Setting Fardriver Regen cut-off for lithium battery
Vložit
- čas přidán 24. 07. 2024
- Since every legit Lithium Ion battery has a BMS properly installed, every real controller has a setting that ensured it doesn’t regen into a battery with closed charge port.
This video shows how to set the Fardriver regen cutoff.
Basic steps:
Set voltage in Parameters to the nomimal voltage of your battery by multiplying the number of cells in series times nomimal cell voltage.
In my case 16s li-ion, its 16•3.7v=59.2v, so i used 59v (60v would also be acceptable)
The regen will cutoff when the dashboard SOC is 90% or higher.
So in - Protect section, adjust:
BattSignal to 3-lithium
Full BattCoeff until the SOC shows 90% at the battery voltage your battery can accept the regen amps you have dialed in.
Your battery C-rate (high drain large capacity or low drain small capacity) determines the voltage surge that occurs at the regen level you selected.
A good battery properly top balanced will be able to accept regen up to about 4.18v/cell. So you would set the fardriver to show 90-91% at this voltage, as shown on your BMS app.
If your battery is weak and has significant surge during regen, you can set SOC to 100% when fully charged and just know it will not regen until you drain the battery to 90% SOC on the fardriver app dashboard.
You can later fine tune the coeff until you get regen as soon as possible without trying to regen when the port closes.
NOTE: SOME CONTROLLERS WILL FRY THEIR MOSFETS IF YOU ARE REGENING HIGH CURRENT WHEN THE BMS CLOSES THE CHARGE PORT. MAKE SURE THE FARDRIVER STOPS REGEN BEFORE THE BMS DOES.
0:00 Setting Fardriver regen cutoff
0:10 when the battery capacity on the app is less than 90%, the fardriver will regen.
0:26 you can see at 79% SOC during braking the regen is working (few hundred watts going in the battery)
0:37 make sire your rated voltage is the true nominal voltage of your battery based on its chemistry. Mine is 16*3.7v=59v
0:47 I Change Full BattCoeff until it shows 98% to demonstrate no regen occurs
1:07 now you see during braking only 47 watts going in the battery. Not enough to cause a surge in voltage
3:39 you can see the cutoff point is right at 90% capacity as shown on the fardriver app
4:03 I open the BMS app to check the real SOC, its 73%
4:29 I set Full BattCoeff back to the 1200 I set earlier.
4:37 now the SOC of the fardriver is back to a reasonable estimate 74%
4:44 tune this setting to get regen to come on as soon as you feel your battery is ready to absorb it.
0:00 Setting Fardriver regen cutoff
0:10 when the battery capacity on the app is less than 90%, the fardriver will regen.
0:26 you can see at 79% SOC during braking the regen is working (few hundred watts going in the battery)
0:37 make sire your rated voltage is the true nominal voltage of your battery based on its chemistry. Mine is 16*3.7v=59v
0:47 I Change Full BattCoeff until it shows 98% to demonstrate no regen occurs
1:07 now you see during braking only 47 watts going in the battery. Not enough to cause a surge in voltage
3:39 you can see the cutoff point is right at 90% capacity as shown on the fardriver app
4:03 I open the BMS app to check the real SOC, its 73%
4:29 I set Full BattCoeff back to the 1200 I set earlier.
4:37 now the SOC of the fardriver is back to a reasonable estimate 74%
4:44 tune this setting to get regen to come on as soon as you feel your battery is ready to absorb it.
So if I have a big capacity battery, I would need to lower down the Full BattCoeff to calibrate the controller with the battery, right?
The calibration just changes the value of SOC % corresponding to max pack voltage. So if you just calibrate it to be correct at 100%, regen will not work until you get below 90%.
If you have a high capacity battery, or more important one that can absorb a charge fast, compared to amount of regen you have set, you can move the calibration point up so that 95% corresponds to fully charged, and than would allow regen to start sooner.
For my battery which can charge at 40a and my tiny ebike which only used 10a/15a for regen, i moved my calibration point such that my actual SOC is 98% when the fardriver is seeing 90. This allows my regen to start working right away.
The main goal is to avoid a conflict between the BMS closing the port if regen causes too much voltage surge. Fardriver uses a very conservative 90% but that means you won’t have regen for the first few stops in city driving.
Interest..so regen never works on a battery with over 90% charge??
Only based on what the Fardriver thinks is 90%, but not based on actual SOC. Your real battery SOC may be 98% when the fardriver is calibrated to show 90% so that regen starts working as soon as your battery can absorb it,
@imho7250 could you calibrate the fardriver way over the actual SOC and then it will always read above 90%? Of course the dashboard SOC on the dashboard wouldnt be accurate i guess
@@MrDeceptacon88 , well rather than making it always over 90% it’s easier to just turn regen off. And I think you can make it over 90% for a longer time but the midpoint, which is what your nominal voltage is, will still be somewhat near nominal voltage.
I discovered it by accident because normally I don’t fully charge the battery but this time i did, and i noticed no regen so i thought it was broke. Lol
@imho7250 but i like to use regen...puts a bit of energy back in the battery and saves the disc brakes
@MrDeceptacon88 , yes, me too. So why would you want the battery capacity to stay over 90% longer than needed if you want regen as early as it is safe for your battery?