Some products (such as Presto and Badger) say that they don’t have inbuilt battery charging so that you can use AAA batteries too. Can you use rechargeable/NiMH AAA batteries with devices that do support inbuilt charging or devices that don’t have inbuilt, but have the LiPo Amigo Pro in between it and the batteries?
You should not do so. Typical lipo-chargers expect a standard 3.6V lipo. If you try to charge three 1.2V NiMH batteries, you will run into trouble. The charger will try to press up to 4.2V into these batteries, so this won’t work. It is even dangerous.
For 1.2V NiMH you should use a dedicated charger. Using them with the Badger does work, but it is a bad choice because they have a high self discharge rate. Since the Presto is not really suitable for battery use, they might be a better fit for the Presto.