Recommendation for 48 v inboard motor + generator.

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03/23/23
From: julienweiller

Greetings!

Looking for recommendations to go hybrid (series, not parallel) .

I will need a 48 v electric propulsion plus adequate diesel generator/range extender for a 15000 pound full keel 30 footer sailboat, 24”6“ waterline, hull speed 6.5 kn (Baba 30).

Getting rid of actual engine, a 3 cylinders 30 hp diesel.

Plan is to start with 4 x 12v 150 Ah AGM (just enough to go dock down the basin)

Switch to high kWh lithium in the future for ocean sailing

Will also add solar to the equation.

I am looking for a diesel generator/range extender that could pretty much keep the batteries up while motoring.

So, that’s a lot of questions at once:
1 motor ?
2 compatible AGM/lithium controller ?
3 diesel generator?
4 solar?
5 lithium batteries?
6 compatible with all the above +220/110 charger?
7 BMS added if not battery integrated?

Sorry if this is a repeat question but it’s 2023 and it seems that technology is fast evolving!

Pretty please: no 96 nor 72 volts suggestions I am sticking with 48, 52 max.

All best and in advance, much thanks!
03/23/23
From: jeffsschwartz

I went with the Thunderstruck 10Kw kit in my Kirby 30, it's working great. The boat's lighter than yours (~6,000 lbs) so you'd probably want to go with their 12KW kit, the only issue is that it's liquid cooled.

I'm using 3 Dakota Lithium 48V/96 Ah batteries with Victron MPPT controllers and 6 110W panels on my deck when I'm not using the boat. I race the boat 1-2 nights/week and daysail one day on the weekend, I found that I only needed to charge the batteries once per month.

I went with LIFEPO4 since I use my boat mostly for racing and was not into taking the weight penalty. When we brought the boat from Bowmanville to Toronto in light winds last year we used about 70% of the battery capacity (motoring at 4-5 knots for 9 hours in flat water). Unless you're doing a ton of long distance cruising, I'd hold off on the diesel generator.
03/23/23
From: Dan Pfeiffer

I'll second the suggestion for the Thunderstruck 12kW kit. I used that in my Pearson 10M (12,400 lbs) with great success. With the 10kW motor I would be running at 70-8% for standard cruise. It's more like 50-60% with the 12kW. It's not using less power but it is at a more moderate load for the components in the system. Also I have more reserve power for the occasional needs (like a choppy entrance). The 12kW is liquid cooled with adds some complexity but I think it's the only way to get reasonable sustained cruising speed in a boat this size or larger. If you're content with being constrained to 3-4 knots then the 10kW might do. But you'll be pushing it hard to get more speed if needed.

If you already have the AGM batteries then by all means use them. If not don't waste your money. Go straight to LiFePo4. Over the lifetime of the batteries they will be cheaper. And your usable capacity (and range) will be almost double for the same size AH bank. I built my own 48v from 16 cells in series. There are a lot more off-the-shelf options around now. But the cost savings would still lead me to build. See details on my battery here:

Lots of details on my installation here including component choices, reduction drive, cooling system, costs, performance...

I got a 2nd 12kW motor to use as a generator with a 3cyl Kubota diesel I have (18hp) but have not built the genset yet. The diesel is very compact and I figured I could get a 10-12kW 48VDC generator from the combo. After 2 seasons of use I think a smaller genset would do fine. Maybe 5-6kW. I could motor at decent cruising speed with that. Your use may be different. Genset info:

I like to think of the electric drive system in terms of limits. You run into limits everywhere in the process. Understanding them will guide you in the selection of components. I have tried to organize my thoughts on limits here:

Good luck, we're all counting on you...

Dan Pfeiffer
03/23/23
From: Ryan Sweet

I’ll second Dan - I love my 10kw in a similar size and weight and occasionally wish it had just a little more oomph, especially in strong tidal curents against the wind. It’s enough to be safe, but requires more vigilance than if it just WENT.
03/23/23
From: twowheelingguy

I would concur about skipping the AGM batteries unless you already have them and even then I would consider switching straight to lithium. Take it from someone who ran lead acid for 10 years and over 5000 miles, lead pails in comparison to lithium and it has gotten so cheap now it is almost on par with lead. Amazon sells 100amp hour, 12v batteries with bms and a charger for less than $300 that can be series to 48V and the ones I bought seem to work great. If freezing is an issue make sure you spec one with freeze protection and consider getting 8 of them to make a parallel bank of two four packs because the bms limits you to 100 amp output.

