Yessss, more updates please, i have been following this thread and read it multiple times as i plan on doing the same, dual carvons, and a big question mark on the battery set up.
Just when I thought everything was hunky dory, it stopped working.
I’m not really sure the best approach for debugging this issue but here are some details in case anyone has some tips.
I’ve only ridden this thing a few times. The last time I rode it, I got the battery down to around 12% and it started acting a little squirrelly. Not too bad. It just didn’t respond to the throttle for a few seconds.
I recharged the battery to 100%. Everything still seemed fine on the bench. It was responding fine to the controller. When I tried to ride it, it wasn’t responding under any load. It would start to respond but then die out. In fact I even tried letting it roll down a slight incline without any load on it and tested the brakes. The brakes didn’t work. A couple seconds later the brakes kinda started to work but not much.
I flipped the board over on it’s back, it responds just fine to the throttle and brake.
I’m not really sure where to start debugging this. I hooked it up to the BLDC tool. The motor detects just fine and I don’t get any faults in the realtime tab. But that’s all on the bench without any load on it.
I tried dropping down to a single motor to rule out the canbus connector. Still the same problem. Although 1 motor seems to respond a little better than the other under load.
I’m assuming it’s a problem with my VESCs. I have another pair of VESCs I can try that I’ve never used before but I need to do some soldering work to get them working with the 4mm bullets on the Carvons.
Anyway, my next steps will be to get my backup VESCs soldered up and test those out. I’ll keep searching the forum for similar issues.
I replaced the fuse on the battery pack and the board started working again!
I took it out for a ride to see if it was all good. The first 50 yards were great. I thought I was in the clear. Then it started cutting out on me. I guess I might also have a problem with the transmitter/receiver. A fresh set of batteries didn’t solve the problem so i’ll have to look into it some more tomorrow.
Blowing the fuse could’ve been from running it too hard on the single motor, causing it to pull more amps.
I’d just make sure your VESC settings are alligned so that combined they won’t pull more than your battery can handle- people had this problem with the first batch of space cells before fuses became a standard feature.
I definitely need to double check my VESC settings to make sure they’re set properly.
I forgot to mention about the old fuse. It didn’t actually blow the fuse. When I inspected it, the fuse wasn’t seated properly. I think it was just jostled loose. I pushed it back in and it worked. I only replaced the fuse because I had another one on hand that fit more snugly than the old one.
First I made sure all connections were tight (especially the receiver). This didn’t fix the issue. It was still cutting out a bit.
Then I connected the board to my computer & the BLDC tool and I checked the realtime tab while I rode it around a couple hundred meters. It cut out a few times during the test but I didn’t see any faults in the realtime tab or the terminal.
Next, I reconfigured the FOC tab and wrote the new configuration to the VESC. It started acting a little better. This might have just been a coincidence.
Anyway, I still suspect the receiver or servo wires. I also need to verify I’ve setup my BLDC settings properly.
Max input is set to 57.00V. Not sure why I set it that high. I believe this should be 50.4V. That’s the first change I’ll make.
I tried dropping the max input voltage down to 50.4 and I started getting over_current faults
Fault : FAULT_CODE_OVER_VOLTAGE
Current : -13.6
Current filtered : -12.3
Voltage : 50.07
Duty : 0.45
RPM : 27608.3
Tacho : 47344
Cycles running : 270
TIM duty : 3782
TIM val samp : 5
TIM current samp : 8398
TIM top : 8400
Comm step : 3
Temperature : 29.33
I was still getting over_current faults with max input 51V and 52V. I guess I’ll stick with my original 57V for now. I’ll have to read more about the max input setting. Next step is to investigate that servo wire and the receiver.
DSomeone please correct me if I’m wrong but u will only have more power with 12s when u are going over what the max speed of the 10s would be. Only then will u realize moe power. If u aren’t up to that speed u will be more inefficient than u were on 10s and more heat in the motor. The only benefit to 12s is keeping ur battery wires cool and possibly the vesc, not drawing quite as many amps from the battery (the voltae gets converted to amps for the motor) and you et a higher top speed. you will have the same amps put into the motor with 12s or 10s…In fact ull need a tiny bit more amperage with the 12s, to the motor, compared to 10s. But if ur vesc is getting hot be better to move to 12s. With those motors being so high kv, as been said, you would be better served in a way running 4s 5s or 6s…as long as the vescs can take it. I
Riding so far from the no-load max rpm …is not efficient period. maybe do a 6s vs 12s comparison. Ur amps to the motor limit …no from battery…can stay the same …but the amp limit from the battery ud maybe have to increase on 6s
I read on the voltsge limit st u tripped there ar spikes going both ways and that’s why we’re limited to 50v when the components are specked to higher
Well, it’s my first build and I’m not yet familiar with the calculations or physics related to batteries. However, it looks like you and @Namasaki gathered some interesting data here:
I already have a PRO4 on order. I was just starting to think about how I might be able to compare the two. I remember seeing a vedder overlay with his bldc-logging code. Not sure what the state is of that project though. Then I was thinking about adding an amp meter. In your post it looks like you guys put an inline or clamp amp meter to monitor the amp draw. Does that keep a log of the usage or are you literally just looking down at the amp meter while you’re blazing around town?
My testing with the clamp amp meter not the 3 phase motor wires was a bench test.
The testing I did while riding was done with the inline meter on the battery side of the Esc’s
Nope, holding off on that…doesn’t seem like the benefits outweigh the potential risks at this point. Some people are running it without problems though so I am not really sure if there’s an issue with settings for some people or what. BLDC is working just fine for me. I am going to need some threaded insets in the board though, had a screw come loose after a couple hours of riding today and it doesn’t want to stay back in now.
As far as over heating, my motors got pretty hot today, vesc’s were putting a bit of heat to the wood enclosure but nothing crazy. Everything worked out fine, and that’s pulling buddy’s uphill at full throttle and maintaining pretty slow speeds at times which definitely seems to put more strain on the motors. Enclosure is air tight and doesn’t seem to be getting the components too hot.
You get more power with more voltage which appears as more torque and quicker acceleration at all speeds.
And of course, you also get higher top speed.
The difference is huge when comparing 12s to 6s but comparing 12s to 10s the difference is likely to be less pronounced.
The Esc,(which acts as a voltage regulator) delivers voltage to the motors: more throttle=more voltage. The current that the motor draws from the Esc stays constant until you put load on the motor. more load=more current. However the higher the voltage, the less current the motor draws for a given load.
Voltage is the difference in charge between two points.
Current is the rate at which charge is flowing.
Resistance is a material’s tendency to resist the flow of charge (current).
Voltage is not converted to amperage. they are 2 different measurements.
The difference between riding 6s vs 12s if the kv is adjusted to match…should be no difference. U can get just as much power with the same motor running either on the different voltages if the kv is adjusted to match. From vedder’s site after asking what voltage does in a motor it doesn’t matter the battery voltage the amp limit “to the motor” is what decides the power. Volts convert to amps going to the motor. The amps decide what the motor can do
