Lipo / LiFePO4 ebike battery information
There is a solution: dividing a battery into smaller packages. Grin Technologies sells e-bike batteries that are allowed in aircraft luggage.
Don’t charge to 100%
This article explains why, in order to extend battery life, you shouldn’t charge to 100%: How to make a lithium battery last, or…kill it, if you like.
Common battery types for ebikes
Batteries for e-bikes can be broadly divided into two types, lithium and LiFePO4. The latter is also lithium but has a lower cell voltage and a very long life. Batteries for e-bikes can be broadly divided into two types, lithium and LiFePO4. The latter is also lithium but has a lower cell voltage and a very long life. The voltage of lithium cells varies considerably during discharge and the nominal voltage is therefore stated with 3.6V or 3.7V.
| Lithium [V] | LiFePO4 [V] | |
| Nominal voltage | 3.7 | 3.3 |
| Charge cut-off voltage | 4.2 | 3.65 |
| Number cells in series for “36V” | 10 | 12 |
| Battery “36V” | 37 | 39.6 |
| Battery charge cut-off voltage | 42 | 43.8 |
Chemistries
Commonly, e-bikes use lithium ion batteries which are available in different chemistries: LiCoO2, LiNiO2, Li-NiCoMn, LiFePO4 etc. LiFePO4 batteries have some advantages: longer cycle life and fast charge capability. The disadvantage is the lower energy density [Wh/kg], but note that the energy density of other lithium ion batteries degrade drastically after some years of usage.
A123 ANR26650
Note that I built this battery in 2014 so higher capacity batteries are available in the meantime. I prefer LiFePO4 battery cells ANR26650 from manufacturer A123. This battery offer high charge rates of 15 minutes, which allow fast charging on the go. There are more LiFePO4 manufacturers, but they differ in quality. Not just the LiFePO4 technology is the key to success, but its patented method in nanotechnology. LiFePO4, like any other multi cell lithium battery needs a BMS, which protects cells from over discharge and over charge. Also a balancer is required which usually combined with the protection circuit.
A123 LiFePO4 battery cell ANR26650
Here are some figures of the A123 LiFePO4 battery cell ANR26650:
- Battery cells old: 3.3V, 2.3Ah, 7.6Wh, 70g, specific energy: 108Wh/kg
- Battery cells new: 3.3V, 2.5Ah, 8.3Wh, 76g, specific energy: 108Wh/kg
- Recommended fast charge current 10A to 3.6V CCCV, 15 min
- Cycle life at 10C discharge 1000 cycles
- Self-discharge 2% / month
LiFePO4 A123 battery 12s2p 4.6Ah 180Wh 43.2Vmax
Chinese LiFePO4 battery 36V / 10Ah
Note that I built this battery in 2014 so higher capacity batteries are available in the meantime.
