Lot of mis info. There is no correlation that has been proved that a low battery will blow boards. Even so that was only applicable for 5V boards. The BCR2 is for PS-2 3V boards.
You can scramble a PS-1 engine with a BCR if you try to come out of reset before the BCR is fully charged. It would act just like a low battery. But again early PS-1 susceptible to this, the 97 and later not as much.
Use your BCR. For 3 V boards when the BCR is not fully charged to run the engine in conventional, you will have reduced volume. Once BCR charges up to about 2.4V (same as battery) volume will go back to normal. It will hold charge for quite a while, but when first received it will take longer to reach full charge. G
