suitcase generator vs running the (main) engine?

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Chae_73

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looking to get our boat kitted out for some (hopefully) longer journeys next year.

we don't generally marina hop so being able to have enough electricity to do what we need to do is a factor we are thinking about. The boat isn't full of bells and whistles so power use isn't huge but will run to lighting, forced air heating (hopefully!), auto-helm, instruments, charging phones, tablet etc.

one possible solution is to carry a suitcase generator such as a Honda eu 10i, and run this as and when needed. It's likely that we will already be carrying petrol for the 4 stroke tender outboard (although I have been looking at Torqueedos).

My question is, other than being more efficient, is there much advantage in a suitcase generator over running the main donk when batteries need charging?
 
Chae_73 said:
My question is, other than being more efficient, is there much advantage in a suitcase generator over running the main donk when batteries need charging?
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Not sure whether it would be more efficient. People generally warn against using the main diesel engine for battery charging alone, as it may lead to bore polishing. However, thousands of taxis spend countless hours at tickover without massive problems.

Your most cost-effective solution will probably be to increase the size of your battery bank. This will (a) accept charge more readily, and (b) give you longer autonomy.
 
Yes, increasing the battery bank capacity is also on our list.

I had temporarily forgotten about the advice not to run diesels under low load. With a bigger bank, can likely overcome the need to run the engine at anchor by motoring / motor sailing for some part of each passage. Not normally a problem for non purist sailors like me!
 
I have only run the engine very rarely specifically for charging in the last 10 years. I do use a Honda generator for charging early and late season as solar provides sufficient power most of the time.

You get hot water as well as charging from the main engine.
Running a small generator to heat water is usually pretty noisy and something I avoid

Mains chargers usually have more options and modes than alternators and likely to have higher charge rates. However, your battery acceptance will probably mean you aren't charging at a very high rate for too long unless you are down at 50%-60% SOC. Solar makes a much better job of topping up batteries once an engine or charger gets most of the charge back in.

I imagine you will only get back to 80%-85% with a generator or specifically using engine for charging.
 
We don't get hot water from the running the engine as it's a raw water cooled VP MD2002. Old, but runs very well.

We were planning to replace it this winter but it starts and runs so well that we are now prioritising other jobs over re-engine.
 
Chae_73 said:
We don't get hot water from the running the engine as it's a raw water cooled VP MD2002. Old, but runs very well.

We were planning to replace it this winter but it starts and runs so well that we are now prioritising other jobs over re-engine.
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You can run a calorifier off a raw water cooled Volvo 200x series engine; I have one! The connection at the engine is "after market" - basically, cut the pipe running from the thermostat housing to the exhaust elbow and connect the two ends to the calorifier. There's a picture of mine and others on @vyv_cox website (Calorifier installation)

Note that running a suitcase generator needs care - even running it in the cockpit can result in carbon monoxide getting into the cabin. You need to be absolutely certain that the exhaust is being carried away from the boat.
 
Chae_73 said:
Yes, increasing the battery bank capacity is also on our list.

I had temporarily forgotten about the advice not to run diesels under low load. With a bigger bank, can likely overcome the need to run the engine at anchor by motoring / motor sailing for some part of each passage. Not normally a problem for non purist sailors like me!
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Remember that it is a system and just changing one part might not be as effective as you hope (unless you are lucky).

Power use, usage pattern, battery type & capacity, charging components (generator, engine, solar etc.) and many other factors interact.

e.g. Using a laptop on internal batteries and fully recharging when motoring is more efficient than running off lead acid and then re-charging them. Silly example of course.

Having a huge battery bank is great if it allows you to spend a weekend afloat and charge during the week in a marina. However, it isn't so great if you need to motor for 10 hours to get a decent charge back into the batteries.

I'm really just saying that you should give some thought to all the elements, not just triple battery size. It sounds as if you have a basic system just now but want to make quite a few changes likely to significantly impact consumption and storage (e.g. Heating system and battery size). What's your sailing area, usage pattern and available space for solar (best single thing you can fit)?
 
I would say that in comparison to the cost, you could fit a pretty big set of solar panels and or wind and larger alternator (though you might want to hold off on that if your thinking of changing the engine in the short term)

That would likely be sufficient for your modest power needs combined with the occasional bit of motoring for supplementing the charge levels. Dont charge the batteries to 100 soc on the main engine as it will take ages. Top them up in the morning before much sun comes up and then leave the solar to do the rest, you will get a good idea what the daily yield is like with experiance and therefore what you need to put in to get up to 100% soc. Use a victron mppt its efficient and allows you to keep track of the yield.

