NEWBIE, Land rover electric bike project

docw009 said:
Would each phase current in a BLDC be like 1/3 of the controller's max current?
Click to expand...
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.
 
docw009 said:
Would each phase current in a BLDC be like 1/3 of the controller's max current?
Click to expand...

Chalo said:
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.
Click to expand...
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 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 said:
What's your thoughts chaps ?
Click to expand...
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.
 
Chalo said:
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).
Click to expand...
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.
 
Hi chaps, ots been very busy lately so haven't done much at all on my bike but I've spent a few hours on it over the last few days, I've managed to test the hall sensors and phase wires with the tester and all seems OK however when I connect the motor battery and motor nothing happens when I turn the throttle, is there a way for me to test the controller ?
 
I have purchased stuff from both of these suppliers and they both delivered promptly.

They are more expensive than ordering direct from China, but if you want a UK supplier then these two are as good as any.

thelayerlaboratory.co.uk

TorqueTech

The Layer Laboratory : A dynamic additive manufacturing enterprise. Providing practical solutions to real problems with unique & innovative products. UK stock. Free UK Delivery. Fast dispatch. Great service. Unbeatable support.
thelayerlaboratory.co.uk thelayerlaboratory.co.uk


ebikesolution.co.uk

Ebike Controllers

Ebike motor controller are the most important part of your ebike, it connects all other parts like motor, battery, display, pedal assist, throttle together to power up and control your ebike.
ebikesolution.co.uk ebikesolution.co.uk
 
You will be better off using a KT controller and make sure it’s not too big for your battery and motors.

The controller you linked to is 40 amps. Can your battery deliver that much current? And can your motors run at 2kW without overheating?
 
AGS said:
You will be better off using a KT controller and make sure it’s not too big for your battery and motors.

The controller you linked to is 40 amps. Can your battery deliver that much current? And can your motors run at 2kW without overheating?
Click to expand...
Kt controller ?? Where can I find one of those, this is the battery spec I have purchased,
 

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Both of those suppliers I linked to sell KT controllers. Your battery is good for 1500 watts. 2000 watts is pushing it too hard.

You also need to know how much power your motors will take without overheating.
 
I was planning to run the front wheel which is larger than the 350w rear wheel please see pics, haven't a clue what power the front is , what would be the best Controller knowing this ??
 

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It’s probably not safe to run the rear motor above 1000 watts. I do not recognise either motor.

I have fitted temperature sensors to a couple of my motors. They can get very hot, very quickly when they are run at high power, especially if you are climbing hills.

I have also oil cooled my geared hub motor to keep the temperature at a sensible level.
 
I'm not really sure I'm getting anywhere here lol, so am I right in saying for example, if I purchased a controller for the front hub let's say its 1000w, would it not work for the 350w rear motor or vice versa? Is there a controller that would suit ?
 
You should do some testing to find out why it’s not working before spending any more money.

Grin has put together some nice instructions for troubleshooting an e-bike. Here are a couple of links.

Main page

Troubleshooting - Learn

One of the things about meshing complex electrical and mechanical systems together is that occasionally things can go wrong! We've seen more than our fair share of ebike issues come and go over the years - from shot ball bearings, seized freewheels and stripped threads to defective hall sensors...
ebikes.ca ebikes.ca

Hall sensor test

MOSFET testing

 
It could be a connection problem, or maybe a mosfet problem inside the controller.

One way is to do some more testing to find out what’s going on and another way is to replace parts until it works.

Do you have a display connected to the controller. If so does it show any error codes?
 
Unfortunately no display fitted,I've just checked the misfits again and they seem to be fine,there are a red and black thin wire with no connector attached on the controller, this wouldn't be any other power supply would it ?
 
If you are going to replace the controller you should get a decent one with a good display. That’s why I suggested KT because they are reliable, aren’t expensive and easy to configure. There are many other good controllers, some are very expensive and not necessary for either of your motors.

The controller you have is widely used, but not as good as a KT and you have no way to configure it without a display.

You just need to decide how many amps you want it to supply and size it accordingly.

KT controllers can be configured to limit the current to 50%. So if you buy a 35 amp controller that matches your battery, you can limit it to 17.5 amps to protect your motors.

So in future if you decide to run your motors at higher power levels you won’t have to buy another controller.

Also running a controller below it’s maximum capacity means it runs cooler and won’t blow up.
 
AGS said:
If you are going to replace the controller you should get a decent one with a good display. That’s why I suggested KT because they are reliable, aren’t expensive and easy to configure. There are many other good controllers, some are very expensive and not necessary for either of your motors.

The controller you have is widely used, but not as good as a KT and you have no way to configure it without a display.

You just need to decide how many amps you want it to supply and size it accordingly.

KT controllers can be configured to limit the current to 50%. So if you buy a 35 amp controller that matches your battery, you can limit it to 17.5 amps to protect your motors.

So in future if you decide to run your motors at higher power levels you won’t have to buy another controller.

Also running a controller below it’s maximum capacity means it runs cooler and won’t blow up.
Click to expand...
Thanks pal, what do you think of this controller ?

ebikesolution.co.uk

Ebike Motor Controller 35A KT LCD3 Full Twist Throttle KIT

Ebike Motor Controller 35A KT LCD3 Full Twist Throttle UK Stock Fast Delivery Product details: Support KT LED Control Panel or KT LCD Control Panel or without any Control Panel (Universal)Support 48V Light Control Rated current: 17A Maximum Current: 35A It only applies to hub motors with Hall...
ebikesolution.co.uk ebikesolution.co.uk
 
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