Battery Knowledge Base
Want to learn more about how to take care of your battery or how batteries behave? You’re in the right spot, we’ve got plenty of info for all your battery related questions!
Battery safety & health
You’ve no doubt seen headlines on the news about battery fires and thought to yourself "Is my ride safe?” If you’ve kept good care of your device and made sure not to mistreat it, it is perfectly safe. All (properly designed) devices contain a BMS to monitor the battery and ensure it is operating safely. If you are concerned you may have mistreated your battery, ask yourself the following questions:
- Has the battery gotten wet or has the battery been punctured/dented?
- Has the battery been exposed to extreme temperatures during charging? (0°C/40°C) or has the battery been exposed to extreme temperatures while riding? (-15°C/40°C)
If the the answer to 1 is yes, your battery may be unsafe. Get in touch with us and we can provide advice. If the answer to 2 is yes, then your battery may have been damaged but should still be safe, just make sure to follow the tips and instructions below. If you have any questions feel free to reach out and we can answer your questions.
Battery Maintenance
Batteries don’t require “maintenance” in the regular sense, they just need to be stored and used in particular ways to ensure safety and longevity. Here’s a brief overview, detailed breakdowns can be found further below:
- Moisture and water: Batteries must never get wet, or they risk catching fire. This sounds counterintuitive but it's true.
- Impacts and punctures: Never puncture, dent, smash or cut the battery pack, this can damage them enough to catch on fire.
- Temperature: Never place a battery in front of a heat source where they could exceed 40°C or charge a battery at or below freezing. Both can cause damage or lead to a fire.
- Proper charging: Never use a charger you are not 100% certain is compatible. Incorrect voltage or current can damage the battery, charging circuitry or protection systems. Using an incompatible charger is a leading cause of battery fires.
- Storage: If you are not going to use a device, make sure to charge the battery every month to keep the battery between 40% and 80%. Read: “Deep Dive: Storage” below for details on proper storage.
Deep Dive: Storage
Don’t plan on using your PEV for a bit? There are a few important things to note. Your device’s battery will discharge over time when not in use so proper care is key. Here’s how you keep your battery in good condition:
To store a PEV, you should…
To store a PEV, you should charge it up to 80%. Once this is achieved you should place the device in transport mode and move it to the storage location. Colder temperatures reduce self discharge (down to a maximum of -20°C where you risk cell damage). Storing a device in a warmer environment allows you to immediately charge it rather than waiting for the battery to warm up to the required 10°C temperature. However, this will also increase the self discharge rate.
Once devices are in storage, regular check-ins should be performed, with the first check-in after 1 month to determine the self discharge rate. Depending on the discharge rate you can either charge the device every month or once every two months. The main thing to focus on is preventing the battery from discharging below 30% for best results.
After checking the battery health, leave the device plugged in to charge to 60-80%. After a recharge, put the device in transport mode and return it to the storage area. When you’re done storing the device, and ready to take it for a ride, warm it up to room temperature and charge to full 2-3+ hours for cell balancing. After that, make sure to check the tire pressure and firmware updates. Then it's ready to ride!
Turbo Nerd info:
Lithium cells have an average discharge over time of 2% per month. This typically varies with temperature.
Deep Dive: Charging, Use and Battery Health
Charging and battery levels are pretty simple in theory, charge when empty and use when full. But the devil lies in the details.
The main concerns can be broken down into three categories: Charge/discharge speed, charging/riding temperature and battery health management.
Charge/Discharge Speed
Batteries will heat up the faster they are charged/discharged due to the natural internal resistance they have. Heat accelerates the natural capacity loss that lithium batteries experience as they age and are used. Because of this, when charging your device you should try to charge it as slow as reasonably possible. Slower charging = less heat = greater longevity.
Similar to charging, the harder you ride your device the faster you discharge your battery. This also generates heat and can lead to reduced battery lifetimes. This isn't as big of a concern as charging quickly, but it should still be mentioned.