I would consider a battery monitor like a victron bmv 712 so you know exactly what's going into and out the battery bank.
 
Yes, it's a basic system at the moment. Two lead acid batteries, engine alternator and shore power socket.

Currently all we are doing is a little bit of pootling around the east coast after having been away from sailing for a few decades (first season with this boat). So what we have is quite adequate for out current usage, however aim is to go a bit further in the next few years, Scotland and Europe (probably northern parts, Belgian, Holland, Frisians etc) so looking to make changes that will make more time aboard as comfortable as reasonably possible.

The main problem with solar is where to put the panels - there is not a lot of free space. I have considered "solar dodgers" and could revisit that idea.

Boat is a Westerly Storm 33
 
Chae_73 said:
Yes, it's a basic system at the moment. Two lead acid batteries, engine alternator and shore power socket.

Currently all we are doing is a little bit of pootling around the east coast after having been away from sailing for a few decades (first season with this boat). So what we have is quite adequate for out current usage, however aim is to go a bit further in the next few years, Scotland and Europe (probably northern parts, Belgian, Holland, Frisians etc) so looking to make changes that will make more time aboard as comfortable as reasonably possible.

The main problem with solar is where to put the panels - there is not a lot of free space. I have considered "solar dodgers" and could revisit that idea.

Boat is a Westerly Storm 33
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Yes not the most friendly of vessels to mount significant solar panels to. Room for some on the coach roof though.

Personally I would sink the money into the new engine now and get the use out of it if your going cruising Long distance. Find the one that fits with the biggest alternator you can find. If your budget will stretch to it fit lithium batteries as they will charge far quicker though careful planning on the alternator protection is important. A yanmar 3ym20 or 30 comes to mind as the stock alternator can be plugged into a balmer controller and then is lion compatible.

Having said that, I subscribe to the using less power philosophy so fit an efficient fridge, led lights and tri/anchor. Etc
 
Chae_73 said:
Yes, it's a basic system at the moment. Two lead acid batteries, engine alternator and shore power socket.

Currently all we are doing is a little bit of pootling around the east coast after having been away from sailing for a few decades (first season with this boat). So what we have is quite adequate for out current usage, however aim is to go a bit further in the next few years, Scotland and Europe (probably northern parts, Belgian, Holland, Frisians etc) so looking to make changes that will make more time aboard as comfortable as reasonably possible.

The main problem with solar is where to put the panels - there is not a lot of free space. I have considered "solar dodgers" and could revisit that idea.

Boat is a Westerly Storm 33
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Solar is of limited use as a major source of charging to replace daily consumption as you can't get big enough panels on that size boat, nor is the sun reliable enough in northern climates. Useful though to top up in the week if you do not have access to shorepower. Different if you have a 40'+ in the Med and a liveaboard where you might get enough solar to cover your daily consumption at anchor.

As Mistroma says you need to look at your expected consumption and available sources of power generation. realistically most will come from the engine or shorepower. The starting point is your power consumption so useful to have a monitor to check on this. The biggest consumers are the fridge and nav systems when sailing then lights (particularly nav lights if sailing at night). First reduce consumption where you can - LEDs make a big difference, insulation with fridge, turning nav off when not underway. To give you an idea, with my similar size boat the fridge consumes about 35-40 amps a day, nav including autopilot about 30amps for 6 hours sailing, overnight lights, radio, phone charging etc 10 amps. Total around 70 amps a day. I have a 285ah bank so keeping within the discharge to 50% I have 2 days and nights sailing and anchoring before I need to think about charging. one hour engine running will put back about 20 amps, 2 hours 30 amps. So with an hour motoring at the beginning and end of a sailing day gives me a deficit of 40amps a day. Solar would not make much of a dent in that.

With typical coastal cruising with a mixture of overnight anchoring and the odd marina night on shorepower you can manage comfortably with this size battery bank. Choice of battery type can improve performance - for example AGMs generally have higher charge acceptance rates and lower self discharge plus longer life and have come down in price such that the potential longer life is greater than the price premium over FLA. Modern engines have better self regulating alternators which leads to faster charging.

