John angel NYC

ONYX RCR 41AH BATTERY

BEST PRACTICES, ANSWERS, AND SAFETY
ASSISTANCE, BLOG UPDATES, AND LEARNING THE ROPES

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WHAT’S ON THIS PAGE

This post provides a wealth of information about battery balancing an Onyx RCR and CTY2, including any PEV (eBike, eBoard, eScooter, and EUC). With this information, battery balancing can be verified, since not all Battery Management Systems (BMS) provide auto battery balancing with or without a balance-compatible charger.

Battery Pack

In any personal electric vehicle, you have a battery pack consisting of multiple individual batteries on average ranging from 160 (72v) individual batteries to 200 (72v) individual batteries. These individual batteries are almost always Lithium-ion 18650 or 21700 NMC (Lithium Nickel Manganese Cobalt Oxide) type batteries. Each one of these batteries will operate fully charged at 4.2 volts and discharge to 3.0 volts.

Cell Drifting and delta

It is normal and expected for individual battery cells in a battery pack to slightly drift apart in voltage from each other, which is refered to as "cell drifting" as in an unbalanced state. There is no preventative measure for cell drifting, which is taken care of by the BMS. Cell drifting happens because of loads placed on the battery by time, peaks, constants, temperatures, and regenerative braking. When many or a few individual battery cells are at a slightly different voltages, that is commonly meassured to as "cell delta". Cell delta reading are generally values from a helathy 0.005 volts to 0.040 volts, as in the lower the cell delta value, the better.

Battery Management System

The battery management system (BMS) located inside the wrapped battery pack manages battery balancing. In the balancing function, it balances the charge voltage of the battery cells to be as close as possible to each other in voltage with a value of 0.005 volts being excellent.

Not all battery management systems (BMS) operate the same when it comes to battery balancing. Some will require that a balance-compatible charger be plugged in for a duration of time to activate the battery management system "balance function". Other battery management systems (BMS) do not require a balance-compatioble charger or any charger to be plugged in for the "balance function" to operate, instead they continuously balance the battery automatically.

Newer battery management systems are capable of displaying their real-time reading through an iOS or Android app via Bluetooth, independant of the bike. These newer battery management systems also display battery series voltage levels and the battery delta voltage value.

In passive battery balancing, energy is drawn from the most charged cell and dissipated as heat, usually through resistors. In active battery balancing, energy is drawn from the most charged cell and transferred to the least charged cells, usually through capacitor-based, inductor-based, or DC-DC converters.

Can The Battery Balance

Not all battery management systems (BMS) are capable of balancing the battery and can only manage the charge current limit, discharge current limit, and internal impedance. An inexpensive, non-destructive, and easy way to verify if a battery management system (BMS) is capable of balancing a battery is with an outlet meter and time.

Not all battery management systems (BMS) are capable of balancing the battery and can only manage the charge current limit, discharge current limit, and internal impedance. An inexpensive, non-destructive, and easy way to verify if a battery management system (BMS) is capable of balancing a battery is with an outlet meter and time.

Test a battery management system (BMS) that is charger dependant (balance compatible charger) for the "balance function", by plugging the charger into the “outlet meter” and having the meter set to display watts. Check the meter 3 hours after the battery has been fully charged to 100%. It should display 2.9 watts and above with every few seconds fluctuating higher to 3.2 watts or above. If it does, then that means the battery management system (BMS) is capable of balancing the battery. If the outlet meter reads 0.5 watts after three hours from the battery being fully charged, then that means the battery management system (BMS) is incapable of balancing the battery.

All batteries take extra time to charge from 97% to 100%. This is called “constant voltage charging (trickle charging)” and is not the same as battery balancing. A 72-volt battery in a 20 series and 8 parallel arraignments with a charger ranging from 2 to 8 amps will take roughly 95 minutes to charge from 97% to 100%.

Balance With The Charger

Most battery management systems (BMS) are the kind that requires the charger to be plugged into power on the battery management systems itself so it can balance the battery. The other kind of battery management systems that can power themselves from the battery is more expensive, which is why they are not common.

Different battery voltages and how long it takes to balance them.

