Electrical plans for off-grid boat ....

[Baggywrinkle]

I'm in the process of buying the next boat, it's taken a while and I've been doing lots of research on generators, high-power alternators, lithium battery systems and I'm fairly certain what I want. Here is the diagram ....


It looks more complex than it is, but I'm pretty certain it'll cover our energy budget as long term med layabouts. I'm a big Victron fan having used their stuff on my last boat and my camper van, I also did a project on a Raspberry Pi with Venus OS.

The big gamble on this system is the Integrel E-Power system - it is endorsed by Nigel Caulder and it is way more sophisticated than alternative high-power alternator solutions (at a cost too) but I am probably going to give it a go on my next boat.

The diagram will be modified once I take delivery to show how I will graft it into the existing electrical system, mainly concerning the 12V part on the right hand side of the diagram. I have multiple electric winches, bowthruster, and electric genoa furling to consider, and 510Ah of AGM batteries that were new in 2023 - I will probably keep them 'till they expire.

This thread will document my experiences and any observations, comments, glaring mistakes will be gratefully received.

 

[Baggywrinkle]

PS: The diagram is based on downloadable Victron schematics and is created in Photoshop before anyone asks, I used o do them in Powerpoint. A good understanding of layers, clone tools and transformations etc. is required to create these diagrams relatively quickly and it is not for the faint hearted. It is also time consuming.

 

[rotrax]

We have 400W of solar, 660 AH AGM battery bank, we run two fridges and a freezer 24/7 when we are aboard in the UK and Ireland. We are never short of Amps and Volts. Also have an 8KW Genset, used primarily for electric cooking and heating the calorifier. The washing machine, instant pot, vacuum cleaner (an old corded type), electric flat grill and device charging from the 3,000W Inverter. The solar was fitted May 2021. The batteries have only had charging when the main engine is running apart from the solar since.

If your new boat is situated where you can get more sun than we do in the UK, you might be overdoing it a bit.

We have no Watermaker. Water is what takes us into port, plus food re-supply and gash disposal.

Apart from that, we can do 3 weeks without touching the shore if we are frugal with the water. And that means not wasting it doing the washing....................

 

[Baggywrinkle]

We have 400W of solar, 660 AH AGM battery bank, we run two fridges and a freezer 24/7 when we are aboard in the UK and Ireland. We are never short of Amps and Volts. Also have an 8KW Genset, used primarily for electric cooking and heating the calorifier. The washing machine, instant pot, vacuum cleaner (an old corded type), electric flat grill and device charging from the 3,000W Inverter. The solar was fitted May 2021. The batteries have only had charging when the main engine is running apart from the solar since.

If your new boat is situated where you can get more sun than we do in the UK, you might be overdoing it a bit.

We have no Watermaker. Water is what takes us into port, plus food re-supply and gash disposal.

Apart from that, we can do 3 weeks without touching the shore if we are frugal with the water. And that means not wasting it doing the washing....................

I don't want a separate generator and I want an extended season, even though it is in the Med the winter is difficult with only solar. This should be total overkill for summer, but that is the point. My energy budget when pared down looks like around 3kWh a day sitting at anchor, in winter I can only get around 1-2 kWh with this solar set-up. The Integrel will provide the rest with Lithium accepting a massive charge current and about 20 mins runtime per day. I want no worries about water, heating, washing etc. - would also like to move to induction cooking. Will see how it goes.



The Integrel on-engine generator has a 2.6 multiplier applied to engine revs, and this is the claimed output ...



... a 1200 idle speed will be putting out 5,8 kW so just pulling up the anchor and moving anchorage should cover the daily needs even without solar.

Demo here ...

 

[rotrax]

The 1200 RPM might not give much load on the engine, be wary of light load bore polishing.

It would have been far cheaper and easier for me to have fitted another alternator to the main engine in addition to the OE Balmar. I did not do so as the main engine is a 110BHP Yanmar 4JH4-HTE turbo diesel.

I am not going to run that lightly loaded. The 8KW Westerbeke has a 900cc three cylinder diesel, so that gets a good load when producing power and heating the calorifier, kettle microwave or toaster. Sometimes all of them.

It was an ebay purchase and I fitted it myself. All in, including van hire to collect it, engine crane hire to unload it, all the bits to renovate and install it and the hire of the yard crane it cost 2K.

Be hard to live without it now. A new one was quoted at 20K fitted.

Solar is the best bang for your buck. We often stay onboard in the winter, hooked up to shore power, but the charger is never on. Even in short December days the 400W solar keeps up with the two fridges- the Dometic fridge/freezer has a smart switch, so will automaticaly take 240V when on shore power.

