How to "Shunt MOD" your Bosch Gen4 for 70+ km/h and 729+ Watts 

hi , motor will handle more than 1kw , but sadly the battery will shut down and give error at about 21 amp .... so you will need to make the same modification on bms to se less amps , and yes ... you will need more ( or high power ) cells as the stock battery will sag .

Corect , sunt din fier pinioanele tin fara probleme , feturile la fel .

@@ebikeunlock Super, ai o poza cu PCB-ul la motorul de la un smart system? Sunt curios ce fel de senzor hall folosesc. Observ ca sunt greu de pacalit dar probabil sunt 2 senzori se se masoara si defazaju dintre ei si metoda cu bobina pacaleste doar unul. Nimeni nu a reusit sa pacaleasca un smart system, dupa 1000Km toti au eroarea setata,

hi , yes 700 ohm is ok

Salut , da dar cu alt controller extern ....

Hi , yes you can use the standard battery .

Just this video , i will post more when make a custom battery ( with bosch bms ) .

@@ebikeunlock Do you think it`s possible to do that on a "CX Speed" (350W, 45km/h) , too?

@@MrINKOMPATIBEL yes but possible you must "shunt mod " the bms to .... ( pack will shut down at 22-25a )

Gen4 cx 14-15a before mod , 20-21a after

@@ebikeunlock I'm surprised the peak amps was so low before, I watched a drag race vs a bafang m600 which is 1100w peak and it was very close. How come instead of soldering the shunt inline with the others you connected the two traces?

@@Bengy22 the bosch gen4 is a very efficient motor . The shunt has 2 resistors in line towards the gate driver , with the resistors i put i limit the signal that the gate chip see's .

@@ebikeunlock But shouldn't the extra shunt be placed on top of the two already there facing the same direction? So it looks like this: III :not: I_I? I ask because I've shunt modded my bafang before an that's how it was done so I'm curious now

@@Bengy22 you can put an extra shunt to lower the voltage drop across it , or you can alter the signal after it , with normal resistors ( what i have done ) . Hope it make sense now , if not , please tell me and i will make a drawing :D

i have tried , it works also on gen2 , i will make a video about it also .

@@ebikeunlock Thank u for the quick response. Do u by any chance know which resistors u used on the Gen 2. Next monday I have to order some things from Farnell, it would be nice if I could add the right resistors for the gen 2 to this shipment. Kindly regards.

@@WimHgH i will try to find a board to make a picture to show you where to put them in 1-2 days :D , also tell you what resistor to order

@@ebikeunlock I Always tought the battery bms Was communicating the electrical consumption to the motor and then the motor checks if this is correct with the mount of Energy hè consumes. So I'm very surprised that u don't get an error with those shunt mods.

@@WimHgH i was thinking like that also , but as you can see is not the case :D

In the video is original wiring (~ 80cm cable ) but the voltage drop is big ... So new wires are recomanded .

@@ebikeunlock What are the original wires? To compensate the voltage sag you would need to increase wires size at about 30% however most likely the voltage sag comes from the cells, their internal impedance is quite high but sure enough for 15A applications. I have used MH1 5P for 30Amps and they dropped the voltage as well but not that dramatically but they heated quite much, I could easily reach 50+C at the end of the ride, considering the tight bosch battery pack it might be a serious problem.

Salut , ce eroare iti da motorul poate il pot repara , daca dai subscribe la about gaseati mail-ul sa putem vb mai usor .

Deja am dat subscribe dar n am observat emailul. O sa il iau si iti voi trimite maine daca am timp mai multe detalii, nu imi da eroare, e putin crapat si a stat afara un an si ceva…

Stiu ca mai sta radarul ... cu modificarea asta mergi cu 50 pe drum drept lejer , intradevar la vale poti prionde si fara motor 60 daca ai fizic pt asa ceva :D . Sunt mtb-uri pedelec-s cu bosch speed line ( 45 km/h ) dar sunt greu de gasit .

