generator to battery direct @ 250 volts?

t00lst00ls Solar Expert Posts: 234 ✭✭✭
I recently took down my windblue generator ....not enough wind here to effect my battery bank

Here's what I have,

xantrex 4548 inverter and a 60-150 mppt controller, fed by 6 evergreen (sun) 190w panels

the generator has a 540 stator in it ....this is a picture of the graph

what I did is rigged it up to my riding mowers output pulley and it put out 250 +volts at idle

my question to those in the know, can I connect this directly to my battery bank which is made up of 3 parallel and 4 series 12 volt for 315 amp hours

I understand I will need a dump load or something to switch the power off when the batteries are charged.....just need to know if the 200 volt thing will fry the batteries.........or will it pull the generator down to the battery voltage

by the by...I just told the electric company where to stick their electric I am completely off grid, and very happy, it's like a big weight lifted off me


  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: generator to battery direct @ 250 volts?

    basically you converted the turbine into a gasoline dc generator and it should work as long as there is proper regulation to keep the batteries from overcharging. 250v is a lot of voltage and the regulator or controller must be able to handle the voltages that can be reached without blowing it out. maybe throttle back on the rpms.:confused:
  • t00lst00ls Solar Expert Posts: 234 ✭✭✭
    Re: generator to battery direct @ 250 volts?

    that voltage test was done at idle...!....I dont want to know what it will put out at half throttle

    next question....where can I find a controller that can handle 250 plus volts
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: generator to battery direct @ 250 volts?

    According to the specs page of that alternator you can connect it directly to the battery:

    "Note: WindBlue External Rectifier output equipped alternators can still be connected for DC output by using the battery terminal on the back of alternator, however, only one output should be connected to your batteries at a time. The other should be left unconnected."

    They say that on the test stand they got 15a at 2000 rpm. If you look at the graph that you linked it hits 100v at about 1200 rpm. So if they spun it up to 2000 rpm they must have been hitting around the 250v that you are seeing.

    "Also, the voltage will rise until it meets the voltage of your battery and then level off as the battery is “absorbing” the excess voltage as it charges."

    So, from what I'm seeing there, it should work connected to the battery and run at 2000 rpm (probably about where you are now). And it won't be putting out 250v when it's connected to the battery.

    As for a charge controller - probably one of the ones they sell on their site? You might ask them.
  • t00lst00ls Solar Expert Posts: 234 ✭✭✭
    Re: generator to battery direct @ 250 volts?

    well I decided to put the other stator back in.....and I learned somethng

    I can hook this one up to my xw mppt controller.......but I cant use the mppt function

    I can manipulate the target voltage and if it's higher than the voltamps being put out ....the motor doesnt bog down any

    if I put it at the right volts for the only pulls the motor down a little

    if I put it below the voltage at the same rpm.....the amperage jumps up, and the wattage goes way up

    hmmmm.........more to study eh
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: generator to battery direct @ 250 volts?

    Hmmm...I guess it's trying to find the MPP of your home made generator. Makes sense.
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: generator to battery direct @ 250 volts?

    I wonder if you could do this cheaper without having to use an MPPT controller by putting a transformer on the output? Presumably the PMA outputs wild 3 phase AC which you should be able to bring down to a lower voltage AC with 3 transformers (e.g. 60V or thereabouts for your 48V battery), then rectify it to DC and connect to an ordinary charge controller.
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