Generator substitute

Discussion in 'Motorhome Chat' started by Reallyretired, Mar 28, 2011.

  1. Reallyretired

    Reallyretired Funster

    Apr 27, 2008
    Eastbourne East Sussex
    On the generator front I had an idea, though don’t know how well it would work, if you(or anyone else) wanted to run a microwave/toaster/hairdryer how about connecting a highish output inverter to the vehicle battery and just running the engine when you needed it. The standard alternator can produce 70A+ so if started before use and let to run on a bit afterwards I reckon it would do the biz without the hassle of a generator (1Kw inverter draws 90A and can be bought for around £200). The engine would be as quiet as a lot of gennys and might even be more economical as it would only be ticking over on diesel. Or is this another daft idea. It is possible to obtain a 160A high output alternator for around £200 (as used in ice cream vans) which could run a 2Kw inverter.

    I await expert opinion on why this wouldn't work :Cool:
  2. aba


    Oct 27, 2009
    in theory good idea.
    however our small leisure battery got low this weekend at newark so as we hadn't the genie with us i decided to run the van engine to charge it.
    the alternator feeds the starter battery first so that gets the big amps the leisure battery gets slightly less amps the alternator gives its best output with the engine above 1500 rpm so at tick over 800 rpm ish its not getting enough revs to give its best.
    also with the diesel engine idling for any length of time it fills the turbo with unburned fuel so when you do set off you get a cloud of black sooty diesel smoke.
    as for efficiency its cheaper to run a generator as in the short time i had the van running over the weekend it probably used a gallon of fuel.
  3. haganap

    haganap Funster Life Member

    Dec 5, 2007

    Yes you are right, there is a method of doing this as some do. The option was explained to me by Monsi and CLS (mark) ages ago, however I sort of got lost at the point they mentioned sentence two. It does involve Ice cream vans though or more importantly the set up used to power and Ice cream machine.

    for me though, I just love me Honda Genny and with my 1500w inverter can do all that I want and just use the honda to recharge the leisure's when required.
  4. jonandshell

    jonandshell Funster

    Dec 12, 2010
    Most onboard chargers are only 17A or so.
    Running your genny to provide 230v will charge your leisure battery at 17A.

    We have a sterling battery to battery charger. At idle, our 'leisure' (actually traction) battery charges at 50A (measured with a clamp-meter). Therefore, we run our engine for one third of the time somebody would run their genny to get the same amount of charge. Plus we get 'free' heat from the cab heater!

    Therefore my advice is don't worry about a bit of soot, buy a Sterling Power Products battery to battery charger.::bigsmile:

    Of course, if you were to run a bloody great inverter together with a battery to battery charger, either have a couple of decent batteries and use the inverter with the engine turned off or ensure your inverter is connected directly to the starter battery. Otherwise the charger would just error and switch off!

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