Re: [electricboats] Electric Drive Update

Good question.  I will expand that on the write up. 

I am building a 48VDC generator that will charge the batteries directly.  You can do AC and run through the chargers and that is a very good option with some advantages.  AC generators are more readily available, you can use it to power AC house loads directly, the higher output voltage means less amps through the genset output wiring.   But, if you want to run on the generator at sustained speeds of 0.85x to .90x hull speed (my target) you will need enough charging capacity to put that much power from the genset through to the batteries/motor.   And you have an extra stage where you loose efficiency (going through charger).  But it can certainly be done.

There is a very nice AC setup on a boat in Seattle by someone who was on this forum?  Boat was sold last year.  He has a 240VAC genset and 3x of the Thunderstruck chargers which can run at 2500 watts each at 240V input.  So he has 7500 watts out of the chargers (assuming the genset can deliver that much).   The ad is still out there on the interwebs:
https://plugboats.com/acadp_listings/cruiser-liveaboard-sailboat-w-new-hybrid-propulsion/

AC to chargers has a bit greater efficiency loss but is easier to source parts I think.   DC is simpler parts wise and you don't need as large a charger.   But I still need to sort out what I will do for rectifying the genset output to DC and regulating it.  I could end up changing to AC of that is too much of a problem. 

Fischer Panda makes a 5 or 6 kW DC genset with a 48V output.  Probably $12K?    Kind of blows up the economics of the electric conversion the same way a 14kWh Battleborn battery bank would?   I am at $3300 so far for my DC genset (engine and gen head).  Still need a bunch of stuff (rectifier, regulator, cooling system, mounts,...) but I don't think that will cost $9000 more?  I hope to be under $5K and have a 8 or 10 kW unit.


Dan Pfeiffer

On 2022-01-12 12:01 pm, jesper.malmberg86@gmail.com wrote:

Well done Dan and thanks for the detailed writeup. Looks like you got a very well executed project!

I saw on your blog that you were looking at getting a diesel genset. In what direction are you leaning, traditional genset and increase the charger outputs or are you looking at 48V or possibly building your own?

Regards,

Jesper