overclocking 1000W 48v direct hub on 24S?

Building a new bike and aiming to use a 1000W direct drive rear hub motor with a 26" rim and 12x 4110 LYEN controller, along with a 24S lithium polymer battery. The intial configuration will probably be 4x turnigy 20C 6S 5Ah in series, unless that is inadequate or I will run into issues having packs in series. If everything works well, the battery capacity will be expanded to give the bike a reasonable range of 25+ miles in reasonable conditions at lower speed.

How much power will I be able to run into your typical 1000W 48V motor using the above controller and battery AND a liquid cooling solution for the hub, if that's possible. I've heard 5KW burst is possible without augmented cooling, and with lower voltages than 88+ V. Also, is there more capable rear hub I can use than a 1000W 48V from the bay? My goal with the build is to take this bike on the local mountain bike trails, and ride them without human power.

One word..Cromotor

Will I have issues running the lipos in series for my battery? How do I get all of them charging without using several chargers?

The only way would be bulk charging, which can be dangerous.

I'm not sure there exists a 24S charger or BMS?

The 1000W yescom/GM pro901 motors are said to take 2Kw for riding if you're careful with them. You can pour in 5Kw peak but only very briefly.

Also, absolutely no way you're going 25 miles on a 400Wh battery unless you're happy to do 20mph and pedal a lot. Think more like 10 miles at 30mph.

You're very likely going to need more motor and more battery...

You need to double your phase wires. They won't handle +80A phase current.
On 24s, you are looking at poor efficiency at speed under 30mph.

I'm strongly considering the hubzilla v2 now. Waiting on Lyen to get back to me about which controller would be right. Don't want to be left wishing for more power with a wimpy motor.

24S LiPo at 4.10V per cell would be 98.4V when fully charged.

The generic DD hubs on ebay are 9C clones with a 28mm wide stator (a rough measure of copper fill). It is the amps that make most of the heat, so start with the highest volts that will fit your budget and frame, then use a temp sensor to creep up on the max possible amps that your user-profile likes. I recommend 93C/200F as a safe internal temp limit that will allow your motor to last years.

Here are two builds that are similar to what you describe, both the Crystalyte HT35XX, which has a 35mm wide stator (Cromotor is 50mm wide):

http://www.electricbike.com/big-hit-fsr/

Crystalyte HT3525 rear hubmotor
12 gauge spokes
12-FET controller, with a 3-speed switch (limited to 50A/5,000W = 6.6 Horse Power)
CA-DP, CycleAnalyst-Direct Plugin
Magura throttle
24S-2P / 10-Ah LiPo (86V-100V, 3.6V-4.15V per cell)

Click to expand...

http://www.electricbike.com/custom-build-gallery-nicks-etownie/

...Lyen’s 12-FET controller is now set at 60A battery current, and 135A phase, for driving the HT3525 [on flat land]...Now, I’m hitting 42-MPH on 24S (24 X 4.10V per cell = 98.4V), and…nothing is getting too hot. The temp gauge in the motor never shows more than 80C (176F), and that is with bursts of 5500W (55A)...

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Fortunately that kind of motor is pretty cheap, and melting them is kinda fun. Particularly on a steep mountain trail, you can cook them off nice and fast.

But if you were to lower the voltage to 48v, and limit amps to about 30-40, you could get a little farther before the meltdown. 1500w, 2000w, is about the max these motors can take. On flat street, they can push 3000w for about 10 miles of fun.

Learn to walk before you run, get some 6s packs, and learn to manage them in 12s. Then it's pretty easy to just do it twice for 24s. When you get a much stronger motor that is.

I run 24s on my 1000W GM901 motor (same as the Yescom motor) with the Lyen 12fet 4110 controller programmed to 45 battery amps and 100 phase amps. I am thinking about lowering the phase amps a bit, though, since the throttle is twitchier than I would like when cruising in the mid-upper 30s.

With that setup, I often see over 4kW. The thing is, most of my rides are 1.5 - 2 miles per leg on pretty flat road. So I feel ok with a hard burn for such a short period. After a quick run to the store and back pushing hard, the motor and controller feel quite toasty. Not uncomfortably hot, but I could see it getting there with a few more miles.

I know that Wes runs the same setup so he might have more input on how they do over longer trips. I would guess that if you were aiming for running 24s over 25 miles, you would want to follow the advice of the others and get a stouter motor or keep it under 2kW.

*** update ***
I just noticed that you said you planned on riding mountain bike trails. Trigger has one of these motors on his EVG bike that he takes on the trails and he said it works well for him, but I would think a beefier motor with a slower wind would work our better in that case. The Yescom/GM901/eBay clone motor is a pretty fast wind, something like 470 rpm? I would think it would heat up like a mofo on the trails.

