One of our customers recently asked us if he could store his ebike in one of the outdoor train station bike lockers. Its a great question as it brings into play how heat affects lithium ion batteries. The answer is relevant to all ebike owners looking to get the best out of their battery life so we thought we would share.
Our thanks to Bosch for their input too. While the ebike in question is Bosch-powered, our response is applicable to all batteries that use the same technology.
EBB's response: “... The conclusion is that it’s probably best not to, unless you know for sure that the temperature won’t go above 30 degrees.
With the sort of temperatures we are getting in summers now, if the locker is not cool enough during the day it will affect the long-term life of your battery. And it may also feel underpowered when you ride it at the end of the day. The diagram below from Bosch will help explain why."
As a side note and on a practical level, if you have a battery that is easily removable and can take with you then leaving the bike only in the locker should pose no issues.
Our thanks to our friends at Bosch for this technical response and their diagram on maximising the serviceable life of your eBike batteries:
“Whenever we speak about the thermal range of the battery from -10 deg C to 60 deg C, it is the actual battery cell temperature. So it does take a bit of external heat to see the cell temperature reach this. However looking at these bike storage boxes I assume the heat will be extreme in the middle of summer.
The battery management system (BMS) is continually recording cell temperature regardless of the bike being in use or not so if it did creep over the 60-degree [threshold,] then the customer will lose the warranty on the product.
Prolonged heat also can reduce the battery life significantly as the simple document below shows. Also, on those extreme days once the battery temp reaches more than 40 degrees the BMS will reduce the output power of the battery. So, in this particular situation the customer could return to their bike after it being in the storage all day and then hop on it to go home and the bike will feel underpowered if it is still holding heat above 40 degrees from the day’s storage.
If it is even hotter and at 60 degrees, the system will not even operate for the customer.”
Modern batteries are designed to operate efficiently at a specific range of temperatures. Dropping below or going above the limit will have a significant impact on their service life and actual performance.
The flipside to this is that most electronic systems, eBikes included, will have battery management safeguards to mitigate the circumstances that may arise from temperature issues.
For more information on looking after you battery see this article:
If you are looking for more handy info on looking after and using your ebike see this articles also:
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