Many people avoid electric options mainly due to fear and uncertainty about battery life – or that the costs of batteries can potentially be very high, especially after reading a lot of horror stories over the years.
A modern lithium battery in a smaller electric vehicle, such as an electric scooter, moped, motocross or bicycle, of anything between 1–15 kWh can cost between 5,000 and 50,000 SEK and is in principle always the single most expensive component.
In an electric or hybrid car with a battery of 15–100 kWh, the cost can instead be between 50,000 and 250,000 SEK.
It is therefore not surprising that people feel uncertain about the lifespan and durability of these devices and batteries before purchasing – and during the time they own them. But the battery often survives longer than many people think, and there is much you can do yourself to increase the chances of trouble-free use and maintain resale value for a long time.
A modern battery should easily survive for at least 10 years or 1000–2000 full charge cycles (explanation below), if cared for as recommended. (Tip: If you are looking for an electric vehicle or battery-powered device from 2020 onwards, be aware that terms like “lead-acid”, “AGM”, “GEL”, “WET” or “EFB” are all linked to outdated technology for this type of use – look for modern lithium batteries with built-in BMS instead.)
After a few years in the industry and hundreds of battery troubleshooting, we have identified two over-represented causes of battery problems. Both of these problems could often be avoided by the consumer in the first place – with proper maintenance and use.
- Small “handling errors” over a long period of time, which can be easily avoided with the recommendations we present below, are a common reason why the battery does not last as long as intended.
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“You get what you pay for”
Many people instinctively have a tendency to sort and choose the cheapest option when shopping, but then expect to get something completely different than "the cheapest". Just like with many other things: You get what you pay for.
In this article, we will review recommendations based on the most common modern BMS-monitored lithium batteries, which are found in everything from small power tools to larger vehicles. Although the article primarily targets these battery types, the tips can often be applied to other chemistries as well.
*To get more information about exact values and detailed recommendations for your particular battery, we recommend that you look at the technical documentation from the manufacturer.*
Below are our “nerd-by-the-book” recommendations – knowing that reality sometimes forces compromises. But if you keep these points in mind, you already have a significant advantage over many other users!
Charging & Discharging – “20-80 Rule” Temperature Limits
- Prevent overcharging: Disconnect devices as soon as the battery reaches full charge to avoid unnecessary stress.
- Optimal Charge Levels & Partial Charge: Do not fully charge the battery and avoid draining it completely. Instead, it is recommended to charge up to about 80% and down to about 20% to reduce stress on the cells.
- 100% Charge when needed: If you absolutely need to charge the battery to 100%, do so just before use, so that it doesn't spend any longer than absolutely necessary at the 100% charge level.
Storage and Temperature
- Temperature control: Charge and use batteries within the range of approximately +5 to +40 degrees Celsius to minimize accelerated degradation.
- Storage recommendations: For longer storage periods, the battery performs best at 50–70% charge.
- Disconnect the battery from the device it is in to minimize self-discharge (in addition to the small battery's own BMS consumption).
- Check the charge level every 1-2 months and recharge if necessary.
- Also store the battery in a place with a temperature of 10-25 degrees Celsius and below 70% humidity 24 hours a day to preserve its integrity.
Charge Cycles & DOD (Depth of Discharge)
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What is a charging cycle?
A charge cycle is defined as the process of charging a battery from its lowest to its full capacity and then discharging it back to its lowest capacity (0-100-0%) . Each complete cycle contributes to a gradual deterioration of the battery's capacity. - The importance of cycles: Tracking the number of cycles is important because each cycle degrades the battery slightly. By avoiding full discharges and instead using partial charges, this wear and tear is significantly reduced.
- Optimize through shallow charging: Regularly use an optimized charging method where the battery is not always charged to the max – but supplement with periodic full charges (where the charger actually completes the charge, not just shows 100% on the display) to maintain cell balance.
The Right Charger and Charging Technique
- Use recommended charger: Always use the charger recommended by the manufacturer, as these are designed to match the specific requirements of the battery.
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Limit fast charging: Fast charging can be convenient, but it increases battery wear over time. Use fast charging in moderation to avoid overheating and increased chemical stress.
Usage Habits, Maintenance & Calibration
- Firmware updates: Keep your device's software up to date to ensure that the BMS (Battery Management System) functions optimally and adapts charging to the battery's needs and external circumstances.
- Periodic Calibration: To be able to read an accurate battery level and maintain maximum capacity, it is recommended that you periodically "calibrate the battery" by allowing it to go through a full cycle (according to the guidelines mentioned above).
- Load management: Avoid loading the battery with multiple resource-intensive processes at the same time if not necessary. A smooth and balanced load contributes to a longer lifespan.
- Protect from extreme environments: Make sure your battery is not exposed to extreme temperatures or humid conditions. Regular checks and monitoring of battery health (through diagnostics or dedicated apps) can provide early warning of potential problems.
Summary
To maximize the lifespan of your lithium battery, you should:
- Follow the “20-80 rule”: Partially charge the battery and avoid spending long periods above 80% or below 20% charge.
- Store the battery at optimal temperatures: +5 to +40 °C and store it at 50–70% charge during longer periods of storage.
- Limit deep discharges: Keep track of the number of charge cycles and avoid completely draining the battery.
- Use the right charger: Follow the manufacturer's recommendations and reduce the use of fast charging.
- Maintain regularly: Update firmware, calibrate the battery, and monitor its health.
- What you absolutely should not do: quick-charge to 100% or discharge to 0% in sub-zero temperatures, then store it outdoors or in cold storage all winter.
By following these guidelines and being aware of the battery's limitations, you can not only extend its lifespan but also maintain stable performance and high resale value.
Investing a little time in understanding and maintaining your battery will pay off in the long run – both financially and in terms of reliable operation. With proper handling and preventative maintenance, you can confidently use your lithium battery well into the future without worrying about premature wear or unexpected costly repairs or replacements.
With these tips in mind, you have a good foundation for maximizing both the lifespan and performance of your lithium battery – whether it's in your electric car, electric bike or screwdriver!