| Battery | |
| Configuration | |
| Charge cut-off voltage | |
| Discharge cut-off voltage | |
| Measured battery capacity at 5.5A | 398Wh |
| Measured specific energy at 5.5A | |
| Battery cells weight | |
| Total weight | 3.68kg |
| Battery holder weight | 0.36kg |
LiFePO4 battery discharge graph
Panasonic CGR18650CG Li-NiCoMn battery 36V / 9Ah
| Battery cells | |
| Rated capacity | 3.6V / 2.25Ah |
| Weight | 44g |
| Rated specific energy | 184Wh/kg |
| Max. charge current | 1C |
| Cycle life at 1C discharge | 600 cycles |
| Battery | |
| Configuration | 10S4P |
| Charge cut-off voltage | 42.5V |
| Discharge cut-off voltage | 30V |
| Measured battery capacity at 5.5A | 308Wh / 7.7Wh per cell |
| Measured specific energy at 5.5A | 175Wh/kg |
| Battery cells weight | 1.76kg |
| Total weight | 2.85kg |
| Battery holder weight | 0.31kg |
Li-NiCoMn battery discharge graph
LiNiCoAl Lithium Nickel Cobalt Aluminum
This information is out of date, who can make an update? The highest specific energy of 265Wh/kg can be obtained with the new lithium ion battery chemistry LiNiCoAl from Panasonic and Samsung
| Battery cells | |
| Rated capacity | 3.6V / 3.4Ah |
| Weight | 46g |
| Rated specific energy | 265Wh/kg |
| Max. charge current | 0.7C |
| Cycle life at 1C discharge |
| Battery | |
| Configuration | 10S3P |
| Charge cut-off voltage | |
| Discharge cut-off voltage | |
| Measured battery capacity at 5.5A | |
| Measured specific energy at 5.5A | 224Wh/kg |
| Battery cells weight | 1.38kg |
| Total weight |
Fast charge Lipo batteries
Standard Lipo batteries have a low maximum charge current of about 0.2C, but Lipo batteries for model aircraft allow higher charge and discharge currents. Some Lipo batteries have a maximum charge rate of 10C. ZIPPY Compact 5000mAh 10S 25C Lipo Pack Specific energy: 5A 37V / 1.161kg = 160Wh/kgMax. charge rate 5C.Note that Lipo batteries are not intrinsically safe, there is a risk of explosion or fire.
Lipo battery, charge rate 5C, specific energy 160Wh/kg
Hybrid supercapacitor battery
A hybrid battery contains batteries of different technologies. In this way, the hybrid battery can have better properties than the individual batteries. An example is the combination of ultracapacitors and lithium-ion batteries. The ultracapacitor withstands high peak current in contrast to the lithium-ion battery, so the combination has a higher lifetime.
LiFePO4 battery energy storage efficiency versus voltage
When the battery efficiency is 100%, the stored energy is U I t. The battery efficiency however varies as function of the voltage. Between 3.0V and 3.4V the efficiency is high; here most of the energy is stored. At the end of the charging cycle, not only the voltage rises rapidly but the battery efficiency is very low too. In other words, there is less energy stored in the battery between 3.6V and 4V.
The evidence of the limited energy storage above 3.6V is that after charging, the voltage drops quickly without load. See the charge curve.
LiFePO4 batteries overcharge tolerance
Usually it is recommended that LiFePO4 batteries should be charged until the voltage reaches 3.6V. They can however be overcharged to about 4V without degradation or safety issues. To store more energy it doesn’t make sense to overcharge a LiFePO4 battery.
How to store lithium-ion batteries
Batteries will age, even at storage. In order to extend the lifetime when stored for a longer time, treat the battery as follows:
- Try to keep the battery temperature between 15°C and 25°C.
- Discharge the battery and then charge the battery to 40% of the capacity. For instance, a 10Ah battery should be charged 2 hours at 2A.
Determining the number battery cells
As an example we take the LiFePO4 battery A123 ANR26650.
At 5A the average cell voltage is 3.15V:
LiFePO4 discharge characteristics
For a motor voltage of 36V the number of cells in series is 12. To get a capacity of for instance 180Wh, we need 24 batteries.
Battery internal resistance loss
As an example we take the LiFePO4 battery A123 ANR26650.
As we can see below, the internal resistance of the 12s2p battery pack is 110mΩ. Assume the motor input power is 200W:
Measuring battery internal resistance
As an example we take the LiFePO4 battery A123 ANR26650.
Battery nickel solder tabs
The A123 solder tabs are not made of copper but of nickel 200/201, which has a high electrical resistivity ρ compared with copper.
The dimensions of the solder tab between two battery cells are 9mm x 0,25mm x 35mm. The resistance is thus 9.6 10.8 35 10.3 / (9 10.3 0.25 10.3 ) = 1.5mΩ.