A good rule of thumb to maximize battery health in relation to charging and discharging: Charge as slowly as possible, minimize high intensity riding (lots of fast acceleration and high power draw).
Charging/Riding Temperature
Cold temperatures reduce the output power of batteries by a noticeable degree and can cause damage if they are used or charged at extreme temperatures. Thankfully the effects can be mitigated with some foresight and planning.
Cold Temperature Charging
Ambient temperatures at or below 10
If you need to charge your battery at lower temperatures, ensure the cells are at or above 10°C. If the cells are between 5-10°C you can still charge if absolutely necessary, but you must use a slower charger to prevent damage. Charging at or below freezing should NEVER be done as that can damage your battery at best or lead to a fire at worst.
Warming up your battery for charging is easy thankfully, but it can take a bit depending on how cold it is outside. The best strategy for warming your batteries is by taking your device inside and leaving it for an hour or two. It’s important not to place your device near a heat source as that can overheat the batteries and lead to damage. Point a fan at your device to circulate the warm inside air if you want it to warm up faster. Most devices let you check the battery temperature using an app. Make sure to look for “Battery Temperature” and avoid looking at just “Temperature” as the second one is just an average of everything on the device and not just the battery.
Cold Temperature Riding
Riding at cold temperatures is possible but you should be mindful of the reduced performance. The chemical reaction that powers batteries will not work as well below 10°C and means your top speed and torque will be lower. Thankfully all you really need to do is be mindful not to push your device as hard.
However, if the batteries drop below freezing then you risk damaging them while riding. (This is actually the #1 source of dead power tool batteries, cold temps are no joke!) Thankfully this can be mitigated by bringing your device inside 1-2 hours before you ride to let the batteries warm up to room temperature. If you’re in a rush you can point a fan at your device to circulate the warm inside air, make sure not to place it in front of a heat source as you risk overheating your device.
Through testing, we have determined that high speed riding will cool batteries down very quickly despite being warmed up beforehand. City riding keeps your batteries a bit warmer due to the constant acceleration and braking, however its not enough to keep the cells warm for long periods. Keep this in mind when you ride as your performance will drop and you’ll have to wait for them to warm up when you charge.
Battery Health Management
The battery found in your PEV is lithium-ion, which experience a loss of capacity or “health” over time and from various factors. The good news is that if you put a bit of effort into how you use, store and recharge your battery you can extend its life!
Batteries will lose the least amount of capacity over time at 40%-60% charge, if you plan on storing your device try to keep it at those levels. Temperature also reduces the health of batteries over time, storing a battery at 0°C will reduce capacity loss compared to storing it at 40°C (94% total capacity vs 65% total capacity when stored for a year at 100% charge). Another important factor is “depth of discharge." Simply put: draining a battery from 100% to 0% once is harder on it than draining it from 100% to 50% twice. If you can, try to minimize how low you drain the battery between recharges. The last thing to consider is the two extremes of battery charge. Batteries will degrade quickly if left at very low or very high battery levels. If you leave a device for a while when its battery is fully discharged, the battery could fall into a deep discharge state, which renders it incapable of holding a charge. Leaving a battery at 100% charge for a while isn’t as bad, but is definitely not ideal. If you don’t need to use your device right away, charge it to 80% and leave it there until you need to ride it next.
Now, all of that sounds like a lot of work but thankfully it can all be distilled down to a few easy things to keep in mind:
- Your battery will keep more of its original capacity if you charge it up to 80% instead of 100%. But make sure to charge it up to 100% every month to let the cells balance.
- Avoid deep discharges if possible, it’s better to charge a battery up so that its at 50% instead of 20% at the end of a ride.
- Never store or leave your device at 0% charge for a long time, this can kill a battery.
- Avoid high temperatures if you can, the warmer batteries get the more they’ll degrade. Batteries like being between 15°C and 35°C.
If you keep those four things in mind your battery should keep its capacity for a long time!
Have some more questions? Shoot an email to onyx@eevees.com