It would not be enough on the hook in winter as the inverter would have a significant effect on battery capacity.

Interesting idea. Let the forum know how it goes please, technology is always evolving.

 

[Tranona]

The 1200 RPM might not give much load on the engine, be wary of light load bore polishing.

I think you will find that the generator does put a full load on the engine at 1200rpm - that is the whole point of the system, to make full use of the potential output of the engine at any given revs.

 

[Baggywrinkle]

The 1200 RPM might not give much load on the engine, be wary of light load bore polishing.

It would have been far cheaper and easier for me to have fitted another alternator to the main engine in addition to the OE Balmar. I did not do so as the main engine is a 110BHP Yanmar 4JH4-HTE turbo diesel.

I am not going to run that lightly loaded. The 8KW Westerbeke has a 900cc three cylinder diesel, so that gets a good load when producing power and heating the calorifier, kettle microwave or toaster. Sometimes all of them.

It was an ebay purchase and I fitted it myself. All in, including van hire to collect it, engine crane hire to unload it, all the bits to renovate and install it and the hire of the yard crane it cost 2K.

Be hard to live without it now. A new one was quoted at 20K fitted.

Solar is the best bang for your buck. We often stay onboard in the winter, hooked up to shore power, but the charger is never on. Even in short December days the 400W solar keeps up with the two fridges- the Dometic fridge/freezer has a smart switch, so will automaticaly take 240V when on shore power.

It would not be enough on the hook in winter as the inverter would have a significant effect on battery capacity.

Interesting idea. Let the forum know how it goes please, technology is always evolving.

The Integrel system can produce around 6 kW at idle, but of course it won't do that if the power has nowhere to go. This is why pairing it with Lithium is the game changer .... Lithium batteries with a less than 80% charge will pretty much take anything you can throw at them. They also don't mind being cycled between 20% and 80%, in fact it is better for them if they aren't fully charged with every cycle ... so you have a combination of a generator that can take 6-9 kW of unused power from the engine, and a battery system that can accept that power, resulting in very short recharge times from a partially loaded engine.

My boat has a D2-55 engine (40 kW) ... so at full whack, the Integrel is capable of taking almost 25% of the engine power (9 kw) .... but the system is intelligent enough to determine when the boat is in gear and to regulate how much load it actually puts on the engine dependent on rpm. If not in gear it goes all out and puts it's max load on the engine if the batteries can take it - in gear it operates in the area indicated by the graph below ...

The power curve for the D2-55 looks like this ...


That difference between the propeller load and the full load output is what the Integrel system extracts and turns into usable electrical power, so the effect is that the engine is fully loaded if the electrical system can accept the charge, without affecting the power at the prop - and as you get closer to needing full load for the prop, the Integrel backs off and you get more and more power for propulsion. It is quite a clever system IMO.

This system makes little sense combined with lead acid batteries however as they shouldn't be cycled as low as lithium and they need a lot of time to achieve full charge, so to get to full charge on lead acid means running a generator on light load for a long time. This system will put a large charge current into the Li batteries in a short time, so I'm really not worried about bore polishing as I will not need to run the engine for long at all, and when I do run it just as a genny, it will be 25% loaded.

I looked at a Balmer alternator coupled to a Wakespeed controller but it doesn't come close to the power and sophistication of the Integrel unfortunately - it would certainly be a lot cheaper.

 

[Baggywrinkle]

I mentioned earlier that I might graft the boats AGM batteries into the system ...

....

The diagram will be modified once I take delivery to show how I will graft it into the existing electrical system, mainly concerning the 12V part on the right hand side of the diagram. I have multiple electric winches, bowthruster, and electric genoa furling to consider, and 510Ah of AGM batteries that were new in 2023 - I will probably keep them 'till they expire.

.....

... the idea is that the 48V lithium system will be fast charged from the Integrel, and will then bleed charge into the AGMs over time at a rate they can accept until they are fully charged. This is effectively what we designed into our electric vehicles to keep the 12V part operating and continue to make use of the cheaper 12V parts bin components.

 

[Fr J Hackett]

Assuming you have a fully electric boat ie induction cooker, air conditioning etc is the 48V lithium battery bank sufficient to supply that or are you going to need to increase the Lithium bank or will you simply be running the engine instead of the generator whenever you have large loads. If you went for a bigger Lithium bank are you going to be constrained to Integrel supplied batteries.
At least with a generator and a large Lithium bank and high output alternator and regulator at least all your eggs are not in one basket.
Having been sceptical it does seem an elegant solution though.

