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    Brushless Motor problem
    by ChrisR πŸ‡ΊπŸ‡Έ ( Master Seaman)
    πŸ“£










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    ChrisR
    Master Seaman
    πŸ“ Brushless Motor problem
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    Country: πŸ‡ΊπŸ‡Έ United States
    Online: 11 days ago
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    Thank you Doug. I will follow your recommendation. I will go for the two 2x 10 Cells connected in series. It is a big boat to push through the water. That should be a good bit of ballast too.
    Regards
    Chris
    1
    ChrisR
    RNinMunich
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    πŸ“ Brushless Motor problem
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    Country: πŸ‡©πŸ‡ͺ Germany
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    "I assume the two x 10 Cell NiMh Batteries would be connected in Parallel not in series. Otherwise the voltage would be too high. Do you agree?"
    ABSOLUTELY NOT CHRIS!
    Connecting batteries in parallel can be dangerous, unless both have identical characteristics and charge states. Which is seldom the case! Danger is if that if one battery is at a significantly lower state of charge (voltage/capacity) then the other will try to charge it, which can cause very high current to flow --> FIREπŸ”₯😭 So called Back Charging.
    The way to prevent that is to connect the two batteries via fast Schottky diodes to prevent the reverse current flow. Connecting two 12V NiMh (10 cell) in parallel still only gives you 12V supply for the ESC and motor.

    BUT, you NEED the high voltage to make the ESC and motor you are using work properly.
    Connect the two batteries in series; i.e. + of one to the - of the other. Giving a nominal 24V using 10 cells or 19.2V NOM for the using 8 cell batteries. If you're worried go for 8 cells.
    Should still give you decent performance
    Make sure that the two batts are from the same manufacturer and of the same capacity (mAH).
    When you get the new batts put them through 2 or 3 discharge / charge cycles to condition them for their new life πŸ˜‰ That will help to get them both to the same charge state and prolong their useful life.
    If you don't already have one I recommend that you get a voltage / capacity checker. Available all over Amazon/Ebay for a few quid.
    Happy BattingπŸ˜‰
    Cheers, Doug 😎
    2
    Young at heart πŸ˜‰ Slightly older in other places.;-/ Cheers Doug
    ChrisR
    Master Seaman
    πŸ“ Brushless Motor problem
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    Country: πŸ‡ΊπŸ‡Έ United States
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    Doug, I assume the two x 10 Cell NiMh Batteries would be connected in Parallel not in series. Otherwise the voltage would be too high. Do you agree?

    Chris
    1
    ChrisR
    ChrisR
    Master Seaman
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    Country: πŸ‡ΊπŸ‡Έ United States
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    Thank yoy Doug. I will take your advice. Will let you know how it goes I need to get that problem sorted before going any further.
    Chris
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    ChrisR
    RNinMunich
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    πŸ“ Brushless Motor problem
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    Country: πŸ‡©πŸ‡ͺ Germany
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    Hi Chris,
    I kinda figured that ballast came into the SLA equation there πŸ‘
    I do that with my larger warships (ca 1.5m) as well.
    I too prefer 'power ballast' to 'dead lead' if possible.

    Reckon you'll be pushed to find NiCads nowadays.
    They're rather environmentally infradig these days due to the cadmium.
    I'd go for two (8 or 10cell) NiMh of the highest capacity that fit the budget.
    That should provide decent ballast and decent performance/endurance.
    You could also consider fitting one either side of the hull to help with roll stability in turns.
    Just a few thunksπŸ˜‰. Happy sea trials🀞
    Cheers, Doug 😎
    4
    Young at heart πŸ˜‰ Slightly older in other places.;-/ Cheers Doug
    ChrisR
    Master Seaman
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    Country: πŸ‡ΊπŸ‡Έ United States
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    Doug, I went for the 12v SLA because it actually acted as good ballast.
    I will certainly consider your suggestion of the 14 NiCad batteries. that should be a good ballast as well. My speed controller is the Hawk 100A. I will keep you updated.
    Many thanks
    3
    ChrisR
    ChrisR
    Master Seaman
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    Country: πŸ‡ΊπŸ‡Έ United States
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    Yes I have gone through that.
    Thank you
    1
    ChrisR
    ChrisR
    Master Seaman
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    Country: πŸ‡ΊπŸ‡Έ United States
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    Thank you very much for this information. I will certainly check this out. I don't think it is a binding issue because the other servos are working corretly.
    Regards
    Chis
    1
    ChrisR
    RNinMunich
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    Country: πŸ‡©πŸ‡ͺ Germany
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    Hi Rowen, Graham, Chris,
    All very valid points, but -
    I started with an even simpler thing - looking up the Specs of the components and Battery voltage required! (My test engineer instincts coming through πŸ˜‰)

    I believe that 12V is not enough for this ESC / Motor combo.
    I found the same manual as Graham and checked the ESC specs, see page 1.
    Esp. Operating voltage and Battery type (relevant for Cut off voltage!)
    The ESC expects a minimum of
    14 NiCad / NMIH cells, =16.8V NOM
    or 4 LiPo cells. = 14.8V NOM.
    So I strongly suspect that it detects a 12V SLA as a deep discharged battery and goes into Cut Off mode, i.e. shut down, with beep beep beep ... alarm.
    Unfortunately the ESC manual does not specify the default values.
    These may well be in the Programming Card manual though.
    Strongly recommend that you buy the programmer Chris, much easier and quicker than 'beeping around'.

    The motor spec also specifies higher voltage;-
    https://www.cornwallmodelboats.co.uk/acatalog/P4445810.html
    "Energ Brushless motor, suitable for large model boats such as Sea Queen
    Battery - 5-6 cell Li-Poly, 20 Cell Nimh (18.5V / 22.2V NOM Lipo, 24V NOM NiMH)
    Weight - 300g
    670Kv
    Connectors - Gold included
    Working current - 40-80A : Peak 85A
    Shaft diameter - 6mm
    Speed Controller requirement - 85A."

    So Chris;
    Either get another 12V SLA and put the two in series or (and much better cos the ESC won't recognise the two SLAs and may 'think' they are a 20 cell NMIH) get yourself a 5 or 6 cell LiPo.
    That will be much lighter and have a much better power to weight ratio than the SLA.
    SLAs are generally not happy delivering high currents.
    They were developed essentially for long term back up low current supplies.

    Hope this helps.
    Cheers, Doug 😎
    https://www.cornwallmodelboats.co.uk/acatalog/P4445810.html
    πŸ”—
    3
    Young at heart πŸ˜‰ Slightly older in other places.;-/ Cheers Doug
    Rowen
    Lieutenant Commander
    πŸ“ Brushless Motor problem
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    Country: πŸ‡¨πŸ‡¦ Canada
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    Think would start at the simplest thing-check your Tx/Rx binding.
    For some inexplicable reason mine occasionally loose bind and it causes similar problems
    Good luck
    3
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