Using the outlet meter readings, it can be determined at what state the battery is at regardless of it being 100 volts, 72 volts, 52 volts or 48 volts because they all share one common thing, and that’s either a 18650 or 21700 battery.

Outlet Meter Readings

Regardless of how many amps a charger is capable of outputting ranging from 2 amps to 12 amps, it has to follow the same rules of trickle charging, constant voltage charging, and battery balancing.

If the battery management system (BMS) is capable of balancing the battery, then the gains are performance, longevity, and the absence of numerous voltage-related issues like premature cutoffs. A battery management system (BMS) that can’t balance the battery will result in a PEV whose range and performance will diminish more quickly.

CHARGing

Plug the charger into the wall outlet before plugging the charger cable into the battery’s (XLR) circular three-prong connector located on the battery. Connecting the charger to the wall outlet before connecting it to the battery will prevent sparking from occurring.

CHARGING TIMES

5 AMP CHARGING TO 100% (84 VOLTS)

5 AMP CHARGING TO 97% (83.3 VOLTS)

10 AMP CHARGING TO 100% (84 VOLTS)

10 AMP CHARGING TO 97% (83.3 VOLTS)

RANGE

These are real-world range averages based on my experience and that of others. Your range will most likely differ to be either greater or less based on where you live, temperatures, conditioning of the battery, riding style, and many other factors.

NEW YORK CITY - FLAT

SAN FRANCISCO - HILLS

discharge LEVEL

The Onyx RCR display has both a battery charge bar and a voltmeter. I suggest primarily use the voltmeter on the display for the exact state of charge percentage level of the battery. The Onyx RCR draws 0.6 volts while it is turned on. The new Onyx RCR v1.5 accounts for this.

On the Onyx Motorbikes 41ah battery page, it states that the operational range of the battery is from 84 volts fully charged to 56 volts depleted which is correct considering 60 volts depleted is also true (plot twist). Looking into the programmed fields of the battery management system the fully charged “cell full voltage” field shows 4.15 volts as the maximum voltage for each cell which adds up to 83 volts. Presumably, this conflicts with the “total battery capacity” field of 41000mah which adds up to 84 volts.

Also, the depleted “total cycle capacity” field of 32800mah conflicts with the “cell 20% capacity voltage” field of 3.300 volts. The reasoning for both the fully charged and fully depleted conflicts is battery balancing. In other words, there’s nothing to worry about because the battery management system is making sure to deliver 100% of the 41ah battery’s full capacity.

Right-click or long-press over the image and choose “save image as” to save to your phone or desktop.

High temp CHARGING

When the weather temperature is above 85° Fahrenheit, lithium batteries will simply put, react differently during charging and discharging. More aggressive, faster, and intense hill climbing will generate higher internal battery temperatures.

The Onyx 41ah battery cells are rated to 140° Fahrenheit with the BMS triggering battery cut off at 158° Fahrenheit. The Onyx 41ah battery can communicate its temperatures via the BMS app.

Watch for temperatures reaching 120° Fahrenheit as your sign to lean off the throttle. The better you treat your battery on hot days, the better it will continue to perform over time and without sacrificing its charge cycle count.

BATTERY SAFETY

After riding allow the Onyx RCR 41ah battery to rest in the shade for a half-hour before charging, especially with a 10 amp fast charger. On days above 90 Fahrenheit after riding wait an hour before charging. Use the Onyx BMS app or Xiaoxiang BMS app to see your battery’s internal temperatures. If the battery is above 105 Fahrenheit, wait till it drops below 95 Fahrenheit before charging at 5 amps and especially at 10 amps.

By allowing the battery to rest after riding before charging has a positive longevity and performance effect. It increases the charge cycle count, allows the ions and electrons to rest, reduces its operating temperature, and prevents potential thermal runaways that no BMS can stop on hot days after a hard ride.

CHARGING SAFETY

Overnight charging is safe as the Onyx RCR stock 5 amp charger, 10 amp charger, and the battery management system provides redundant fail-safe mechanisms. As the battery charge level arrives at 97% 83 volts the charger will reduce its amperage output substantially lower and begin trickle charging. In turn, reducing its heat output and shutting off its cooling fan for the remainder of the charging and trickle charging. The Onyx 41ah battery management system cuts off the Onyx stock 5 amp charger and Onyx 10 amp SFX charger after fully charging.

