Sabvaton Power switch & throttle

Joined
Oct 18, 2017
Messages
104
I went out for a ride yesterday on my e-moped that has a QS205, SVMC72150 & a 72v 70amp 18650 battery. Beautiful fall day here, leaves were rustling under my tires. Everything was going great, hitting 45mph, but was just on some back roads and cruising between 20-35mph mostly, and on and off the throttle. Then the throttle started to show voltage dropping super quickly, all the way down to nothing and powered the whole system down. I couldn't get it going. Luckily was with a friend who got his jeep and we took it home. This is the second throttle to have this same "plummeting voltage" symptom. As soon as i got a new throttle, it was fine the last time, I thought, maybe it was that throttle was junk. But now I know there is something else going on that is causing it. I do have a small 10 amp fuse between the battery + and the power key switch wire on the throttle.
Also, when I got off the bike after it stopped, the motor was cool, the controller was cold, the battery was slightly warm to the touch. The battery charged right back up to 84v.

This is the throttle im using https://www.aliexpress.com/item/DC-12V-24V-36V-48V-60V-72V-Electric-Scooter-Twist-Throttle-3-Wire-Speed-Control-Power/32822899317.html?src=google&albslr=226930569&src=google&albch=shopping&acnt=494-037-6276&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&ds_rl=1258652&albcp=1581905725&albag=59263823906&trgt=349615372042&crea=en32822899317&netw=g&device=c&gclid=EAIaIQobChMIqpiXiuCX3gIVjEoNCh14cQIgEAQYAiABEgJBqvD_BwE&gclsrc=aw.ds

This is the fuse between yellow key switch wire on throttle and connected to the B+. https://www.amazon.com/20mm-Glass-Holder-Inline-Screw/dp/B00L9RW5Y2/ref=asc_df_B00L9RW5Y2/?tag=hyprod-20&linkCode=df0&hvadid=198087646496&hvpos=1o19&hvnetw=g&hvrand=9143930672579770088&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9001923&hvtargid=pla-392464500949&psc=1

Can i use a separate switch for the SVMC? Can I get a more reliable throttle?? Any suggestions??
Any help??
 
Has anyone used a switch to turn on the SVMC controller other than the one on the chinese throttle? Any help is appreciated.
 
Sorry to hear your still having issues.

I got rid of the cheapy twist throttle I had and upgraded to an actual needle bearing twist throttle and used one of these spring return ebike adapters like shortcircuit911 has on his build.

shortcircuit911 said:
I received all the parts to convert the bike to a proper dirtbike throttle. I ordered a pitbike throttle kit off of amazon for $13 or so and then ordered a throttle adapter:

http://www.eastgem.net/throttle-adapter.html

I'm slowly assembling it on the bench then I'll install it on the bike. Still working out how I'll do this, but will likely cut the throttle connector off of my current throttle (special 3 pin connector that mates with sabvoton) and connect that to the adapter. This will be a much more robust solution when riding off road. I grew up on dirtbikes and often like to get silly, so chances are I'll drop this bike. If the bike lands on the throttle side I don't want it to break, and the stock one IMO would break immediately. I hope to get this integrated into the bike before the motor shows up, we'll see

Not sure what to tell you about the switch and diminishing voltage.

Personally, I use a marine grade 12v battery isolator on/off switch, then that switches a 72v 200a contactor and I use 4 gauge wire for all power leads.

Are you sure the battery pack isn't sagging past LVC?

Have you tried a wire nut? Hate to say it but since it's fused... maybe try to connect the power on wire to B+ with just a wire nut or twisted together and see if you still have the drop?

That cheap key switch's contacts may not be good enough for 72v without some sort of pre-charge resistor to keep the contacts from arcing and creating more resistance over time with each turn of the key.
 
2WheelsMovesTheSoul said:
Sorry to hear your still having issues.

