combo platter

[evglobal19]

First my apologies for the question but the more I read the more confused I become:
with voltage options from 36 to 48 to 72 ( I know there are more)
and wattage from 350W to 5kw (I know there are more
the question become how to mix and match. I've seen 3000W and 5000W saying it "can " run at 48V, 2500W starting at 48V, 2000W at 60V, 3000W at 60V and the list goes on. I have a 48V23.4aH battery by Unit Pack Power from Aliexpress. it states 13S9P 30 amp cont and 70amp max. and 30A BMS. . Can I take the battery and find a 48V3000W wheel?

how would a 1500W at 48V be different from a 2500W at 48V.
what about 2000W at 36V

just don't know how to mix and match.

 

[evglobal19]

maybe better way to ask is with that battery what can it properly run for a motor wattage at 48V?

 

[pwd]

Keep reading until you do understand. It sounds like the key thing you are missing is current. Voltage X Current (Amperes) = Power (Watts)

Here is a good article on motor power ratings etc..:
https://www.ebikes.ca/learn/power-ratings.html

 

[E-HP]

I have a 48V23.4aH battery by Unit Pack Power from Aliexpress. it states 13S9P 30 amp cont and 70amp max. and 30A BMS. . Can I take the battery and find a 48V3000W wheel?

how would a 1500W at 48V be different from a 2500W at 48V.
what about 2000W at 36V

just don't know how to mix and match.

48V x 30A = 1440 watts that you can draw from the battery continuously, or 3360 in bursts, although the BMS may shut it down before that. For example, I have a 52V 20 aH battery rated at 30 amps, but the motor will pull 2000 watts on a steep grade without the BMS shutting it down, but not good for the battery to do that continuously. You should try to get a motor that will handle the continuous 1440 watts, but if you're not always drawing that much, you can runs something closer to what you will use continuously. My motor is 1000w rated, and I have no issues, even though my battery and controller support 1560 watts continuous.

 

[Drunkskunk]

Your battery, with a continuous rating of 30 amps and a 30 amp BMS means you are are best matched to a 1500 watt or smaller motor kit.
Wattage is figured by Volts times Amps. 48V x 30A = 1440 watts. So No, it wouldn't be a good idea to use your battery with a 3000w wheel kit.

Understanding how all this fits together can be confusing. So lets explain it with a bucket.
Voltage is how tall the bucket is. Amperage is how wide the bucket is. Wattage is how much water fits in the bucket.
A tall skinny bucket can be made that holds the same amount of water as a short wide bucket. Meaning the voltage and amperage are both different, but the wattage is the same. Say you have a bucket 72 volts high, and 20 amps wide. it holds 1440 watts.
And say you also have a second bucket 36 volts high, and 40 amps wide, it also holds 1440 watts.

If those 2 buckets were batteries, they would hold the same amount of total energy.
If those 2 buckets were motors, they would have the same amount of strength.


When motor kits are listed as as "48v 2500w", or what ever, it's less about the motor's capabilities, and more about the rating of the controller. that motor would be rated for 48 volts and a peak output of 2500 watts. So if you had a 36 volt battery with a 20 amp BMS, you would know that you didn't have enough voltage to run it, and because 36V x 20A = 720W, you would know the battery couldn't handle the amperage output.

When a motor is listed with just the wattage, and no voltage, it's usually a bare motor without the controller. the wattage given is often the nominal power rating, though sometimes it's the peak power rating. There isn't a standard here, though most reputable vendors will list the motor by it's nominal power rating, meaning it's peak power is much higher.

 

[dogman dan]

What can be confusing, is the way kits, motors, and controllers sell by wattage. Some vendors pretty much say whatever will sell, and send you something.

A very good choice for you would be a controller with 48v, and 30 amps max wattage. Some won't say what the amps are, but in the cheaper controllers its not hard to take a flyer on one. Often they will call a 30 amps controller 800w, or 1000w. Not sure why, but the 800w number is what the controller can take with hardly any heating up, and last infinitely.

As for the motor, for 1500w or less, you don't need a huge motor. The motors typical in 1000w kits ( which do typically have 30 amps controllers) are 500w rated motors. they go 1500w with little problem. So you don't need to buy a 3000w rated motor at all. All you need is a typical 48v 1000w kit.


