In Part 1 of our review of Nigel Calder’s Integrel machine, we dug into how it works, why it’s innovative, my worries about reliability, and why it is neither fault tolerant nor easily repairable in the field.
And, finally, we concluded that it was too expensive and complicated to be of use to cruisers who have reasonably modest daily power needs.
But what about those of us who want all the comforts of home and therefore use a lot of power in the run of a day, or even those with one foot in each camp?
Up until now, the only realistic way to achieve that was by fitting a separate generator. Yes, I know some cruisers are harvesting huge amounts of power using renewables, but, although I think that can be done on motorboats with plenty of deck space and little shading, doing this on sailboats results in un-seamanlike clutter and windage. Yea, I know, that’s not a popular view, but when did that ever stop me?
So before you go any further into this chapter, you may want to take our simple test to see if you even need a generator, or Nigel’s Integrel machine.
OK, still with us…you luster after all the comforts of home, you? Let’s shine the bright light of arithmetic rigour and analytical thinking on this thing.
Hi John,
Excellent article and analysis of power generating even aside from the focus on Nigel’s contribution. With your other articles, the whole is a great and realistic model for any cruiser, experienced or otherwise, to think about their power needs and approach designing a system to meet those needs.
You report MC being in the 200-400 amp range and that you do an hour or so of generator running per day. I am curious about the battery charger set up you use: is it one big charger or a few strung together? What is the initial amp output if you start at 50% depleted and how many amps are being put into the battery bank when you reach 80% about an hour later?
I am also curious about whether there is a drop-off in amp output when you add load such as a water heater.
My little experience with AC gensets is that it is hard to get the full kw capacity of the genset into DC amps, at least in any sustained way. Then, when you tried to load up the genset by adding loads like the water heater, the output of the battery chargers drops.
Thanks for your thoughts,
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
Just to clarify, 200-400 amps was a range for this recommendation, not what Phyllis and I use (we are at the low end and often, at least at anchor, under the range).
We currently use three chargers in parallel yielding 120 amps at 12 volts. Now that we have a larger battery bank I need to replace one of the chargers with a larger one to up our total to 180-200 amps. When I said an hour a day, I assumed that upgrade since it’s on the list and the fact I have not got around to it is neither here nor there for the discussion. More here: https://www.morganscloud.com/2018/06/29/reducing-ac-generator-run-time/
The battery bank will take everything we can give it from 50-80% charged, after that it does not matter how big the chargers are because the internal resistance of the batteries starts to increase:https://www.morganscloud.com/2016/06/04/how-batteries-charge-multiple-charging-sources-too/
Of course if it’s a big load day (max of about 250 amp hours for us) then it’s more like two hours with the freezer run, but that almost never happens because although we may get a net deficit on a heavy day, that gets made up for by a light day, or a day we motor. Or sometimes, now we have a bigger bank, we skip the daily charge and then run two hours the next day.
Adding AC loads has no effect at all on how much an AC generator can put in the battery. That is simply a function of the size of the charger(s). Of course if the combination of the chargers and AC loads adds up to more than the capacity of the generator it will lug, or even stall, but that’s never going to be a problem with our loads and usage. For example even if we put 200 amps DC into the batteries at 14.4 volts that would only be 3.3kW (assuming 90% charger efficiency).
As I said in the first post, a bigger problem for us with a 5kW generator is fully loading it, not overload. (We accomplish this with the water-heater, giving the boat a good vacuum, and charging everything we can think of.)
Anyway, the key thing to understand is that turning on an AC load will not reduce what goes into the batteries, rather either the generator will stall or it won’t.
And the key to efficiency is sizing the chargers, generator, and battery bank to fully load the generator. So, for example, someone at the high end of this range would want even more charging capacity than we have, but probably still get away with our 5kW generator. The other thing is not to fixate on an hour a day. For example two hours a day is just fine as long as the generator is fully loaded.
Hi
There is another alternative to recharge batteries. Each summer, I am cruising New England for 3 months and when I anchor in an idyllic harbor I do not appreciate to have my pleasure ruined by other boats starting their generators. If you are cruising in popular places, you know what I mean. This can become horrible. I have a DC Fischer Panda and I stoped using it in 2015 when I had an EFOY 210 installed in my Cabo Rico 42. I loved it immediately. I would not cruise without it. At anchor, we can enjoy music or silence on board and this is priceless. The EFOY has zero maintenance, do not beak, can be used sailing or at anchor and operate in an auto mode. I start my season bringing 10 gallons ($900) on board. I can be anchored for days up to a week and never have to start my generator. I run a freezer, fridge and electronics and need about 250 amps per day. My solar panels with the fuel cell do provide all the amps I need daily. For me, the Efoy is the second most valued item on my boat, after the autopilot.
Jean Jutras
s/v Mahi Mahi
Hi Jean,
I agree, people can be horribly inconsiderate with generators. The advantage of the battery bank / generator method that I advocate for here is that the generator can be run at times that are less disturbing, and for much shorter times too.
And I agree, there’s a lot to like about the EFOY system: https://www.morganscloud.com/2013/09/28/whats-new-in-alternative-energy/
If the machine used fuel that was easier to source, particularly in remote places, I would replace our generator with one in a heartbeat, even though $90/gallon is a shocking price.
Excellent article…little bit wordy but Nigel Calder pieces are not brief either ?
All this hoopla only strengthen my belief that “conservation is better than generation”. If somebody wants all the comforts of home buy a home. BTW in many tripical countries beachfront property will cost less than the whole Intergel system and the breeze is free….keep up the good work John!
Some Nordhavns take a more efficient approach to power generation underway, obviously does not change the consumption. They typically have hydraulic stabilising fins driven by a pump on the main engine gearbox PTO and this system can be expanded to include a hydraulically driven A.C. cruising generator
Hi Alan,
That’s interesting. I have, from time to time, wondered about using a hydraulic PTO in exactly that way. The good thing is that, at least on larger engines, this is something the designer expected and planned for. Of course hydraulics are not very efficient, but I don’t think that really matters since most Nordhavns are horribly over-engined so there’s a ton of “free” power to be harvested between the engine and prop power curves.
Steve Dashew experimented with that, I believe, in some of his early sundeer boats. He had a hydraulic PTO running a crash pump, generator head, and something else I thought too. The blogpost said in the end it did not work the way he hoped.
Hi Conor,
I remember that he tried a jack shaft but I had not realized he tried a hydraulic PTO. That said, I would be surprised if, when properly engineered, the latter would not work given that fishing boats use hydraulics for just about everything.
Hi all,
I am rather surprised and curious about why Nigel, or one of his team, has not responded to John’s article and the comments generated. Just as I appreciate it when principles get involved (like the man who commented on Colin’s anchor article), I notice when an article gets ignored. The marine community benefits from a respectful give and take.
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
Yes, that surprises me too. Nigel asked me for a copy. We don’t send out copies of member only articles so I gave him a one month complimentary membership so that he could comment. So far no response.