How long do batteries last in V3?

New pedals with about 15 hours riding (150 miles) and the batteries seem to be suddenly to low to sustain. They will start then I lose them. 

After trying various things I measured the Voltage with a volt meter - a bit less than 2.9 V initially but that's with no load. They recovered to just over 2.9V later.

These were the CR1 supplied with the pedals. 

Why didn't they last longer?

1. They may have been in the boxes a while and maybe they were old?

2. Would they have activated as they were transported and tried to connect?

3. They were connected to my phone via BT. Would they have stayed connected and transmitting if they stayed in range of the phone?

4. They were cheap batteries? They don't seem to have any manufacture marking. They are Stamped "CR-1/3N Li-Mn CELL 3VOLTS JAPAN" on the + end, on the side they have "EW" printed in black

5. Any other ideas?

I guess I've been messing with them a bit so connecting to the Head Unit and the phone a few times but that should not have exhausted them so quickly.

I've had Vector 2 for a good few years and I've not really had any problems since I ensured I always used a decent battery from a trustworthy store. In the winter they would often give low battery when cold. The V3 batteries didn't give me a low battery warning but just would not connect. 

I've replaced the CR1 with some CR1's I purchased from Duracell direct (as online shopping is all that is available at the moment). Fortunately I'd purchased these ready for when needed. I didn't expect it to be so soon.

Let's see how long the new ones last.