There are 3 batteries on the Optima CM. The first is the internal battery located inside the controller.
The controller displays this battery voltage in yellow when the battery is low and needs replacement. It will display flashing red when the battery is critically low and must be replaced as soon as possible. To replace this battery, see the Changing the Battery section of the Shearwater Petrel Dive CAN
Rebreather Controller Model Operations Manual.
The other two batteries are located inside the external electronics/battery canisters. One canister houses the battery that powers the SOLO board as well as the solenoid. This battery is a standard 9 volt battery.
The external battery voltage for the SOLO/solenoid battery can also be checked on the controller. This voltage is only checked when the solenoid is fired, so if the solenoid has not yet fired the value is unknown and displays as a yellow “?”. If this is the case, adjust the controller setpoint to a higher PO2 and allow the solenoid to fire for several seconds and then recheck the voltage.
The second canister contains the battery which powers the OBOE board and HUD. This battery is a standard AA type. The HUD does not have its own battery-it only receives power from the OBOE board.
A low OBOE/HUD battery voltage will be displayed on the HUD. After turn on, the yellow row of LEDs will remain on for 30 seconds to indicate a low battery that should be replaced.
A high quality alkaline 9V battery will typically provide approximately 50-60 hours of dive time before needing replacement. However, there is a slight battery drain at all times when the batteries are in place even if the HUD and controller are turned off. If the unit is stored for an extended period of time with the batteries in place, the batteries may need replacing even it the unit has not been used.
Typically, the SOLO/solenoid 9V battery will need changing more frequently than the OBOE/HUD AA battery. Dive Rite recommends changing both batteries at the same time once either one indicates a low battery voltage. Rechargeable batteries are not recommended for use in these locations. Only high quality, name brand batteries are recommended. It is important to remember that this is LIFE SUPPORT equipment-this is not the place to be cheap on batteries. For the correct replacement batteries, please see the Battery Recommendations section below.
To replace either of the external canister batteries, begin by unscrewing the cap on the end of the canister. While unscrewing the cap, hold the canister with the cap pointed down. This will prevent any residual water that might be located on the sealing O-rings or cap threads from running down into the canister and damaging the electronics (see Figure 36). With the cap removed, carefully dry any excess water before proceeding.
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The battery can now be replaced paying special attention to the “+” and “” orientation as marked on the canister.
Inspect the canister O-rings before reinstalling the cap. They should be clean and undamaged. If needed, carefully remove the O-rings and wipe them clean along with the O-ring grooves on the cap. Lightly lubricate the O-rings with a silicone grease such as Dow Corning Molykote 111.
With the O-rings correctly in place, reinstall the canister cap by threading it into the body. The cap only needs to be hand tight. Do not over tighten.