Wednesday, September 4, 2013

Battery box & vent fan

        This time around I built a wooden box bolted to the floor which will keep the battery from sliding around and tipping over. I cut a hole into the cabinet for a 120 mm computer fan, it runs at about 70 CFM. The fan is rated at 100,000 hours. At the max rate when equalizing, the 400 amp hour flooded battery only makes 1/2 CFM - people are just to paranoid about blowing themselves up while charging the battery. Truth is batteries like the same temp you and I do. 

Here is my wooden battery box
Installed over the axel &
bolted to the floor to prevent sliding

On the exterior is the vent for the fan.


  1. I wonder if you have thought of using a mini split AC system. The compressor would be easily mounted in front on the trailer tongue.

    I saw that many new mini split systems use inverter-type of motors, and these have variable speed as well as the soft start feature. The latter avoids the high surge starting current of the conventional motor. I wish someone will make a roof-top AC with this new type of motor.

  2. Great question
    I would love a mini split, however most run on 240 volts , that is the major problem.
    It would be better to run this system with 24 volt batteries & 240 inverter,
    Also much more expensive
    Finally the cost, when I started looking the Fijitsu Rs9 was $1,499 - today they are $1,899
    I could also not get an answer from their engineers if it runs on MSW or only PSW
    No matter how hard I tried. Finally they also do not want to give you a warranty unless installed
    By a tripple certified installer, they don't wanna deal with DIY installers.
    What I liked for over the top is that it heats down to 17 deg & cools to 117 deg F

    But I really really wanted on - just got to many roadblock for this time around
    Therefore I'm goinging with the 3" blue board insulation.
    Time will tell

    Cheers Jerry

  3. That RS9 might be a top-of-the-line unit. My casual search on the Web found some off-brand 9,000-BTU/hr heating/cooling unit for around $900. It draws only 750W from 115V line, and being an inverter motor, it should be able to run off a 2KW pure sine wave inverter. I have one such inverter made by Xantrex, and it only cost $400.

    In contrast, I saw a $500 mini-slit system with a conventional compressor. It also draws only 750W running, but the current at start-up (LRA or locked rotor amp) is 40A. Yikes!

    Anyway, I am very interested in how you tackle the heating/cooling problem. You are more handy and inclined to experiment and try different approaches than other RV bloggers I have found. This makes your blog much more interesting.

    Keep up the good work. Best wishes to you.

  4. NWBound

    you can follow more detail about solar here also, not to hurt your feelings $400 for 2000 watt pure sine wave inverter is on the very low end, most are around $1800

    Thanks for following along

    Look for the "OverTheTopCargoTrailer" postings / thread



Please leave your thoughts, I am always looking for new ideas.