Battery DC load test
There’s a lot to talk about how to measure the impedance of batteries, if you google on “battery impedance testing” you’ll find a lot. Determining the internal battery resistance can be done by using a DC load and measuring the discharge current and voltage drop. The load is simply created with a power MOSFET and three 12V/100W halogen lamps which give a load current of 8.4A
Measuring internal battery resistance
I have connected and disconnected the load several times and measured the battery voltage with a digital storage oscilloscope built with an Arduino.
12s2p LiFePO4 A123 ANR26650 load test 60sec
12s2p LiFePO4 A123 ANR26650 load test 10sec
The negative voltage spikes occurs because the lamps have a positive temperature coefficient. As we can see in the chart, after the voltage jump, the voltage decreases exponentially during more than 60 seconds. Also there is a recovery period after disconnecting the load.
The resistance is measured at the value of the voltage jumps, which average value is ~ 0.8V. This gives a battery pack resistance of 95mΩ (0.8V / 8.4A). It is clear that measuring the Rapid voltage jumps with a multi meter is not possible; by the slowness of the measurement we get too large resistance values.
The internal resistance per cell is about 16mΩ which is far more than the value of 10mΩ according to the manufacturer. A123 uses a pulse load test to measure the internal resistance but that gives the AC resistance instead of the DC resistance.
Battery pulse load test
The pulse load is simply created with a 50Hz square wave generator connected to the gate. Use an oscilloscope to measure the battery voltage change.
Battery pulse load measurement
- T battery = 34°C
- VDC = 40V
- I average = 4.95A, I = 9.9A
- Δ Ubat = 0.6V, see scope:
A123/ANR26650 34°C VDC=40V scope 200mV 5ms. Internal resistance = 8.6mΩ
Calculation battery internal resistance
- The battery has 12 cells in series and 2 cells parallel (12s2p)
- The A123 ANR26650 internal resistance = 60.6mΩ / 6.1.5mΩ = 8.6mΩ
At 25°C the internal resistance is about 10mΩ which is equal to the value in the ANR26650 datasheet. However, this value is too optimistic and practically unusable.
Internal resistance temperature dependence
As the LiFePO4 temperature increases, the internal resistance decreases. See here the results of the measurements that I have done. Note that the chart is measured with the pulse load test.
A123 ANR26650 LiFePO4 internal resistance versus temperature. VDC=40V
Li-ion, like other battery types, performs better at high temperatures than at low ones. But heat also stresses the battery.
Impedance characteristic temperature dependence
As we see here, the impedance characteristic changes with temperature too.
A123/ANR26650 17°C VDC=40V scope 200mV 5ms. Internal resistance = 12.5mΩ
Battery equivalent electrical circuit
I have created a LiFePO4 cell model that corresponds to the measurements at different temperatures. See more about the so called “randles circuit” here. Please note, it is just a rough approximation and the pulse load test is used. I still have to make a randles circuit with the DC load test.
A123 ANR26650 LiFePO4 battery simple cell model
Reviving over-discharged Li-ion batteries
One of my Li-ion batteries was fully discharged because a faulty battery fuel gauge pulled constantly 6mA out of the battery, outside of the BMS. Charging was not possible anymore. If the voltage of a one ore more battery cells comes below the cut-off voltage, the BMS comes into action and the battery will be switched off forever. I have done the following to awake the battery back to life:
Open the battery housing. Charge the battery manually with a current of 100mA, outside of the BMS, until the voltage of each cell is higher than the cut-off voltage. This normally just takes less than one minute. The BMS will reset the blockade and charging can be continued in the normal way with the battery charger. The cut-off voltage is 2V to 3V, depending on the battery type. Recovering a single battery cell works the same way. Beware, the procedure is not without risk: if a cell is defective, then the above may result in fire or explosion.
The energy required for climbing hills can be calculated roughly with the potential energy. The motor power loss is not included.
Eupen – Baraque Michel: E = 90 9.81 410 / 3600 = 101Wh.
The history of A123
2001: A123 was founded in the USA. 2012, The Chinese Wanxiang Group acquire 80% of A123 after A123 was bankrupted, the name changed to 123 Systems.2018: Battery manufacturer Lithium Werks in the USA took over 123 Systems from China.
