No low voltage cut-off on battery?

[adam]

Hi @magnusmyklebost,

Please see this thread for some possible procedures to possibly partially recover the battery.

Charging a battery with low voltage

I experienced that the Bluerobotics charger would not charge my battery with the reason that the voltage was too low. Since I needed the battery for the operation to continue, I had to find a solution. My solution was to connect the “dead” battery to my second battery with the charging cable, for app 10 - 20 seconds. This was enough to raise the voltage enough for the charger to accept the battery and recharge it. Is there a more correct way to charge a “dead” battery?

Note that this procedure caries a certain amount of risk, and the utmost caution should be used!

However, if in your case the cells are in fact completely dead (0 V) you should not attempt this procedure and instead safely dispose of the battery at a battery recycling center. In any case, over discharging the battery below the bare minimum of 10 V total (2.5 V per cell) will cause some degree of permanent damage, and capacity/discharge capability will be affected even if recovered.

The is no BMS or low voltage cut off system built into the battery or the BlueROV2, voltage should be monitored with the PSM and voltage display in QGC while diving to determine when the battery needs recharging. Due to the high current the BlueROV2 can draw (bursts of up to around 130-135 A) a cutoff or switch that can handle this is difficult to implement and would be expensive. We are working on this, and are developing a reasonable cost solution that will work.

-Adam