RonR
Contributor
It's not surprising for the Cobalts to require charging after a long time idle, but they should start up once charged. I'm guessing you have confirmed that the cables and adapter are all OK, also the charger if you are using also. I've seen some situations like this where the A/C charger turned out to be the issue.
One thing to try with the Cobalt 2's is to connect them to a PC/ Mac and go through the firmware updating process. See: Cobalt Firmware Downloads - Atomic Aquatics They should show up on the computer desktop as "BOOTLOADER", even if the battery is missing. If so, just drag the new firmware file onto this and wait a minute or so for it to copy, then eject BOOTLOADER and restart the Cobalt. Here is a link to the latest firmware version for the Cobalt 2. Cobalt_2602_User.S19.zip
I'd be happy to take a look at them to diagnose if that doesn't work. I will sen you a message with information.
Ron
One thing to try with the Cobalt 2's is to connect them to a PC/ Mac and go through the firmware updating process. See: Cobalt Firmware Downloads - Atomic Aquatics They should show up on the computer desktop as "BOOTLOADER", even if the battery is missing. If so, just drag the new firmware file onto this and wait a minute or so for it to copy, then eject BOOTLOADER and restart the Cobalt. Here is a link to the latest firmware version for the Cobalt 2. Cobalt_2602_User.S19.zip
I'd be happy to take a look at them to diagnose if that doesn't work. I will sen you a message with information.
Ron