If you want to step up to a little higher quality, Signature Solar has a very nice 100amp, 48V, waterproof series with a whopping 5 kWhrs of usable energy for about $1600 each but again I'd consider getting two in parallel because of the 100amp limitation. I've got both systems on the Arc and performance wise I can't tell the difference but I'm guessing the cheap batteries won't last as long. Time will tell but I'm telling you, don't waste your money on AGMs because unless you need cold cranking amps for a big ICE, lead is dead, imo.

Capt. Carter
www.shipofimagination.com
03/23/23
From: Ryan Sweet

+1 to this - I just wasn’t going to plug it because I’m a lithium battery dealer ;-)

If you can start with a smallish lithium bank you will save on hassle, frustration, and accessories.
 
Last edited:
06/01/23
From: Robert McArthur

Dan (and anyone else who wants to explain!),
Delving back a little...

On Fri, 24 Mar 2023, 3:03 am Dan Pfeiffer, <dan@...> wrote:
I got a 2nd 12kW motor to use as a generator with a 3cyl Kubota diesel I have (18hp) but have not built the genset yet. The diesel is very compact and I figured I could get a 10-12kW 48VDC generator from the combo. After 2 seasons of use I think a smaller genset would do fine. Maybe 5-6kW. I could motor at decent cruising speed with that. Your use may be different. Genset info:
http://dan.pfeiffer.net/10m/diesel_genset.htm
Click to expand...

I just got a quote from one of the few marine DC genset places, and unfortunately it matches what I could find from the others - a new 16kW continuous 48V DC genset is about AU$28,000 or US$18,500. Not installed. Ouch!!

I see above Dan you thought about getting around it with a self-marinised bobtail, connected to a ME1616.
I'm thinking of similar, but perhaps an already marinised Beta 20 connected to the ME1616 (another of which will be propulsion) since I am not particularly mechanically minded to self marinise.

Could you explain to a layman why, if using the ME1616, you would need rectifier or regulator? I thought the ME1616 already put out 48V DC (I presumed an actual 54V or so) with controller. Or would you replace the usual Thunderstruck kit controller with the rectifier and reg for the genset?

Since a brand new marinised kubota (Beta 20) could be less than US$8000, and the ME1616 is about US$1500, it looks about half the cost of buying a named brand 48V DC marine genset! Thoughts?

Another option for marinised is a Yanmar 3YM20. Neither though are a perfect rpm match for the ME1616 which is only (!) 12kW. But if I can spend US$10,000 for 12kW vs $18,500 for 16Kw then it seems a big win.

Rob
06/01/23
From: Dan Pfeiffer

I have not built the genset yet. It was suggested to me by one of the engineers at Thunderstruck that I could do it with the ME1616 with a rectifier and regulator. But I have not researched it any further.

I have a 3cyl 12kW Kubota diesel that was a removal from a new excavator converted to all electric. It is not a marinized engine and I will need to sort that out but it doesn't seem too difficult. Mostly to do with the heat exchanger and associated pumps and plumbing. I may also need a belt drive to better match RPM's to get the desired output. Direct drive would be preferred and the ME1616 is rated at 38.46 rpm/v so that's is in the ball park (57.2V @ 2200rpm). Have to consider voltage drop through rectifier stages to get proper charging voltage input to regulator? More research needed...

BUT, after running my electric drive for two seasons I don't know that I need such a large genset (10kW). I could probably do with 5 or 6kW rather that 10. See my reasoning here:
http://dan.pfeiffer.net/10m/diesel_genset.htm

Perhaps as a general rule of thumb the genset capacity needed for reasonable continuous cruise at 75 to 85% of hull speed (for a monohull) you can do with 65 to 75% of the motor kW capacity needed to get to hull speed. So if you need 10kW to get to hull speed that would be 5.5 to 6.5 kW gen set for reasonable continuous cruise. By continuous cruise I mean maintaining desired speed without drawing down batteries. For me that's 5.5 to 6 knots cruise. From my observations I can do that at about 5kW. But I always want to consider having sufficient headroom that I am not running any of the components at 100% to get the desired performance. That gets me to 6 or 7kW genset? But 5kW would get me at a comfortable continuous cruise at 5 to 5.5 knots with headroom.
http://dan.pfeiffer.net/10m/electric_drive_performance.htm

My boat is a 12,500lb monohull with a 28.3ft waterline.
My boat is a 5,700 kg monohull with a 8.6m waterline.

