VX1 Li Ion 18650 conversion

Hi Vortex,
INR18650-35E with 12 batteries in parallel would not work in Vectrix VX1. This battery is for low drain consumer appliances. The batteries would not produce enough current to power the scooter.
The Li-Ion firmware is available from the Laird on this forum.

Hi LithiumVectrix,

Are you sure? We are talking about the same batteries? This batteries have 3.5ah capacity and 10A(3C) discharge. If we are talking about the same batteries, do you thing if i will put 75ah with this batteries it's a good idea? Sorry i know is too much questions but your opinion it's important to me.

Regards

Nope, won't work.

12 cells in parallel * 10A each is 120A max.
The Vectrix on acceleration draws 200A easily.

You need at least 20cells in parallel and then its is still on the edge,

Ok, i get it!! Where you buy your samsung battery??

Regards

The vectrix peak power is 21 kw.This power rating respond from 136v x 160 A =21.760w.That's the reason why the 120 A fuses of the firsts generation melted.So they puted the 200A fuse.I have read that the vectrix draws 200-240A during acceleration , but it has no sense , cause if you multiply 136 v x 200-240 (27.200-32.640 w)and the motor power rating is 7kw nominal and 21 kw peak.So if you say for example that 20*3500mah=70Ah x 3C rating = 210 A.So it will work if you put NCA cells with a rating of 3C and above.So in that configuration if you put 720 cells (9,3 kwh) (34,5 kg), it,s enough for the amperage handling.

I have read that the vectrix draws 200-240A during acceleration , but it has no sense , cause if you multiply 136 v x 200-240 ...

I'm afraid you are not accurate enough: The vectrix was designed to handle a 3.7kwh NIMH battery.
Under full acceleration the NIMH battery is severely crushed, and its voltage shrinks down to 102v (First firmwares allowed low voltage limit of 102V). 102Vx200A= 20.400W

the motor power rating is 7kw nominal and 21 kw peak.

I have read that the vectrix draws 200-240A during acceleration , but it has no sense , cause if you multiply 136 v x 200-240 ...

I'm afraid you are not accurate enough: The vectrix was designed to handle a 3.7kwh NIMH battery.
Under full acceleration the NIMH battery is severely crushed, and its voltage shrinks down to 102v (First firmwares allowed low voltage limit of 102V). 102Vx200A= 20.400W

The MC battery current limit is ~240A, whether your battery can supply it is another matter.
The limit is amps, not power

High capacity lithium batteries don't sag as much as the original nimh battery.
the battery current under hard acceleration doesn't go down with higher voltage (it actually goes up)

When I used to run 44 x TS 60Ah cells, my peak power in summer was 30kw (240A @ 125V)

The vectrix peak power is 21 kw.This power rating respond from 136v x 160 A =21.760w.That's the reason why the 120 A fuses of the firsts generation melted.So they puted the 200A fuse.I have read that the vectrix draws 200-240A during acceleration , but it has no sense , cause if you multiply 136 v x 200-240 (27.200-32.640 w)and the motor power rating is 7kw nominal and 21 kw peak.So if you say for example that 20*3500mah=70Ah x 3C rating = 210 A.So it will work if you put NCA cells with a rating of 3C and above.So in that configuration if you put 720 cells (9,3 kwh) (34,5 kg), it,s enough for the amperage handling.

But now i only have 504 cells, so if I limit my vectrix to 120A (ok i will loose some speed) but within a few months i will put more 216 cells.

In your opinion, can I have some trouble with this situation?

Best regards,

First , you can't limit the amps the motorcontroller sucks.And second , is a bad idea , mixing used cells with new cells.I'm making a 18650 lappy conversion , just for fun and experiement , but i doubt it will last many cycles.

the motor power rating is 7kw nominal and 21 kw peak.

I have read that the vectrix draws 200-240A during acceleration , but it has no sense , cause if you multiply 136 v x 200-240 ...

I'm afraid you are not accurate enough: The vectrix was designed to handle a 3.7kwh NIMH battery.
Under full acceleration the NIMH battery is severely crushed, and its voltage shrinks down to 102v (First firmwares allowed low voltage limit of 102V). 102Vx200A= 20.400W

The MC battery current limit is ~240A, whether your battery can supply it is another matter.
The limit is amps, not power

High capacity lithium batteries don't sag as much as the original nimh battery.
the battery current under hard acceleration doesn't go down with higher voltage (it actually goes up)

When I used to run 44 x TS 60Ah cells, my peak power in summer was 30kw (240A @ 125V)

Ok now i'm confused , so then the peak power the motor handles it's not 21 kw? It's funny , cause one says that the vectrix draws 110 amps , going up a hill , another says that you never will see more than 160 amps.Then fuse is rated to 120 A - 200A.Then another says 240 amps , then antoher 270 amps...

Is there any official data , where there's that info?I'll honestly aprecciate the data.

The MC limits the phase current too, not just the bus current. The phase current is limited to a peak of 375A, which was the limiting factor on Ni bikes. Under hard acceleration the bus current peaks at about 200A on the Ni bikes, but only for a brief time. On the Li bikes, the MC also limited the bus current to 160A.