I got rid of the cheapy twist throttle I had and upgraded to an actual needle bearing twist throttle and used one of these spring return ebike adapters like shortcircuit911 has on his build.

shortcircuit911 said:
I received all the parts to convert the bike to a proper dirtbike throttle. I ordered a pitbike throttle kit off of amazon for $13 or so and then ordered a throttle adapter:

http://www.eastgem.net/throttle-adapter.html

I'm slowly assembling it on the bench then I'll install it on the bike. Still working out how I'll do this, but will likely cut the throttle connector off of my current throttle (special 3 pin connector that mates with sabvoton) and connect that to the adapter. This will be a much more robust solution when riding off road. I grew up on dirtbikes and often like to get silly, so chances are I'll drop this bike. If the bike lands on the throttle side I don't want it to break, and the stock one IMO would break immediately. I hope to get this integrated into the bike before the motor shows up, we'll see

Not sure what to tell you about the switch and diminishing voltage.

Personally, I use a marine grade 12v battery isolator on/off switch, then that switches a 72v 200a contactor and I use 4 gauge wire for all power leads.

Are you sure the battery pack isn't sagging past LVC?

Have you tried a wire nut? Hate to say it but since it's fused... maybe try to connect the power on wire to B+ with just a wire nut or twisted together and see if you still have the drop?

That cheap key switch's contacts may not be good enough for 72v without some sort of pre-charge resistor to keep the contacts from arcing and creating more resistance over time with each turn of the key.

Thanks for some insights. If it were sagging past LVC, would it come right back on once it is charged back up? I charged the battery to full and turned the key switch with no response. Battery is registering 83.7 on the multimeter, on the charger and on a volt meter.

I am unfamiliar with the marine grade 12v battery isolator on/off switch but i will research how it potentially would work.
I was thinking about putting a separate key switch that powered the controller on, then using a simple 3 wire throttle and keeping an extra with me of each in the case one of those failed. something like this: https://smile.amazon.com/Wingsmoto-Ignition-Electrical-Scooter-Position/dp/B0118LT2U8/ref=sr_1_7?ie=UTF8&qid=1540315078&sr=8-7&keywords=key+power+switch

But wondered about the power needed or risks involved in using a simple switch like that.
You'd think these parts would all do together a lot easier than this. All the trouble I have had has taken the fun out of it. I love problem solving believe, I converted a gas 125cc to a fully electric bike, lots of customization and creativity, but these mystery issues are taxing to the brink. Thanks for the help.
 
changeissimple said:
Thanks for some insights. If it were sagging past LVC, would it come right back on once it is charged back up? Yes, however if the diminishing voltage is happening at a standstill with no load, the problem is else ware.

I charged the battery to full and turned the key switch with no response. Battery is registering 83.7 on the multimeter, on the charger and on a volt meter. So, after that ride when it turned itself off, you still haven't even got it to turn on again? I'd bypass the key (making sure its fused) and disconnect the B+ wire going to the LED voltage indicator. What happens?

I am unfamiliar with the marine grade 12v battery isolator on/off switch but i will research how it potentially would work. https://www.ebay.com/itm/300A-Batte...-Off-Kill-Switch-Boat-Cars-Vans-/192685745032 I use this just like a normal removable key. However, I have a small momentary switch next to it, connected to B+ and a 1k 10w resistor (came with Kelly KLS-7230S) that I push and hold for about 6 seconds. This allows a small amount of voltage to ramp up from 0v to 72v into the controller and the DC/DC converters to slowly/safely charge the caps. When the isolator is turned on it connects B+ to the controllers on switch, turns on the contactor and also turns on my 12v DC/DC Converters.

I was thinking about putting a separate key switch that powered the controller on, then using a simple 3 wire throttle and keeping an extra with me of each in the case one of those failed. It could work just as well, I'm almost certain the issue is with that particular throttle since it has a LED, key switch, and throttle. It's all wired with a common ground for the LED and halls, maybe something is causing some resistance. Try bypassing the key and disconnect that LED and tell us what happens with meter on the battery.

Thanks for the help. No prob
 
2WheelsMovesTheSoul said:
changeissimple said:
Thanks for some insights. If it were sagging past LVC, would it come right back on once it is charged back up? Yes, however if the diminishing voltage is happening at a standstill with no load, the problem is else ware.

