Too rapid or deep discharging is detrimental to any battery. This can be the result of long up-hill rides or extended operation in grass etc. The rider’s weight is an importrant factor as well.
There are various battery chemistries. Virtually all vehicles use either lead-acid (SLA) or lithium-ion (Li-ion).
Batteries are available with different chemical compositions but as a drive for vehicles of all types are mainly only lead acid batteries (SLA) and lithium-ion (Li-ion) batteries are used.
Lead-acid batteries in battery-powered vehicles have a nominal voltage of 24 Volts, and consist of two 12 Volt batteries connected in series. These must be stored fully charged. When not in use, these batteries slowly discharge, and must be recharged every 6 to 8 weeks. A 24 Volt;battery has approximately 26 Volts when fully charged; at 23 Volts the battery is considered fully discharged. After roughly 30 such charge/discharge cycle, the lead-acid battery’s capacity (= range) is reduced by about half. Further storage at this low voltage will likely ruin the battery completely. Therefore, the best way to get the most out of your battery is discharge it only partway, and recharge as fast a possible.
Lead-acid batteries are a popular choice for use in electric vehicles because they are inexpensive and available world-wide in standard sizes. However, these batteries are heavy, and have relatively low energy density. They also lack overload and discharge protection, which leads to a shortened life. A lead-acid battery may look brand new, but may already be good nothing but recycling.
Li-ion batteries have about 7 times the energy density of lead-acid batteries. That means that, at the same weight, they provide seven times the range, or to put it differently, weigh one-seventh of a lead-acid battery of equal capacity. A full discharge to the point of automatic shutoff is also no problem.
The high cost is the main drawback, but this is more than balanced out by the li-ion’s battery’s long lifespan, which is several times that of the lead-acid battery, and the ease of handling a significantly lighter battery. The li-ion battery can remain in storage without requiring a periodic recharge, and can be stored partially discharged.
Li-ion batteries are not available in standard sizes, but are assembled from indivicual cells* for each vehicle according to voltage, capacity and dimensions (TravelScoot Li-ion batteries use Panasonic cells). One of the main components of these batteries in the built-in electronics, which control the complex charging process and protect against overload and low voltage. The battery is shut down before the sensitive cells are damaged. After an overload shutdown the battery can be turned back on immediately.
Since most electric vehicles are quite heavy, it makes little sense to install an expensive li-ion battery. The smallest conventional mobility scooters use a 24 Volt, 12 Ampere-hour lead-acid battery (as in the TravelScoot Standard), which weighs about 18 lbs. These scooters usually have a total weight of around 100 lbs and upward. If one were to substitute a 5 lbs lithium-ion battery (as used in the TravelScoot Deluxe), the conventional scooter would still weigh about 87 lbs. For most people with disabilities there is little difference between 100 and 87 lbs when it comes to lifting; it simply can’t be done.
Compare this with the TravelScoot Standard at only 47 lbs and the TravelScoot Deluxe at an even lower 35 lbs. Two batteries (either the same type or different) can be stacked for additional range. While they can be used only one at a time, switching connections only takes a few seconds.
After about 35 of these deep-discharge cycles, battery capacity will be reduced by about half, with no chance of recovery. Therefore, avoid prolonged operation in the amber caution light range. We recommend keeping an additional battery ready for longer trips.
Batteries in storage will discharge by themselves, and should be charged every 6 to 8 weeks, and stored in a cool location.
Due to the extraordinarily high weight of the sealed lead-acid (SLA) battery we no longer offer the TravelScoot with this battery option, as this completely contradicts the design philosophy of an extreme light-weight mobility scooter.