Can someone translate this and explain this bus vs. phase current in laymen's terms, please? I suppose "bus current" is what the controller draws from the battery? On my Li conversion I don't think I have seen instantaneous readings over 180A on the bike's display, which I think is the bus current.

As for "speed", on flat roads, it only takes around 90A to maintain full speed. With limited current below 100A, hypothetically, it will just take longer to get there. I assume David can reprogram the current if needed to limit the current.

I'd like higher peak currents myself than what I am currently getting - the acceleration could be snappier (with a limited current it would be a rather sluggish experience). But suspect more current would not be safe for the motor and controller - they get quite hot as it is on warmer days even without reaching peak currents too often and only for short times...

The MC limits the phase current too, not just the bus current. The phase current is limited to a peak of 375A, which was the limiting factor on Ni bikes. Under hard acceleration the bus current peaks at about 200A on the Ni bikes, but only for a brief time. On the Li bikes, the MC also limited the bus current to 160A.

Ok now i'm confused , so then the peak power the motor handles it's not 21 kw? It's funny , cause one says that the vectrix draws 110 amps , going up a hill , another says that you never will see more than 160 amps.Then fuse is rated to 120 A - 200A.Then another says 240 amps , then antoher 270 amps...

Is there any official data , where there's that info?I'll honestly aprecciate the data.

It depends upon what firmware you are using, as well as what battery you have

I use MC1017
I measure power drawn with a cycle analyst in real time
peak power with 44 x TS60AH cells was at 80kmh (30kw, 240A @ 125V)

Not to be confused with the ~50A needed to maintain 80kmh

The most I have ever drawn continuously was 120A (110kmh uphill, strong head wind)

with different firmware you can have different current limits, but the power needed to maintain a speed remains the same

Ok now i'm confused , so then the peak power the motor handles it's not 21 kw? It's funny , cause one says that the vectrix draws 110 amps , going up a hill , another says that you never will see more than 160 amps.Then fuse is rated to 120 A - 200A.Then another says 240 amps , then antoher 270 amps...

Is there any official data , where there's that info?I'll honestly aprecciate the data.

It depends upon what firmware you are using, as well as what battery you have

I use MC1017
I measure power drawn with a cycle analyst in real time
peak power with 44 x TS60AH cells was at 80kmh (30kw, 240A @ 125V)

Not to be confused with the ~50A needed to maintain 80kmh

The most I have ever drawn continuously was 120A (110kmh uphill, strong head wind)

I understand that the power to mantain any speed it's much lower that the requiered power to full throttle to any speed.But my question is , for example , accelerating full throttle with a battery thats perfect and don't sag , wich will be the max kw , and max Amps extracted from the battery till full speed , wich will the worse case scenario?

with different firmware you can have different current limits, but the power needed to maintain a speed remains the same

I understand that the power to mantain any speed it's much lower that the requiered power to full throttle to any speed.But my question is , for example , accelerating full throttle with a battery thats perfect and don't sag , wich will be the max kw , and max Amps extracted from the battery till full speed , wich will the worse case scenario?

Sorry i don't know how to quote correcty.

I think antiscab answered your question: in his case, he calculated 30KW for the specific motor controller firmware and a good battery, happened at speed of 80km/h apparently accelerating hard he saw a current draw of 240A for a short time. Here's what he wrote above:

"It depends upon what firmware you are using, as well as what battery you have. I use MC1017. I measure power drawn with a cycle analyst in real time peak power with 44 x TS60AH cells was at 80kmh (30kw, 240A @ 125V)"

I understand that the power to mantain any speed it's much lower that the requiered power to full throttle to any speed.But my question is , for example , accelerating full throttle with a battery thats perfect and don't sag , wich will be the max kw , and max Amps extracted from the battery till full speed , wich will the worse case scenario?

Sorry i don't know how to quote correcty.

Acceleration was from 0 , or was from 80 kmh?So it's false the peak motor-power is 21kw¿?I'm missing something?

I guess the acceleration must have been from 80km/h or ending at 80 km/h, i.e., around 80 km/h and not from 0. From 0 I don't get max current. But at high speed I do if I open it up to max throttle.

And yes, if it pulled X amps at Y volts, you multiply these and get the peak power. When I accelerate as fast as it would go at highway speeds, say it pulls 200A and the voltage is 140V. 200A x 140V = 28,000 W (28KW).

I have not seen more than 200A on my bike, but I rely on the bike's display, which is a bit slow to react, so instantaneous current might be in excess of that for very short periods of time (under 1 second). And the battery voltage can be anywhere from 140V down to 130V as I do that (this is after the voltage drop during hard acceleration, which could be something like 6V: fully charged pack for me is 146V, hence the 140V I used in the calculation). You check the math for antiscab's numbers...

Acceleration was from 0 , or was from 80 kmh?So it's false the peak motor-power is 21kw¿?I'm missing something?

30 kw , and 28 kw , seems too much for a motor with 20,2kw peak, extracted from wikipedia.

