Electric vehicles

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#1328677 21-Jun-2015 14:35

raytaylor: You guys have got me all excited about that outlander PHEV
Except looking at the specifications I dont know if it can come near the Korando I drive now.
And thats highly annoying - I want something electric but wont change unless it feels like it has a bit of power when i put down my foot.
The korando is not super fast like a v8 commodore, but its much better than a typical 2 litre petrol.

Diesel Korando: 129kw @ 4000rpm + 360 Nm @ 2000rpm + 0-100 in
Outlander PHEV: 80kw + 332 Nm

So both have similar torques, but one has only 60% of the horsepowers, yet both claim 0-100 in about 9.5-10 seconds.

What do you guys think?

You are misreading the power figures.

The outlander PHEV has a small 88kW petrol engine, Plus twin 60kW electric motors (one for each axle).

Combined these add up to 200BHP at the wheels (149kW) source (How these power sources add together is a bit complicated as, peak power for each axle occurrences at a different speed, and the transmission only allows the engine to drive the wheels directly (parallel hybrid mode) at higher speeds, at lower speeds it runs in series hybrid mode with a 70kW generator, making power for the electric motors. Of course for most of your driving the petrol motor won't run at all, and the car will use power from the battery by the two 60kW(each) electric motors.) - Don't worry if this seems complicated, the car does it on its own, I'm a mechanical engineer who is interested in such things)

The outlander PHEV is also the performance model of the range (replaces the V6 version that was available on the previous generation outlander)

Source: http://www.mmnz.co.nz/assets/NZ-Cargo-Outlander-PHEV-Review-Feb-2014.pdf

also: "On road, the PHEV has a very useful turn of speed; underfoot, if you didn't know, you would swear there was a V6 under the bonnet"

Source:http://www.themotorreport.com.au/58753/mitsubishi-outlander-phev-aspire-highway-travel-review

Suffice to say, I would expect the outlander PHEV to hold it's own performance wise with other vehicles in its class, But of course take it for a test drive to see how all the motors come together.

Other things to note with outlander PHEV:

Best acoustic insulation in the outlander range
No 7 seat option
No spare tire (replaced with flat tire fixing kit).

dwl

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#1328762 21-Jun-2015 18:31

Fred99:
Scott3: Acceleration & hills aren't really an issue for boats, (nor are speed limits), hence most boats cruse at around 75% of maximum power. For example a 5.5m planing runabout would have a similar size engine as the car (say 80kW), but would need to use around 60kW to cruse at 40 - 50 kmph. A 10m displacement yacht (efficient hull shape for sailing) might have a 10kW engine, and use 8kW to curse at 12kmph.

I don't think the estimate of of 80% of full power to maintain a reasonable cruise speed (at just below hull speed) for an efficient displacement hull is correct. My guess is that (in ideal conditions) it will be closer to 20% than 80%. The problem is however that with a boat, you don't want to be limited to "ideal" conditions for either range or power (ie to make way against wind or sea), so need plenty in reserve (power and fuel).

An interesting topic. I have a few kayaks and was wondering how electric might work. Using this as an example of a displacement hull I found this graphic in a thread about Typical Wh/Mi for an electric kayak? :

The problem is what speed reduction is being considered for the reduced power. We think of cars in terms of speed limits and that is where maybe 20% is needed to maintain cruise speed. For boats using the kayak example above, what would be considered a maximum power and what would be reasonable cruise? Typically around 4-5 knots is as fast as you would push under human power. Dropping to 20% of max cruise might be quite a reduction in speed.

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#1328829 21-Jun-2015 20:38

Scott3:

No spare tire (replaced with flat tire fixing kit).

Thanks - its quite interesting now you have explained it.
That missing spare tyre is a bit annoying. The last two times I have had to replace a flat tyre, i was in a hurry to get to an appointment and so being able to quickly change to the spare is quite handy.

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#1328848 21-Jun-2015 21:22

Fred99:

I don't think the estimate of of 80% of full power to maintain a reasonable cruise speed (at just below hull speed) for an efficient displacement hull is correct. My guess is that (in ideal conditions) it will be closer to 20% than 80%. The problem is however that with a boat, you don't want to be limited to "ideal" conditions for either range or power (ie to make way against wind or sea), so need plenty in reserve (power and fuel).