If you want more, your battery is very unlikely to handle more than 30 amps for long. To pull 3000w continuous you need a much higher quality cell than is typical from ali express packs that cost 400 bucks or so. If you put a 40 amps controller (2000w, 48v x 40 amps) it will quickly kill your battery by overheating it. In fact, you might find that 30 amps continuous overheats your battery. But 30 mph takes only about 20 amps, so you should be able to cruise 25 mph fine.

 

[evglobal19]

Okay, I'm starting to feel like I understand a little more. next question is, 3000W, 4000W, 5000W, 8000W..... If I'm going to limit myself to 72V and they can all run at 72V what would one actually gain by going up the ladder to 4kw or 6kw etc.. On the QS site I see that they recommend limiting at 100km/h at 72v so more watts on the hub must be good for something?

 

[www.recumbents.com]

You have a 48V battery so you should get a 48V controller and motor to match.

 

[markz]

dogman dan said all there is to say about wattage and sellers.
Sellers will sell the same motor stated as 250W to gleam sales from the UK crowd, and the same motor states as 500W to gleam sales from the Kiwi crowd, even go so far as to state 1000W on the same 250W. Some sellers will do whatever it takes to grab your cash. Dont matter to them if they state you can go 100 miles on that small 5Ah battery. Be lucky if you get 10 miles, but going downhill for 90 miles is just a little white lie.

Go for a trusted motor, like the Leaf 1500W if you want that kind of power.

 

[flat tire]

You've made things more complicated than they need to be and confused yourself. Figure out what you want your bike to do. Figure out what the bike needs to do it. Find some components. Can they support that power level for the duration you need? If yes good. If not no good. There is an enormous amount of valid combinations for a given spec.

 

[evglobal19]

I completely agree that I've made myself confused and over thinking all this. The 48V 1500W EV Global is all set and matched. Like "some" of us, now that this one is done thinking already about the next. I picked up a 1980 Sachs Prima G3 with a non working 50cc motor. stripped it down to the frame and thinking about the 'next' project. Perhaps that was misdirecting my questions about a "bigger" combination.

Between me and the frame as is it's about 230lbs. I'd like the 'ability' to reach 60mph/100km/h but probably wouldn't. I wouldn't want to go higher than 72V because of battery cost so if lower voltage works all the better. it would be for street use (virtually) no hill climbing and range would be great at about 20-25 miles. Two companies I've looked at are NB Power and QS which I know folks seem to prefer. the information is what they describe so cant vouch for the validity:

NB Power has both a 3kw and a 5kw kit at 72V.
the 3kw comes with an 80A sine wave programmable controller throttle, display, brakes etc. all under $400.

The 5kw kit has a 100A 3 phase programmable controller, etc.
Kv: 3T @ 12.5 kv and 4T at 9kv (whatever that means)
peak phase current 300A
max Torque 190nm
$500


QS 205 3kw V3 72V
SVMC 72150 controller display throttle disc etc.
basically $1,000

QS 273 4kw V33
SVMC 72200
basically $1,300

is it honestly worth almost triple?

 

[flat tire]

Don't go too fast with a lot of weight and only bicycle brakes. The bike won't stop well over 30 mph and your brakes may temporarily overheat and give out in an emergency stop.

Since you just want versatility and not hot rodding I would go with the $500 5kw kit.

With the right controller and battery either a QS205 or QS273 can easily go way faster than you would want, as in effortless power wheelies up to 40+ mph even at your weight. If that sounds fun consider getting a more expensive setup.

 

[evglobal19]

are you saying that the 5kw NB Power would do wheelies or if I wanted more power on tap go with the QS?

 

[evglobal19]

ok, QS it is then. cleaning up the donor frame now and will need to construct framing to mount the battery. Cleaning and refurbishing I understand, electronics, not so much... seems like the tab is going to be closer to $3k USD than not. For $5k I can find a used Zero S ready to go, but, it wouldn't be as 'stealthy' to buzz around on as a modded 50cc moped. thanks for all the suggestions and comments.