Yes, voltage diminishes at a standstill. Now, i get nothing at all when hooked up properly.



I charged the battery to full and turned the key switch with no response. Battery is registering 83.7 on the multimeter, on the charger and on a volt meter. So, after that ride when it turned itself off, you still haven't even got it to turn on again? I'd bypass the key (making sure its fused) and disconnect the B+ wire going to the LED voltage indicator. What happens?

Nothing happens when I bypass key switch. I took a lead from the B+ wire and connected directly to the 72v lock and the controller did not turn on.

I am unfamiliar with the marine grade 12v battery isolator on/off switch but i will research how it potentially would work. https://www.ebay.com/itm/300A-Batte...-Off-Kill-Switch-Boat-Cars-Vans-/192685745032 I use this just like a normal removable key. However, I have a small momentary switch next to it, connected to B+ and a 1k 10w resistor (came with Kelly KLS-7230S) that I push and hold for about 6 seconds. This allows a small amount of voltage to ramp up from 0v to 72v into the controller and the DC/DC converters to slowly/safely charge the caps. When the isolator is turned on it connects B+ to the controllers on switch, turns on the contactor and also turns on my 12v DC/DC Converters.

I think I know what you mean, I used the precharge resistor to hook up the battery to the controller and it worked well. Held inline until voltage rose slowly. I can see how a momentary switch would make this easier. Right now, my main concern is identifying the problem. I am confused why this has happened with two throttles (both new) and two batteries and two controllers (KLS & SVMC) I would get this diminishing voltage when I turned the key on and it would drop from 78 down within 6-10 seconds to 5v then shut down. ONe time it dropped like that with no load over the course of two hours and held around 10v.

I was thinking about putting a separate key switch that powered the controller on, then using a simple 3 wire throttle and keeping an extra with me of each in the case one of those failed. It could work just as well, I'm almost certain the issue is with that particular throttle since it has a LED, key switch, and throttle. It's all wired with a common ground for the LED and halls, maybe something is causing some resistance. Try bypassing the key and disconnect that LED and tell us what happens with meter on the battery.

When i bypass LED and the Key switch wire (so yellow & blue on the 5 wire throttle) I took a line from the B+ to the 72v lock, with and without a 2amp fuse, nothing happens. The controller lights do not turn on, nothing. BUT when i place the multimeter on the B+&- of the controller I get a proper reading of 83v. I am baffled.

Thanks for the help. No prob Very appreciated. AND I need a lot more help!! AHHH.
 
changeissimple said:
Yes, voltage diminishes at a standstill. Now, i get nothing at all when hooked up properly.

So, after that ride when it turned itself off, you still haven't even got it to turn on again? I'd bypass the key (making sure its fused) and disconnect the B+ wire going to the LED voltage indicator. What happens? Nothing happens when I bypass key switch. I took a lead from the B+ wire and connected directly to the 72v lock and the controller did not turn on.

This is very strange... indeed.

Did you use a main fuse or breaker for the battery to controller connection?

Considering this is a true motorcycle conversion, by chance did you ground anything to the chassis like the stock wiring did?

Right now, my main concern is identifying the problem. I am confused why this has happened with two throttles (both new) and two batteries and two controllers (KLS & SVMC) I would get this diminishing voltage when I turned the key on and it would drop from 78 down within 6-10 seconds to 5v then shut down. One time it dropped like that with no load over the course of two hours and held around 10v. Welp. Back to absolute basics.

When i bypass LED and the Key switch wire (so yellow & blue on the 5 wire throttle) I took a line from the B+ to the 72v lock, with and without a 2amp fuse, nothing happens. The controller lights do not turn on, nothing. BUT when i place the multimeter on the B+&- of the controller I get a proper reading of 83v. I am baffled. Me too.

This sounds like circuit for the turn on wire is shot. If you can give it power and ground on the main wires and the turn on wire (controller hooked up to those 3 wires ONLY- no motor, no throttle no sensors, nothing else) and the controller is still not showing ON or lighting up the LEDs... that controller might be toast.
 