WOOD COVER
PROTECTIVE CAP

The Onyx RCR now comes with a charging cable protective holding cap just outside the right-side porthole. During winter or rainy days switch to an XLR rubber cap to further protect it from the elements.

CLEAN CONNECTORS

Cleaning the male charger pins and female battery porthole connector reduces electrical resistance. Electrical resistance makes for an inefficient connection and generates heat. First, turn off the battery through the BMS app then proceed to clean the battery female portholes and charge male pins by removing the cotton from one end of the cotton swab, place two drops of contact cleaner bare end of the cotton swab. Insert the bare end of the cotton swab with contact cleaner into the battery female portholes while twisting. The end of the cotton swab where the cotton hasn’t been removed also gets two drops of contact cleaner to clean the male end of the charger.

BMS APP

The Onyx 41ah battery does not have a physical power switch. Rather, the Onyx BMS app and Xiaoxiang BMS app is what is used to turn the battery off and on when unplugging it from and to the Onyx RCR. The BMS apps provide battery status information, battery balancing meters, power gauges, voltage meters, and usage logs. The Xiaoxiang battery management system app gives more comprehensive readings and logs than the Onyx BMS app.

The Xiaoxiang battery management systems apps allow for the battery management system to be configured. I highly advise against changing any of the battery management system settings as it can damage the battery, void the warranty, and present safety issues. Keep in mind that I achieved over 17,500 watts with the battery management system stock settings.

BMS APP BENEFITS

OFFICIAL ONYX BMS APPS

XIAOXIANG BMS APPS

OSE 8 CONNECTOR soldering

Always make sure the Onyx 41ah battery is off via the app before soldering a new battery connector on the battery itself. Also, discharge the Onyx RCR by unplugging the battery from the bike while the bike is on. This will ensure that you are working with a cold bike battery connector. If you’re not sure about switching out the stock SB50 battery connector to an OSE 8 battery connector both on the battery and the bike, always seek out the help of a professional.

AMPERAGE UPDATE

The Onyx 41ah BMS boards have recently been upgraded from the 80 amp model to the 100 amp model. Previous discharge overcurrent configurations in the BMS app were set to 90 amps where now the discharge overcurrent configuration is set to 110 amps. The Onyx 41ah battery now outputs 20 more amps which translates to more power as in torque with a possible speed bump. The challenge though is that the stock battery connector is an SB50 limited to 50 amps with a peak of 70 amps. The revised Onyx RCR 1.5 also introduced a 100 fuse.

What this means is that the Onyx RCR will function just fine with the stock SB50 battery connector but to take advantage of this battery BMS amperage bump up, the stock SB50 will need to be upgraded to OSE 8 connector.

XIAOXIANG BMS APPS

Use the Xiaoxiang BMS iOS App to verify your BMS model. Start by connecting to your battery, followed by taping “BMS Settings” at the bottom of the screen. Tap “BMS Read” and scroll down to the line that reads “BMS Name”. If your model number ends in “80A” then you have the 80 amp model. If it ends in “100A” then you have the 100 amp model.

This image demonstrates a 100 amp Onyx 41ah BMS in the “BMS Name” field which ends in 100A.

BMS FIX

First, verify which BMS model you have. The Onyx 41ah battery has an 80 amp BMS and newer revisions have the 100 amp BMS and in some cases, the “Charge” and “Discharge” over current protection fields are misconfigured. The battery sometimes also has its “Total Cycle Capacity” field misconfigured to 32500 which will give inaccurate charge level readings and cause premature cut-offs.

It does not matter if the Onyx 41ah battery is in or outside the bike or plugged in. Make sure to be within 5 feet of the battery before making changes to the BMS. Use the Xiaoxiang BMS iOS App screenshots below as a reference. I’m currently figuring out which is the best Android App to make changes to the BMS with.

