Can I use a lower wattage charger to charge my mini 4 ie 5w

While some very old models of iPad were supplied with either a 5W or 10W Power Adapter (with the older USB Type-A connector), most models of iPad require a Power Adapter rated at 12W (i.e., 2.4A @5V) or greater to reliably charge.

5W Power Adapters (1.0A @5V) intended for older models of iPhone are inadequate to charge the majority of iPad models; if the iPad charges at all, charging will be very slow.

Recent models of iPad are supplied with a 20W USB-C Power Adapter.

You can safely try.

You might find that it will only raise the charge state when you’re not actively using the device.

We routinely “overnight charge” an iPad Pro w/ an “ancient” 5W Apple “icecube” power adaptor.