I run 18s on a GM 901, with a Lyen 18 FET low RDS. Works pretty well, as long as I don't run it past 4000W often or long. For your stated purposes, a Cromotor or a similar one is the way for you to go.

I don't do mountain riding with mine. I'm 270 lbs and I have ridden up some short 20% grades without a problem at 30mph. Now if I were only 150 lbs, I'd think I could ride mountain trails pretty good with it. I've made a few 10 miles runs at 30-35mph up and on some hilly roads without a problem.

For sure, the cheapest 28mm magent dd motors of the 9c, yes, etc type can take some serious abuse for a short enough hill, short enough race, or a quick dash down a 45 mph street to the next street where you slow down to ride "normal"

I'm not sure how much I ever shoved in, because above 100v I had no wattmeter to measure it anymore. At a theoretical 5000w, I melted a motor really good in about 7 miles of race riding.

For serious trail riding, you will need either the larger motor approach, or the slower winding approach. My trail bike has a crazy slow winding, and bogs down on 20 degrees, which is something like 35% or thereabouts. But if I am riding above 15% grades, I will still need to keep my speed above 12-15 mph even with the slow winding. Untill I got my health ruined, and had to stop riding agressively, I was melting at least the halls of a 28mm magnet motor every year. I was running 3000w only in winter, because in my hot climate, trail riding with 3000w would melt my motor too quick. With the faster winding, I can kill a motor in 15 min easy. Even the crazy slow motor can be murdered in 45 min. Now I rarely go to the mountains, and ride a flat trail near my house with only 1200w.

The catch 22 is, here in the rockiest part of the rocky mountains, hanging on at 15 mph riding up a pile of softball size rocks gets hard. Also, about 20% you start having some issues with just wheelie-ing off the bike if you have much power. Other places, people have trails they can ride up at 20-30 mph. For them, the big motor works great.

But go ahead and start with one of these cheap motors, and try 12s, then 18s, then 24s. Find out about torque arms, and how beefy they need to be to have the motor stay on the bike long enough to melt one. Then go melt one. It's fun. After that, you will have the personal experience to decide whether you want to try a big motor, a chain drive, or a slower motor for the trails. .

I often write too much, and lose clarity.

Build and enjoy a 24s battery with one of these entry level motors. Just don't expect stellar trail performance. I have bikes for street, and bikes for trail. It's difficult to get top performance in both from one bike.

So think in terms of learning about ebikes in the street version, then go for it for a real trail bike. The cheap motor will ride easy trails, those you can ride at 15-20 mph without crashing. 10% grades for longer hills won't be much of a problem.

With the battery, take some baby steps at first. Figure out which approach you want, bms, no bms etc. Figure out where you can store and charge the RC batteries. They will burn your house down if you are careless with them.

If you want to climb mountains, you need a mid drive that can leverage your bike gears and you will be able to climb it on 1 wheel with only 2000 watts and lots less money. You need the absolute best and most expensive hub motor there is to survive those conditions. They are just not meant for high tork low rpm applications. Especially not those 1000 w 48v ebay motors.

Wishes

If uphill sections are only a few seconds in duration and I can get a running start for any severe grades of 20% - 30% will a hubzilla v2 be up to the task? What equipment do I need to attach a mid drive, and what is a popular mid drive motor with similar output to the hubzilla?

i use a 24S lipo D131 BMS from bestechpower. good for 80A continuous and 200 surge.

pchen92 said:

On 24s, you are looking at poor efficiency at speed under 30mph.

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What do mean about
So if I have a 48V installation I will have a much better efficiency than the 24s at the same low cruising speed
Below 30mph better is 48V and above better efficiency is 24s Am I correct

MixhaL said:

pchen92 said:

On 24s, you are looking at poor efficiency at speed under 30mph.

Click to expand...

What do mean about
So if I have a 48V installation I will have a much better efficiency than the 24s at the same low cruising speed
Below 30mph better is 48V and above better efficiency is 24s Am I correct

Click to expand...

The motor is most efficient at 72 volts. Anything above that and the benefits are minimal and there is a lot of wasted energy.. They become highly inefficient when you have 100v and are riding under 30km, even more wasted energy.

The motors are best at 72v and around 40amps. Anything more than that you enter inefficiency zones. It doesn't mean they won't run and it doesn't mean they won't last at those power levels. They are just not efficient on batteries. But most people running 24s, don't do it for the long distance haul lol.

Do let that stop you, many people run 24s at 40 amps. I did for a while, then switched back to my 72 Lyen controller. My 30s Lync controller is sitting on a shelf waiting for he next test run.