Hello everyone,
We want to connect two Bluerobotics Mega batteries (6S7P) in parallel to power up an underwater vehicle and we have a question regarding the connections.
In this case we think we can connect them using a BlueBoat 6S Battery Splitter cable while following the BlueBoat 6S Battery Splitter Cable Installation guide.
We understand that, by using this cable, the batteries will be connected in parallel and that the charge of the batteries can be controlled if the JST XH connector is plugged into a proper charger.
Our questions are:
- How can the discharge of the batteries be controlled? Is a BMS necesary?
- How does the BlueBoat controls the discharge (if it does)?
- What are the advantages of using a BMS in our system vs not using it? Is it possible to use this setup without a BMS?
- Are there any recommended BMS out there in the market recommended for this setup?
Best regards
Hi @Alex_UJI1 -
A BMS is not used on the BlueROV2 or BlueBoat, so that the full potential power output of the batteries can be used. It is very difficult to find a BMS rated for this high power output! If you intend to charge via solar, or run for long periods, connecting a battery balance module to the batteries in parallel is a good idea.
The BlueBoat “controls” discharge by using the power it needs - if the throttle of the motors is high, more power flows!
I’ve not seen a BMS that can handle the discharge current for this kind of setup. Best of luck finding one if you feel it is necessary! It may be easier to find for the BlueBoat than the BlueROV2, as it uses signficantly less current. However, in general you’ll want to limit your throttle values when using 6S batteries and the M200s that propel the BlueBoat, as they are not rated for more than ~700 watts each.
If you’re concerned about over-discharging the batteries, the UVLO setting on the power switch module in the starboard hull can be set so that the batteries are disconnected when a low-voltage threshold is reached.