I have measured the current drawn by a Vectrix VX-1 from the battery during acceleration. It is over 200 amps for 3 seconds between 25km/Hr and 70 Km/hr. This peaks at 240 amps. If you want your battery to last many years this intermittent current must be provided for in the battery specifications. For a 30 ampHr battery the Samsung INR18650-25R is up to this. Another battery is LG 18650 HE2. In a larger battery 65 - 80 AmpHr, then a wise choice is the Samsung INR18650-29E. This is a popular and good value Ebike battery. The reason Tesla can use the 3200 - 3500 low current batteries is because there pack is so large. You can build a Vectrix using Samsung INR18650-35E cells and the battery would have to be 120 AmpHr to provide sufficient current to make a lasting battery.
For those who would prefer LiFePO4 then Headway cells rather than prismatics will last in a Vectrix.
The motor phase currents are higher than 240 amps during acceleration. This is because the motor controller works as a buck converter at low speeds. It reduces the voltage and increases the current in the 3 phase leads. This is of no concern with battery specs, just a confusing issue when phase currents are quoted.

Do you think a leaf battery is a wise choice for 60Ah?So you are suggesting that the max current of the vectrix is 240 A?

I have measured the current drawn by a Vectrix VX-1 from the battery during acceleration. It is over 200 amps for 3 seconds between 25km/Hr and 70 Km/hr. This peaks at 240 amps. If you want your battery to last many years this intermittent current must be provided for in the battery specifications. For a 30 ampHr battery the Samsung INR18650-25R is up to this. Another battery is LG 18650 HE2. In a larger battery 65 - 80 AmpHr, then a wise choice is the Samsung INR18650-29E. This is a popular and good value Ebike battery. The reason Tesla can use the 3200 - 3500 low current batteries is because there pack is so large. You can build a Vectrix using Samsung INR18650-35E cells and the battery would have to be 120 AmpHr to provide sufficient current to make a lasting battery.
For those who would prefer LiFePO4 then Headway cells rather than prismatics will last in a Vectrix.
The motor phase currents are higher than 240 amps during acceleration. This is because the motor controller works as a buck converter at low speeds. It reduces the voltage and increases the current in the 3 phase leads. This is of no concern with battery specs, just a confusing issue when phase currents are quoted.

Now is too late, i already bought the 504 cells 35E. I need to find out other solution :\

Regards

Vortex this cells are rated 8A the 35E , so in fact you have purchased around 6 kwh.Buy another 500 cells , and then you can have 12kwh with a 5-10 seconds 30 kw peak power.If you don't go to nurburgring to race with your vectrix it shall work.Your advantage is that your shave around 40-50 kg to the nimh bike weight , so in theory your vectrix will be a lot less stressed.

Today i started a conversion like Prensel. I'm going for 36S36P with the Samsung INR18650 29E 3,7V 2900mAh.

"May the force be with me"

Prensel i sent you a pm.

I envy you!

Today i started a conversion like Prensel. I'm going for 36S36P with the Samsung INR18650 29E 3,7V 2900mAh.

"May the force be with me"

Prensel i sent you a pm.

Prensel used 16mm2 busbars for his 36S30P 85Ah setup. Mine will be 36S36P 104AH. What size should my busbars be? 25mm2 ?

I used two 16mm2 busbars in parallel so it is good for a max of 320Amps (10 Amps for each 1mm2)

In my case 10mm2 would have been enough since the Vectrix doesn't draw more then the fuse which is 200Amps.

ah no, current ratings don't work like that

10mm2 is only good for ~40A continuous
25mm2 is only good for 120A continuous
both with 60 deg C temp rise above ambient

the buss bars on my conversions are 50mm2 braided - rated to 185A continuous (still at 60 deg C temp rise)
If keeping to only 30 Deg C temp rise, the 50mm2 braided is good for 90A continuous - which is the most a vectrix will draw continuous at top speed in hot weather

2 x 16mm2 is as good as 1 x 50mm2 from a temp rise perspective, though higher losses (2 x 16mm2 has better cooling)
2 x 25mm2 is better than a single 50mm2 from a temp rise perspective, but same losses

Wow. That's a serious project for battery conversion. Best of luck.
Please updating your progress. Would love to see your final step and the outcome
of the performance of your Vectrix.

I am wondering about thermal management.

My understanding is that as Li-ion batteries charge, they heat up. They probably heat up as they discharge, too.

Is this not correct?

Teslas have a cooling (heating too?) system for the battery pack.

Is there some reason you feel thermal management is not necessary?

Excellent project and great work.

I bought 400 laptop batteries for my Zapino scooter conversion for my wife, but can't do anything with it until my new garage is finished.

Good Li-ion batteries have such low impedance that the warming during charge and discharge at normal rates (1 to 3C) is rather marginal. With my prismatic 40Ah LiFePO4 cells it was never never more than 5°C, even when they were creaking with old age and high impedance. 2...3 °C when new.
How things are with the small 18650 cells with many of them in parallel could be a different thing though, as there are bound to be additional equalisation currents between parallel cells.