Safe charging and storing lithium-ion batteries
Lithium-ion batteries can catch fire or explode during use and sometimes even when just stored. The safety depends entirely on built in fail-safe circuity electronics.
Charging lithium-ion batteries battery can cause fire. For safety, charge batteries in a fireproof container. But that is not enough, also use fire extinguishing granulate: This is the perfect solution for the safe storage and in the event of a fire, the extinguishing of lithium polymer batteries. When charging, place it over the battery and you have effective and good fire protection. When shipping LiPo batteries, simply pack them neatly around the battery and you don’t have to worry anymore.
Safer battery types are LiFePO4, Li-Mn and Lithium-titanate (LT).
Comprehensive lithium-ion battery test
Henrik K. Jensen from www.lygte-info.dk has tested many battery cells used for flashlights; these battery cells are used in e-bike batteries too. For instance HERE, 18650 size lithium-ion batteries are tested on capacity:
18650 size lithium-ion battery capacity comparison
The 18650 size li-ion battery with the highest capacity is the Panasonic NCR18650B (3400mAh).
Battery links
- Elithion LLC BMS technology, Li-Ion manufacturers etc.
- Batteryuniversity
- Parameterization of a 14.5 Ah LiFePO4-battery cell. Peter Andersson, Olle Collin
- How to rebuild a Li-Ion battery pack
- Tesla Roadster battery technology
Tesla Roadster battery technology
Bosch e Bike batteries
Bosch batteries are an efficient, long-life energy source. Thanks to their enormous mileage, long service life and intelligent battery management system, Bosch lithium-ion batteries are among the most modern on the market. Bosch eBike batteries combine low weight with ergonomic design and simple handling. The battery management system of the high-quality lithium-ion batteries detects potential sources of error and protects cells from overloading. There’s a suitable rechargeable battery for every requirement and every type of eBike; whether it’s the rack variant, frame battery or the integrated solution. The DualBattery is perfect for touring bikers, long-distance commuters or cargo bikers. The combination of two Bosch batteries delivers up to 1,250 Watt hours.
Four battery positions
Frame battery
Sporty dynamic: As a frame battery, the PowerPack sits close to the centre of gravity to ensure optimum weight distribution.
Frame battery
Sporty dynamic: As a frame battery, the PowerPack sits close to the centre of gravity to ensure optimum weight distribution.
Rack battery
Comfortably convenient: On step-through models, the rack battery frees up space and allows the rider to safely mount and dismount.
Rack battery
Comfortably convenient: On step-through models, the rack battery frees up space and allows the rider to safely mount and dismount.
Integrated battery
Stylishly elegant: The PowerTube can be integrated perfectly in the frame, creating a clean eBike look.
Integrated battery
Stylishly elegant: The PowerTube can be integrated perfectly in the frame, creating a clean eBike look.
Double the power: Linking two Bosch batteries can deliver even greater range. Ideal for tour bikers, long-distance commuters and cargo bikers.
DualBattery
Double the power: Linking two Bosch batteries can deliver even greater range. Ideal for tour bikers, long-distance commuters and cargo bikers.
PowerPacks
The versatile power source: PowerPacks from Bosch come in a variety of types. Frame batteries are close to the bike’s centre of gravity. This has a positive effect on riding behaviour. The rack variant is ideal for step-through models (only available in Bosch eBike system 2), offering greater freedom when mounting or dismounting. Charging is very simple in both variants: For charging with a Bosch charger, the PowerPacks can be easily removed with just one hand movement or conveniently charged on the bike itself. The high-quality, long-lasting eBike batteries from Bosch have high energy density with a compact size and light weight.
Battery – variants for the Smart system
New PowerPack 545
Go that extra distance: The PowerPack 545 is your ideal companion for excursions and city trips. You’ll never be caught short – even on last-minute diversions or unplanned uphill climbs.
