today work --> reparing $15k motojet starter

batteryGOLD

100 W
Joined
Dec 14, 2019
Messages
293
Location
PT Portugal
MotoJet board value $15k to surf at Algarve PT beaches does not work..

Starter KO
This starter has 4S Samsung 40T 4000mAh 35A cells

Check picture testing new Sony mobile. Using wide angle lens cells looks like 18650..
load full resolution..
https://ibb.co/vPWf8sp

Problem: Starter does nothing..
Cause: one cell down to 1V bms went down
Solution: balance cell to equal others, and check IR . cell ok 10mohm similar to others

Final result : Board motojet does start OK, problem solved. but need water isolation compound at closing enclosure
 
goatman said:
do you think the bms drained down that cell?
how about replacing bms with active balancer?

the problem was some sea water / condensation inside case.
sea water / humidity inside case affected one cell drained down to one volt

This two starters have same problem due to water isolation failure.
And there are more of this starters with same problem. it seams a bad isolation design for sea water..
 
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