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Thread: esc question...

  1. #1
    Join Date
    Sep 2014
    Location
    NJ
    Posts
    46

    Default esc question...

    Hello boys!
    Any advice would be greatly appreciated.
    I love rc boats...love scale, not speed.
    So heres my question.
    I have 2 OSE Raider 6s 150 Amp Esc,s...they are going into a twin motor scratch built hull. My goal is to have the boat do a scale speed, not a pond rocket.
    Ive been out of the hobby for years...literally. Lipo's were not even invented and the more i learn about them the less i want to use them. Can my two esc's be powered by nimh's ?
    The nimh packs would be slightly heavier but for what I'm after it wouldnt matter.
    Thanks!
    South Jersey Vice

  2. #2
    Join Date
    Jan 2016
    Location
    FL
    Posts
    1,371

    Default

    First, glad to have you back onboard and congratulations in getting the two OSE Raider escs, many that have used them have had positive things to say about them. But, you didn't mention what kind of motors you will be using. When you mentioned nimh batteries the first thing came to mind were in regards to motors. . .brushed motors to be exact. Those OSE escs are brushless so you will have to get brushless motors. I might be wrong but I don't think the OSE Raider can be used with brushed motors. So if I'm right, then you'll also have to get brushless motors. But, if you already have brushless motors and capable up to 6S, then, you're all set with the OSE Raiders. Those escs are meant to be used with 2S(7.4V)-6S(22.2V) lipos. So to answer your question is yes you can use nimh batteries as long as you have the right cell count and within the voltage range of 7.4V-22.2V. But, you shouldn't have any fear of using lipo batteries. As long as you practice lipo safety then there's nothing to not like about them. They are more superior than nimh batteries and for what your goals are, you can get lower C rating lipos that are even cheaper than nimh batteries. But if you use nimh batteries those OSE Raiders have what they call LVC, low voltage cutoff, that are for keeping lipos being drained and ruined. The LVC will kick in before you drain most of your juice in your fully charged nimh packs.. . .meaning less run time because it's possible the LVC will kick in before your nimh pack are even half drained and it will shut down. So now you will have to lower the LVC so you can run your nimh packs longer to use most of the juice it holds and you'll need an esc programmer for that. My advice is to get lipo batteries. . .read about them how to configure 4S, 5S and 6S so can make a wiser decision in what lipo packs to get. For example, if you get two 2S lipos you have the versatility to run those esc on 2S or 4S(two 2S run in series). Then if you stick with running in 2S then you can parallel both your 2S to double the battery capacity(mah) which translates to longer run times. With 5S you'll need a 2S and a 3S battery to run in series but you can run also in 2S or 3S separately. Then in 6S, you'll need to get two 3S batteries to run in series but you can also run your boat with a single 3S or two 3S in parallel increasing your run time but then your stuck running in 3S only. . but remember whatever batteries you get you must have the same capacity(mah) and the same C rating. Also, you will need a lipo charger but if you plan to use nimh packs getting a nice lipo charger will also quickly charge your nimh packs than those older nimh only chargers. I know it's a lot to swallow right now and I'm probably not explaining everything that well or have forgotten to mention other things related, as I just got home from work and quite tired. But, I hope some of this makes sense to you. . .
    Last edited by Bp9145; 03-05-2019 at 12:34 AM.

  3. #3
    Join Date
    Apr 2007
    Location
    AZ
    Posts
    7,633

    Default

    We ran brushless motors on NiMH cells for years before LiPos, they will work just fine.



    .
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  4. #4
    Join Date
    Sep 2014
    Location
    NJ
    Posts
    46

    Default

    Wow!
    Thanks for the detailed explanation!!!!
    Yes, I have two brushless motors that Steve recommended for the build.
    I'm reconsidering my view on lipo's...did some lengthy YouTube trolling last night on the subject and I've come to the conclusion that you can't be willy nilly with these batteries.
    I am still going to wire up some nimh packs just for wiring the mock up...2 mini water pumps and a sound module. This way I don't have to be concerned with discharging the lipo's...
    I started this build several years ago and abandoned it after finding several flaws in the final design. I picked it up again a little over a year ago. I have a small start up company and was tasked to learn CAD and 3d printing for our prototypes . We have 2 patents in the works and I have lots of time on my hands.
    Anyway...the project is a 38 kv Scarab. I found a model from the mid 80s of the boat on ebay. I sent the hull and deck to be 3d scanned...the scans were broken down into 27 pieces and enlarged 444% making the final length 61". What I have now are two plugs...deck and hull ready to make molds out of. The final size of the boat was determined by the size if the outdrives I found. The drives are German and cool looking but they have an rpm limit...so if my math is correct the boat will do a scale speed of 75mph by just doing 18-22mph real life. Steve picked out the motors/esc's for me and said this was the first he had to do a combo to run slow.! The combo setup at full throttle would destroy the outdrives so I'm going to have to retard the throttle drastically.
    So far the plugs look incredible...this 3d printing is the most amazing stuff I've seen in my life. Parts for the outdrives that are inside the hull had to be designed and without cad/3d printing it would have been impossible. The parts are pla plastic and too soft for this application so silicone molds were made from them and were cast from 2 part poly's...bulletproof!
    I have to post some pics!
    Again...thanks for your input and insight!!

  5. #5
    Join Date
    May 2018
    Location
    TX
    Posts
    196

    Default

    Very interesting please post pics! I'm also building a 38KV at 54" but the late 90s version.

  6. #6
    Join Date
    Sep 2014
    Location
    NJ
    Posts
    46

    Default

    I'll get some pics together this weekend and post...wanna see you boat to!

  7. #7
    Join Date
    Jan 2017
    Location
    TX
    Posts
    3

    Default

    What type of solder is best for soldering 5.5 mm connectors to an esc and motor? TIA

  8. #8
    Join Date
    May 2018
    Location
    TX
    Posts
    196

    Default

    Here's mine. With the exception of a few hours of eyeballing and brainstorming no real work has begun yet, but the parts pile is nearly complete.
    Attached Images Attached Images

  9. #9
    Join Date
    Sep 2014
    Location
    NJ
    Posts
    46

    Default

    That's a great looking hull!
    What color scheme you gonna do?
    Take a pic of the pile if goodies!

  10. #10
    Join Date
    Feb 2008
    Location
    GB
    Posts
    2,320

    Default

    I use a flux cored 63/37 solder which is a eutectic mix minimising the chances of a high resistance cold solder joint. I would recommend it if you can get it, but in these health and safety conscious days you may be forced to use a lead frree alternative.

    Sorry if this pisses in your fireworks, but it is better to know your goal is off before you get too far in to the project. The scale speed is the square of the scale factor in order to scale time as well as distance, 61" is 1:7.5 scale of 38', so to do a realistic looking scale 75mph you need to be doing a real 27mph.
    Paul "tug Killer" Upton-Taylor, Cat lover.
    FastElectricBoats.co.uk

  11. #11
    Join Date
    Apr 2007
    Location
    AZ
    Posts
    7,633

    Default

    Retarding the throttle for extended running is generally not a good idea with brushless motors. This can overheat the ESCs unless the Kv of the motors is low and the prop is small. Exactly what motors is the OP using? Depending on motor and prop he may be better off running fewer NiMH cells.
    ERROR 403 - This is not the page you are looking for


  12. #12
    Join Date
    Sep 2014
    Location
    NJ
    Posts
    46

    Default

    Nice!
    Thanks for the info!
    South Jersey Vice

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