New PowerPack 545
Go that extra distance: The PowerPack 545 is your ideal companion for excursions and city trips. You’ll never be caught short – even on last-minute diversions or unplanned uphill climbs.
New PowerPack 725
power and stamina: The PowerPack 725 is the perfect choice for longer tours or more demanding rides. It is ideally suited to eCargo Bikes or speed pedelecs with higher energy requirements.
New PowerPack 725
power and stamina: The PowerPack 725 is the perfect choice for longer tours or more demanding rides. It is ideally suited to eCargo Bikes or speed pedelecs with higher energy requirements.
Battery – variants for Bosch eBike system 2
PowerPack 300
The ideal companion on short, high-speed tours: The PowerPack 300 rack and frame battery variants for Bosch eBike system 2 are suitable for everyday use and short distances.
PowerPack 300
The ideal companion on short, high-speed tours: The PowerPack 300 rack and frame battery variants for Bosch eBike system 2 are suitable for everyday use and short distances.
PowerPack 400
Go further: The power of the PowerPack 400 (as a frame or rack battery version) means you can spontaneously explore new routes, visit friends or run errands.
PowerPack 400
Go further: The power of the PowerPack 400 (as a frame or rack battery version) means you can spontaneously explore new routes, visit friends or run errands.
PowerPack 500
Perfect for long journeys: A PowerPack 500 is the same size as and only slightly heavier than a PowerPack 400 but extends the range for longer trips. Available as either frame or rack batteries.
PowerPack 500
Perfect for long journeys: A PowerPack 500 is the same size as and only slightly heavier than a PowerPack 400 but extends the range for longer trips. Available as either frame or rack batteries.
Filter options
- PowerPack 300
- PowerPack 400
- PowerPack 500
- PowerPack 545 Frame
- PowerPack 725 Frame
- System
- Mounting type
- Voltage
- Capacity
- Energy content
- Weight, Frame battery/ Rack battery
- Dimensions, Frame battery/ Rack battery
- Compatible with DualBattery
- Compact Charger
- Standard Charger
- Fast Charger
- 4A Charger
Unfortunately the selected combination is not available.
PowerPack 300
PowerPack 400
PowerPack 500
PowerPack 545 Frame
PowerPack 725 Frame
approx. 2.5 kg/ approx. 2.6 kg
Dimensions, Frame battery/ Rack battery
50% charge: Approx. 2 hours 100% charge: Approx. 5 hours
PowerPack 300
PowerPack 400
PowerPack 500
PowerPack 545 Frame
PowerPack 725 Frame
approx. 2.5 kg/ approx. 2.6 kg
Dimensions, Frame battery/ Rack battery
50% charge: Approx. 2 hours 100% charge: Approx. 5 hours
PowerTubes
For the highest demands in terms of performance and aesthetics: Bosch PowerTubes have the power to drive any ride and, thanks to their compact size and minimalist design, can be integrated within the eBike to ideal effect. There are two versions which are installed directly by the manufacturer, depending on the eBike model; horizontal or vertical. The sophisticated technology ensures carefree riding enjoyment: A safety catch prevents the batteries from falling out, while still allowing them to be removed with ease. Bosch offers three integrable lithium-ion batteries variants in the Smart system and in the Bosch eBike system 2, which cover all areas of application with different energy contents.
Battery – variants for the Smart system
New PowerTube 500
Elegantly integrated within the frame and the smallest PowerTube in the battery portfolio for the Smart system: The PowerTube 500 is the perfect match for minimalist lightweight eBikes.
New PowerTube 500
Elegantly integrated within the frame and the smallest PowerTube in the battery portfolio for the Smart system: The PowerTube 500 is the perfect match for minimalist lightweight eBikes.
New PowerTube 625
With the PowerTube 625 you have found the perfect fit for your eMTB adventures and longer trekking tours.
New PowerTube 625
With the PowerTube 625 you have found the perfect fit for your eMTB adventures and longer trekking tours.
