Cyc Photon Battery Recommendation
I recently picked up a Cyc Photon and now need to get a battery. The bike is for my wife and so we are looking for a fairly low power machine (I chose the cyc for its torque sensor, not its power); just enough to make pulling the kids in a trailer a little easier while still pedaling. I need a minimum of 20mi range.
I'd like to go with a reputable (ie not Chinese made) brand, and was looking at the Em3ev 36V (10S4P) Super Shark 35E 13.6AH. The 35E is rated for 20A continuous, 25A burst. At 36V, this would give me 720W continuous power (which is probably more than I need, I think 500W would be sufficient, but we do live in CO with some pretty steep hills). This is probably my top choice because I think it weights the least.
The other option would be the EM3ev 52V (14S4P) which comes with either 28A (High Power, 11AH, 40A continuous) or 35E (High Energy, 13.6AH, 20A continuous) cells. At 52V these would yield 2080W and 1040W, respectively. I'd be leaning towards the 35E in this case for the higher capacity.
My questions are:
(1) Is the power calculation just Ohm's law, multiplying the nominal voltage by the max current rating? Should I use a 0.8 derating factor? Is something else I need to consider (initial current in-rush for example)?
(2) Do I need to take the cyc photon's controller (builtin XP6) limits into account. I think it allows 50A, but it's hard to find the spec. The 28A cell option says for controllers up to 50, whereas the 35E says for controllers up to 25A. Looking at the controller manual, it looks like I can specify the max power, but not max current draw, but with a fixed voltage, I assume I should just set the max power to max_rated_current * nominal_voltage.
Please let me know your thoughts and any advice is much appreciated.
Posted Jul 22, 2023, 5:30 AM UTC
While the battery should have a max discharge over the max pull of the motor, the battery doesn't dictate how much power the motor will put out. Just because you get a 52v battery that can put out 40a, the photon won't pull 2kw. Also, the photon comes out of the box with 3 street and 3 race modes. Only the level 3 race mode goes to 1kw. The street modes have it all around 300-500w. It has different settings for PAS and throttle. Level 1 doesn't allow throttle. Level 2 street only allows something like. 250w. And it's all configurable.
So get the biggest battery you can, definitely 52v and at least 30a max current draw. I'd want at least 40a so the motor only pulls half of what the pack can put out, then just set the photon to run at whatever power level you want.
Thanks for the info. The only issue with trying to get a 40A battery is that it limits me to the 52V 28A cell which only has 11AH capacity. If I leave it on street mode (likely) I'd only be pulling 500/52=9.6A, so 40A which seems overkill.
It's definitely not. The photon has the ability to go into ludicrous mode. I often pull 1900 watts. That is pulling close to 40 amps
Yes, but you're probably not a balding, middle aged guy hauling two kids around. I have no interest in ludicrous mode. Our use cases are profoundly different.
Your missing the point. Just because it can go into ludicrous mode does not mean your going to go fast. It means you have additional torque and acceleration. The photon comes tuned down to appear to follow registrations. Accessing the increase mode is exactly what bennifits fat hair challenged dudes. You can't take advantage of the Xtra power if you cheep out of. Batteries
Your just wrong. My photon pulls 1900 watts. There is a unlocked setting. In that setting you still have race and street mode. The controller will handle 40 amps so be sure your battery can put out the same. 52v is the max the photon will handle.
Wasn't going to say anything until you started attacking the OP...
Let the OP use it how it's intended. Stop being a d!ck.
My apologies. My opening comment came out wrong. I understand why you called me out. But calling me a dick was inappropriate.
Now on to my comment. I did have a rather long conversation with both cyc and my supplier. The motor can operate in the extended power mode all day. That is why there is a temp monitoring system and a over heat throttle. Think about it for a min. If there was any harm being done to the motor using the mode day in and day out do you think cyc would make that available? They have to warrant the motor.
The base power settings are normal for acceptance in regulated areas. I personally don't under any circumstances exceed our local speed rules on our trails. The higher power mode is very useful for higher initial torque to climb better, faster, better gear range, even in extended power mode my bike will not go faster than 30mph. But the higher available torque and my peddle power allows me to accelerate in line with the car traffic I live in a community where there are very few side walks. I got stopped by our community police. Not for riding quickly. He asked about my bike. Was interested in purchasing one and he saw me accelerate quicker than most bikes he has tried out. During the conversation it was made clear that they have absolutely no interest in managing ebikes. He does go after surons. Don't think I spelled that right. Anyway I have to travel 3 miles to get to my local trail system. I have to do some on street riding. Keeping up with the traffic is a safety feature TO ME. In high power mode I seldom pull 1900 watts. Only during acceleration. I you push it for extended time the motor and controller starts to heat up. The reason cyc put the temp indicators on the screen is to monotor them. If you start to exceed cyc limit the controller will throttle down. What the op does is his choice. The op was asking about battery selection. If he chooses one that is not capable of sustaing the current draw that he might use in the future he is short changing him or her self. In three months they might want to take advantage of additional torque. I'm warning that if in the future if that mode is accesed and the battery and cables are under powered stress on the controller will occur. When designing my bike around the photon I was advised that no matter what Ah battery I choose make sure it's capable of close to 40amp output. My normal wattage range in high mode is between 40 watts and 350 watts, race mode once I get to speed. I ride my trails at approx 11mph. Once I get there I use my peddles. I have a brand new ankle and a bum knee. No way can I pull of a stop sign and be anyware compatible with traffic. I shift to 5th and use bot peddling and throttle. During the initial pull my wattage is around 1100. Once I get to my intended speed, in about 100 feet I decrease my consumption and settle in at around 100 to 150 watts. I set my peddle power curve to match my throttle curve. I absolutely love the software the photon has!! Very very rarely do I pull 1900 watts. But it's there.
You're right. I shouldn't have cursed. Apologies. Edited my comment.