The SMA iPads came with a brand new 12W charger and USB to lightning cable (or 20W charger and USB-C to lightning cable - Generation 8 & 9).
These should easily last 4+ years with proper care and will charge your iPad very quickly. iPads will typically charge with others sources but not as quickly. For example, the charger that comes with the iPhone only delivers 5W of charging power so it will be much slower.
With online collaboration relying heavily on video communications this can often drain the battery more quickly. Thus iPads may have to be plugged in during the school day. Note: Using a different charger other than what came with the iPad may result in the battery charge going down when using even if plugged into power.
If your charger or cable has become damaged or lost:
Please submit a request above or email Tech Help @ SMA if you have any questions.