A typical yacht (Best base case to use as it is essentially only yachts, ships and kayaks that have efficient hull forms), most powerboats have planing hulls or inefficient displacement hull forms (optimised around other aspects such as stability, or interior space, not efficiency)

A typically 28 - 35 footer yacht (4 - 6 tonne) will have around a 15 - 30 horsepower (11- 22kW) diesel engine. A normal cruising engine speed would be around 2800RPM, and normally the engine propeller would be selected to give 3200-3400RPM at full power, with the red line sitting around 3500RPM. Or course without advanced instrumentation or a dyno it is very hard to find out the actual power output.

Engines are more efficient near full power (although are better at lower RPM). This is why hybrids are more efficient than conventional cars. They have a smaller engine tuned for efficiency (at the expense of peak power), with a battery & electric motor to provide additional power for short periods such as acceleration and hill climbing.

As such it makes little sense to oversize a displacement boat engine (or implement a Prius style hybrid system). Once you get near hull speed you get very little speed gain for a lot more power input. The power input required for this speed can be estimated by a navel architect. Usually an engine just slightly bigger (to account for strong head winds, heaver loading, and to mean the engine isn't running flat our for longevity, efficiency and acoustic reasons. Usually it is accepted that you will motor slower in an adverse sea state, at similar or higher power levels, (resulting in higher fuel use per distance).

Of course an owner can put a larger engine in their displacement boat. It will cost more to buy and run (less efficient), weigh more, but it will allow the boat to accelerate faster, and motor into a stronger head wind. Increase in top speed will be small. I'm used to racing yachts. typically they are fitted with the smallest engine allowed in the rules, to minimise weight.

If you run well below hull speed displacement boats can be really efficient, which is key if you want to keep battery size and hence cost down. I think this is what you would want to realistically look at for an electric fishing boat.

Be careful though as the likes of head winds have much more of an impact on an efficient boat than an inefficient overpowered one. We had a 5.9m racing trailer Sailer with a 2hp outboard (no engine required by class, but if it was, the racing rules would have required a 3.5hp engine). That engine could barely move the boat against a 25knot headwind (crew had to lie down low to reduce wind-age etc to move forwards). Of course it was a racing yacht so all we cared about was lightweight.

The torquedo outboard range looks really good, keen to see one in action.

Scott3

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#1328888 21-Jun-2015 22:17

raytaylor:
Scott3:

No spare tire (replaced with flat tire fixing kit).

Thanks - its quite interesting now you have explained it.
That missing spare tyre is a bit annoying. The last two times I have had to replace a flat tyre, i was in a hurry to get to an appointment and so being able to quickly change to the spare is quite handy.

Having no spare is become much more common on modern cars, due to consumer pressure for more boot space, better performance and lower fuel economy. Eliminating the spare tire is quite a weight saving.

Modern tires are less prone to flats than older cars.

I have been driving several years (including lots of long distance travel), and have never had to change a flat tire on my car. (I have a 12v compressor in the boot from an old engineering project, and have used this once when I noticed the tire low (easier than swapping to the spare).

Research in the USA shows many drivers don't know how to change a tire, and of those who do many will chose to call road service to do it for them.

Extra tool in our arsenal compared to older cars is "TPMS" or tire pressure management system. This is required on all new cars in the USA (but not nz so might want to check the outlander PHEV has it). This gives the driver an early warning of lower tire pressure (about 10% low, well before it is viable before looking). Meaning most slow leaks will be able to be detected and fixed while the car is still drivable.

There are differing approaches to going without a spare:

Run-flats

No BMW's come with spare tires any-more (I think the SUV's have them as options but not standard). They have run flat tires that can be driven on flat for 50Km or so. The theory is that it is very dangerous to change a tire on the side of the motorway or in a rough neighbourhood (Not thinking of NZ here), and that it is much safer to be able to drive the car somewhere near and safe, then sort the problem out than try to fix it on the moterway. Other brands also use run flat tires on selected models.

Fix a flat kit

Kit with compressor, and a can of "fix a flat" goo.

Tesla, Outlander PHEV, My grandparents $100k plus fiat camper-van, some sports cars use this approach.

