Comparison of prices for electric motors and diesel engines
Probably one of the most interesting questions, which for some reason is talked about last. I'll try to write objectively.
So, in this article we are only talking about a stationary diesel engine and a stationary electric motor. Outboard gasoline and electric motors are not discussed in this article.
All links to online stores are not for promotional purposes, but to compare real price offers.
A new diesel engine with a capacity of 13 hp, the price is 155 thousand UAH. or $5700.
BU diesel of the same power - $2750
The cost of installing a diesel engine is about $1000. Depends on the difficulty of access to the engine compartment and other factors. It will be difficult to install it completely on your own, due to the large weight of the motor and, as a rule, inconvenient access to the engine compartment. You can save money if you are well versed in diesel engines, then after the collective installation of the motor in its place, you can connect it yourself.
A cheaper option is the installation of a general industrial diesel engine for agricultural machinery. The main problems are very noisy operation, low reliability and a lot of installation work, which includes adapting the cooling system and exhaust to sailboat conditions.
The cost of a new stationary kit-set of an electric motor 10 kW - $ 2100
Read more about the selection of electric motor power here .
Electric motors are mainly installed on their own, because. their weight is small, you can lift them with your hands and the connection will not cause any special difficulties for those who have ever tinkered with electrics. Personally, my first electric motor with a power of 3 kW cost me $900, and the second, semi-homemade, with a power of 10 kW - $1100. The price includes motor, controller and wires.
Used options are usually electric motors from loaders or dismantled from an electric car. The price of an electric motor from a 3-5 kW loader is about $500 with a controller. With an electric car, not everything is so simple, because. there motors are usually designed for high voltage 400V. To adapt to low voltage, you need to do it yourself or order a specialist to rewind it. So you can get a fairly powerful engine for $1000-$1500 (with controller).
Now about the battery - the "narrowest" place for electric sailboats.
It is possible to purchase new lead batteries or BU, as well as new lithium or BU. In any case, the range on batteries will be significantly less than on a full tank of a diesel engine.
Considering the number of cycles that lead and lithium batteries are designed to last, lithium ones end up being more profitable, even at a slightly higher initial price.
I see no point in buying lithium batteries from "brand" manufacturers. They cost so much that I can't even think of a reason. In my case, I did this: I bought one Chevrolet bolt electric car module , which has a voltage of 36V and a capacity of 180Ah. Total 6.5 kWh of energy. Inside it has 30 lithium cells LG 3.6V and 60Ah each. The module cost me $850, plus I also bought a contactor and BMS, and also ordered the manufacture of a waterproof case for this stuff. In total, this amounted to approx.$1150. How long does this module last for me?
1) At a speed of 5.5 knots in calm water - 3 hours (the speed of the hull of my 25 foot boat, weight 2300 kg)
2) At a speed of 4 knots in calm water - 6 hours
3) At a speed of 3 knots in calm water - 9 hours
Read more about batteries here .
A total of 10 kW motor, controller, battery and wiring cost me $2250.
Weight 13 hp diesel - 82 kg. The weight of my 10 kW motor with battery is 60 kg.
For the next boat, a 30ft 4000kg boat, I plan to use the same 10kW motor but add another module from the same chevrolet bolt to get 72V and 13kWh of power.
I don’t know if it makes sense to put a larger and more expensive battery. For most situations, it will be enough, given that there are sails, and for other situations - read here .
Everyone knows where to get diesel fuel, a lot has been written about the cost of diesel fuel in different parts of the world, but where to get electricity to charge batteries? From the outlet in the marina, the most obvious answer. Slower but cheaper (almost free) energy sources are:
1) Energy regeneration when sailing, provided that your boat has a lot of sails and sails faster than 5 knots. Of course, the screw should not be folding.
2) Solar energy . On my boat it is possible to charge the battery from zero to 100% only from the sun in a week. Those. if you use the engine mainly to get off the pier and go in, then this is a very good option. Read more here .
3) Wind turbines . I don't recommend it. they make a lot of noise, have little power and are generally prone to breakage in strong winds.
As a result : a new electric motor with a battery will be cheaper than a used diesel engine. But, you need to understand what limitations the electric motor has in terms of operating time from a single battery charge. If silence under the engine is important to you, almost no repairs, and you rely on sails for long distances, then an electric motor will do.