PowerTube 750
The strongest and most robust PowerTube is made for long and demanding trail adventures. With this battery on board no mountain is too steep and no path too long.
PowerTube 750
The strongest and most robust PowerTube is made for long and demanding trail adventures. With this battery on board no mountain is too steep and no path too long.
Battery – variants for Bosch eBike system 2
PowerTube 400
The PowerTube 400 for Bosch eBike system 2 brings your stylish lightweight city bike up to speed and ensures carefree riding fun.
PowerTube 400
The PowerTube 400 for Bosch eBike system 2 brings your stylish lightweight city bike up to speed and ensures carefree riding fun.
PowerTube 500
The PowerTube 500 makes it easy for trekking and eMountain bikes to tackle long distances and the battery integrated in the frame provides a clean eBike look.
PowerTube 500
The PowerTube 500 makes it easy for trekking and eMountain bikes to tackle long distances and the battery integrated in the frame provides a clean eBike look.
PowerTube 625
Ready for any adventure: The PowerTube 625 for Bosch eBike system 2 lets you take on long and mountainous tours and offers plenty of power for maximum range and elevation.
PowerTube 625
Ready for any adventure: The PowerTube 625 for Bosch eBike system 2 lets you take on long and mountainous tours and offers plenty of power for maximum range and elevation.
Filter options
- System
- Mounting type
- Voltage
- Capacity
- Energy content
- Weight
- Dimensions, horizontal battery/ vertical battery
- Compatible with DualBattery
- Compact Charger
- Standard Charger
- Fast Charger
- 4A Charger
Unfortunately the selected combination is not available.
PowerTube 400
PowerTube 500
PowerTube 500
PowerTube 625
PowerTube 625
PowerTube 750
Dimensions, horizontal battery/ vertical battery
50% charge: Approx. 2.5 hours 100% charge: Approx. 6.5 hours
PowerTube 400
PowerTube 500
PowerTube 500
PowerTube 625
PowerTube 625
PowerTube 750
Dimensions, horizontal battery/ vertical battery
50% charge: Approx. 2.5 hours 100% charge: Approx. 6.5 hours
DualBattery
No journey is too long: DualBattery is the perfect solution for tourers, long-distance commuters, cargo bikers and eMountain bikers. The combination of two Bosch batteries delivers up to 1,250 Wh and can be installed in almost any battery combination from the manufacturer. The system switches intelligently between the two batteries both during charging and discharging. This ensures that both batteries are charged and discharged evenly, significantly increasing their service life. Depending on what is planned, a single battery can also be used.
DualBattery is only available for Bosch eBike system 2.
PowerPack 300 and PowerTube 400 don’t work in any combination with DualBattery.
Awards and test wins
For more than 10 years, Bosch eBike Systems has been delivering innovative eBike drive systems that offer the best performance and quality. Numerous awards and test wins confirm this and allow us to pursue our daily work with pride.
E-Bike Batteries Are Causing Fires: Is Your E-Bike Safe?
Repeated fires have prompted the FDNY to release recommendations for the care and keeping of e-bike and other lithium-ion batteries.
- A spate of fires caused by lithium-ion batteries throughout New York City on April 21 has prompted the FDNY to issue lithium-ion battery safety tips, including for e-bike batteries.
- Similarly, a Florida bike shop burned down on April 9, after a refurbished e-bike battery was left on the charger overnight.
- E-bike batteries can be fire hazards when used and stored incorrectly. Below, we discuss how to use an e-bike battery correctly.
Between New York City’s fire department (FDNY) issuing a warning about e-bike batteries and a Florida bike shop going up in flames after a battery was left unattended on a charger overnight, it’s been a worrisome week for e-bike owners. But don’t panic: Your e-bike is likely safe, but consider this a warning to check your e-bike battery charging and storage practices.
Because lithium ion batteries—commonly found in everything from cell phones and laptops, to e-bikes, scooters, and electric cars—can store a large amount of energy, improper care and keeping of the batteries can result in fires.
