Precision 165 Electric propulsion upgrade and review.

[Straander]

Hello. I made a upgrade to my precision 165's electric motoring system this year and I thought I'd share the results with this community as I know electric motoring is fairly popular.

My new system consists of a Newport Vessels NV, 86lb thrust trolling motor and a Eco-Worthy 24V, 100Ah LiFPO4 lithium battery.
These can currently be found on Amazon for $250 for the newport motor and $630 for the battery for a total of $880. The battery has a capacity of 2560 Watt-hours

Comparing to the Torqueedo 1103 CL which I think is the only motor in their lineup with a long enough shaft to use on a sailboat, the cost is $2950, it has a static thrust of 70lbs and a battery capacity of 915 watt-hours.

Now the Torqueedo can most likely get the boat to a much higher speed because the newport vessels motor has a low pitch prop and a limiting maximum RPM. On the two trips I've used the newport motor on, I've measured a speed of 3.85knots with 3 passengers and calm conditions, and 3.5-3.6knots with 4 passengers and slightly windy conditions. On my last trip, I had to motor 3.5 miles at max throttle and amazingly the battery voltage implied a depletion of only 7.5%. The theoretical range of this system looks very impressive, though I'll have to use it on longer trips to confirm.

Still too research is if the P165's primary power panel is compatible with 24V. I know I can find 24V bulbs for most of the lights, I just need to dig deeper in to all the individual electronics.

The battery barely fits in the boat's forward compartment, I'm waiting for some sheetmetal to make a proper mount for it as you can see below.

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[tjspiel]

Interesting !

What are you using to step the voltage down to 12 Volts for the other electrical stuff on the boat?

[Straander]

I'm hoping that if the electrical panel is compatible with 24 volts, and I replace all the bulbs on the boat, then I can just run the entire boat wired up for 24V right off the battery.

[tjspiel]

I'm hoping that if the electrical panel is compatible with 24 volts, and I replace all the bulbs on the boat, then I can just run the entire boat wired up for 24V right off the battery.

Oh, I see you mentioned that in your original post. Sorry I missed that. You could get something like this:

5 Amp Step Down Converter

That one is 5 Amp but on the same link you can purchase ones up to 20. Pretty inexpensive but I'm not sure if that would end up being a phantom load off of your battery.

[tjspiel]

I'm hoping that if the electrical panel is compatible with 24 volts, and I replace all the bulbs on the boat, then I can just run the entire boat wired up for 24V right off the battery.

Oh, I see you mentioned that in your original post. Sorry I missed that.

If you decided you needed some 12 volt accessories, you could get something like this:

5 Amp Step Down Converter

That one is 5 Amp but on the same link you can purchase ones up to 20. Pretty inexpensive but I'm not sure if that would end up being a phantom load off of your battery.

[Straander]

Thank you. I may end up going down this route if I can't upgrade everything to 24V

I'm hoping that if the electrical panel is compatible with 24 volts, and I replace all the bulbs on the boat, then I can just run the entire boat wired up for 24V right off the battery.

Oh, I see you mentioned that in your original post. Sorry I missed that. You could get something like this:

5 Amp Step Down Converter

That one is 5 Amp but on the same link you can purchase ones up to 20. Pretty inexpensive but I'm not sure if that would end up being a phantom load off of your battery.

[Brian N.]

Thanks for a very informative post. Do you have figures for the voltage draw of the engine, or power consumption at various throttle settings? Impressive that the engine pushed a fully loaded boat at over 3.5 knots.

As far as the OEM electrical panel ((Sea Dog Brand) I would think the concern would be the amperage going to individual circuits and wire gauge. As I remember, the wires look to be 12AWG, which should be fine for lighting which are low power draw. There is a substantial bus, which should not be a problem. However the fuses and panel lights may not be compatible. Why not just leave the lights on the original panel and use a small light weight 30 amp-hour 12V battery, and set up a separate switch/panel for the engine?

[Quantico Frank]

VERY interesting, Straander. I hope someone else will step in with some technical thoughts on this. I'm just barely holding my own with 12v at this point.

[Riggerdood]

I would think it would make the most sense to dedicate the 24 V side of things to the propulsion, and leave the 12 V side as is? If you have room for 2 batteries that is ... ?

[Shesaidno]

Thanks Straander for sharing this helpful information. I would love to go back to electrical propulsion. I don't know of anyone with a gas engine who hasn't had some type of problem with it so the more we know about an alternative, the better, especially economical solutions!

[Straander]

Do you mean Amperage draw not voltage draw? At full throttle it was pulling about 32ADC, or about 800 watts. I'm actually a little confused as to why the battery showed such minimal depletion after the trip, because just the amps X time implies a higher percentage of its charge should have been used up. Maybe it'll give me a more reliable figure after a longer trip.

I'm not concerned about the amperage of any of the pre-existing wiring. If I upgrade all the loads to 24V equivalents, then the amperages will be cut in half. Fuses should still work, only they'd be harder to blow since they're rated for the 12V equiv. loads. The only thing I'd be concerned of is the little LED's inside each rocker switch which might burn out.

Thanks for a very informative post. Do you have figures for the voltage draw of the engine, or power consumption at various throttle settings? Impressive that the engine pushed a fully loaded boat at over 3.5 knots.

As far as the OEM electrical panel ((Sea Dog Brand) I would think the concern would be the amperage going to individual circuits and wire gauge. As I remember, the wires look to be 12AWG, which should be fine for lighting which are low power draw. There is a substantial bus, which should not be a problem. However the fuses and panel lights may not be compatible. Why not just leave the lights on the original panel and use a small light weight 30 amp-hour 12V battery, and set up a separate switch/panel for the engine?

[Straander]

At the moment, I think I'd rather use a stepdown transformer then have to worry about individually managing charging and lifecycle maintenance on two different batteries in my boat.

I would think it would make the most sense to dedicate the 24 V side of things to the propulsion, and leave the 12 V side as is? If you have room for 2 batteries that is ... ?

[Brian N.]

Yes - I did mean amp draw. Just looking quickly at the draw you can probably get 2 plus hours running time, wow!

[Riggerdood]

At the moment, I think I'd rather use a stepdown transformer then have to worry about individually managing charging and lifecycle maintenance on two different batteries in my boat.

Yeah, there is that ...

[Brian S]

Thinking of the amperage draw for a stepdown converter, if you change all nav and interior lighting from incandescent to LED, you would significantly reduce your draw.

Also, do some research into propellers for the trolling motor. I know there are some companies out there that are making supposed "performance" propellers for trolling motors. Given the more constant and higher voltage supply of a LiFPO4 battery, you might have higher torque, and thus be able to find something with more pitch or slightly bigger diameter to give you better speed numbers.