their own hands by implementing other solutions.  The simple and inexpensive solution we implemented was to install a voltage regulator between the trailer power leads and the fan (the MaxxFan tech agreed with us that this is a good solution).  The voltage regulator we chose accepts 9V – 36V input (a much higher range than the new MaxxFan mother board accepts) and puts out a consistent 12 volts, and is rated waterproof, dust-proof, moisture-proof and shock-proof (and currently sells new on Amazon for less than $15!).  It’s also really small and fits nicely in the MaxxFan housing.  So overall, the nice thing about this solution is that it’s inexpensive and addresses both very low and high voltages.

The installation of the voltage regulator inside the MaxxFan is fairly simple and just about anyone should be able to do it in less than an hour with the right supplies and tools.  A significant point to note is that it is very important to figure out the polarities of all the wires before connecting them because some trailers (and even the MaxxFan itself) have some strange things going on with polarity.  Specifically, for example, our Scamp trailer has a positive black wire and negative white wire providing power to the fan.  Additionally, MaxxFan also wires their fan this way with the black wire being positive.  This wiring convention is contrary to what most people learn, being that black is usually negative and red is positive.

A voltmeter is a good simple way to determine polarity (set your voltmeter on DC V and use the black probe on the black wire and the red probe on the other colored wire – if the voltage shows a positive number, then the black wire is negative polarity, if it shows a negative number, then black is positive polarity).  On our installation, we determined that our Scamp 13’ black wire is actually positive and the white wire is negative. These are the wires that provide power to the fan and attach to the input side of the voltage regulator.   On our voltage regulator, the input and output polarities are clearly labeled (with black being negative and red/yellow positive).  The MaxxFan wiring polarity matches our Scamp trailer with black being positive and white negative.

Project Supplies and Tools:

1. MaxxFan
2. 12V DC Voltage Regulator
3. Voltmeter
4. Wago wire connectors
5. Scotch Fastener Tape
6. Gorilla Tape
7. Braided copper wire (AWG 14)
8. Robertson Square #2 Screwdriver or
   1. Electric screw driver which accepts ¼” bits
   2. Robertson Square #2 bits 
9. Wire cutters
10. Wire stripper

Here are the Project Steps I took to install the 12V voltage regulator in the MaxxFan (also, reference video).

Project Steps:

1. SAFETY: I made sure my Scamp 13’ was parked on a flat level surface (my garage), the tongue jack was stable, and I used heavy duty wheel chocks to prevent the trailer from rolling.  I also wore safety glasses to help prevent anything from getting into my eyes while working.  I made sure there was no power to the fan while working on it (by pulling fuse).
2. Cut power to fan by removing fuse powering fan (fan won’t turn on after fuse is removed)
3. Take off the fan screen by rotating the holders
4. Remove the bezel/trim using the Robertson Square #2 Driver.
5. Remove fan with Phillips head screwdriver (including screw on black manual fan knob).
6. Unclip zip tie on the fan holding wires together
7. Remove a bit more plastic sheath on each of the wires coming out each side of the voltage regulator to allow for more exposed copper to plug into the Wago connectors.
8. Apply scotch Velcro tape (two sides) to the backside of the voltage regulator.
9. Tape the voltage regulator into one corner of the inner casing of the fan.
10. Cut trailer power wires attached to fan and test their polarity.
11. Attach Wago connectors to the end of the trailer power wires as well as the voltage regulator wires and fan power wires.
12. Create wire extensions and once polarities are identified, connect the trailer power wires to the voltage regulator and the voltage regulator wires to the fan (all using Wago connectors).
13. Plug in fuse and test fan to ensure it works.
14. Carefully insert wiring back into fan (using zip ties and Gorilla tape to secure loose wires)
15. Screw fan back into place using a Phillips head screwdriver.
16. Reattach bezel/trim using Robertson Square #2 Driver (and notch out bezel if necessary)
17. Clean fan screen.
18. Reinstall fan screen.

Disclaimer:  You will get the same great Amazon price by clicking on the links here compared to buying directly on Amazon, but by buying here you will also be supporting the continuation of this website as we get a small commission from each sale.  These are products and procedures we use for our own Scamp that we selected and developed from our own research and experiences.  However, we do not endorse any specific product and cannot guarantee that the products we use are exemplary and the procedures we use are complete, accurate, detail the correct recommended procedures, or apply to your model small travel trailer.  It’s always best to double check with your manufacturer or operation manuals to ensure you are doing everything correctly.