More details on my electric drive conversion here:
http://dan.pfeiffer.net/10m/electric_drive.htm

Dan Pfeiffer
06/01/23
From: Robert McArthur

Thanks Dan. You're a trove of good information!

Have you had any issues with the ME1616?
06/02/23
From: ChristopherH

Have you looked into the Victron Quattro Charger/Inverters? There are models that can output up to 140 amps at 48V. This would allow use of less expensive, AC generators. Then you would have AC power anytime while cruising/ at anchor. I have the 5KVA Quattro with 70 amp output. Unfortunately I don’t have a big enough generator to use it to full potential.

Chris
06/02/23
From: Robert McArthur

Thanks Chris,
I did briefly think about it. We've a 48V multiplus ii, the 5kva version, so not enough by itself.
Another A$8,500 for the 15kva version, and still have to buy a large enough AC genset.
And then there's the efficiency of AC, wires, inverter to DC, wires. I'm not entirely convinced the DC genset with rectifier is that much better, given that in my situation both will be running at highish rpms to fill the lithium battery pack, negating some of the dc gensets benefit of variable speed.
06/04/23
From: jeremy baker

I have a 4.5Kw, 48 volt, alternator powered by a 8hp propane fueled engine. But no boat yet. Sigh
06/04/23
From: Dan Pfeiffer

Is this a commercially available unit or something you put together? That is a reasonable power output for continuous cruise on about a 10,000 lb monohull I think.
06/04/23
From: reesekc

I'm presently using a 2kw generator (Harbor Freight) and a 48vdc golf cart charger. Also have 200 watts of solar power (12vdc in series for 24vdc with a boost controller to 48vdc). All of that is pretty cheep. But I can hold 4.8 knots all day long with the sun shining.
06/04/23
From: Dan Pfeiffer

Are you saying you can hold 4.8 knots at 2200 watts (2000+200)? What are the boat specs? Have you measured actual output from generator and solar?
06/04/23
From: reesekc

Hughes 35.5 ft sailboat. Ran several days, anchored at night. Had volt meter continually monitoring. Slowed down when volts reduced, sped up when volts went up. Everything settled at 4.8 knots speed.
 
06/05/23
From: Jerome Mouton

Hello Rob,

I went the easier (but more expensive route) of buying a DC genset (I settled on a Fischer Panda AGT 18000 --> 18KVA). I am running at 96VDC, and that was a 5% premium on top of their 48VDC catalog price.

The larger price tag compared to an equivalent power AC genset makes sense to me, as the rectifier box is an additional piece of equipment provided in the system. The rectifier diodes are water cooled (connected to the sea water circuit of the generator). If you were to go this path, you need to account for the space requirement for the rectifier box, and how you will route not only the electric wire, but the water cooling circuit.
As you described, running the output of an AC generator to a DC charger is not practical for 10kW+, due to the lack of battery charger designed for that much power.

The advantage of the DC genset I see is that the output of the generator feeding the rectifier box is 3 phases AC. That means that the output of the rectifier box is a quite stable voltage. If you were to rectify a single phase AC, your DC voltage would drop to 0V around 120 times per second, so the current would do the same (when the rectified DC voltage is less than the battery voltage, no current flows from the generator to the battery or to the load).

Regarding your question on the ME1616 motor, it is not a DC motor. The ME1616 is a 3 phase AC motor. In traction mode, we use a motor controller that we feed DC to, and the controller creates the 3 phase AC to drive the motor at the RPM specified to the controller.

Cheers,

Jerome
 
12/26/23
From: Scott E Erdman

Hey Folks - I apologize for not maybe having all the specifics needed for this but related to this thread and a somewhat more simple question:

I did buy the Pearson 10M that had been converted to 10 kW Thunderstruck with 2x24 x 2 48V bank w/ 196 AH.
Presently there is no other way on the boat to recharge other than plugged in on a slip.
Looking at everything, I figure that purchasing a gas generator is the best insurance on expanding range and dealing with extended draw conditions (currents, etc)
So my question is this - does it make a big difference whether the generator I get is 2,000 vs. 5000 W ?
I am looking on Craigslist and I can find quite a few used 5,000 W generators for good prices - I expect space is a consideration as well. I guess my main question is what would I gain from getting a 5,000 W generator vs. the smaller, more portable and perhaps more quiet 2,000W ones?

