I assume you use a recent 2.4 snapshot ?
Did you properly delete and redefine your things as explained here ?
Not sure what you mean by
I don’t know these devices but assume they’re battery operated.
You mustn’t poll these. Effectively you cannot anyway. They’ll either report when there’s a change (if they support this functionality to report on changes) or you will have to wait for them to wakeup to send a reply.
Wakeup interval is determined by zwave parameter on the device.
Binding will take care of polling all by itself anyway, so no need to even issue a single poll query.
Your “poll” action (I assume by that you refer to send a REFRESH) will end up in a queue of un-answered messages, eventually slowing down OH as you noticed yourself.
I suggest you enable ZWave debugging to see what’s going on.
And I had to make three assumptions on information required to understand your problem (not sure I did). Please try to be more specific when asking next time.