@@ebikeunlock pai cu 50 pe plat cred ca poti merge doar cu speedbox fara sa modifici placa electronica. Eu folosesc bicicleta in general in off road si numar pe dege situatiile in care am ramas fara asistenta pentru ca am depasit 25km/h.

Thanks , for gen 4 is hard to do throttle mode ... the torque sensor is magnetoresistive . But you can put a VESC on it :D

@@ebikeunlock hello friend ,will it be correct working torque sensor with VESC ?

@@luxfx1711 hi , the gen4 with vesc works good ~ 1.2 kw on 10s but the torque sensor can not be connected .. the circuit for the coils is on the oem pcb and is hard to replicate ....

work in every mode , each mode is a little stronger .

Battery will handle it , the wires have some drop on them if are long , controller is verry eazy to take out (after you dissasamble the motor , remove the screws from board and is out ), but this is not for every one .... the rezistors are 0603 , some people need magnifiing glass to see them .

@@ebikeunlock yes but handle and working ok without sag is not same… but ok short life battery .

@@Vedrinec394 the cells in a power pack are LG MG1 ( 10A discharge ) , 4 in parallel , so half of what they can deliver , yes sag will be there but from the stock 15a discharge to 20-21a (engine with mod ) no a big difference .

@@ebikeunlock 10 amps discharge on paper, Mj1 can handle 6 amps discharge , everything above will heat them and sag big

@@Vedrinec394 6x4 = 24 so still good :D , i understand your point but if you like ebikes you know that every watt matters , and you can sacrifice a little of live span of the battery for performance , if not ... don't modify it .

Tipla , am pus ei eu asa : vesc + 13s pe yamaha 1.2 - 1.5 kw , vesc + 10s pe bafang cam 1 kw , urmeaza vesc 75100 pe bosch gen2 si gen4 dar la min 16s :D vedem ce iese . Ai un film cu boschu la 13s?

@@ebikeunlock fac curand , are cuplu am rupt o zala deja ;)))

nu reusesc sa fac bine cred detectia ca de pe loc nu pleaca mereu mai ales cand schimb viteza pinionu dar cred că e de la rulmentul de sens când cuplează când nu trebuie sa dau de pedale înapoi ,

in the video was a 500wh power tube , now i have a 625wh one .

@@ebikeunlock Thanks for your answer. It would be nery interesting to me if you repeat the test to see how many amps you have now and how much is the voltage drop. We may see more amps and less Voltage drop because the 625Wh battery pack would produse less heat than the 500Wh batterry pack . It is 50 cells instead of 40 for the same job.

@@stratosaba cell inside will support up to 10a eatch , the wiring has more loss than the cells :D

the same resistances as the previous time soldered more cleanly, some problems with vibration of tightened battery connectors. before welding. the error occurs above 44km/h. before it’s crazy how it grows.

*errer 603

@@guillaumecamus8031 hi , check the wiring ( see the voltage drop) , if you can also the amp ( must not exceed 21-22a ) , if still got error must increase the mod resistors . Error 6xx is from the battery .

i have made a few GEN4 motors with this mod , no problem so far , i must find a smart system one to test , but i think it will work also .

@@ebikeunlock I’m tempted to give it a try on a Whyte 160s.

Yes , but you must change the shunt resistors because it doesn't have inline signal resistors ...

@@ebikeunlock Thank you. I will do some research into this and see what information i can find👍

@@ebikeunlock Current sense resistors are what i think i need to change?

@andrewwhite986 Yes , make a picture (or tell me the marking on them ) of the stock resistors, and i will give you info (part number ) of what you should put in and what gain to expect .

After a while is easy ;)

hi , it will work .

thank's !

error 603... after max torq. shutoff and reboot... i make bad soldering?

@@guillaumecamus8031 603 is battery related error ( check the battery connection ) if you have a diagnostic , check what is cause that ( the full error code ) . Also the resistor could be out of spec ( lower than 470 ohm ) , or you soldered bad ( shorted ) and now the motor will take more than 22 amp .

i will desoldering resistor next week. now, if i check torque bar on my trip, it cutting at 90% motor power and i will be carefull to don't exceed this point. it usable 😁. thank for your diagnostics.

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