Trying to take care of some of these purchases this winter -

Thanks,
12/26/23
From: Reuben Trane

If you’re thinking a portable gas generator, I like the Harbor Freight 3.5kW inverter unit. Quiet. Electric start. Wait for a 25% off coupon.

https://www.harborfreight.com/gener...enerator-with-co-secure-technology-59137.html

I am just now putting together a 48v charger to maximize the available current (3.0kW) of the generator. I’m using a pair of 24v chargers in series.
12/26/23
From: Dan Pfeiffer

The answer to your question is (of course), it depends. What is the output capacity of your AC charging system? The gas generators you are considering are 120VAC output? (The 5,000 watt may have a 220VAC output?) You will be delivering the power to the batteries or the motor through the battery charger that you would plug in to shore power. That means you have a max power limit that is set by the charger output. If your charger output is 1500 watts max that's your limit. You can't get more through the charger. So you can't use any generator capacity beyond what the charger can put through to the battteries/motor.

You have speed limit on generator of whatever the max output of the charger is. If it's 1500 watts that's all you can deliver from the genset through the charger regardless of the genset output capacity. For your boat (assuming a well matched prop) that going to be about 4 knots. Probably a bit less but I don't know the details of the installation (reduction, prop specs). You can go faster but you'll be drawing the additional required power from the batteries.

You can increase the charger capacity but there is no point in having a generator that has capacity several times what you can actually use? My charger (Thunderstruck EV TSM2500) puts out 1500 watts with 120VAC input. If I had 220VAC it could put out 2500 watts. So a 220 VAC generator of 2500 watts could in theory get me motoring at about 5kts. These chargers can be paralleled and two of them would get me to 5000 watts and 6kts continuous with a 220VAC generator.

But there are some other limits as you start to try to motor at higher speeds. Mainly heat. Can your motor run at that output level continuously? That's why I went with the 12kW liquid cooled motor. It can. The 10kW? Not sure what it's limits are but its quite a bit lower for continuous operation.

My project (same boat) is still developing and I thought I would want about 10kW of generator capacity to get continuous motoring speeds of 6+ knots (need that to transit Detroit river in reasonable time) but after running the electric drive for a few seasons I think I would be fine with 5 or 6kW.
As to the generator, I would rather NOT have a gas powered generator on board. Refueling underway from a gas can sounds like a sloppy process. Gas fumes can accumulate in the bilge though that can be mitigated with careful handling. I would consider a propane powered unit. Same fume issues but swapping out a new propane tank seems a lot easier at sea than re-filling the gas tank on the generator. A little less output on propane Vs gas but the handling advantages seem worth it to me. And these generators are strictly for above deck use. Same for the fuel storage.

Dan Pfeiffer

More on limits here:
http://dan.pfeiffer.net/10m/electric_drive_limits.htm

More on gensets:
http://dan.pfeiffer.net/10m/diesel_genset.htm
12/26/23
From: Scott E Erdman

Hi Dan,
Thanks very much for replying and once again thanks for your 10M page – a superb reference that I’m using all the time now!
So it looks like I have a decent line on a Westinghouse iGEN2500 which is 2,200 W output for $600. https://westinghouse.com/products/igen2500-inverter-generator

I do need to get a generator in the next few months because, though I don’t want to be using it much, my boat will come out of storage in April or early May and the marina it is presently at will only give me about 2 weeks of slip time since they are full and I won’t be there for the summer. I did find a marina in Saket’s Harbor and it is about a 2-3 day trip from Sodus Bay to Saket’s Harbor. Due to these considerations and unpredictability of the weather and crew availability around then, I plan to go via Oswego where there is a town dock with overnight slips that have power and I can recharge fully there as needed. Still I want to have backup onboard even though we will sail as much as possible and the trip is a favorable one for travel by sail.

I don’t plan to use this very much but want to have it at the ready just in case I get stuck really needing it.
Down the road there will be a few passages where it will be needed – St. Lawrence Seaway, Detroit River – for all these I am hoping that it may be possible to split the trip in half, thirds or quarters for the power intensive section and just plan to recharge whenever possible. One of the folks at the marina my boat is at went on and on and on about the Georgian Islands – looks super for when I am retired in a few years and have the time to get my boat up there and back in a season or so –

I am sure I’ll have some more questions about the 10M. I have to reconnect the water system in mine so that is my main item aside from fixing the anchor light. Very much looking forward to spring!

