Thanks for the replies so far.

Before starting this thread, I did a search for adapters for Ryobi batteries to Hobbico starters. Not Dewalt or Milwaukee batteries, and not Sullivan starters.

I have Ryobi batteries and a Hobbico starter, and I am not going to buy other brands. I am trying to save money.

I found nothing in that search, and was hoping someone else had gone through this particular challenge, and had already came up with a solution. I guess I will probably end up being the pioneer on this.