Do i really need a pre-charge resistor line for my kelly controller?

brumbrum

brumbrum

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Due to bike and battery box design i am having trouble finding a place for the pre-charge resistor placement for a new kelly controller.. KBS72181e ( square wave brushless).
I never used one on my lyen controllers, do i really need one on a kelly?
Anyone using a kelly without one?

Thanks
Andrew
 
Can i use a pre-charge line by bypassing the circuit breaker like in this diagram?

bdlifl.jpg
 
I dont use them on my controllers and nothing has died or broke on me, but it is a good idea for longevity sake to do so id imagine. That pre charge spot will work as long as the circuit breaker is off upon battery connection.
 
skeetab5780 said:
I dont use them on my controllers and nothing has died or broke on me, but it is a good idea for longevity sake to do so id imagine. That pre charge spot will work as long as the circuit breaker is off upon battery connection.
Click to expand...

Thanks, I just needed a second opinion. Yes the idea being that the circuit breaker be switched off when the battery is plugged in.
 
put the resistor across the breaker. simple.

and DO use it if you have a high amps battery, you will blow the arse out of the caps and the board if you dont.
 
I believe the purpose of the pre-charge resistor is to protect the components and connectors used for switching the battery power to the controller from the high, but brief, inrush current caused by the controller's capacitors charging up.. As an example: to eliminate the nasty spark when using an XT90 connector only to provide power...which is why they came up with the a spark resistant -S (with the green exterior markings) model that has the pre-charge resistor internal to the connector. In the OP's case it would be to protect the circuit breaker contact points. Or in the case of the Kelly installation manual, protection of the main contactor contacts from arcing damage.

Regards,
T.C.
 
the precharge resistor is exactly as it's name implies: it pre-charges. in this case the capacitors.

having really good caps with very low ESR (and a lot of them) combined with a power supply (battery) that can deliver short currents well into the thousands of amps you get basically a dead short when the caps are charging. this will blow the are out of the caps, the pcb they are mounted to and probably a couple of other things. if the caps are charged in a controlled manner like with a 1K resistor you dont have that problem because the caps are already charged.
 
And while you're at it, see "Appendix D. Adding a CA-DP Connector to a Generic Controller" of the CA v3 [strike]Un[/strike]Offical Guide to see how to hook up those 'unused' CA wires to your controller so all the standard CA speed and limiting functions work normally even though your controller has no CA-DP plug (e.g. LVC, speed, current limiting). Of course in the illustration there you will be plugging the throttle into the controller and using a CA V2.

If you already have a wheel sensor on your CA2, then you already have a speed signal. However, you have the option of converting the CA-DPS to a CA-DP by following the instructions in "Appendix B. Add/Remove Wheel Speed Pickup Sensor" of the Guide. This would ditch the wheel pickup and allow you to instead drive the yellow SPD wire hookup from the motor/controller as described above.

This stuff will work with any CA V2.3 or CA 2.4 (or 2.23 after PCB rev12). The 2.4 actually is just a stripped down V3 so the pictures of the wiring and PCB pads are the same for the CA_DP to CA-DPS conversion. The PCB is a little different for the pre-V2.4 versions - see the matching manual.
 
I'm pretty sure he knows what a pre-charge resistor is. He is just asking if its necessary. I think if your building a daily driver then yes you should probably use it, it also voids the warranty with Kelly I think if you do not. But I have four Kelly controllers now one of them being over two years old and connect it without a pre-charge resistor daily and it sparks obviously pretty nicely and cooks connectors a bit...but it still works perfectly fine still to this day
 
Thanks guys. As said, i only want to protect the caps and board and dont really give a hoot about sparks chipping away at connectors.
One last question. I take it that its ok to keep the precharge line connected permanently? For instance, When battery amps are pulled by the motor/controller will the current just flow directly through the easiest passage i.e the thick main cable and not the auxillary cable with the resistor? Or should i just connect and then disconnect it before flicking the main breaker switch on? I suppose that if the breaker did ever kick in then the current would have to go through the resistor line,,, so actually , would it be a bad idea?
 
teklektik said:
And while you're at it, see "Appendix D. Adding a CA-DP Connector to a Generic Controller" of the CA v3 [strike]Un[/strike]Offical Guide to see how to hook up those 'unused' CA wires to your controller so all the standard CA speed and limiting functions work normally even though your controller has no CA-DP plug (e.g. LVC, speed, current limiting). Of course in the illustration there you will be plugging the throttle into the controller and using a CA V2.

If you already have a wheel sensor on your CA2, then you already have a speed signal. However, you have the option of converting the CA-DPS to a CA-DP by following the instructions in "Appendix B. Add/Remove Wheel Speed Pickup Sensor" of the Guide. This would ditch the wheel pickup and allow you to instead drive the yellow SPD wire hookup from the motor/controller as described above.

This stuff will work with any CA V2.3 or CA 2.4 (or 2.23 after PCB rev12). The 2.4 actually is just a stripped down V3 so the pictures of the wiring and PCB pads are the same for the CA_DP to CA-DPS conversion. The PCB is a little different for the pre-V2.4 versions - see the matching manual.
Click to expand...

Great! A big thumbs up, and thanks for all the CA work you do. So just add the yellow wire coming directly from the CA to a hall signal wire?
 
brumbrum said:
So just add the yellow wire coming directly from the CA to a hall signal wire?
Click to expand...
Yep. Then just configure the number of poles in the speedometer settings and you are good to go.

The funky 1K resistor thingie in the throttle wire allows the CA V2 to override the operator throttle so it can do limiting. This is essentially the wiring spec that Grin gives to controller manufacturres to 'build in' a CA-DP cable. There are ways to add a CA-DP cable by opening the controller and soldering stuff, but the external shunt plus the green and yellow wire mods shown in the Guide are exactly equivalent and work with any controller - no fuss and pretty doable by the novice DIYer.

Good luck with your build!
 
teklektik said:
brumbrum said:
So just add the yellow wire coming directly from the CA to a hall signal wire?
Click to expand...
Yep. Then just configure the number of poles in the speedometer settings and you are good to go.

The funky 1K resistor thingie in the throttle wire allows the CA V2 to override the operator throttle so it can do limiting. This is essentially the wiring spec that Grin gives to controller manufacturres to 'build in' a CA-DP cable. There are ways to add a CA-DP cable by opening the controller and soldering stuff, but the external shunt plus the green and yellow wire mods shown in the Guide are exactly equivalent and work with any controller - no fuss and pretty doable by the novice DIYer.

Good luck with your build!
Click to expand...

Hmmm, maybe i will also attach the green throttle wire with resistor to the controller throttle signal too. :D
 
I chucked a momentary ON switch in series with my pre-charge R. That way it doesn't end up as a firestarter if the circuit breaker flips under load. Press and flip the CB then release.
 
kdog said:
I chucked a momentary ON switch in series with my pre-charge R. That way it doesn't end up as a firestarter if the circuit breaker flips under load. Press and flip the CB then release.
Click to expand...
Cool, thanks
 
I've had two kellys that functioned before charging and were dead after, only thing that happened between that was the charging and spark when doing the connection between charger and battery

I think the precharge resistor might be needed even towards the charger if controller and battery is always in this circuit.

These occasions were in three years of charging daily so about 1/500 risk in this case.
 
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