Chalo
100 TW
No, because the controller can do voltage conversion to trade volts against amps unless it's limited by the supply of one or the other.
NEWBIE, Land rover electric bike project
- Thread starter okmatey
- Start date
I think it depends on the condition (load, speed, etc.) and the controllers ability to provide phase amps. Note, this is opinion, based on reading different articles and posts and playing with the simulator to understand how my specific bike performs or can perform, but there are several folks on this forum that could explain it better than I can, and the technical aspects of these observations.
Using the Grin simulator, you can see the relationship between battery and motor amps. In this example, both systems are the same, with a 70A controller (battery amps). At full speed, the system is flowing 51.7A (battery), and the motor is pulling 57.7A (motor). If you drag the slider (dotted line) for system B to the left (bike accelerating under full throttle), both the battery and motor amps rise, but by the inflection point in the torque curve (40mph in the example), battery amps max out at 70A. Moving further to the left, battery amps remains pegged, but motor amps continues to rise all the way up to 176A at stall speed; battery amps still pegged at 70A.
Motor Simulator - Tools
Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...
ebikes.ca
In this example, the controller is able to provide the 176A of phase current, but not all controllers can do that. Seems like phase current typically falls somewhere between 2 and 3 times battery current for our controllers.
Last edited:
okmatey
10 mW
What's your thoughts chaps ?
48V 20AH BMS 40A Samsung 50E 3500mAh cells li-ion Ebike battery
48V 20AH BMS 40A Samsung 50E 3500mAh cells li-ion Ebike battery UK Stock Fast Delivery Product details: Model U009 Battery type Li ion Battery Rated Voltage 48V Rated Capacity 20Ah Battery cell Samsung 3500mAh Dimension(mm) 385*97*120 Battery weight 6 KG BMS current 40A Max.charge current 5 A...ebikesolution.co.uk
Would this be OK?
Chalo
100 TW
It's a typical inexpensive battery made out of vape/flashlight cells. It's from a known and prolific e-bike battery seller that has mostly upheld a reputation for good-enough products. Construction quality is expedient, BMS is primitive unless you get a custom upgrade (which I think they will do if you ask).
The battery housing is convenient and functional, but can accumulate water if it's mounted upside down. So try not to do that.
Cells and BMS can support 40A continuous current if ratings are accurate, and the mounting rail discharge pins are probably good enough for that too, but might fall short after some wear, grime, and corrosion.
If you really want a kWh of energy onboard and you want to run both motors full blast with confidence, I recommend at least trying to find an automotive module that wasn't assembled in a hurry with hundreds of spot welds and hand soldered connections.
Many many threads and posts here on ES concerning UPP batteries. Ratings all over the board. Some have had good experiences but many have not. Some teardowns showed poor components, poor workmanship, poor materials. Hard to tell which version you will receive.
I think requesting the BMS upgrade probably helps in more ways than one. When I bought my last (2nd) UPP battery off of eBay, the tech/rep called me a day later, from China (I was looking at my phone, wondering who would be calling me from China). Anyway, we had a brief conversation about my system, and the cells and BMS, and eventually just confirmed that I was getting the right battery. I think they may have been subtly seeing if I would switch to LG cells instead of the Samsungs, but only by offering. My guess is they had more LG packs on hand. I don't know if they had to construct my pack when I ordered it, but it's been reliable and construction seems OK (sags no more that would be expected from 35E cells). I suspect if you custom order a balancing bluetooth BMS, that it wouldn't just be something off the assembly line, and perhaps more like buying a Wednesday car vs one built on Friday afternoon.
lots of posts and pages about that
