• Welcome to ScubaBoard


  1. Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

    Benefits of registering include

    • Ability to post and comment on topics and discussions.
    • A Free photo gallery to share your dive photos with the world.
    • You can make this box go away

    Joining is quick and easy. Login or Register now by clicking on the button

Dive Xtras Echo ESC question

Discussion in 'Dive Propulsion Vehicles' started by bada3003, Jan 4, 2021.

  1. bada3003

    bada3003 Solo Diver

    # of Dives: 200 - 499
    Location: Indiana
    240
    40
    28
    Does anyone know the specs of the Echo (pre-Sierra) electronic speed controller, in particular, if it can tolerate 7s Li-ion input voltage? I contacted Dive Xtras but the person replying did not know. I opened the ESC heat shrink wrapping but no identifying information.
     
  2. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    10,705
    5,229
    113
    The sierra ESC (pre programmable) sometimes tolerates 7s and sometimes they burn up. Since the Sierra itself kind of randomly does or doesnt tolerate the 7S voltage, I suspect the Echo is the same - and that nobody actually knows the specs. They were made before li-ion batteries were even invented afterall. All you can do is try it and see if it lasts.
     
  3. bada3003

    bada3003 Solo Diver

    # of Dives: 200 - 499
    Location: Indiana
    240
    40
    28
    Thanks for the info.
     
  4. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    10,705
    5,229
    113
    I have a 7s7p li-ion battery with a 30amp BMS in my Sierra and to date it seems fine.
     
  5. maxtrax

    maxtrax Angel Fish

    # of Dives: 500 - 999
    Location: Seattle, WA
    18
    12
    3
    Original echo/sierra electronics were likely designed around 24v nominal NiMH pack (i.e. 30V at full charge). A 7s Liion pack is going to be around 29.4 to 30.8v fresh off the charger depending on exact cell and charger. If you don't plug the pack in straight off the charger and wait a little bit for the voltage to dip back below 30v you ought to be fine. (Ignoring the age and potential lifespan of components in an echo ESC). This is the same potential issue/resolution as folks blowing up cuda ESCs with 12s Liion packs.
     
  6. dofleini

    dofleini Solo Diver

    3
    2
    3
    Howdy, wanna resurrect my trusty 2007 sierra and i'm a techno pheasant appealing for help.
    Having gone down the NiMH rebuild route with Rabbit West 2x.
    Have ordered the electronics from Dive Xtras
    to convert the pre LiON tail section to accept PTB and 2 Milwaukee 4 amp drill batterys. (not alot of juice I know)
    I'll fabbercoble the battery holder to accept Milwaukees as thats what I've got.
    Open to suggestions as to how to power it. What is 7S 7P designation?
    ESC= Electronis Speed Control?
    BMO= Battery Monitor?
    Have logged 1200 jumps on the Sierra and also love riding my P1.
    Apparently the electronic swap converts the Sierra to a P1 so any input from those wiser appreciated.
     
  7. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    10,705
    5,229
    113
    Just get the proper 9 or 12ah dewalts or one of the dewalt knock offs which actually fit into the PTB holder.

    7s7p is 7 cells in series 7 in parallel and not applicable to the PTB conversion.
     
    dofleini likes this.
  8. dofleini

    dofleini Solo Diver

    3
    2
    3
    Got it. @rjack321 was your 7s7p battery an off the shelf item?
    was it a tricky mount to install in sierra tube?
    As the ol sierra electronics are getting swapped for P1 guts, would explore other options.

    Im guessing you went that route for 24 V and not melting original sierra electronics.
    did you have compass deflection increase when you swapped?
     
  9. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    10,705
    5,229
    113
    I gutted the original NIMH battery and installed the 18650 cells in there along with a BMS and ALOT of lead to get the battery heavy enough so the scooter is still neutral. You can buy li-ion Sierra batteries from various aftermarket builders.

    The Sierra is a 24V scooter, the motor can tolerate up to about 34V but the ESC cannot.
     
  10. bada3003

    bada3003 Solo Diver

    # of Dives: 200 - 499
    Location: Indiana
    240
    40
    28
    That was my original thinking as well. However, looking at the various 30-40 amp ESCs with similar form factors as the Echo's, they specify 6s for Li-ion batteries (if at all) which leads me to believe that rjack321's observations on reliability is likely to hold. As I use DPVs only on certain dives where reliability is important, I'll go with 6s and build a 30Ah pack.
     

Share This Page