Fishing forum > Electric boat conversion

Author Topic: Electric boat conversion

My 2010 project is converting my 1979 Sangster 18ft Boat, either partially or completely to electric. It currently has a 120hp Mercruiser. I only want to use it for fishing the bigger lakes, but when I do I want enough energy store for a full day.

At this point I am mesmerised by all the information available on the internet. Mainly in the conversion from 120hp to lb's thrust and battery storage requirements.

So for a start I am looking at a 50hp rated electric motor to replace the 120hp mercruiser. But quite how this will link to the existing leg and what battery power will keep me running all day, and if to have a gas generator as back up, and perhaps some solar/wind power, and then there are hydrogen fuel cells......

I will try to keep up to date on progress if there are enough of you interested.

definitely sounds interesting. keep us informed.

Are you sure, 120 hp ?
(about the size of a 2 liters car engine)
For that boat I think a 12 hp engine would be fine, but I dont have to much experience.
Electric motors are for trolling only. Usually a boat has a gas engine for high speed, and an electric one for trolling, quietly, at low speed.
Electric motors are presented by thrust, and 30 lb thrust is about 3 hp, but is very hard to make a precise comparision because they are very different.
For the boat in the picture, a 50 Lb thrust electric engine looks fine.
They are very easy to install.

find a wrecked hybrid car

Accoding to my research so far, the electric trolling motor is designed to max out at 5mph. The lbs thrust is to get you to that speed. There is a balance between the the weight of the boat and lbs thrust so that the motor can in fact deliver enough thrust to get that weight of boat to that speed quickly.

To have an electric motor to replace the existing engine would require a lot of battery, a lot of amp/hours, and be quite expensive to accomplish if at all workable.

Gas engines are good at speed, and easy to refuel. Electric are good at low down torque but not speed, as compared to gas, and therefore more efficient at trolling speed.

If you can do without speed then a total electric convertion can be done, replacing the gas engine with a 5-8hp electric motor (depending on boat size). But in adverse weather conditions my render you with flat batteries unless you pack a generator.

So I think I'll keep the gas engine and decide what trolling motor configuration to use.

Do yourself a big favor and just put an electric trolling motor mounted on the stern somehow. Leave the leg alone!!!

I love gadgets, so the Minn Kota iPilot looks very interesting but it only stores 3 routes, I think that is not enough and although fun does restrict my choice of motor.

Bow mount looks good theoretically and I may revisit this possibility.

But I did find this:

Yes it is salt water, but that does not matter. The 160lb thrust may be a little overkill and at $1,049.99 + batteries looks good on budget. There is enough power there to overcome most adverse wind conditions.

I use all existing controls with the exception of the remote speed control. I am not sure what battery power will give me a day's trolling as Minn Kota are not specific on this, so a little more research here.

I did look at the Torquedo range but they are all transom mount, and I don't have a suitable mount. Interesting though.

Just thought I should throw this in ! (Not for my boat) but interesting all the same

Well that is it, previously repaired block, pi**ing water. With the milder weather, I attached the garden hose and as you see, big problem.

So now I am thinking of pulling everything and going electric. 12hp 48v motor, 4 100amp/hr batteries, 10kW generator.

Not sure if to keep the leg or replace it with a simpler mechanism that is more efficient.

So come on teckies, how does this sound?

Must have it ready for March and then perhaps I'll have a biggest fish story.

SO what I have found out so far is that trolling motors cannot run on full power for too long without burning out, that is according to Minn Kota. For primary power you need to have something designed for that purpose.

Minn Kota do the E-Drive (2hp) @ $2600 plus 4 batteries and charger. Then there is the Torqeedo range up to 9hp and proportionatly more to buy.

The final idea is to place an inboard motor, probably 8hp continuous, 48v system. This would use the exisiting leg.

In any case the budget is going to be around $4000-$5000.

Keep up to date on my research on you will find many links and ideas.

Fishing forum > Electric boat conversion


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