“If using a lithium-ion battery, follow the manufacturer’s instructions for charging and storage. Always use the manufacturer’s cord and power adapter made specifically for the device. If a battery overheats, discontinue use immediately,” the FDNY tweeted earlier this week.
From Bicycling
New York Daily News reports that the FDNY was called to the scene of four different fires caused by lithium-ion batteries, all on April 21. The batteries were used in an array of vehicles ranging between electric motorbikes and scooters. The vehicles pictured in the fire department’s tweets are all motorbikes, rather than e-bikes—but e-bike batteries have caused fires in the past.
The largest of the four fires reportedly happened due to several batteries stored on a work shelf. While no deaths were reported, 12 people were injured in the fires. And the FDNY issued the grim reminder that four people were killed last year in fires caused by these batteries.
How do you prevent charging incidents like this from happening to your e-bike? Avoid aftermarket and off-brand or bargain batteries for your bike, first of all. Stick to the manufacturer’s specifications and recommendations. Furthermore, e-bike batteries that are charging should never be left unattended. If you’re charging your e-bike in the garage, set a timer to remind yourself to unplug it when it’s done, and if you’re leaving the house, unplug it and finish charging it when you return.
Bike shop owners should be just as careful. Unfortunately, earlier this month, Andante Bike Shop in Cutler Bay, Florida, learned this the hard way. The shop was destroyed on April 9 when a rebuilt battery was left on a charger overnight. While a normal e-bike battery from a reputable brand shouldn’t set itself ablaze when left too long on the charger, a malfunctioning battery is a serious fire hazard. Inexpensive lithium-ion batteries also present a serious risk of malfunctioning. Regardless, it’s important to never leave any e-bike battery charging overnight or without supervision.
Related Stories
It may sound excessive, but considering the number of buildings destroyed just this month due to these batteries, it’s worth taking precautions. New York Daily News reported that in the U.S. alone, charging lithium-ion batteries caused 330 fires from 2015 to 2018.
Human Powered Solutions provided Bicycle Retailer a detailed set of instructions for bike shop e-bike charging protocol, and you may want to take some of their advice for your own at-home e-bike charging station.
Li-Ion Ebike Battery Charge Charts
Whats an 80% charge on a 48v battery? on a 36v? 52v? These charts give answers to questions like these on all common ebike battery voltages.
Remember, ALL numeric charts show ballpark values that may be numerically correct, but no generic chart can match your individual cell characteristics, your pack’s age or its chemistry. Bottom line: imperfect charts like this are still good baseline references. Use these and teach yourself how to read the voltage gauge on your display screen.
Quite some time ago, I produced a series of charge status charts for a variety of common lithium-ion battery voltages. They’ve become a fairly common link to help folks out on various groups who use these battery voltages in their ebikes.
I built them using Google Sheets, so they are not web pages, which I suppose has kept them from being widely linked in search engine results when people are looking at such things.
Here for the first time are direct links to the charts on a normal web page.
Volt (10S) Battery Charge Chart
The first link is to the lowest voltage: 36v. Generally this is the lowest voltage you will find on a modern, commercial ebike. Note that its called ’36 volt’ but really that is the ‘nominal’ value. A 36v battery is actually fully charged when it is at 42.0 volts.
Volt (13S) Battery Charge Chart
The next common size is 48v. These batteries are fully charged at 54.6 volts.
Volt (14S) Battery Charge Chart
The next battery voltage is 52v and very common. 52v batteries will work on systems designed for 48v, and why is easier to understand when you become aware that a ’48v’ battery really tops out at over 54 volts. A ’52v’ battery tops out at 58.8v, so it essentially lets you use a 48v system for a longer time at higher voltage levels that it is already designed to utilize.
Volt (16S) Battery Charge Chart
With a 100% charge voltage of 67.2 volts, when you have one of these you are getting into high voltage territory