Download the Xiaoxiang BMS iOS App to your iPhone or iPad. Open the Xiaoxiang App, connect to your Onyx 41ah battery, tap on “Config” and purchase the Pro version of the app. Tap on “BMS Settings” then tap on “BMS Read”. Make sure your “Total Battery Capacity” field is set to 41000 and that the “Total Cycle Capacity” field is 32800. If the “Total Cycle Capacity” is set to anything else, tap on the field and change it to 32800. Tap “BMS Write” on the top right-hand side of the App.

XIAOXIANG BMS APPS

Tap “BMS Read” to confirm the changes have been applied. Scroll down the screen and check that the “Charge Over Current” field and “Discharge Over Current” field both say 90000. If not then tap each field and change it to 90000. Tap “BMS Write” on the top of the right-hand side of the app. A message confirming the changes have successfully been written will appear. Tap “BMS Read” once more to confirm the changes have indeed been applied.

80 AMP BMS MODEL

100 AMP BMS MODEL

BALANCER CONFIGURATION

The balancer configuration field can be tweaked to a specific rider. I like to leave the “Start Voltage” field at 3900 and the “Delta to Balance” field to 10 along with the “Balance Only When Charging” toggle set to “On” because I ride aggressively. I recommend setting the “Start Voltage” field to 4000 and the “Delta to Balance” field to 20 with the “Balance Only When Charging” toggle set to “OFF”.

Occasionally look at the main screen of the Xiaoxiang BMS iOS App and look at the reading “Cells” with a triangle next to it. You will find it towards the top of the screen on the left located below “Power”. A healthy reading for that field specifically for the Onyx RCR is 0.040 and below. If yours is above 0.040 then charge your battery to full and make sure the “Balance Only When Charging” toggle is set to “Off”. Allow a day or two for your “Cells” field to balance below 0.020. Some peoples charging habits have allowed this field to climb above 0.060 which will cause premature cut-offs during acceleration or when the battery is low.

If you’re not sure about anything about the Onyx 41ah BMS fix, then post your question to the Onyx AF Facebook group.

BALANCING

Balancing is completely handled by the internal battery management system, regardless of whether the battery is in or outside the Onyx RCR with or without a charger. The need for a compatible battery balancing charger is eliminated. The 41ah battery automatically handles all battery balancing itself 24/7/365 without intervention.

CHARGE CYCLES

Increase the charge cycles by more than double by unplugging the stock Onyx 5 amp charger or Onyx SFX 10 amp charger when the charge reaches 80 volts. Charge the battery to 82 volts or 84 volts before riding, depending on how far you think you are going.

PERFORMANCE

Charging with the stock Onyx 5 amp charger will result in a longer battery run time in the long run. While charging with the Onyx 10 amp SFX charger will provide more performance acceleration but impact the batteries long term health.

SAG

Sag is described as the amount of electricity drawn by how much throttle is given. On cold days at throttle expect the voltage sag in sports mode to be 3 volts and on hot days for it to be 4 volts.

CUT OFF

If cut off occurs because of low voltage or sag, wait 10 seconds for the battery management system to reengage the battery automatically.

STORING

Storing the Onyx RCR 41ah battery is done by charging the battery to 74 volts. There is no need or benefit to turning the battery off when storing the battery. The battery never turns off, rather turning off the battery disables the charge and discharge cables.

TECHNICAL SPECS

BATTERY CELL SPECS

OPERATING TEMPERATURE

RACING TEMPERATURE

STORAGE TEMPERATURE

LIFE CYCLE

POTENTIAL POWER OUTPUT

DISCHARGE CURVE

The Onyx RCR 41ah battery does not discharge in a straight constant line, it is more like a curve where the top of the charge above 82 volts and the charge below 66 volts deplete faster. The entire 84 volts are available but spread out and discharged at a different rate towards the top of the charge and bottom of the charge.

LOW VOLTAGE DISCHARGE CURVE

ARTICLE LINKS
TUNING SCREENSHOT

This screenshot is an Onyx 41AH battery around 60 volts after being tuned with an extra 5AH remaining. The extra 5AH translates to an additional range between 4 miles and 10 miles depending on how you throttle. The extra 5AH also increases the top-end charge for an extra 4 miles of full-throttle racing.

