Gen set or Battery/inverter

The other day my 5kw Westerbeke gen set stopped making AC. The gen set is in a sound case and a 3 ft gulfstar trawler. What I am getting at is it takes up a fair amount of space in the engine compartment. Quick diagnosis shows one coil on the stationary side reads .5 ohms and the other .2. I believe they should be the same. Conclusion, replace the generator portion. It weight 155 lbs and not easy to get to. I am thinking of pulling the gen set out and replacing with batteries, inverter, and solar panels. The heavy user is the electric stove and hot water heater. The stove I could change to propane, and tie the hot water heater to the diesel engines. I would appreciate any comments.
Ken

If you don't have air conditioning or an electric stove and water heat, there is almost no reason for a genset in these modern times. The only other justification would be spending a lot of consecutive days on the hook and no solar (or an area without sunshine). Depends on how you use your boat.

Never had a generator on my sail boat. Had diesel heat, alcohol stove and engine made hot water, life was good.

Had a generator on my unfiltered 42. Almost never used it. Had diesel heat, propane stove and engines made hot water but was much more efficient to use generator to make hot water. Life was good.

Current boat uses generator all the time. While I have diesel heat the HVAC system is much nicer, still use propane stove and engines heat water but not practical while at anchor. Then there is the washer and dryer plus the satellite tv and the list of power consumption goes on. Life is still good.

Even with an electric stove, ditching the generator may be possible depending on how much battery and solar you can fit.

My boat didn't have solar/inverter, PO must have run the generator all the time underway, but he hardly ever left the dock so that wasn't much. I put in a 2000w/80a inverter charger and 400w solar, 800ah batteries. Stove is propane. Runs everything but the hot water and 2 ac units. We have 2 household refrigerators, the solar doesn't keep up with those but it's enough to last 2 days at anchor. Works well for us, we only run the generator if we're anchored longer or there no sun. The engines will recharge the bats in 6 hours running or so so if we move every two days we're good. Hot water is a problem though, it doesn't have engine heat input so it's on the upgrade list. Just have to figure out where to plumb it in on my old Perkins engines. We came to this boat from a sailboat, so we manage our power the same way we did there.

I think adding the inverter and solar is a good idea, but I would try to keep the generator. Unless you are one of the luck few, you will be hard pressed to fit enough solar, free of shading, to really run the boat. On most boats, shading is a real challenge. I have 1300W of solar and typically only see 500w or so out of it, all because of shading. Between radar antennas, mast, and all the crap up their, something is always shaded, or more accurately, it’s rare for anything to be unshaded. The most I have ever seen is about 1100W.

I'm undergoing a major refit including swapping 30 & 10kva auxiliaries for 5000w of solar, 10kw inverters and 840ah 48v batteries. I've created a tonne of space in the engine room, drastically reduced noise and vibration and eliminated spares and maintenance requirements.

Note, I'm very power hungry (full technical dive setup, electric domestic galley and teenage kids) but do have the luxury of a lot of flat roof space.

Full story is here:

GoneDiving said:

The following is how an idiot, namely myself, builds a 840ah 48v Lifepo4 battery. Follow at your peril. Or you could just learn from my mistakes and do it properly.

Click to expand...

I've also toyed with the idea of fitting a small generator head to my mains should I need more power or a backup for overcast weeks

Simi 60 said:

Which gets me back to something I have mentioned before but had no real response to.

Why not use the existing charger onboard and connect a 3.5kva generator head to it?

(Below is a Mecc Alte head as an example)
https://www.ebay.com/itm/Mecc-Alte-...7-0022-4897-bea4-95cb8a78672f&redirect=mobile

Click to expand...

Good luck.

We don't have AC but the hot water could be a problem. I have old perkins engines also and not sure how to plumb the hot water. I am thinking of changing the stove to propane but the propane locker placement could be a problem. Probably keep generator and add solar panels for when we are not on the boat. Also with propane may wife will not forget to turn the genset off since it will not be needed. Many times it ran all day needlessly.
I purchased 2200 honda that I am going to plug into the shore power and see how that works till we can get the genset repaired. This will also give me the chance to enforce energy management.
Ken

I have old Perkins engines which are plumbed for hot water. If you’re interested I could take some pictures. I think a coolant line runs through the hot water heater.

When I added an inverter and decent battery bank, it cut generator use about 95%. I have alternators on my mains that keep the bank charged, when running I don't need a generator and only run one to charge on the hook, making water, laundry, etc. But I have a diesel stove that also keeps the water hot.

SEAdog AK I would love to see how they are plumbed.
Thanks, Ken

So long as you have 12v refrigeration you will be OK without your Gen.

Resistance heating is too big a load for solar to keep up to, so you won't be heating your domestic water or electric space heat without a generator when away from shore power.

My usage of my generator dropped as Lepke indicates, when I added Solar. I now don't need to be plugged in unless I am going to need hot water, and then only if I am staying put and not using the main engines.

If you have domestic fridges, you need a working generator.
Your inverter, at rest but waiting for a load, can draw more than your 12v fridges, so keep the inverter and extra batteries for backup.
My load with just an idle Inverter, is 6.5 amps.
My 12v Fridge draws under 3 amps, when cycled on, as does my 12v Freezer.

Inverter idle draw varies a lot depending on the inverter. My 2kva Victron inverter draws about 0.8 amps at idle with no load. The 3kva version is spec-ed at about double, so 1.5 - 1.6 amps. For less than an amp, we just leave ours on 24/7 (basic idle draw for that, battery monitoring for the solar, cellular internet setup, etc. is about 2 amps total).

Regarding inverters and batteries, I couldn't imagine my boat without the inverter and house battery bank. While I do have an electric stove, I've only used it 5 times in 7 years, preferring to grill or use the microwave for heating. The generator gets used for climate control, stove and rarely battery charging or water heating at anchor. Currently I'm cruising and doing a load of laundry in the Splendide washer dryer through the inverter.

The one caution regarding inverters is that whatever you consume (appliances) you need to replenish into the battery bank. I run a second alternator on my engine which is a commercial grade 220 amp model with an external regulator. This gives me the power to consume lots of DC and also recharge the batteries as quickly as possible.

Ted

I think there might actually be two different questions here, depending on where you are starting from.

If you have no inverter then you are running everything off DC, and running a generator for the times when you want AC. In this case I think and Inverter is a great add for most boats, providing AC power all the time rather than requiring a generator. The generator use is then reduced to heavy AC loads, and battery recharging after prolonged anchoring. It’s nearly all upside and nearly no downside.

The other question presumes an inverter, and may involve an inverter upgrade to handle larger loads. The real question is whether the addition of solar, maybe a bigger engine alternator, and maybe a wind machine can provide enough charging to eliminate the need for a generator. I think I’m most cases the answer is no, but it’s not universal. A number of people manage to fit enough solar and live in a favorable climate that makes this work, or at least enough to reduce the need for a generator to a very small percentage of time such that running the main & alternator can bridge any gaps. It’s great when it works, but from what I’ve seen most boats suffer from limited space for panels, and shading that can be minimized, but not eliminated. Also, horizontal panel mounting is often sub optimal. The result is real world performance that’s well below the nameplate ratings. Any amount is good, so I’m very much in favor of solar in boats, but you need to be cautious and realistic about what yield you will actually get.

If I were contemplating removal of a generator, I would leave it in for at least one full season with any replacement power system to assess actual performance. Then remove the generator only once you are confident the new system meets your needs.