 

[Baggywrinkle]

Assuming you have a fully electric boat ie induction cooker, air conditioning etc is the 48V lithium battery bank sufficient to supply that or are you going to need to increase the Lithium bank or will you simply be running the engine instead of the generator whenever you have large loads. If you went for a bigger Lithium bank are you going to be constrained to Integrel supplied batteries.
At least with a generator and a large Lithium bank and high output alternator and regulator at least all your eggs are not in one basket.
Having been sceptical it does seem an elegant solution though.

I can double this up to 20 kWh storage relatively easily, and Integrel can display info and diagnostic data from MG, Victron, MasterVolt and Lithionics ... that's all that using specific batteries gets you. Otherwise you can use any battery with the battery suppliers BT connection or monitoring system directly. Integrel uses a current sensor to measure what is actually going into the battery pack.

From the Integrel user manual ... this is what got me hooked ...

CHARGING AT ANCHOR
After being at anchor for 1-2 days, the battery charge may become low;
the Integrel Touchscreen shows a battery low warning and sounds an
alert. Simply start your engine(s) to charge the batteries.
If you do not plan to leave anchor, leave the engine(s) in neutral and
adjust the revs to a fast idle between 1200 – 1400 RPM. This engine
speed typically generates between 6.0 – 7.5 kW of power.

Charging Time
A 10 kWh Lithium battery bank charges from below 20% to above 90% in
about an hour from a single Integrel system.

I plan to buy an induction grill/hob like this for the cockpit ....


.... which will enable me to see how well it works with the battery system and then I can move onto a gimballed induction solution.

I suspect that from other users experience like @geem I will have enough energy for induction cooking.

... aircon might be pushing it but who knows.

 

[B27]

It looks very complicated.
A lot of boxes.
A lot to go wrong.
The MIL 1629 FMEA report would be quite long...

 

[geem]

It looks like a very expensive system for an 'all your eggs in one basket' solution. May be not a big issue if it all goes wrong and you aren't too far off grid, but I would have issues with the lack of resilience of such as system for the type of sailing we do.

 

[Fr J Hackett]

It looks like a very expensive system for an 'all your eggs in one basket' solution. May be not a big issue if it all goes wrong and you aren't too far off grid, but I would have issues with the lack of resilience of such as system for the type of sailing we do.

That would be my worry as well as capacity, however carrying a spare generator which is the most likely failure should go a long way towards solving the "eggs in one basket" problem. They seem to have a reasonable spread of agents so help should be reasonable and equivalent to what most manufacturers could / do supply. Costs would be interesting, there doesn't short of making an enquiry seem to be a way of determining those.

 

[Zing]

Too complex. With 1kW solar the engine alternator is likely to be rarely needed backup in summer, especially if you control power use well, so the Integrel is an overkill. Maybe not if you have a boat full and all want multiple showers per day. Depends on your plans. You can easily do the sums. Also not enough redundancy. I’d get two inverter/chargers and two solar chargers or more. If you have room and need a bit extra power over solar a small genset and a cheap large output alternator on the engine will do the same job for similar money and give you an extra layer of redundancy.

 

[Sea Change]

Interesting to see how you can do this when you have a large budget. 20kwh of storage would be very impressive, you're into EV territory at that point.
Just FYI we have 6.6kwh and it runs everything (except propulsion), charging from 1kw solar with essentially no engine charging capability at all. But we spend winter in the Caribbean, not the Med

Our backup option of power is getting short is to turn the gas back on. Since we doubled our battery capacity we don't really have to do this any more.

Keep us posted, it's an impressive project.

 

[geem]

Interesting to see how you can do this when you have a large budget. 20kwh of storage would be very impressive, you're into EV territory at that point.
Just FYI we have 6.6kwh and it runs everything (except propulsion), charging from 1kw solar with essentially no engine charging capability at all. But we spend winter in the Caribbean, not the Med

Our backup option of power is getting short is to turn the gas back on. Since we doubled our battery capacity we don't really have to do this any more.

Keep us posted, it's an impressive project.

We have over 10kw of battery capacity. Plan to increase this to 14kw this winter. The diesel genset can charge at 110A at 24v. We rarely use it as 920w of solar does the vast majority of the charging work. The Duogen will be retired this winter as its worn out and too expensive to keep throwing parts at it. Having just crossed the pond, we realise we no longer need it with lithium. It's 20 years old and there is no need for wind/ hydro power in our cruising lifestyle with lithium and plenty of solar.

