I'm working on a submersible ROV and could use some information on voltage regulation. Please read through the following overview first.
The ROV has three 12V DC motors that will draw a maximum of 10A when engaged. In addition, I have two 20watt 12V lamps that will constantly draw 4.2A. Therefore my maximum total draw will be around 15A.
I have a series of DPDT relays (2 for each motor) onboard the ROV that receive 5v inputs for their coils from a control box on the surface via CAT-5.
The 12V power for the motors will be supplied from the surface with two 12V batteries run in series to produce 24V and will come down to the ROV on 160feet of 14AWG wire and distributed to the relays for power to the motors.
Using an online voltage drop calculator, I determined that the available volts at the end of the wire will be 12.38 volts based on the assumed amp draw, gauge and length of cable, etc. The calculator is located at the bottom of this page: http://www.powerstream.com/Wire_Size.htm.
Realizing that the actual AMP draw will often be much less than 15A, I'm now starting to worry about "over-volting" the system. The Relay Contacts are rated up to 8A @ 30VDC but I'm not sure about how well the motors will handle extra voltage. Relay Spec Sheet (model RTE24005)
QUESTION:
Is there some sort of simplistic voltage regulation circuit that I could build to limit voltage (coming into the relays) to 12V no matter what the amp load is?
I've looked into DC-DC converters online but the ones in my price range can only provide 100watts of 12V. According to my calculations, I'll be using up to 180 watts.
Thanks in advance,
Pcolaboy
The ROV has three 12V DC motors that will draw a maximum of 10A when engaged. In addition, I have two 20watt 12V lamps that will constantly draw 4.2A. Therefore my maximum total draw will be around 15A.
I have a series of DPDT relays (2 for each motor) onboard the ROV that receive 5v inputs for their coils from a control box on the surface via CAT-5.
The 12V power for the motors will be supplied from the surface with two 12V batteries run in series to produce 24V and will come down to the ROV on 160feet of 14AWG wire and distributed to the relays for power to the motors.
Using an online voltage drop calculator, I determined that the available volts at the end of the wire will be 12.38 volts based on the assumed amp draw, gauge and length of cable, etc. The calculator is located at the bottom of this page: http://www.powerstream.com/Wire_Size.htm.
Realizing that the actual AMP draw will often be much less than 15A, I'm now starting to worry about "over-volting" the system. The Relay Contacts are rated up to 8A @ 30VDC but I'm not sure about how well the motors will handle extra voltage. Relay Spec Sheet (model RTE24005)
QUESTION:
Is there some sort of simplistic voltage regulation circuit that I could build to limit voltage (coming into the relays) to 12V no matter what the amp load is?
I've looked into DC-DC converters online but the ones in my price range can only provide 100watts of 12V. According to my calculations, I'll be using up to 180 watts.
Thanks in advance,
Pcolaboy