Theory is many people don't know how to fix a flat with a conventional spare tire, and that using the kit both less complicated and physically easier (don't have to lift 18"+ wheels, or break the lug nuts free). With the kit for a slow leak you can just pump the tire back up and go on you way, and with a medium leak you can use the goo to seal it and pump the tire back up, and be on your way as a temporary fix. (apparently you want to avoid using the goo if possible as it is a real chore for the tire guy to remove from the inside of the tire when the puncture is permanently fixed (needs to be removed for the tire to pass its balancing), and it can kill the tire pressure sensor.

If you have major tire damage such as a blowout (typically caused by running on an semi flat tire, TPMS should prevent this), or long side wall gash, then you will need to call a tow truck or roadside tire service. (remember based on research most people would have called, and waited for help anyway)

Nothing at all

This option is becoming the norm for trucking fleets. Equptment required to change a tire on a truck is bulky, heavy (eats into you payload that you could otherwise sell to your customers), and expensive, many trucks use multiple tire sizes for different axles, so multiple spares would be required. Many fleets have worked out that the lost productivity from waiting, and cost of a tire service truck callous is less than the cost of equipping every truck with spare tires, jacks, breaker bars, and training drivers in their safe use.

If a long hall truck (without spares) gets a flat tire they stop, radio/ call for a tire service truck to be dispatched and wait. The tire service truck is typically has many unmounted tires of the sizes of the fleets it services, equptment to mount tiers to trucks existing rims (so no need to buy spare rims) (I think), commercial size air compresses, commercial grade jacks, pneumatic impact wrenches etc.

Of course if you are going go to remote locations, puncture prone areas such as forestry roads or go off roading these options are probably not sufficient, and you should buy a spare and but it in the boot or on a custom rear mount (common in the 4x4 world where increasing tire size means the spare no longer fits in the stock location).

But consider how many flat tires you have got in the last 5 or 10 years, then consider the number that having TPMS, and a compressor would have made a non issue before deciding to carry a spare.

Fred99

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#1328896 21-Jun-2015 22:31

dwl:
Fred99:
Scott3: Acceleration & hills aren't really an issue for boats, (nor are speed limits), hence most boats cruse at around 75% of maximum power. For example a 5.5m planing runabout would have a similar size engine as the car (say 80kW), but would need to use around 60kW to cruse at 40 - 50 kmph. A 10m displacement yacht (efficient hull shape for sailing) might have a 10kW engine, and use 8kW to curse at 12kmph.

I don't think the estimate of of 80% of full power to maintain a reasonable cruise speed (at just below hull speed) for an efficient displacement hull is correct. My guess is that (in ideal conditions) it will be closer to 20% than 80%. The problem is however that with a boat, you don't want to be limited to "ideal" conditions for either range or power (ie to make way against wind or sea), so need plenty in reserve (power and fuel).

An interesting topic. I have a few kayaks and was wondering how electric might work. Using this as an example of a displacement hull I found this graphic in a thread about Typical Wh/Mi for an electric kayak? :

The problem is what speed reduction is being considered for the reduced power. We think of cars in terms of speed limits and that is where maybe 20% is needed to maintain cruise speed. For boats using the kayak example above, what would be considered a maximum power and what would be reasonable cruise? Typically around 4-5 knots is as fast as you would push under human power. Dropping to 20% of max cruise might be quite a reduction in speed.

Guessing that the kayak is 10ft, then the "hull speed" (sq root of length at waterline x 1.43) is about 4.5 knots. The canoe is long and skinny, so the penalty for exceeding hull speed without planing isn't as high as it would be in the case of a wider vessel., but there's no bonus when it does exceed hull speed. If it could plane, then the graph should steepen sharply before it hits hull speed, then flatten out or even drop a bit.
This is why a catamaran style hull might be more suited - for a wider beam more practical electric boat which can cruise at higher than hull speed.
The graphic is interesting, but you don't know what's really going on with regard to optimal prop performance and RPM.

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#1329158 22-Jun-2015 12:12

Scott3:

No spare tire.

Your arsenal is missing one important tool - a big fat nail - you hummer it in a puncture - and you can drive for ages!

RUKI

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#1329169 22-Jun-2015 12:19

dwl:
linw: What would scare me is having a huge Li battery charging in my internal garage every night. Have you seen the fires from MUCH smaller radio control Lipo batteries?
..........
........... Worth noting that the charging systems are high current and poor electrical practices could result in electrical fires attributable to the EV but actually not in the car.

