Understanding gendsets as they pertain to hybrid propulsion.

[unbusted67]

Sorry “gensets” and I’m not saying I’m doing this but I am researching hybrid propulsion and find myself a bit confused regarding generator/batt bank sizing for a 24kw electrical DC motor.

Assuming no solar or regen how would I calculate bank size and more importantly generator size?

[SailingHarmonie]

Once you know what the electrical demand of your engine is a cruising speed, and how far you want to go on battery only power, that tells you how big your battery bank needs to be. If you want to the generator to supply enough power to run the boat at cruising speed, you need a generator big enough to power the motor, plus enough to add some to the batteries, plus enough for house loads.

In terms of gross fuel usage, capital cost, and maintenance cost, it is hard to design such a system that is more efficient than a properly sized straight diesel power plant.

[unbusted67]

Let’s say I’ve got a 24kv motor and am looking at a 400ah bank at 96volts (2 banks of 8 series/parallel) that’s 400x96=38000kwh so I could run the motor at WOT for 1.5 hrs. I’d need an absolutely massive generator to both run the engine and charge house bank and propel the boat. Something in the order of 50kw, which you’d be hard pressed to fit in and engine room. Does this sound right?

[unbusted67]

I just did days of research when I could have just watched a 7 minute YouTube video. �� https://youtu.be/ktLksMWVb0s

[Statistical]

Originally Posted by unbusted67

Let’s say I’ve got a 24kv motor and am looking at a 400ah bank at 96volts (2 banks of 8 series/parallel) that’s 400x96=38000kwh so I could run the motor at WOT for 1.5 hrs. I’d need an absolutely massive generator to both run the engine and charge house bank and propel the boat. Something in the order of 50kw, which you’d be hard pressed to fit in and engine room. Does this sound right?

If you are going to use a generator large enough to power the full output of the electric motor 24/7 there is no point just have the engine turn the propshaft.

The idea of a hybrid propulsion is you mostly use the electric motor for populsion and the generator backfills some of the required power and also recharges the batteries as needed.

A 24 kW electric motor coupled to a 24 kW diesel generator/engine is pointless. Have the 24 kW engine just turn the propshaft.