In your situation I agree with others. First thing is to replace the engine - the Beta 25 is a popular choice for your boat, or you could stick with Volvo and fit a D1 30. Both fresh water cooled so you can fit a calorifier and hot water system if you wish as well as being smoother quieter and more refined than the existing engine. Change the charging system to a split charge which will allow you to fit a smaller engine start battery (because it will always be fully charged) and a larger house bank. This is exactly how new boats of this size are set up. My 33' has 2*95ah AGMs as standard but I added the optional additional house battery to give 285ah total. Never have any worries in normal cruising mode and go on shorepower if the resting voltage is below 12.7A - perhaps 2 or 3 times a year.

Petrol generators are bad news on a small boat. OK if you need power for tools if you are on a swinging mooring, but not something you would want to take with you on a cruise.
 
Tranona is quite correct with his analysis but solar is still worth considering. It is certainly useful to top up in your absence but can also make a decent contribution to reduce engine run time. I charge early from engine (i.e. motor out of anchorage) or run a generator in the morning (early or late season). Solar then tops up over the rest of the day.

Even in the Clyde you'd get good average sunshine vs. the Spanish Rias but it drops off rapidly earlier in the season. Approx. 75% in May but only 65% in August. You would need about 170W to get around 40Ah/day in May, June and July with 30Ah by August. That is an average figure for panels lying flat, not shaded and would probably cover about 1.25 sq.m.

Solar panels are pretty cheap BUT:

1) Finding unshaded mounting position tends to cost a bit (it would have to be an arch for best effect)
2) It wouldn't be a matter of putting 40Ah back in if you use 40Ah (unless you take a can opener to a Tesla)

Forget a wind-gen but fit solar first until you run out of space. I did say that panels should be unshaded but that's not quite true. I have 145W (2x40W + 65W) lying on deck and they are worth having. Zero mounting cost and output is still useful because they aren't all in the shade together. I can also move them outboard if required but usually don't bother. I tend to do that in special circumstances such as spending weeks in the Guadiana river with predictable orientation wrt sun. Often not worth the effort when swinging at anchor.
 
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Mounting panels on the guardwires on either side of the cockpit is a popular solution. Framed panels are pretty cheap. We replaced the wire between the last two stanchions with a solid continues 25mm stainless tube so we could mount two panels per side. With this arrangement you can wire the pair of panels on each side in series so you can take advantage of very low volt drop. Wire the two series pairs in parallel at a good Mppt solar reg and you will have a very good addition to you battery charging system.
 
You don’t say which fridge you have fitted but that always seems to be a large drain as noted above so I just wonder if crusing to locations without shore power a keel cooler type might be worth consideration on basis more efficient plus improving insulation ? You could spend a lot on a stainless arch to hold panels but you can create a diy version using poles for cockpit tents as opposed to funding the lifestyle of a steel fabricator who might want £6k to build an arch. A 42ft boat which just near us and set off for ARC built their own frame but clearly sun might be higher than found in Suffolk. Again ugly drop down guardrail dodger types on solid frames might be made. Initially you might find a flat deck panel in front of mast is around 100w but I doubt this will supply enough to meet fridge needs but maybe a cheap toe in water of solar option as a first step As for generator they are quite heavy and will eu10 Honda be man enough ? If you are spending this sum maybe a large 20 version ?
maybe a new engine is higher priority if the original still fitted -could you add a new panda genset set as part of rengining ?
 
Just a word of caution about the smaller generators in so much as the output is often quite noisy. I swear that my generator took out the ECU in my old Eberspacher when it ran low on petrol and revved up and down a few times as it was cutting out. Now I make sure that all sensitive equipment is disconnected if I charge the batteries using the generator, which is normally only when laid up.
 
Tranona said:
Solar is of limited use as a major source of charging to replace daily consumption as you can't get big enough panels on that size boat, nor is the sun reliable enough in northern climates.
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This is wrong, wrong, wrong.

The OP has a 33ft boat, which can accomodate more than enough solar for his modest needs. My Westerly Discus is a similar size to the OPs Storm and is fitted with a pair of 100W panels, connected via a Victron MPPT controller. During a UK Summer i can stay aboard for weeks/months on end, powering my fridge, TV, sound system, water pumps, lights, laptop/phone chargers etc without the need for shore power. There are odd times, when we get a few cloudy days in a row, when i have to turn the mains charger on, but not many.

To the OP: i'd forget the noisy generator and fit as much solar as you have room for. Some panels on the guard wires work OK, or you could splash out on a gantry (which is what i have). On the odd occasion in the Summer when the Sun doesn't shine enough you might need to run the main engine for a while, but it will be quieter than the generator, something less to buy and lug around, less petrol to buy and lug around and you'll get a free tank of hot water (assuming you have a calorifier).
 
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