Fire from DC High Voltage systems may be caused by arching which does not estinguish itself unlike with AC current. Hence special provisions are required with DC systems - whether it is solar or EV charging.
e.g. Fuses, rated for AC current will not protect DC circuits with the same current. This is not a common knowledge.

Scott3

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#1329624 22-Jun-2015 23:52

I think that comment was referring to a case in the USA where household AC wiring caught fire while an EV was charging.

EV was drawing correct amount of current, and just happened to be the first thing that tested that socket (with poor/damaged wiring) with a high current draw for a long time.

Many EV's in NZ only draw 8A on a 10A socket, or require a 15A socket for a 10A draw, I assume to try and avoid being the "straw that breaks the camels back" by putting in some extra safety margin.

Generally wiring in NZ is to a higher standard than the USA from what I have heard.

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#1329756 23-Jun-2015 10:17

Scott3:

Be careful though as the likes of head winds have much more of an impact on an efficient boat than an inefficient overpowered one. We had a 5.9m racing trailer Sailer with a 2hp outboard (no engine required by class, but if it was, the racing rules would have required a 3.5hp engine). That engine could barely move the boat against a 25knot headwind (crew had to lie down low to reduce wind-age etc to move forwards). Of course it was a racing yacht so all we cared about was lightweight.

The torquedo outboard range looks really good, keen to see one in action.

TYA minimum rules are not good enough IMO. HP ratings alone aren't good - many TY owners skimp and use dinghy props, too short shafts for when it cuts up. They end up relying on club rescue boats too often. If you're cruising, rescue might be a long way away. You do need plenty in reserve. It's not safe if you don't. Many keelers are also under-powered and have inadequate/poorly matched props.

RUKI

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#1329901 23-Jun-2015 14:09

Scott3: ...
Many EV's in NZ only draw 8A on a 10A socket, or require a 15A socket for a 10A draw, ...
Generally wiring in NZ is to a higher standard than the USA from what I have heard.

I've read about people in NZ building their own non-isolated DIY 15+ Amp chargers - that is a worry.

Every house is different and not nessesarily adhere to standards keeping in mind numerous do-ups in New Zealand.

I've heard from two guys who did renovation on their houses in Auckland and discovered:
- live wire left behind the gib (perhaps at the time the house was built) and never been connected to anything and
- wiring found to be a mixture of aluminium and copper in one circuit just hand-twisted.

When it comes to EV charging - it is a good idea to engage certified electrician to do the inspection. It worth it.

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#1330004 23-Jun-2015 15:40

The reason I don't go out more often is the cost of fuel. If I'm careful it costs me about $100 per trip in fuel. Then there are the maintenance costs. About $500 per year for servicing.

I think the capital cost is too high at the moment and the battery tech (kwh/kg) just isn't there.

What is interesting is that due to the torque of electric motors, less kW are required per unit of thrust.

Gripper propellers are able to be used which would overload a petrol engine. You have to prop a petrol engine so that it can reach close to maximum rated RPM. Otherwise you over load and wear out the motor.

Electric motors seem to be more like diesel engines. I think you could probably go with something like a duo-prop configuration that is efficient and thrust efficient.

An interesting electric motor application is hydro-foiling. A foil assisted power boat could have the motors and batteries in a torpedo shaped housings at the bottoms of the foils, with a foiling wing in between. That puts the weight down low for a quite stable set up that would allow safe foiling in a low swell.

The foils could be retractable into pockets under the hull for shallow water, rough conditions, or slow speeds.

There would be a reduction in surface friction and resulting efficiency gains from the hull cutting through air instead of water.

Scott3:

While it is technically possible to build a wide range of capable electric boats. I think there are only quite limited situations where a recreational electric boat will make sense.

One of the key issues is that most recreational boaties get out as much as they would like, hence don't use enough petrol to pay off the expensive batteries.

That said if you are an enthusiast, and are prepared to part with some coin to build a sweet rig go for it.

Key issue you hit up against with boats is that, compared to cars, engines are run fairly hard.

A typical car will have around an 80kW engine, and will require around 15 kW to cruse at open road speeds. The rest of the power is in reserve for accelerating & ascending hills.

