DIY parallel hybrid - anyone done it?

[Q Xopa]

Originally Posted by Tibor- Puma 38

by Genset, i mean a small diesel+an alternator which provides high DC voltagecurrent to the battery. As the diesel motor+alternator will be mechanically independent from the traction motor and the propshaft, It counts as a paralell hybrid, i think.

It sounds like a 'Series' hybrid setup to me.
'Parallel' hybrid, as in the title of this thread, is connected mechanically to the prop shaft.
As the definition of parallel electrical, batteries, elec/ mechanical hybrid, or any other parallel arrangements- if one parallel input fails there is still an output. In this case if either one of the elec or diesel motor fails the other can still drive the propshaft and boat.
Series- if either the diesel, gen or elec motor fails you are stopped. Ie if any component in the drive train Series stops the boat stops.
So I may have misunderstood your system but it sound to me like the later?

[Tibor- Puma 38]

Yes, You are right and I am wrong in my explanation. It is a paralell hybrid as the electric drive and the genset are not only independent from each other but can also drive the propshaft independently - although i plan to use the diesel direct drive only in emergency.

[Eigenvector]

Originally Posted by Sailmonkey

You need to tread carefully tensioning a belt against the shaft.

The shaft is supported on one end by the transmission, the other by the cutlass. Adding belt tension can/will adversely effect alignment.

But, if you put a custom built shaft spacer that just so happens to be drive sprocket between the shaft and the gear you’ll eliminate most of the tension worries. Not all, but most.

Some Engineering Advice: (for the parallel system)



(1) The above is partially true. But you also need to add the drive torque tension on the belt under load which adds to the side loading of the shaft. The gear tooth pressure angle also contributes to the side loading (Toothed belt or gears, same effect)


2) Be carfeul using aluminum shafts.Since the stiffness (modulas) is 60% that of Steel (SS or CS) the elastic stability will be affected. Thus rotational stability needs to be checked.


3) Be careful using Aluminum. Aluminum does not have an Endurance Limit like Steels. Given enough stress cycles..........it will crack under low stresses. It will have an estimated design life. Side loading of an aluminm shaft under rotation is the Rotating Bend Specimine Test used to determine fatigue life of materials.

[Q Xopa]

Originally Posted by Tibor- Puma 38

Yes, You are right and I am wrong in my explanation. It is a paralell hybrid as the electric drive and the genset are not only independent from each other but can also drive the propshaft independently - although i plan to use the diesel direct drive only in emergency.

Honestly, Im still not clear on what youre describing.

My understanding of a Parallel hybrid is they dont usually have a Genset. It would traditionally have a diesel eng connected to the propshaft. It also has an electric motor also connected to the propshaft.

The elec motor is normally powered by a battery bank.

The battery bank is usually charged by the main diesel motor by using the the elec motor as a generator. And/ or a shore charger.

I guess you could use a Genset but that is putting an extra diesel into an already expensive and complicated setup.

A Series Hybrid would have an electric motor connected to the propshaft only. It would also have a huge battery bank and/ or Genset to power the electric motor. Genset is usual as batts dont push a boat far.

But as long as you know what you have is the main thing.

[ajmarshall1001]

I have a 8mtr catalac and have fitted electric drives, one is a hybrid, using a toothed belt with with the drive cog mounted on the gearbox output shaft.
the system has about 250hrs electric run time atm with no major problems.
The motor acts as a generator when the diesel is running.

[bluenomads]

Originally Posted by ajmarshall1001

I have a 8mtr catalac and have fitted electric drives, one is a hybrid, using a toothed belt with with the drive cog mounted on the gearbox output shaft.
the system has about 250hrs electric run time atm with no major problems.
The motor acts as a generator when the diesel is running.

Sounds really interesting - can you tell us more: what size electric and diesel motor, battery bank, speed you get, etc.?

Did you go with DIY or a manufacturers? I'm not aware of any manufacturers though working on smaller sizes that the Catalac would use I imagine!

[john61ct]

details please

[ajmarshall1001]

I am slowly finding my way around please be patient.
I will put up pictures when I have worked it out.

2 x 5kw Marlin 48v motors from lynch marine based in the uk
12hp kubota self marinized with Beta parts.
12v 175ah alternator fitted to the engine
7.5kwhr bank for the drive
4kwhr house bank
400w solar fitted ATM

Power from the house can be drawn and fed to the drive system using a 2.4kw inverter and 48v power supplies.

speed
3.5kts using 55amps
diesel only 5kts / 6.5k with clean props and hulls
I have used diesel / electric to push against 4.5kts of tide and 30kts of wind to get into sheltered water when myself and crew both seasick, I don't normally use more than 30% of the drive bank (so as not to kill the batteries) and keep the power for if needed, with diesel running motor can be used as a generator to recharge batteries and supply 2nd electric drive.
under sail with motors at idle with a 3.5amp draw this will drop to about 1amp when sail speed reaches 5-6kts. Unfortunately I can't swing props large enough for the motors to regen under sail.

I am hoping to fit enough solar to maintain 1.5 - 2kts on solar only sunny days of course.