 

[Tranona]

The Integrel system can produce around 6 kW at idle, but of course it won't do that if the power has nowhere to go. This is why pairing it with Lithium is the game changer .... Lithium batteries with a less than 80% charge will pretty much take anything you can throw at them. They also don't mind being cycled between 20% and 80%, in fact it is better for them if they aren't fully charged with every cycle ... so you have a combination of a generator that can take 6-9 kW of unused power from the engine, and a battery system that can accept that power, resulting in very short recharge times from a partially loaded engine.

My boat has a D2-55 engine (40 kW) ... so at full whack, the Integrel is capable of taking almost 25% of the engine power (9 kw) .... but the system is intelligent enough to determine when the boat is in gear and to regulate how much load it actually puts on the engine dependent on rpm. If not in gear it goes all out and puts it's max load on the engine if the batteries can take it - in gear it operates in the area indicated by the graph below ...

The power curve for the D2-55 looks like this ...

View attachment 177980
That difference between the propeller load and the full load output is what the Integrel system extracts and turns into usable electrical power, so the effect is that the engine is fully loaded if the electrical system can accept the charge, without affecting the power at the prop - and as you get closer to needing full load for the prop, the Integrel backs off and you get more and more power for propulsion. It is quite a clever system IMO.

This system makes little sense combined with lead acid batteries however as they shouldn't be cycled as low as lithium and they need a lot of time to achieve full charge, so to get to full charge on lead acid means running a generator on light load for a long time. This system will put a large charge current into the Li batteries in a short time, so I'm really not worried about bore polishing as I will not need to run the engine for long at all, and when I do run it just as a genny, it will be 25% loaded.

I looked at a Balmer alternator coupled to a Wakespeed controller but it doesn't come close to the power and sophistication of the Integrel unfortunately - it would certainly be a lot cheaper.

Similar to the parallel systems offered by Hybrid Marine with mostly Beta engines. Same principle of exploiting the unutilised power from the propulsion system and providing a base for a similar system to yours in both canal boats and larger sailboats, particularly multihulls which can support a larger solar array and have space to distribute the components around the boat. Unfortunately not suitable for easy retrofitting, particularly to a saildrive.
hybridmarine.co.uk

 

[Sea Change]

We have over 10kw of battery capacity. Plan to increase this to 14kw this winter. The diesel genset can charge at 110A at 24v. We rarely use it as 920w of solar does the vast majority of the charging work. The Duogen will be retired this winter as its worn out and too expensive to keep throwing parts at it. Having just crossed the pond, we realise we no longer need it with lithium. It's 20 years old and there is no need for wind/ hydro power in our cruising lifestyle with lithium and plenty of solar.

I didn't realise you had as much as that, but of course being 24v it will add up!
We did the first 18 months with 3.3kwh of lithium, around the Med, and we did have to resort to gas cooking every so often. Our reserve capacity was really just one day.
Adding the second bank has changed all that, and we can now get through a couple of dull days without any worry. Our backup Campingaz 907 bottle was still going strong after a year.

We didn't have any way of engine charging the lithium at all, until I eventually added an 18A DC-DC charger. I'd rather burn cooking gas than run a diesel engine.

 

[geem]

I didn't realise you had as much as that, but of course being 24v it will add up!
We did the first 18 months with 3.3kwh of lithium, around the Med, and we did have to resort to gas cooking every so often. Our reserve capacity was really just one day.
Adding the second bank has changed all that, and we can now get through a couple of dull days without any worry. Our backup Campingaz 907 bottle was still going strong after a year.

We didn't have any way of engine charging the lithium at all, until I eventually added an 18A DC-DC charger. I'd rather burn cooking gas than run a diesel engine.

We have a pair of Victron 17A/24v B2Bs. We only use them when we are motoring somewhere. We wouldn't start the engine to charge from them.
We had to motor the last bit coming in to Azores so we made about 500L of water for a couple of hours before we arrived. All done on the inverter with solar and the B2Bs. Full batteries when we arrived. We have been here 9 days. Its been a mixture of wet, cloudy and a bit of sun. Still on electric cooking and hot showers via the inverter with batteries over 90% each day. We may need to run the generator to make more water as I can't be bothered to go to the dock to fill the water tank. It's too hectic with all the boats arriving from the Caribbean

 

[Fr J Hackett]

I do hope Baggy continues with this thread and is not discouraged by the general scepticism ( including mine) as it's a new development and deserves to be explored by someone with the balls and commitment to invest his hard earned beer tokens in it. Otherwise we will never know how effective, good or bad it is.