Theradome has a rechargeable lithium battery. It is slightly bigger than an AA battery, and stores enough charge to operate for several treatments. A replacement battery cost is $49.00.
Batteries last about 250 to 450 treatment sessions depending on often it is used and method of charging.
There are two ways of charging the battery: 1) Fully charge the device and then use it without charging until it runs out of charge (about 6-8 treatments per charge for the PRO LH80 and about 6-12 treatments per charge for the EVO LH40). 2) Put the helmet back on the charger after every treatment.
Either way is fine but leaving on the charger at all times assures that the helmet will always be ready for treatment.
Please read our blog on 4 WAYS TO MAXIMIZE THE BATTERY LIFE OF YOUR THERADOME DEVICE