Endless Sphere

A 17A controller probably delivers 8A continuous. A 20A controller probably 10A. Upping to 48V... That's 380W and 480W of power continous... But 800W to 960W burst... I would do it... Your original conttoller on the 250W probably already had burst power of 540W... Should survive no prob. Just dont g...

My guess is this is for a PAS cadence sensor, which you probably don't need on an e-Scooter anyways.

Try Bestech power website

I think he meant 52V as a rounded figure for 51.8V nominal, thus 14S setup. Cause even hot of the charger a 13S setup is not close to that 52V figure (54.6V hot). Of course we assume Li-Ion but not LiFePO4... Given lack of detail specs.

Matador

Would like some as stealthy as a Gruber assist (aka Vivax) but if it could push at least 500-750W, that would be dope !

Matador

A 14S BMS is necessary. Some 14S BMS can be used in 13S configuration.

Peak mechanical output power is not equal to peak electrical input power drawn by the controller... Motors are not 100% efficient. Assume 85% motor efficiency at most, and 1.2 kW electrical input x 85% efficiency = 1.0 kW mechanical output. My guess is that peak rating is specified as mechanical out...

Matching 1) capacity (mAh), and 2) Same cell brand and model (and chemistry) (ex: all VTC4s). Is the most important But if you can additionnaly also match for 3) DCIR 4) Cell Age and number of cycle Then you are golden ! The worst thing to do is mix old laptop cells of different brand, models and ch...

john61ct wrote: ↑

Jul 20 2019 10:01pm

want to build wrote:now i understant the second statement is less important that resistance and year of manufacture.

Capacity matching IMO is #1

Agreed!

Matador

0.05V is fine for paralleling cells. Don't let the V difference be much bigger than 0.10V, because the higher cell will dump a surge of current into the lower voltage cell... And this ca result in exceeding charge curent rating and damaging cells... But I'd be much more concerned if the V difference...

I wish... But to do so in such short time, you'd need to use supercapacitor rather than lithium cells. The bottleneck is the discharge rate for measuring discharge capacity... DCIR can be measured in seconds however... You can thus extrapolate voltage sag by ohm law and knowing how much load you wan...

Want to build First off, number each cell and carfully take note of all resting voltage drift that occured with time, for each cells (make an excell file... To keep a logbook of all cells health parameters). Then figure out the exact manufacture date of each cell from the numbered labelling of the c...

Hey Guys, I got this BMS that has two white thin wires coming out of it and it says that it's the On/Off switch. Why do I need an On/Off switch? the switch for the battery is in the lock while off it's cutting the red wire from the bottom part of the battery to the battery itself. Where do I connec...

Another name for this BMs spec figure is "BMS Quiescent current draw"... This figure should be on any respectable BMS datasheet.

Matador

Could be perfectly Okay... A 28Ah battery is massive and can take a decade to drain from BMS if the pack was stored full... But if it was stored near 0%, then some of the cells could be toast. Assuming the cells were NMC, never used, and stored at 50% and a in a garage at ambient temperature of 25°C...

Hi all, I'm working on my 18650 battery holder project, I red some relevant issues I face and trying to solve being discussed here. Below are some of the features I built into my battery holder : - Cell Level Fuse (just positive ends). Negative ends are all connected. - Stainless Steel Springs (jus...

Interesting. Are you using thread inserts as contacts? Those are made of brass, aren't they? You might want to consider making your own contacts out of copper, maybe even with one end closed for more contact surface. Brass has only 1/3 the conductivity of copper. For low-current situations that'll ...

Sounds like your controller doesn't detect it's a 36v battery and is applying the LVC as though it's a 48v battery. That was my first thought too. I hearr in some dual voltage capable controllers, you may have to solder certain pins togoether to enable the right LVC combo. But then he said on the b...

More torque (amps) requires bigger controller. Or you can do a shunt mod and trick the controller to think it sees less current than it actually lets go through, beefing up thensoldering traces too might be helpfull... There's probably a limit to how much you'd want to overamp your controller before...

Havent got to it yet since i mouved of the country for a while and all my stuff is in a storage unit in Canada. I will get back at it in tue coming months... My BBSHD is on a bike with no battery pack on the bike, so i will have to tackle this task.

Matador

Swamp cooler work great in dry climates, but if it's a humide climate, swamp coolers are not very effective if at all.

What he said ^
Super nice stealthy eBike!
Thumbs up!

If I recall correctly, the 40T are rated 35A continuous. If there is a temperature cutoff, they are then rated 45A continuous. The 30Q are rated for 15A... An 18650 has a volume of 16.54 mL, whereas a 21700 has a volume of 24.24 mL... The 40T cell has a volumetric power density of 1.444 A/mL By comp...

I have a 20s7p 30Q pack. Am at 250 cycles since 06/2017. I typically charge to 80.1V (95%). I'd say 90% of the 250 cycles were to 80.1V. I'd typically use around 12Ah per ride. I'd guess I could not get more than 15Ah out of this pack now. I also notice the voltage drop seems to be more severe. I'd...

Damn wish I was in Montreal right now, but stock in Toronto...
I'd love to grab these Orange and Black Vruzends
Matador