teslanv said:
Just got an email from Kathy.
Model SSC096150 can take 150A battery and output up to 300A to the phases. Overvolts to 120V. That sounds perfect for 24S LiPo.
I saw the working specs as 120A battery, 96V and 250A phase at one point. The settings in my 72V controller allow me to set the voltage to 98Vish 150A battery (I wonder if it will let me go higher on this one) and 450A phase, but I am not going any higher than 350A phase, that's asking too much from 4 parallel TO-220 MOSFETs.
I use to be a big advocate of high voltage for high speed, but that was before we had affordable sine wave based controllers. I ran 30S (125V) LiPo for a long time but I no longer see the need for it with ebikes. The main reason people went with 24S was because it let them get to 35-45mph in a 26" setup. The main reason I went to higher voltage in the past was I wanted the motor to be able to take higher currents.
I'm going to simplify this a little. The following is talking about battery current.
At 50V, the motor might only be able to take 80A of battery current from the pack, but if you up the voltage to 75V, now it can take 150A of battery current. Move up again to 100V and now it can pull 200A from the battery pack, so of course at 125A it can take even more current if allowed. How much current it can pull from the battery is determined by the phase current limit and the motor saturation. You can easily generate 300A of phase current from a 25V pack. It will have good initial acceleration but then fall off quickly.
With that said, I don't know where the limits are on something like a Cromotor. I've tried a 50, 75 and 100V pack on a 200phase amp (200A battery) controller I built. At 200A phase the only difference I noticed on my Cromotor setup in a 16" moped tire was top speed. I need to test it at 50-75-100V and +300A phase current and I have not had the chance to do so yet.
I'll try to test out 100V and probably 125V once I get a controller capable of higher phase amps (aka finish building my 18 FET TO-247 controller that's been sitting on my bench for too long). I've been spending the last few months of free time studying theory and learning DSP programming for some controller/inverter projects I'm working on with someone else who is counting on me to do my part.
One argument I would make for 24S on a controller like this is if one is using a slow wind motor or using a small tire diameter <22". I'd toss this controller on my suicide bike at 125V and do an 80mph video if they sketchy bike didn't fall apart (feels so so at 60mph, definitely not "safe" or "confidence inspiring). Thing is once I did the video I'd probably never go that fast again.
I strongly believe it's more effective to drop to 85V max for most "ebike" use, 24S isn't needed like it use to be.
I'm old now
Still a hot rodder at heart, but I've got been there done that syndrome. My daily driver is 3100lbs, 750HP and it doesn't feel fast any more. Even my 3640lb 900HP car stopped feeling fast. When I let people test out my ebikes most of them are freaked out by the power and I have them turned down to 7-10kw, not the 15-18kw I sometimes use (for fun and testing).
BTW, you don't want to see a KFF with a 125V pack. A 200A fuse going off on a 125V pack is about as loud as a 9mm hand gun and literally explodes. At +100v you don't even want to touch the leads, it can easily be lethal. We often toss around the idea of running a 100V pack like it's nothing. It can be done, but you must be safety conscious and know what you are doing. There are a lot of noobs just starting off and they are trying to dive into 100V setups with no electrical experience. I'll sell a product if there is a demand for it, but I want people to understand the safety and risks they are taking.
When I started selling high power parts it was to mostly technical experienced people pushing the limits. Now I'm selling to guys fairly new to this hobby so I feel some responsibility to try and educate as well. Caveat Emptor.