Acceleration & hills aren't really an issue for boats, (nor are speed limits), hence most boats cruse at around 75% of maximum power. For example a 5.5m planing runabout would have a similar size engine as the car (say 80kW), but would need to use around 60kW to cruse at 40 - 50 kmph. A 10m displacement yacht (efficient hull shape for sailing) might have a 10kW engine, and use 8kW to curse at 12kmph.

If you were to run the with a nissan leaf sized battery (24kWh), it would get you around 1.5 hours driving in a car, (or around 120 - 140km), In the runabout you would get about 24 minutes (or 16 to 20km) of boating. In the Yacht, you would get just over 2 hours motoring, but it would only take you around 24km. Of course you actual usable range is lower as you need to keep some energy in reserve as a safety margin to ensure your not stranded.

In terms of boating I can see the following situations being useful:

Electric motor for a dinghy: Many boats are stored on moorings, and owners use small dingies to go to them. Many have small (often 2hp) outboards to go out to their larger boat. An electric outboard would be ideal for this: - it's a known (fairly short) distance, - small irregularly used petrol engines are a real pain/expense to maintain, - Buying, and mixing 2 stroke fuel can be a inconvenient.
A long, skinny displacement boat (catamaran etc). displacement means weight is less of an issue, Could use a bank of lead acid batteries salvaged from a commercial UPS or similar.
When I was doing a regatta in Balboa (Near Newport Beach, California many of the mansions on Newport bay had little electric boats. The bay had a 5knot speed limit, and distances where short, so they looked ideal for trips to friends mansions, Restaurants and the yacht club.
Areas where petrol/diesel engines are banned (some lakes)
For very low speed trawling use.
Commercial use with a regular use pattern.
Check out:

http://www.torqeedo.com/en

Mike

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#1330251 23-Jun-2015 21:20

MikeAqua: The reason I don't go out more often is the cost of fuel. If I'm careful it costs me about $100 per trip in fuel. Then there are the maintenance costs. About $500 per year for servicing.

Typically kiwi runabouts are quite inefficient. The short, wide form is more optimised for stability / cockpit space when fishing, and fitting in parking spaces at peoples houses than efficiency (generally long and narrow boats giver better efficiency for given payload)

$100 of fuel is about 50L or 455 kWh of energy If we assume that your electric motor is 3x as efficient as your petrol engine (efficient petrol 4 stroke engines are around 30% peak efficiency (may be a bit high here), 2 strokes much worse). you would need around 152KWh in your battery bank (plus reserves), or 12 torqueedo lithium battery's (US$200k, 1800kg's).

It's pretty clear this is infeasible, to justify on the basis of fuel savings (Unless you use your boat extraneously much, say you did a trip in the early morning, charged during the day, and did another trip in the evening, everyday, using $30 or electricity per trip, but offsetting $100 of petrol, then your payback time would be over 4 years)

If you were in Europe with $3.00 + per litre petrol it would improve the economics somewhat.

In summary if you want an electric boat, you need a much more efficient design (something that could be driven with a 4 - 15hp petrol outboard), to keep the capital cost/ battery weight down.

You also need to justify it on a basis other than cost (perhaps: Low noise, no emission, advertising point for business, technology enthusiast, ability to use electric only waterways etc) , as the more efficient boat could also be driven with a very small outboard and not use much fuel.

I think the small end of the scale is most practical for recreational boats at the moment(i.e. 2hp outboard replacements for dingies that just go to moorings and back, kayak boosters, enthusiasts with custom easily driven hulls/ converted yachts)

I do think that electric cars, ebikes and electric motorbikes are easier to justify.

MikeAqua

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#1331408 25-Jun-2015 14:31

Your estimates are good ones ...

Torqeedo produce electric outboards. They recommend their 80 model, which produces 32kW thrust from 50kW input as a replacement for a 80HP petrol outboard.

My boat would need two of those running at say 30kW each, so 60kW per hour. Currently it uses about 20L of petrol per hour (ie 200kW).

Energy density is the killer and remains the big advantage of hydrocarbon fuel.

Mike

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#1333290 29-Jun-2015 12:31

Anyone see Top Gear USA on Saturday?? The who program was devoted to EVs from the basic Leaf to Electric drags. Dispite the program being 2 years old they gave EVs the thumbs up with the only reservation being rang. Man the Tesla they took for a drive could sure go fast..

Regards,

Old3eyes

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