[Adelie]

Originally Posted by gmakhs

It wouldn't be easier and simplier if you just add 1 or 2 electric outboards to do the job ???
I am pretty sure you can locate them either on the back of the hulls or the inner side of them or in the middle of the boat .
You can even add only a waterproof electric motor under the hull like the bigger ships have .simpler than messing with belts and pullays

For recreational boats the under hull electric pods have a limited life expectancy when continuously immersed. The seals aren’t prefect and the motor eventually shorts on seepage water.

The azipods on ships have bilge pumps extracting seepage up the pivot stem into the then overboard.

I’ve been discussing this a bit with SeanD who took a boat RTW. He used several trolling motors and my understanding is they all died from water intrusion.

[Adelie]

Originally Posted by gmakhs

I am sorry , Probably I got it wrong

I don't see any point to use both at the same time .

It all depends on what you want to do.

A series hybrid is mechanically much simpler and probably cheaper but at a 15-25% efficiency cost.

With a parallel hybrid both the ICE and electric motor are mechanically links to a prop.

If you want maximum efficiency then you size the ICE to just barely reach hull speed in flat calm conditions. When you throttle back to cruising speed the engine should be near its peak efficiency.

If you need more power than the ICE can deliver because ow adverse wind or seastate you can use the ICE and electric motor at the same time to get that power.

Since the prop is sized for the combined power it is probably oversized for just the ICE and will be more efficient at cruising speed maybe. I’m going to think about that for a bit.

The most efficient system would actually be a parallel hybrid with a controllable pitch prop. Albin Vegas originally came with these.

[Adelie]

Originally Posted by Tibor- Puma 38

by Genset, i mean a small diesel+an alternator which provides high DC voltagecurrent to the battery. As the diesel motor+alternator will be mechanically independent from the traction motor and the propshaft, It counts as a paralell hybrid, i think.

If the ICE motor does not connect mechanically to the prop then it is a series hybrid.

[johnwilde]

Really interesting project - along the lines of something I want to try maybe over this coming winter. Just hijacking this thread with some of my ideas (specific to my situation) to tease out any issues people can see.


I have a Perkins M35 (with a Hurth 100 gearbox that I understand is happy to freewheel in neutral) in our Moody34 and would like to add parallel hybrid - for obvious reasons that don't need to be discussed here.

After the gearbox, we have a flexible coupling that appears to be mounted to a small bulkhead/bearing and thereafter to the propshaft that goes through a PSS Shaft Seal. I've tried to attach an image of this, which unfortunately cuts off most of the important mounting bit to the left.



I can see two options for mounting a motor:

1. Mount a motor with a 2:1 reduction belt pulley on to the section of exposed pro-shaft aft of the bulkhead bearing, just to the left of my photo. This is by far the easiest approach, as the bulkhead is a decent mount position and it will be relatively easy to affix a pulley to 1" shaft here. However, my concern of tension on the pro-shaft so close to the stern gland. It would be very close to the bulkhead bearing as well, but I wonder if this would still potentially allow pressure to be applied to the stern gland that would introduce issues?

2. Try to mount the motor pulley between the gearbox and the flexible coupling (maybe having to push engine back and introduce some shaft attachment for the pulley in a gap created). This is likely to more hard work and it seems to me that the motor would need to be attached to the engine rather than that surrounding structure, as it would be 'moving' or 'vibrating' with the engine forward of the the flexible coupling.

I'd be really interested to know peoples thoughts on the options. Something to mitigate the impact of option 1 would be ideal.

More generally, my thoughts are to use something like one of the Thunderstruck sail kits; maybe the 10kw version - possibly even using the gear reduction kit (for my option 1 anyway). Another question I'd appreciate thoughts on - do I need to be worrying about a clutch arrangement on the motor? Even though I would want to be able to use 'regen' to charge the batteries, I won't always want to do this, say when I want to remove the load from the engine to get full power to the prop or when the batteries are full. But can the motor be left freely spinning in this state without too much worry? How much load would this put on the engine if not engaged and would this cause problems for the motor itself. Obviously there are going to be situations where I don't want the batteries to be charging!

Could ask endless questions on this project, but there are plenty of source of details on batteries; controllers etc. The mounting situation is quite a boaty specific point though.

Thanks

[alaskanviking]

stumbled on this thread and its something I've been thinking about for a while. i ended up rebuilding my engine to give more time for hybrids to develop more.

Boats are probably more similar to Locomotives (parrelel hybrid). however the electric motor would really lengthen things and need more room.

i don't think that running off the shaft is the best idea in this. if so its probably only possible if you use an aquadrive, followed by a short shaft with the gear/belt pully and then a pillow block and aquadrive to the engine. maybe a chain drive with idler where you can pull the link out of the chain. otherwise you wouldn't be able to pull the belt/chain easily for maintenance/replacement. theoretically you could support the gearing this way.

best case scenario is a transmission that is made for this, i don't see that happening without a package deal. still pretty early yet as far as development goes.

