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Thread: Sachs xtc 125 conversion


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  1. #38
    Senior Member
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    Jun 2017
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    Long term- well medium term update

    Hi all,
    now have a little more than 1000km on the xtc (620 ish miles)
    weather was not too favourable to ride lately.

    bike has performed flawlessly so far, using self locking or locktided screws exclusively nothing has come off or got loose.
    So basically the bike is near maintenance free to use.

    Making the most out of the rainy weather i have replaced the back wheels bearings like i already did on the front.
    Now the power consumption at 100kph on a flat is down to about 6,4Kw - the previous mentioned 6,3 have been a typo and should have been 7,3 ish KW.
    Quite a difference and a recomendation to everyone trying to get some more miles out of their ev - look after the bearings as well.
    Total cost of two sets of skf bearings .. aprox 10 Euro - savings in power consumption at 100kph (62mi) aprox 1,2kw . Well worth it -if not for money spend- at least for range gained.

    Talking about range:
    Reprogrammed the kelly`s cutt off down to 3.2 V per cell so it powers down at aprox 3.35 under load i finally performed a real range test yesturday.
    To get you all facts: my single cell monitors alarm start at 3.45 V per cell
    and i have - for the first time the since the charger arrived ballanced the pack- went from 0,04v difference down to 0,04V difference.
    That only proves two things:
    cells had not drifted in those aprox 12-15 charges and the cells simply "sit" at slightly different voltages.

    Back to the range test:
    first 45km i spend simply hooligan the bike around as much as to stay at least not too far off the legal side of traffic. accellerating fully to say 110kph and staying there, I knew i would get at least that range...
    I then opted to "loop " around my village in a more civilised manner - lets call it commuting style in order to find out how much more there really was. Still accellerating full but keeping it between 85-90, no overtaking...
    Well At exactly 75km (42mi) the weekest cell hit 3,45 Volts causing alarm while speeding up so from than on i rode it more cruizing style to see whats still left in it. Speed was sitll kept at about 85kph..
    80km into the ride (49 ish mi) the Cycle Analyst showed exactly 50Amphrs consumed and Cells showed about 3,49 volts at cruizing load..so i turned home.

    84km , 52 Amphr i stopped at home. cells would still read 3,47V average at cruize and cell voltage jumped up to 3,53 av. at standstill. perfect comparison to my calculations and user profile predifined for the cells.
    I am sure if ridden in a tame manner and somewhat slow i could get another 8-10 km out of the cells - while it may cause some voltage alarms while doing so each cell would surely stay safe above 3.3V at load.
    I wasn`t about to test that for simply not wanting to take chances and maybe even damage the pack for no need at all...

    mostly flat, a few smallish hills in between , hardly any wind and temp about 17-18 deg. C.

    I can savely asume to get about 75 to 80 km per ride, with another 10km or so reserve to "drag me home" at reasonable/slow speed and mild accelleration. If i want to extend my range that is... much more fun to spend it all on say 50-55 km rides

    Power consumption on this ride comes to

    0,61 Amphr/km or exactly 1 Amphr per mile
    asuming average 82Volt (90Volts charged, 77 depleted)
    that translates to
    about 50 whr/ km or aprox 80 whr/mile

    seems quite efficient to me so if one thinks about a conversion maybe consider a light, low and fully faired bike for maximum range.
    Might be of intrest as well:
    Total capacity (charged to 4,2V) would be 90Aphrs /8,1KWh
    as used (4,1V down to 3,45 nominal) slightly above 52 Amphrs - might get 57 out if driven slowly (at 62 nominal)

    so calculate enough extra to actually achive your range..


    Last edited by flo; 23 August 2019 at 0401. Reason: spelling


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