TUNING rule

Before tuning the settings of the BMS for performance and range gains, understand that the voltage level at which the battery rests overnight or for longer periods is super important.

CHARGING AMPERAGE

Charging at a lower amperage of 1-3 amps is healthier for a battery which also has a side effect of adding a few miles of range but with slightly lower peak output. Charging at higher amperages of 7-10 amps is less beneficial for the battery but has the side effect of increasing the peak output levels.

bms BYPASS

Advanced riders with a technical understanding of batteries can bypass the BMS for higher discharge levels but run the risk of a lack of cell group cut-off and short circuit protection which can destroy the battery. Sicko mode with BMS tuning almost makes it unbeneficial to do a BMS bypass. It is not worth losing out on all the discharge safety and protection mechanisms.

CHARGE CYCLES

Every 0.10 volts below 4.20 volts doubles the charge cycles. This means that charging an Onyx 23ah battery to 82 volts instead of 84 volts doubles its charge cycle life. Charge cycles can be defined as the number of times a battery can be charged before it degrades to about 80% of its full capacity and outputs less peak power. The difference in range on an Onyx 23ah battery between 84 volts and 82 volts is about 2 miles. It’s worth giving up two miles of range by charging only to 82 volts on an Onyx 23ah battery to double the charge cycle life from 800 to 1600 charge cycles. It’s never too late to change charging habits and benefit from increasing charge cycles.

I keep my batteries fully charged to 79 volts 90% of the time, which gives me more range than I need. While benefiting from a 5x charge cycle increase and performing at stronger higher peaks. When accounting for the 10% of the time that I charge to 84 volts, I will roughly be benefiting from a 4x charge cycle increase.

CHARGE LEVEL CYCLE INCREASE

Keeping track of how many actual miles are often ridden will reveal that charging the battery to full is not always necessary. By experimenting with charging the battery to only 82 volts, most will discover that it’s more than enough charge level while benefiting from doubling charge cycles.

CHARGE CYCLE TIPS

TUNED CONFIGURATION

BMS CAPACITY CONFIGURATION

Use the Xiaoxiang BMS app to tune the Onyx 41ah battery (Xiaoxiang BMS app link below). In the Xiaoxiang BMS configuration screens, the “Total Battery Capacity” field is set to the total amp hours (AH) of the battery’s capacity, while the “Total Cycle Capacity” field is set to 80% of the battery’s total capacity. This applies to all batteries. As an example, in the Onyx 41ah battery, the “Total Battery Capacity” field would be set to 41000 and the “Total Cycle Capacity” field is set to 32800.

CAPACITY CONFIGURATION

BALANCER CONFIGURATION

FUNCTION CONFIGURATION

PROTECTIONS

T: = Trigger Value / R: = Release Value

STOCK CONFIGURATION

CAPACITY CONFIGURATION

BALANCER CONFIGURATION

FUNCTION CONFIGURATION

PROTECTIONS

T: = Trigger Value / R: = Release Value

DISCHARGE CURVE

This screenshot demonstrates the voltage curve difference between cells as they are discharging. Not all batteries discharge identically, but knowing the characteristics of a battery is beneficial. Charging a battery at different amperages, resting charge levels, ambient temperatures, operating temperatures, charge cycles, and age affect the discharge curve of a battery.

This Onyx RCR 41ah battery is the 80 amp BMS version in full Sicko mode configuration starting from a charge of 83.6 volts. Both the Onyx RCR and the battery are at a cold start doing a dead pull. It has drawn down by 15.4 volts almost reaching the 18,000 watts that this battery can output. The latest revision of the Onyx RCR 41ah is sporting a 100 BMS which will allow for a 20,000-watt pull.

ONYX RCR 41AH DISCHARGE

BMS APPS

ONYX 41AH AND CUSTOM BATTERIES

OTHER BATTERIES

VOLTAGE CHART
BMS IOS AND ANDROID SCREENSHOTS

These screenshots are for demonstration only and are not meant to be used for configuring the BMS.

XIAOXIANG BMS ANDROID APP

ANT BMS IOS APP

ANT BMS ANDROID APP

ANT BMS VBMS ANDROID APP

MY TUNING