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Matt's BGT Battery Upgrade

Discussion in 'Bamboo GT' started by SkaterBoy58, Jan 23, 2018.

More threads by SkaterBoy58
  1. SkaterBoy58

    SkaterBoy58 Member

    This thread is detailing a battery upgrade on an Evolve BGT .

    Basic concept is to
    • replace Evolve BGT stock battery with a 10S6P 18650 pack for increased range and reduced voltage sag.
    • New ABS enclosure for battery pack
    • Retain Evolve ESC and BMS fitted in new enclosure
    I will be doing this in parallel with another DIY board project ( see New Ground Up DIY for Mark ) leading to some time saving and cost sharing benefits
     
  2. OP
    SkaterBoy58

    SkaterBoy58 Member

    MJ1 Cells and lots of other stuff has arrived and battery pack construction has commenced :)

    The battery will be a 10S 6P configuration.
    First thing is check voltage of all cells - all are within 3.5Vto 3.6V so all good.

    Has some spare 18650 cell heatshrinks so used that on outside cells in eack pack ( for additional inter-pack insulation).

    Then hot glue 3 cell packs together.

    Then 3 cell cardboard insulators on all +v ends.

    Ready for nickel strips to be added

    MJ1 cells.jpg

    pack.jpg

    cell.jpg
     
  3. Doug079

    Doug079 Member

     
  4. Doug079

    Doug079 Member

    Hi Skaterboy58, how’s the battery build going?
     
  5. OP
    SkaterBoy58

    SkaterBoy58 Member

    Coming along - all 10 IMG_3273.JPG cell packs glued together and first layer of nickel strips completed
     
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  6. OP
    SkaterBoy58

    SkaterBoy58 Member

    Battery pack building continued - photos show:
    • each 6 cell pack wrapped in Kapton hi-temperature tape and then with fibreglass tape
    • mock up of series connection with 2x 12 awg flexible silicon wire and showing current sharing on packs
    • additional insulation for inter-pack cell outer skin insulation
    • packs taped together to form 2 x 5S blocks
    ready for final nickel strip welding and series wire connections IMG_3277.JPG
    IMG_3278.JPG IMG_3279.JPG IMG_3280.JPG IMG_3282.JPG
     
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  7. MattyG

    MattyG Member

    Looking good mate! thanks
     
    • Like Like x 1
  8. OP
    SkaterBoy58

    SkaterBoy58 Member

    continued with building battery pack . Series connections are 2 x 12awg silicon high temp flexible cables . Final wrap in neoprene foam for protection and heat shrink for moisture/dust protection.

    IMG_3299.JPG

    IMG_3302.JPG

    IMG_3306.JPG

    IMG_3307.JPG

    IMG_3314.JPG

    IMG_3316.JPG
     
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  9. OP
    SkaterBoy58

    SkaterBoy58 Member

    First charge up pack at 2A to 41.7 V
    Then a discharge test using an eight ohm 100W resistor hanging over a fan. This provides approx. 4.5A load ( varies with voltage)
    The discharge test objective is to confirm cell capacity ( Wh and Ah) from full charge to 30V
    Discharge test took four hours with data checked every 30 minutes. Results were identical to discharge test for Marks pack using identical MJ1 cells discharge test 1.jpg discharge test 2.jpg
    Final readings at discharge test conclusion were
    30.0V
    690Wh
    18.5Ah
    with a cells within 0.1V

    These are slightly better than estimated ( Ah capacity of 18Ah and Wh 648) - so cells are all good.!
     
    Last edited: Feb 19, 2018
    • Like Like x 1
  10. OP
    SkaterBoy58

    SkaterBoy58 Member

    ABS Enclosure was sourced as a special order from psychotiller in California USA . Comes in two halves and used special ABS glue to glue together. ABS is ideal for enclosures as it is tough yet flexible and forgiving for scrapes when bottoming out .

    enclosure.jpg
     
    • Like Like x 1
  11. OP
    SkaterBoy58

    SkaterBoy58 Member

    Next - Enclosure and battery pack were given to Matt for enclosure deck mounting and ESC fitting.

    In this build - the Evolve ESC and BMS are being re-used in the new set-up.

    Following on from ideas from my recent DIY builds - utilising an aluminium plate in enclosure for mounting ESC and BMS and as a mass heat sink for ESC.

    Plate is bolted to rubber strips ( for vibration dampening) and rubber strips are glued to bottom of enclosure with ABS glue.
    We are using and XT-60 socket/plug for fitting a 40A fuse and to provide physical isolation from battery +ve ( for piece of mind and safety when being stored)
    photo 1.jpg photo 2.jpg photo 3.jpg
     
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  12. OP
    SkaterBoy58

    SkaterBoy58 Member

    Battery pack is fixed to bottom of enclosure with two full length velcrose strips - don't want battery pack moving under acceleration or braking!

    and all enclosure bits fitted
    • XT60 external 40A fuse and isolator ,
    • on/off switch ( from my old BGT )
    • charging port
    • two holes at rear for motor grommets

    empty chassis.jpg
     
    Last edited: Feb 27, 2018
    • Like Like x 1
  13. OP
    SkaterBoy58

    SkaterBoy58 Member

    Next is to build a BMS harness to connect from Evolve BMS to battery balance socket (green one)
    I always fit in-line fuses on BMS balance leads ( under the black heat-shrink in picture) as these connect directly to battery pack cells with approx. 150A potential current available to feed a fault
    .
    Without fuses , a short on the BMS board could melt the balance wires , start a small fire and could cause the whole battery to go-up.

    Harness is spliced into Evolve BMS plug wiring

    BMS Harness.jpg
     
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  14. OP
    SkaterBoy58

    SkaterBoy58 Member

    BMS is fixed to gear tray with velcrose tape - all wired up ready for fitting to board

    ready for changeover.jpg
     
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  15. OP
    SkaterBoy58

    SkaterBoy58 Member

    For weatherproofing a stick on rubber protrusion ( from Clark Rubber) is stuck onto bottom of deck - and holes drilled to align with enclosure holes

    rubber insert 1.jpg

    rubber insert 2.jpg
     
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  16. OP
    SkaterBoy58

    SkaterBoy58 Member

    Motors connected and all set for test run - Evolve remote pairs OK ( eventually! ) and motors spin - so all good

    ready to go.jpg
     
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