Qs 3000w hub best build

[talgar]

Hi im new
Have a 3000w hub qs motor
It was sold with 80a cheap controller that don't even reach 63a in my clamps
Dont even have regenerative...!

So i was thinking about change it for a votol em100 or even votol em150 2 ?

What do you think if i pair it with a lifepo4 battery with a bms jk bd6a24s12p ?
I think it will only give a 120a continuous current So I'm less than the votol em150 need no ?

JK-BD6A2412P - JK BMS

Overview A lithium battery smart BMS, designed for big capacity series lithium battery packs, is a management system that provides a range of features, including voltage collection, active large current balancing, overcharge, overcurrent, overtemperature protection, Coulombmeter, Bluetooth...

www.jkbms.com

Thanks for your expertise
Leo

 

[amberwolf]

The battery has to supply all the power your system uses, so it is the most important part.

If you want the system to do a particular job, you have to use a battery capable of supplying *at least* as much power as that job requires.

So...first, how much power does it actually take to ride where you need to ride, in the way you like to ride, at the speed you need to go? When you determine how much power (watts) that is, then you can start looking for parts that can do that. There are calculators and simulators like those at ebikes.ca that can help you with that, once you know the details of the terrain and winds and road conditions, and the weight of you and the bike/etc, and other system details you can at least guesstimate. The more hills you have, and the steeper they are, and the more you/the bike weighs, and the faster you need to go, the more power you need to do the job.

Let's randomly say you need 8kw to do the worst-case parts of your ride, and let's say you are going to use a 72v (24s LifePo4 or 20s Li-Ion) pack. 8000w / 72v = 111A. So you'd need a controller that can continuously use *at least* 111A, and a battery that can continuously supply *at least* 111A, (and a motor that can continously handle *at least* 8000w) for the entire time you have those conditions on your ride.

Another consideration is battery capacity: Let's say you have an hour long ride, and 15 minutes of that needs 8000w, and the rest needs an average of only 4000w. 15 minutes is 0.25 of that hour, so you need at least 8000w x 0.25h = 2000wh plus 4000w x 0.75h = 3000wh for a total of 5000wh of battery capacity, minimum. 5000wh / 72v is ~70Ah, so you need *at least* a 72v 70Ah battery for this random example.

You can work out guesstimates of the numbers for your actual situation the same way. I recommend adding some percentage of margin to the numbers to allow for mistakes in calculations or guesses, and for pack aging over time, and for unpredicted headwinds or detours or changes in conditions that will take more power or capacity to overcome, so you don't ever end up stranded out of power.

 

[talgar]

Well my motor is only nominal 3000w...but i feel that it can stand much of my 63a im using right now because it well made and dont warm up so much not at the point where i can touch it with fingers!
Even I talked with the support of qsmotor and they said votol 100 or 150 can do the job and it had a overheat sensor so the motor wont burn anyway

The battery is the harder thing to build im currently waiting to receive the Jk bd6a24s12p in a month
And i want to use for 24s lifepo4 100ah that will give 72v100Ah battery !
I think this bms allow only 120a discharge current
Is not that much i guess and maybe there will not have difference in power if use it a votol 100 or 150
Because the bms will only give 120A ?
Maybe have to found jk bms 15p for the votol em 150 that will give those 150a but its hard to found where i live

 

[amberwolf]

I don't think you understood what I said, but I don't know any other way to get it across, so I'll have to leave this for someone else to help you out.

 

[talgar]

What i understand is the bms that give the current...
So if the bms is weak the controller can never give this full power
What i think i understand is the controller have a boost current that it need from the battery and a phase peak current is what it can give to the motor so
When they said 470a peak phase is what it give to the motor and not what it need from the battery right ?

150A Votol Controller EM-150

programable 150A sinewave VOTOL Controller EM-150 for your powerful bike, scooter and motorcycle.

www.qsmotor.com

 

[talgar]

important question
I finally found the 15p Jkbms but they have differente balancing
One is Bd6a
The other bd1a or bd2a

Since now i was working with li ion and 0.6a balancing was enough
But if i change to a lifepo4 with 100ah cells maybe i need a stronger balancing no?
Because 0.6a will not be fast enough ?

Thanks for give me a quick answer
Leo

 

[glennb]

You can do the maths for 100Ah with 600mA balancing current on paper can’t you? If not, find an online calculator.

 

[talgar]

Well i know but actually i never ever worked with lifepo4 in my life and maybe they dont disbalance has much as li ion? I just know their nominal voltage is 3.2 when li ion is 3.7v
Even 2A dont look enough for an 100ah no ?

Please help me make sense of JK BMS models

This is my first time building a battery - an 8s 230ah 24v lifepo4 for my van's solar, and I'm trying to decide on a BMS. I need at least 125A continuous discharge to be able to use my inverter's full capacity. I've been looking into JK BMS and am finding their website and other internet...

diysolarforum.com

On this site they said its enough But i have huge doubt
Dont want to buy something that will not be enough and will be disbalance all the time so i prefere ask before buying...and regret
Im wrong ?

 

[glennb]

You’ll find a great deal of LifePO4 expertise on solar storage forums. A lot of these sit in a permanent balancing state, using active balancers.

The only packs I’ve come across were 18650s, and that was years ago.

Anyway, time, balancing current, and Ah are the three variables. Your Ah might be fixed, but you can trade time for current. Easy to do with a fixed storage application, not so much with a portable vehicle battery. You might end up having to use an active balancer unless you leave the battery on a trickle charge like lead acid.

 

[talgar]

The jk bms have active bms thats why people like it so much
Im already using one for a 72v55ah li ion with 0.6A balancing
And works very well the battery almost never get more of 20mv in between cells! But each cell is only 2.7ah

But now with the new pack using 24 of 3.5v100ah huge lifepo4 cells im starting to have some doubt...will it work ?
If someone already have some experience with lifepo4 battery will be welcome !

 

[calab]

Good for high discharge for low P-groups, bulky, heavy, and not as safe as anything else, --> not!

 

[glennb]

I’ve seen some active balancing BMS for sale, but didn’t realise any of the JBDs incorporate it, thought they all just burned off high groups.

It’s a nice feature. Since you’ve got it, might as well see how it goes, and if it can’t keep up then add an active balancing board and/or occasionally help it out by manually bleeding/charging the cells that could use the helping hand.

 

[lifepo4ever42]

Well my motor is only nominal 3000w...but i feel that it can stand much of my 63a im using right now because it well made and dont warm up so much not at the point where i can touch it with fingers!
Even I talked with the support of qsmotor and they said votol 100 or 150 can do the job and it had a overheat sensor so the motor wont burn anyway

The battery is the harder thing to build im currently waiting to receive the Jk bd6a24s12p in a month
And i want to use for 24s lifepo4 100ah that will give 72v100Ah battery !
I think this bms allow only 120a discharge current
Is not that much i guess and maybe there will not have difference in power if use it a votol 100 or 150
Because the bms will only give 120A ?
Maybe have to found jk bms 15p for the votol em 150 that will give those 150a but its hard to found where i live

maybe its what you need https://www.aliexpress.com/item/1005002067429895.html

 

[gromike]

I wish, in the demonstration video, that they would speak slower. Then I might be able to know what they're talking about.