Thanks again,
Scott
 
12/27/23
From: john


Scott, the thing you MUST keep in mind about small gasoline generators is that you ABSOLUTELY MUST run them at least every 2 weeks. If you do that, they will start and run great. If you leave it sitting for a month or two, you may well be disappointed the next time you try to start it. You don't have to use it, just start it and let it run for 10-15 min.

Good luck!
John
12/27/23
From: Dan Pfeiffer

I have that exact Westinghouse generator at home to save my ice cream when the power goes out. Decent unit. Access to the carb for cleaning could be better? I had to disassemble it to clean it out after the unit sat un-used with gas left in it and the carb became fouled. Easy enough fix once I got to the carb. Would be better if the gas cutoff didn't also shut off the motor so you could run the carb dry.

I had intended to try it on the boat to see how fast I could motor with it running through the charger and at zero draw from the batteries but I never got around to it. I plan to do it after spring launch. Maybe I'll have some data by the end of May. It can supply more power than I can use through my 1500W charger.

Another thing to consider is motor sailing. It greatly extends range. I do have some data on that from last summer. Should be quite relevant to you with same boat though the prop match is a very important factor.

Motor Sailing Data Point Sunday September 17, 2023
Pearson 10M, 12,500 lbs, 18" 3 blade prop, 3:1 reduction, full main and 100% headsail
Wind S 5-8 diminishing to 0-2, shifting to N 0-2, building to 7-10, Waves <2
TWA 126, TWS 7.1, BSP 5.2, Watts 1024, RPM 1238 (prop RPM 412)
Estimated range 70 miles at this rate and conditions.

What is your AC charging setup?

Sodus to Sackets is 55 nmi. Seems like a manageable single day to me. I would never expect to motor the whole way. I would head out a couple hours before dawn and expect to average 5 knots. In a couple hrs before sunset. Any wind direction but NE which would make it a beat. A good small craft advisory with west wind would make a quick trip of it with perhaps enough boat speed to do regen. In fact I would probably wait for a day when it was blowing 20 to 25 from the NW if I could. But that's just me. I seek out those conditions and I am properly rigged to handle them.

Dan Pfeifffer
12/28/23
[email protected]


I couldn’t get comfortable with the idea of re-fueling with a funnel either. I ended up getting a new 3.8KW dual fuel electric start generator from Firman for a little over $700. I have it strapped down in a segregated seat locker with the exhaust plumbed to an un-used espar heater exhaust. Also added two 110 cfm quiet equipment fans the evacuate the heat. Initial tests this fall went well and I have adjusted the charger amps to optimize the draw on the generator. I have also found it’s a little quieter on propane. This spring I plan to figure out my zero loss cruise speed.
01/06/2024
Scott E Erdman

Hey Dan,
Just wondering if you got to check out using the Westinghouse generator for direct power yet or not. My boat will likely be ready finally this week or so and due to some family commitments I will be looking at shaking out the use of it and moving it to Saket’s during the week of June 7-12.
02/06/2024
Dan Pfeiffer

Not yet. I have only been in the water and rigged for a bit over a week. We also haven't had the right conditions for such a test which has been great for sailing. But thanks for the reminder. I will give it a try this week if I can and report back.

Dan Pfeiffer
11/06/2024
From: Dan Pfeiffer

I have some data.

I ran the boat with the charging system plugged into the Westinghouse generator. But, I forgot my laptop and so couldn't reprogram the charger for full output. It is set at 1000W but can max at 1500W on 120VAC. But I tried it anyway and will again when I can set it for full power.

With generator running and battery draw about 30W (according to Victron) I made
3.3 north, 3.7 south
Call it 3.5 average. Sevcon reported about 1000W at motor. Generator reported 1.07kW load, 4hrs run time with 3L fuel remaining. I have no idea how reliable those numbers are.

I had generator strapped on deck at the mast. Quite noisy by the standards I have become accustomed to over 3 seasons with electric drive.

Ill do another test at full charger power and put generator on foredeck.

Dan Pfeiffer

Pearson 10M (33ft)
12500lbs
ME1616 (12kW@48V)
Sevcon controller
18" 3 blade J-Prop
TSM-2500 charger (set at 1000W max)
Victron 712 shunt mete
 
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