WE BD36 is shutting off when load is applied-Help!
I have a 48volt lithium batt into a crystalite 48volt 30amp controller into a WE bd 36 26" wheel and when i put any load on it the controller cuts out and needs to wait 15minutes before it will work again but it does the same thing. I had a 36volt controller on there and it was working fine for almost a year and is only recently that it started acting up. When I replaced with the 48volt crystalite I thought I had solved the problem but the exact same thing happened which makes me think it is something in the wheel or Amps or I dont know but it is soul crushing to not be on my bike. The other thing that happened is that i replaced the brushes and brush holder and maybe the timing is off? Would the effect of off timing be a shut down when load is applied?How do I know where the right timing is?
Please Obi Wan your my only hope....
Are you sure it's the "controller" that's shutting down?
I've seen a behavior with lithium batteries where the BMS board shuts down the battery when the current draw goes too high. The BMS is there to protect the battery pack, and one thing the BMS protects for is too high a current draw.
What is the specified amp capacity of your battery pack?
The previous controller was how many amps? e.g. a 36v 30A controller will have a max of 1080 watts while a 48v 30A controller will have a max of 1440 watts. Hence at 48 volts the controller will draw more watts than the previous 36 volt controller.
One way to make measurements - what I do - is to use the 'WattsUp' meter you can get via BatterySpace.com and connect the battery pack through the WattsUp to a big variable resistor. I vary the resistor to get different discharge rates and see how the battery pack behaves separately from the rest of the system. By 'big' I mean one that can handle 300 watts or more, the one I have is maybe 8 inches in diameter, a very 30's look to it, and is made by Ohmite.
I suggest getting the WattsUp regardless but maybe getting a big variable resistor isn't within your means.
It occurs to me if you connect up a light to the battery along with its connection to the controller .. if the light remains lit it means the battery is not cutting out and instead it's something to do with the controller.
A question is:- is the controller getting hot? It's plausible there's a high temperature cutoff in the controller.
my guess would be something wrong with the battery. If it's an 18650 round cell type pack from ebay you most likely have some dead cells in there that are causing low voltage and low capacity. Those less expensive packs have a reputation for broken connections inside, or just weak cells in there that drag down the others till they die too.
Checking the voltage of each cell group can often show where the bad cells are. Checking the voltage of the whole pack while the wheel is spinning can show if voltage drop under load is severe.