APU vs. Deep Cycle Batteries

Discussion in 'Trucking Electronics, Gadgets and Software Forum' started by AintNobody, Dec 29, 2010.

  1. AintNobody

    AintNobody Bobtail Member

    Dec 29, 2010
    Why don't trucking companies use banks of deep-cycle batteries instead of APUs? They get charged while the truck is running, can go for at least a few years (if properly configured to avoid full discharges), and at today's fuel prices they seem to be a very economical alternative for powering things while the truck is off. I've only just started researching this, but the benefits seem obvious. Am I missing something? :biggrin_2558:
  2. Allan M

    Allan M Medium Load Member

    Apr 20, 2009
    It depends on what you are planning to use them for.
    No battery powered system will keep a large truck cab comfortable
    in the deep south in the heat of summer. These systems put out far less
    cooling btu's than the APU systems. Also, a battery poweded system is
    useless for a 34 hr reset. You will be lucky to get 11 hrs with the A/C running.
    If you only truck in the north you may get by except for the resets.
    If you just want to run an Espar style heater in winter and a power invertor to run your toys then a battery bank would do but you would have to upsize your alternator and isolate the extra batteries from the rest.
  3. AintNobody

    AintNobody Bobtail Member

    Dec 29, 2010
    You have a good point about the reset - assuming you are spending it in the truck, which I rarely do as my company gets me home for the weekends. As far as the AC efficiency goes I don't know enough to compare, but it seems to me that if electric home units can do it well enough then I don't know why these couldn't manage for the duration of a 10-hour break as well.

    I admit my electrical knowledge is somewhat basic, but I don't know that an upgrade of the alternator (and possibly the wiring) would even be necessary - some sort of controller that automatically switched between battery banks (favoring the starting ones, of course) might be a better choice.

    Maybe a combination of the two would be ideal - the APU would kick in only in high current-draw or low battery power situations. This should squeeze a lot more life out of each gallon of fuel (and simultaneously address the 34 hour reset period issue you mentioned). The fuel savings over the years that the batteries would last would seem to me to make it well worth it.

    Am I nuts?
    Last edited: Dec 30, 2010
  4. Kansas

    Kansas Road Train Member

    Apr 14, 2009
    aircap, Ks.
    TriPac has an all battery unit...
  5. Beer Runner

    Beer Runner Medium Load Member

    Nov 2, 2010
    I like my Carrier model. I get a nice purr (of the Motor) form it and all the rest, and it drowns out all the truck stop noise. I could never sleep with one that make no noise all. Not unless everyone shut down. No not even then. At home I have the fan running. LOL
  6. Cheap Weenie

    Cheap Weenie Light Load Member

    Oct 8, 2010
    Yes. Huge difference in the amount of power deep-cycle batteries can provide vs running off endless 110v household power.
  7. Flying Finn

    Flying Finn Heavy Load Member

    Jun 22, 2010
    Ontario, Canada
    The weight of large banks of batteries is a limitation as well. They tend to take a full 10+ hours to recharge. Then they only will last about 11 hours before needing to have a long drive to recharge. No good for a reset. The AC units run similar to the coleman coolers in basic function. They will not cool really well in a very hot and humid region.

    To run a 120V AC unit will add a large inverter, and the weight of an AC unit and finding the space to put it. Running an inverter will drain your battery backup faster as the inverter is not 100% efficient.
    scottied67 Thanks this.
  8. ZippyNH

    ZippyNH Medium Load Member

    Aug 8, 2010
    Southern NH
    Also legal issues...many states will let a truck go 400 lbs over max gross with an APU....but if you have 400lbs of batteries, unless it is the carrier branded battery APU (or similar) you are loosing 400 lbs of load carrying capicity.
    From a scientific standpoint, it is all about energy density!! When a battery pack can make an electric car drive 200 miles without a recharge, and be long lasting, and cheap to replace, then maybe your argument will hold water, till then battery APU units are barely adquate for 6-8 hrs. Battery technology has to develop much more...and a truck would need a bigger or even a second alternator...easily...ever wonder why an electric car uses a 240 or even a 480 volt charger? It is all about the amps required...even a 120 amp alternator running at 100% capicity (reducing the mpg while in motion) would have a hard time charging a big battery bank, and not all trucks drive 11 hrs a day...many have an occasional, or even regular 4-6 hr days due to loading.
    For longevity, draing a battery below 80% is terrible...so is cold, and vibration...all things a truck has in spades.
    scottied67 Thanks this.
  9. Beer Runner

    Beer Runner Medium Load Member

    Nov 2, 2010
    Get a real APU one that is mounted on the frame. A generator. This thing will keep you warm in the winter and cool in the summer. Puss keeps your batteries charged and coolant warm. Mine also has a built in inverter. Now that's the way to go. I'm a Canadian and it works for me. We live in the cold.
    scottied67 Thanks this.
  10. Markvfl

    Markvfl Road Train Member

    Nov 29, 2007
    Apopka, FL
    I have a Coleman Roughneck roof mounted A/C and heating unit that I'm currently running from a Honda EU3000 gas generator. It uses 1617 watts and 14.8 amps when cooling. Of course it doesn't run constantly, it cycles on and off. I'm wondering if I had an appropriate inverter and a bank of 4 of the Trojan batteries that have 105 amp hours and I'm on a reset, can I run a battery charger to keep them up from a small 1000 watt or similar suitcase style gas powered generator? A charger can be installed on the truck and set up on a plug but it may require too many amps or too much wattage to be effective. I'm not educated in these things. I know just enough to be dangerous!

    BTW, alternator was just replaced with a new 165 so I'm not willing to replace it again.
    scottied67 Thanks this.
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