2WheelsMovesTheSoul said:
changeissimple said:
Yes, voltage diminishes at a standstill. Now, i get nothing at all when hooked up properly.

So, after that ride when it turned itself off, you still haven't even got it to turn on again? I'd bypass the key (making sure its fused) and disconnect the B+ wire going to the LED voltage indicator. What happens? Nothing happens when I bypass key switch. I took a lead from the B+ wire and connected directly to the 72v lock and the controller did not turn on.

This is very strange... indeed.

Did you use a main fuse or breaker for the battery to controller connection?

Considering this is a true motorcycle conversion, by chance did you ground anything to the chassis like the stock wiring did?

Right now, my main concern is identifying the problem. I am confused why this has happened with two throttles (both new) and two batteries and two controllers (KLS & SVMC) I would get this diminishing voltage when I turned the key on and it would drop from 78 down within 6-10 seconds to 5v then shut down. One time it dropped like that with no load over the course of two hours and held around 10v. Welp. Back to absolute basics.

When i bypass LED and the Key switch wire (so yellow & blue on the 5 wire throttle) I took a line from the B+ to the 72v lock, with and without a 2amp fuse, nothing happens. The controller lights do not turn on, nothing. BUT when i place the multimeter on the B+&- of the controller I get a proper reading of 83v. I am baffled. Me too.

This sounds like circuit for the turn on wire is shot. If you can give it power and ground on the main wires and the turn on wire (controller hooked up to those 3 wires ONLY- no motor, no throttle no sensors, nothing else) and the controller is still not showing ON or lighting up the LEDs... that controller might be toast.
I did not run that test (unhooking all wires aside from B+/- and the 72v lock wire to B+.) It is a brand new SVMC72150, less than 10 miles, set my amp limits to 70amps, and a 18650 battery with a BMS of 70amp max. I was running it for 3-5 miles when the whole system konked out. The controller wasn't even warm. Since it initially shut down it has turned on but did the voltage drop thing and then it turns off. But now it is not turning on but i did have phase, halls, brake and throttle connected. Super confused, super frustrated
 
Hi, sorry you're having issues with the sabvoton. Just to be sure, is the sabvoton throwing any errors?

I haven't heard you mention a tft screen, so I'm assuming you dont have one. Did you get the version with the tft screen?
If there's an error the LEDs on the sabvoton will blink. Is that going on?

I got the version with everything included (tft screen, on/off switch, and throttle) so it was plug and play.

Also, did you get the bluetooth version? The app also displays errors if you connect to the MQCON app.

The fact that you can't turn it on and see anything over 36v is troubling. Maybe pull all power let the caps drain and see if that resets the logic in the controller. Without being able to turn it on makes it hard to know if there's an error.

Maybe contact the vendor and see if there's anything they can do?

Keep us updated.
 
shortcircuit911 said:
Hi, sorry you're having issues with the sabvoton. Just to be sure, is the sabvoton throwing any errors?

I haven't heard you mention a tft screen, so I'm assuming you dont have one. Did you get the version with the tft screen?
If there's an error the LEDs on the sabvoton will blink. Is that going on?

I got the version with everything included (tft screen, on/off switch, and throttle) so it was plug and play.

Also, did you get the bluetooth version? The app also displays errors if you connect to the MQCON app.

The fact that you can't turn it on and see anything over 36v is troubling. Maybe pull all power let the caps drain and see if that resets the logic in the controller. Without being able to turn it on makes it hard to know if there's an error.

Maybe contact the vendor and see if there's anything they can do?

Keep us updated.

I didn't get the TFT but i had it hooked up to the Bluetooth app and there were no errors when I was running it. It always read "System Normal" and I had limited the amp draw to that of the BMS limit. But I haven't been able to get it to power on so I could check the app.
I am going to follow your advice and let the caps drain and see if I can get it to restart. Fingers crossed.
I am wondering if the BMS is messing with the system. I think I might do a bypass of the BMS for discharge and then reconnect the BMS for charging.
 
If you have no luck, open up the controller and look at the ignition wires and see if maybe one of the wires had a bad solder joint on the board or something. Worth a shot.
 
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