Charging your electric bike battery

Take care of your battery and it will last longer.

Most lithium batteries are capable of vastly improved cycle life if they are not fully charged to saturation all the time, but at the expense of reduced range.

 Benefits of Partial Charge

One of the key benefits of the Cycle Satiator is its ability to let you easily control the charge level of your battery. It is now well known that most lithium chemistries (with the exception of LiFePO4) can see drastic improvements in calendar and cycle life when they are not held at the nominal full charge voltage of 4.2 V/cell but are charged to a lower voltage instead. That’s how electric car manufacturers are able to 5-8 year battery warranties on cells that usually only test to ~500 cycles.

With most ebike chargers, you have no ability to set the full charge voltage and have to accept topping it up to 4.2 V/cell. This gives the most range on a charge, but if you don’t require the full capacity of your battery on most of your trips then you are unnecessarily reducing the battery life every time you charge it. In many cases that means replacing your ~$1000 lithium battery pack every 1-2 years, when with proper management it could be lasting more like 4-5 years. In fact the further from full charge you go, the more pronounced the life cycle improvements.

With the Charge Simulator we’ve made it really easy to produce profiles that will charge a battery to a given percentage of its full capacity, so you can easily create say 70%, 80%, 90%, and 100% charge curves for your pack, and the Charge Simulator will figure out the required full charge voltage for each. If you have a 20Ah battery, and typical trips only require 12Ah or less, then the 70% charge (to 14Ah) would be fitting most of the time. If you knew you needed just over 16Ah for a longer journey, then you would choose the 90% profile instead, and when you want to get full range from the battery or let the BMS balance the cells, then that is your only occasion to use the 100% profile.

Used in this manner, the Cycle Satiator will pay for itself many times over just by extending the useful life or your expensive lithium battery packs.

Source: Grin Technologies