1975 C&C33 mk1 with brand new 10kw electric drive

[Rocinante_C&C33]

My wife and I spent spring and early summer 23’ on a nearly complete refit of our 75’ C&C 33. We blasted the bottom, ripped out the sea head, revamped the water system and replaced the gas powered atomic 4 With a 10kw thunderstruck setup managed and powered by a 100ah Victron blue smart 48v battery bank.
The boat runs solid, smooth and peacefully. No smells and no maintenance. We couldn’t be happier with the upgrades and am happy to answer questions about any aspect of the refit.
Rocinante is a dream to sail and fun to talk about with other sailors.

 

[MikeHoncho]

The obvious question…..what timeframes are you getting on the batteries at cruise speed ? There are obvious variables but what are you seeing?

 

[Rocinante_C&C33]

At 4-5 knots, I draw between 12-22 amps/hr. At 6-7 knots, it’s double that.
With a 100ah bank, you’re really only getting 80ah effective.
So let’s say I’m motoring into wind and into current at 5 knots SOG. I’ll likely pull between 20-30 amps. So on the conservative side, call it 30ah draw. I only have 2 1/4 hours range. With tide and wind at the stern, I can hit 5 knots drawing 12amps, meaning I can cruise on motor for + 6 hrs.
I went with the 100ah bank to get started, but would like to add a second bank of some new Victron 330AH I just saw at a conference.

 

[jssailem]

Interesting. How do you use your boat when you go or sailing. Is it day sailing? Do you cruise? What types of systems did you install to recharge your stored power?

 

[rgranger]

At 4-5 knots, I draw between 12-22 amps/hr. At 6-7 knots, it’s double that.
With a 100ah bank, you’re really only getting 80ah effective.
So let’s say I’m motoring into wind and into current at 5 knots SOG. I’ll likely pull between 20-30 amps. So on the conservative side, call it 30ah draw. I only have 2 1/4 hours range. With tide and wind at the stern, I can hit 5 knots drawing 12amps, meaning I can cruise on motor for + 6 hrs.
I went with the 100ah bank to get started, but would like to add a second bank of some new Victron 330AH I just saw at a conference.

Great Thread!
That is all very good info. 6 hours is not bad but 2 hours is less than great... but it looks like you are within striking range of a true cruiser. Thanks for the info. I have been wanting an e-aux sailboat for some time now and every now and again, I research what is out there. I had a set of two 55lb-thrust trolling motors on a Coronado 23 (many years ago now) and really loved the silence and reliability of electric (even back then). Things have come a long way and I suspect we are close to making electric aux motors a viable alternative for the cruising sailboat. I would say that electric is already viable for the day sailor.

So... next set of questions.

1. Are you using shore power or a generator or solar or ...???? to recharge your bats?
2. How long does it take you to recharge your bats on the system you are using?
3. Do you know how much actual amperage it takes to get your batteries to full charge (what is the charging efficiency)? This would be great info when trying to size solar.

I would love to hear more about your actual experience using electric in a cruising mode... I'm guessing with a second bank, and at least 50% sailing vs. motoring... you could get by with a few solar panels, and maybe wind and the occasional hook up to shore power.

 

[Rocinante_C&C33]

Interesting. How do you use your boat when you go or sailing. Is it day sailing? Do you cruise? What types of systems did you install to recharge your stored power?

We mostly day sail and weekend. So our power needs are limited. I have 2 400w Canadian Solar modules that run through a Victron charge controller.
We will be installing a DC-DC inverter to be able to charge the 12v system from the charge coming in to the 48v system.
a high quality mppt charge controller will help optimize your charge and lead to improved rate of charge.