For DIY i believe its possible using a velvet drive. they mount them to chevy V8's and 50hp perkins so power range is pretty close. if you look into them they have a few diffrent "nose cones" options. no nose is 1:1, a short cone nose is a geared option like 2:1, and some have a v-drive option that bolts on here. you would have to design an adapter plate to go in place here before the drive shaft or 2:1 cone/vdrive. possible as i believe its a stub axle that comes out here but thats simpler than designing an engine to transmission adapter/interface. you would probably have to add a clutch of some sort to disconnect the engine input so the shaft can spin and generate power through the back end of the gearcase. 4x4/transaxle crowd has been doing stuff like this for decades DIY, essentially this is very similar to a transaxle, and likely you could modify one for this function. power generation should be better on the engine as those big high amp alternators can really mess up the bearings on an engine. i have seen some break the crankshaft because of this side load. a motor/gen off the gearcase would solve that problem.

i believe the brunton autoprop would fit the bill here. never had one but what ive read and researched it appears to be exactly what your looking for. automatically changes the pitch to match the torque/power. size it for both engine and motor, and it should adjust its pitch to either engine or motor alone. it feathers so I'm not sure how it would spin to generate power under sail.

an issue here is that for either running something off the shaft or building what i described the shaft will turn in both directions (FWD/Reverse). assuming a 3 phase motor/gen it probably needs a special controller to generate power this way.

there are a lot of tesla and other electric vehicle motors that would in theory be adaptable for this as far as DIY goes. be cheaper to experiment with anyway.

[johnwilde]

@alaskanviking - Your post has forced me to google 'Aquadrive' and now I realise that is what I have on my engine...

I was aware that the engine mounts were branded as 'Aquadrive' - I just wasn't aware that this was part of system including the thrust bearing and CV joints. I have the previous owner to thank for that. I should probably look into whether this is an installation requiring service?

I don't know about others, but I could quite happily live without a clutch arrangement to disengage the engine/gearbox and sacrifice the ability to operate as a generator - as this appears an additional element of complexity. I note that Hybrid-Marine (referred to earlier in the thread, who work with Beta and Yanmar to make full hybrid engine kits) make this element optional, so by default there is no clutch to disengage the engine. This presumes of course that the gearbox is happy freely spinning in neutral - which I gather some aren't.

Just taking advantage of your thoughts for a moment - in your post you refer to an aquadrive being a mitigation of a direct shaft drive connection. Were you thinking about a connection between the aquadrive thrust bearing and the engine - or a connection between the aquadrive and the stern gland?

I was wondering if, in the second scenario, the introduction of a pillow block/bearing between the pulley and the stern gland might overcome the lateral tension issue on the propshaft. Theoretically this section of the proshaft, aft of the aqua drive thrust bearing, should be subject to no lateral movement as it is firmly mounted to the hull at the thrust bearing - so the introduction of another support bearing would only be a good thing.

[alaskanviking]

Originally Posted by johnwilde

@alaskanviking - Your post has forced me to google 'Aquadrive' and now I realise that is what I have on my engine...

I was aware that the engine mounts were branded as 'Aquadrive' - I just wasn't aware that this was part of system including the thrust bearing and CV joints. I have the previous owner to thank for that. I should probably look into whether this is an installation requiring service?

I don't know about others, but I could quite happily live without a clutch arrangement to disengage the engine/gearbox and sacrifice the ability to operate as a generator - as this appears an additional element of complexity. I note that Hybrid-Marine (referred to earlier in the thread, who work with Beta and Yanmar to make full hybrid engine kits) make this element optional, so by default there is no clutch to disengage the engine. This presumes of course that the gearbox is happy freely spinning in neutral - which I gather some aren't.

Just taking advantage of your thoughts for a moment - in your post you refer to an aquadrive being a mitigation of a direct shaft drive connection. Were you thinking about a connection between the aquadrive thrust bearing and the engine - or a connection between the aquadrive and the stern gland?

I was wondering if, in the second scenario, the introduction of a pillow block/bearing between the pulley and the stern gland might overcome the lateral tension issue on the propshaft. Theoretically this section of the proshaft, aft of the aqua drive thrust bearing, should be subject to no lateral movement as it is firmly mounted to the hull at the thrust bearing - so the introduction of another support bearing would only be a good thing.

i suppose it depends on the transmission, if you can put it in nuetral before the motor gearing than you wouldnt need a clutch. run the motor and the engine wouldnt spin. however if you cant do that then you would need a clutch to disconnect the engine from the motor.

the aqua drive has an thrust bearing followed by a cv joint. its my understanding that there is a stub shaft from the cv joint to the cv joint at the transmission. the pulley or gear would be on this stub shaft. so to replace a belt or chain you would pull this stub shaft. the two cv joints would allow movement. so you would need a pillow block to remove as much of that movement as you can. would need so good measurements here as the cv will need to flex and move but the gear on the shaft shouldn't. i suppose it depends on alignment too. i believe there are two part pillow bearings to make pulling the shaft for maintenance easier.

they have "divorced" transfer cases, essentially separated from the transmission and connected with shafts. these units might apply here well, and work with the cv joints better. some are solid gearing. maybe change the gear to change ratio to suit the motor. thinking about it this would be easy to fabricate a set of mounts and motor mounts for as well. motor connection would actually be simpler