Results 1 to 7 of 7

Thread: ESC for a 12v Johnson 970 motor

  1. #1
    Join Date
    Jan 2020
    Location
    Ns
    Posts
    4

    Default ESC for a 12v Johnson 970 motor

    Hi all- I have an old fairey marine swordsman 33? with a Johnson 970 that has space for a lead acid type batt based in Sydney Australia I?m seeking advice on a suitable speed control and place to buy. I?m not sure on amp draw . Will I need water cooling ?
    Thanks In advance .

  2. #2
    Join Date
    Sep 2012
    Location
    Tg
    Posts
    1,035

    Default

    You may find it easier to replace with a brushless set up. What length is the hull? What size prop? Always liked the FM Swordsman. You may also get away with a Hobbywing 1080 esc. You could make a cooling plate to fit the heatsink on it.
    NZMPBA 2013, 2016 Open Electric Champion. NZMPBA 2016 P Offshore Champion.
    2016 SUHA Q Sport Hydro Hi Points Champion.
    BOPMPBC Open Mono, Open Electric Champion.

  3. #3
    Join Date
    Nov 2008
    Location
    Ql
    Posts
    3,042

    Default

    All depends on what size prop you are running.
    Those motors have a stall current of around 80A I think so an ESC of around 60 A should do.
    It's a big motor for a small boat.
    Here are a few sites to buy some 60A 12v ESC's. some even here in Australia.
    If you don't want to watercool it there are some with fans that work pretty well. I've got a couple of 45A ones in my 44" Higgins PT boat with two Johnson 785 motors in it.
    They don't break a sweat. Props are 35mm 3 blade scale props.

    https://www.google.com/search?q=60a+...52148019165194

    Edit:
    I just did a bit of checking. The 12v 970 motor is only rated at 3,300rpm. Might be a bit slow, depending on what speed you are after. But again, depends on your prop size & type.

    Is this your motor?

    https://vikiwat.com/en/dc-motor-jons...75mm-50mm.html
    Last edited by 785boats; 01-10-2020 at 08:13 PM.

  4. #4
    Join Date
    Jan 2020
    Location
    Ns
    Posts
    4

    Default

    Yes that?s the motor - I agree it?s quite a big one but that?s enough for scale speed when it?s loaded up. I suppose I could run a bigger prop if I wanted more speed as the motor is very torquee.
    The prop is a 40mm plastic 2 blade one.
    Boat is 33 inches long - quite lite unloaded but it needs weight in it to perform.with The 12v lead acid still needs weight in the rear .
    Cheers

  5. #5
    Join Date
    Nov 2008
    Location
    Ql
    Posts
    3,042

    Default

    Cool.
    If that prop gets the boat up on the plane at a good scale speed, then that's all good.
    I just thought that 3,300 revs might have been a bit slow for the boat to plane out.

    It won't be drawing many amps, so the 60A ESC's will work well. Especially at those prices.

    I would try this one. Be sure to select ' with fan '.

    https://www.ebay.com.au/itm/AU-STOCK...4383.l4275.c10

  6. #6
    Join Date
    Jan 2020
    Location
    Ns
    Posts
    4

    Default

    Thankyou very much for that - I have ordered that one and will get a battery next . Much appreciated.

  7. #7
    Join Date
    Jan 2020
    Location
    Ns
    Posts
    4

    Default

    so- i purchased that esc (new rain 60a with fan) from ebay. hooked it up and it literally caught fire within 3 seconds like there was a major short. smoke everywhere. it was wired correctly so im now really confused if it was faulty or i did something wrong . its hooked up to a 12v lead acid battery via a traxxas 2.4 radio. Any clues before I buy another one?

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •