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  1. #1

    Join Date
    Jul 2019
    Posts
    2
    Location
    Florida
    Mower
    Grasshopper

    721D not charging

    Hello all first post. I just bought a new GH mower a couple weeks ago, a 721D rear discharge with the 3 cylinder diesel and love the mower. All was well at first but I noticed one day after mowing at about hour 4 on the meter when I went to move the mower in to the shed that the starter seemed weak, checked and the battery volt gauge was low. Checked the battery and sure enough it was low and agreed with the gauge. I charged the battery then did the normal test to check volts at the battery then started mower and my suspicion was confirmed 12.82 with the mower not running and oddly 12.71 with the mower running, low idle, med high RPM's made no difference. Even used two different multimeters to confirm.

    Am I correct that this mower has a dynamo not an alternator? The Dynamo if that is what it is is working, the juice is just not making it to the battery.

    I checked every connection, every fuse and all of them are perfect.

    I removed the instrument panel and took a peak and all was tight in there as well. There were a few odds and ends wires not connected but believe those would be for the lights which I don't have.

    The only other thing is that sometimes when you start the mower the volt gauge sits at 0 and you have to tap the glass with your finger to get the needle to register.....or when you start to move the first bump will also make it register. Doubt the two are connected but thought I would mention it.

    The battery idiot light is not on and I don't think it was on when the mower started weak but won't swear to that.

    I know what some will say..."take it back to the dealer its under warranty" and I will if I can't solve it easily it is just a pretty long drive and figured if it is something simple fixing it myself would save me some time. I am going to assume it came from the factory with the issue as I had to order the mower to get the rear discharge.

    Any help appreciated.

  2. #2

    1,000 Post Club

    Join Date
    Aug 2015
    Posts
    1,664
    Location
    Kansas
    Mower
    Toro/Cub Cadet/Kubota

    Re: 721D not charging

    You're right, take it back to the dealer. Better yet, call the dealer and have them come get it, fix it, and bring it back to you. If in tinkering with it you damage something else, they could possibly deny warranty service.

    Normal charging voltage is in the 13.5 to 14 volt range. You may have a bad alternator. I don't know what you mean by 'dynamo.'

  3. #3

    Join Date
    Jul 2019
    Posts
    2
    Location
    Florida
    Mower
    Grasshopper

    Re: 721D not charging

    An alternator makes AC power that has to be converted in to DC power to charge the battery.

    A Dynamo makes DC power to feed the battery so no conversion is needed.

  4. #4

    1,000 Post Club

    Join Date
    Aug 2015
    Posts
    1,664
    Location
    Kansas
    Mower
    Toro/Cub Cadet/Kubota

    Re: 721D not charging

    I doubt if you have a dynamo, aka generator.

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