Use AA's. You can get various models such as Uniden that take AA batteries as made, and you can get battery trays to replace the rechargeable battery from places like Overton's. When you lose power just put some new AA's in. I did this years ago after having problems with the handheld VHF holding a charge. It's the way to go.
I am a CA Ins Broker (ret.) and a long term USAA customer. Let your carrier, USAA, deal with the other party's carrier. Don't get involved other than reporting the claim immediately. Your rates won't go up much, or any, at all. Call them asap and follow their advice.
I have two of those exact batteries. They were a good buy and have been excellent so far, but that has only been about six months or so. (They are definitely made by Johnson Controls, it says so right on them.)