issue #1 – How to store your eMTB Battery
This question comes up a lot, especially here in Canada, “How should I store my Battery over winter?”. When the riding season usually takes a break for a solid 4 months, this is a pretty important question. Proper battery storage will make sure your hand-cycle is ready to go come spring and will save you a lot of money on replacements in the future.
Modern Lithium-Ion batteries experience a phenomenon known as self-discharge; a gradual but inevitable loss of its stored energy. This self-discharge rate is extremely low (about 1% per month) but, despite its slow pace, the process has the potential to kill your battery. To avoid this happening while riding or during short term storage, most Li-Ion batteries are designed with discharge protection circuits that ensure that the battery voltage doesn’t drop below this safe, minimum level of charge. However, if stored incorrectly or for too long, the self-discharge phenomenon means that the battery will continue to lose voltage past ‘empty’ but, by now, this discharge is causing irreversible damage to your battery cells. Once the battery has entered this deep discharge state, it finally reaches a point of no-return, where it’s no longer recoverable and officially dead.
Riding season is over, your hand-cycle is clean and tucked away for the winter, everything is good right? Unfortunately wrong, and we will get to the rest in the future. Storing your electric assist motor, which is key to good times, is incredibly important. Before we go any further, disclaimer time. Always check your manufacturers warranty and battery recommendations for storage guidelines. The first thing we do when we put away batteries for the season; is to charge them up so that they rest for the winter between 40-80% power. Storing your battery at 100% power or on the charger, can have negative effects on batter life. If you are planning on storing your batter for a number of months, it is wise to check in on it from time to time to see if it needs a bit of a charge to keep it within acceptable range.
Keeping your battery within an acceptable charge range is step one. Step two of longer term storage is where you choose to keep your battery. Most eMTB battery manufacturers recommend storage in a cool dry place. Even short term storage in high or very low temperatures could damage your eMTB battery. Avoid temperatures below -10°C and above 40°C where possible; Shimano warns that even 4 hours in temperatures between 40°C and 60°C could have a negative effect on battery life. This could easily happen in the back of your vehicle or even in direct sunlight. At the other end of the scale, 20 hours when temperatures hit –20°C could also do irreversible damage. Your battery should be stored in a dry area, away from combustible material in a temperatures between 0°C and 20°C. Manufacturers agree that the optimum storage temperature is a constant 10°C as the decomposition reactions slow, reducing battery ageing rate.
We also recommend removing your battery from the bike and protecting the contacts from corrosion with a thin layer of terminal grease for any storage duration. Check your manufacturers recommendations.
Your First Ride of the Season
Winter is gone and it’s time to hit the trails once again. You’ve properly stored your equipment after last season and it’s time to go. If you chose to use terminal grease on your contact points, make sure that all excess grease is removed before your first ride. Terminal grease helps prevent corrosion, but too much attracts dirt. Charge your battery to 100% and join us for a guided experience.