Good morning.
My battery bank for BowThruster died... so...
I've ordered more LFP cells and want to make a connection like on the diagram.
I have house batter ~700Ah LFP (H.BATT)
I will add Fron Battery Bank (FBB)
FBB will be used only for bowthruster (BT) as a high amp load (UP to 500A) together with house bank via Victron BP220.
How to protect a bowthruster battery:
Use any BMS like DALY on negative and:
connect BP220 "-" cable to the BMS load output line as on the diagram - overcharge protection.
mount additional relay on signal line also grounded to the BMS load output line as on the diagram
A result:
1. if BMS will "decide" to cut load - BT will not work... simple.
2. but... if BMS will decide to cutt off charging it will open BP220 and I won't be able to use FBB capacity to use as additional House Battery until V will drop... hmmmm...
Now my House Battery is charged only to 14,1V so if I will set up Front Battery Bank BMS to higher level probably i will never cut this bank unless there are unbalanced/malfuctioning cells or situation like this but it will come back to normal when it will manage to balance cellls.
What is making me thinking. If the moment of connectiong BP220 will happend when there will be a bigger V difference between bank we can meet a high current between banks what is not recommended... Of course on the line ~20m of cable 95mm2 it shouldn't be a problem and resistance will not allow current to increase dramaticcaly but... there is always a question
Anyone any practical experience?
And a second question:
Does BP220 can work both directions? What are current limitations when it works from OUT -> IN?
[ if it doesn't solution would be to put 2x BP220 connected in parallel but with opposite directions of IN and OUT ]
What to you think?
My battery bank for BowThruster died... so...
I've ordered more LFP cells and want to make a connection like on the diagram.
I have house batter ~700Ah LFP (H.BATT)
I will add Fron Battery Bank (FBB)
FBB will be used only for bowthruster (BT) as a high amp load (UP to 500A) together with house bank via Victron BP220.
How to protect a bowthruster battery:
Use any BMS like DALY on negative and:
connect BP220 "-" cable to the BMS load output line as on the diagram - overcharge protection.
mount additional relay on signal line also grounded to the BMS load output line as on the diagram
A result:
1. if BMS will "decide" to cut load - BT will not work... simple.
2. but... if BMS will decide to cutt off charging it will open BP220 and I won't be able to use FBB capacity to use as additional House Battery until V will drop... hmmmm...
Now my House Battery is charged only to 14,1V so if I will set up Front Battery Bank BMS to higher level probably i will never cut this bank unless there are unbalanced/malfuctioning cells or situation like this but it will come back to normal when it will manage to balance cellls.
What is making me thinking. If the moment of connectiong BP220 will happend when there will be a bigger V difference between bank we can meet a high current between banks what is not recommended... Of course on the line ~20m of cable 95mm2 it shouldn't be a problem and resistance will not allow current to increase dramaticcaly but... there is always a question
Anyone any practical experience?
And a second question:
Does BP220 can work both directions? What are current limitations when it works from OUT -> IN?
[ if it doesn't solution would be to put 2x BP220 connected in parallel but with opposite directions of IN and OUT ]
What to you think?