AC or DC? What options are available? What are the trade-offs? There are so many options and ideas. Used 240v AC electric motors are cheap and could be driven directly off the generators. Similarly fork-lift truck DC motors are cheap and come with controllers and chargers but of course require a large battery bank.

Views: 37

Replies to This Discussion

ELCO have DC motors up to 100HP which are far more than sufficient for this application, but to propel at this rate for long a much larger generator is needed. However a major benefit is that if propulsion is mainly needed to enter and exit port for short periods, this can be done entirely on reusable energy from solar. Further, these motors are regenerative and charge batteries up under sail using the freewheeling propeller.

DC FORKLIFT MOTORS

Electric forklifts are powered by an electric motor (12, 24, 36, 48 or 72 VDC) and typically use large lead-acid batteries (10-75KWh capacity) for traction and lifting power. Forklift motors are very popular for electric car projects and there is a lot of online knowledge, practice and research. There is good information here: https://www.youtube.com/watch?v=UnLEy8p9Xu8

QUESTIONS

  1. Are these motors rated for continuous power or do they have duty cycles?
  2. What cooling do they need?
  3. Can a simple AC-to-DC bridge rectifier provide a high charge rate directly to the batteries during long-term operation? Or would an expensive 20kW charger need to be sourced? (NOTE during continuous thrust operation the battery load would be considerable and the usual Peukert-cycle charging is assumed not required)

SOURCING
There are many of these motors cheaply available online, eBay etc. Similarly, DC controllers are also readily available and cheap (Speed, Fwd, Rev). 

OPERATION

This will require a battery bank that can drive at least 1 hour for propulsion, plus generator-driven charging at a high rate for sustained propulsion.

ADVANTAGES

  1. For anchoring and port purposes, it could be possible to charge using solar over days then for short periods maneuver on battery power alone. This could allow for quiet port entry/exits and into wind for sailing. Instant quiet power is appealing.
  2. However on this vessel generator power to run the ship may take some time and investment to transfer to solar power. Panels, charge controllers and batteries are all expensive BUT could be added gradually to take load off generator usage. 
  3. For propulsion, however, a generator will always be needed to keep the batteries charged during long-term operation.

RSS

DONATIONS AND MEMBERSHIP

Access to this online community is free. Please Sign Upinvite your friends and join the conversations!

International Rescue Group is a 501(c)(3) Public Benefit Nonprofit organization and your donations can be applied against US taxes. IF YOU WANT TO USE A CREDIT CARD, CLICK THE DONATE BUTTON:

IN YOU ALREADY HAVE A PAYPAL ACCOUNT: CLICK HERE for fee-free donations.

To donate a boat or marine equipment email here.

Discussion Forum

TRADE-OFF ANALYSIS

Started by Captain Ray Thackeray, IRG Sep 5. 0 Replies

TYPES OF MOTOR

Started by Captain Ray Thackeray, IRG. Last reply by Captain Ray Thackeray, IRG Sep 3. 2 Replies

BATTERY DISCUSSION

Started by Captain Ray Thackeray, IRG. Last reply by Captain Ray Thackeray, IRG Sep 1. 1 Reply

Photos

  • Add Photos
  • View All

© 2018   Created by Captain Ray Thackeray, IRG.   Powered by

Badges  |  Report an Issue  |  Terms of Service

Google+