Low-budget Project Thread: 23' sailboat with 24v trolling motor and 12v systems / 24v Shed with solar charging.

[SparkyGage]

I've mainly been a lurker, but thought I would share my project - powering my sailboat on the weekends and my shed during the week. I'll put the back story at the bottom. I'll update this first post as I learn more.

Current setup as of Sept 1, '23: (I'll keep this at the top and update as I make changes)
Total relevant spend (sans boat): $1688
Boat: 23' Spirit Sailboat
Transom mounted trolling motor: Newport 24V 86lb thrust ($340) (maximum draw 48A)
Battery: 24V iPowerQueen 100Ah ($700)
Battery Charger Solar: 30A MPPT 12/24v ($95)
Battery Charger AC: 12V-20A/24V-10A ($60)
Battery: 12V Interstate deep-cycle (came with boat)
Quick disconnects 600A forklift style ($33+20)
10' 6ga cable ($40)
1200wt 24v inverter ($200)

Use case:
- I haul the battery between house and boat. I use quick connects much like those found on forklifts. The 24V is lighter than the 12V
- Boat on fresh water lake in Arkansas to move in & out of marina and around coves 3-6 days a month / 9-10 months a year.
- Shed in Arkansas to power lights, hand tools and low amp motors like a drill or bench grinder. 1-2 hours a week
- Operational Temps: Lake 40F-100F / Shed 15F-110F (but more like 40-100 when in use)
- Emergency auxiliary power. Will supplement and eventually replace gasoline generator.

Boat Results after 7 runs: So far so good.
Run 7 - Approx 2hr on trolling motor on level 2-4. 5.7 miles on battery. 80-90F. Battery remained at ambient temps.
NOTE: From what I can see from monitoring my charger, I'm using just shy of 60% of the battery or 50-60Ah of juice per trip.
Run 6 - Approx 2hr on trolling motor on level 2-4. 5.5 miles on battery. 80-90F. Battery remained at ambient temps.
NOTE: Battery Voltage on charger after return shows 26.3V which is approx 50%. For details see post dated Sept 12 below.
NOTE: After charging, my charger indicated that it had put 58Ah+ into it so it's possible it was closer to 60% used on this trip.
Run 5 - Approx 1hr on trolling motor on level 2-4. 3 miles on battery. 85-95F. Battery remained at ambient temps.
Run 4 - Approx 1-1.5 hr on trolling motor on level 2-4. 4 miles on battery. 95-103F. Battery remained at ambient temps.
NOTE: Head wind returning to the marina. Used 3/5-4/5 speed most of way back. Total trip 11 miles.
Run 3 - Approx 1.5hr on trolling motor on level 2-3. 5 miles round trip on battery 85-95F. Battery remained at ambient temps.
NOTE: Head wind returning to the marina. Used 3/5 speed most of the way back. Total trip 7.5 miles.
Run 2 - Approx 1.5hr on trolling motor on level 1&2 5 miles round trip on battery 80F. Battery remained at ambient temps.
NOTE: Light side breeze. Was only under sail 30 minutes of the trip. Total trip 6 miles.
Run 1 - Approx .75hr on trolling motor on level 1 moving around marina. 75F
Observations: Battery meter on motor is useless. Shows 30% charge all the time. Est level 2 is 3mph
Current estimated run time 5hrs on level 2. (will update as I am better able to measure usage)

Planned Expansion and Changes:
Solar panels on shed to charge/maintain the battery (charger for solar shed already purchased with battery),
(Was 2k PSW inverter for shed - went with 1200wt instead after measuring loads and finding a 1200 on sale),
Portable solar generator mainly for use at home but possibly to take to boat,
24v to 12v DC/DC converter on boat when I am comfortable with battery's capacity for overnight trips.
Convert boat to LED lighting.
Solar fan to keep boat cabin aired out when not in use.
Solar panel(s) for boat for extended stays.

Back story:
Bought a 23' sailboat for my favorite lake which is a 30min drive from home/office. I keep on the lake with the goal of being able to be out if the marina 45minutes after I leave the office/house. It's just big enough I can spend a night or two on it. I don't want to use the 6hp outboard it came with because I want my wife to be able to control the boat without having to deal with a traditional outboard in an emergency (MAN OVERBOARD!) Trying to keep this low budget because I'm CHEAP and I am also a Geek so everything is a project to obsess over. Didn't want to spend $$$$ on a system that just sat idle at the boat 90% of the time. And since I haven't mastered the art of being in two places at once, I figured my boat setup could also power my shed when I need it - mainly lights but the tools that I am using a 100' extension cord with as well. Add some solar panels and now my setup is even more efficient. Also a good learning exercise before adding solar at home.

If asked a question, I'll try my best to answer.
(all worthwhile information in this post was blatantly stolen from other posts on this forum or from Will directly)

 

[sunshine_eggo]

Observations: Battery meter on motor is useless. Shows 30% charge all the time. Est level 2 is 3mph
Current estimated run time 5hrs on level 2. (will update as I am better able to measure usage)

The "budget" meter will give you an actual state of charge.

Off-grid Solar Battery Monitors

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

There used to be a 350A option on the same page. I would get that one instead of the 100A version.

 

[SparkyGage]

The "budget" meter will give you an actual state of charge.

Off-grid Solar Battery Monitors

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

There used to be a 350A option on the same page. I would get that one instead of the 100A version.

Thank you! I found the 350A unit you mentioned.

 

[SparkyGage]

Took the boat out this weekend. (Run 3 added to original post.) Battery and motor did fine. Used motor on 2/5 leaving marina (tail wind) and 3/5 returning (head wind). Back home, my charger said I was at 20% when I returned but did not get a V measurement. I need to do better on logging that. Also my AC charger state of charge indicator only increments in 20% blocks so it could have easily been 21-39%.

The motor is adequate, but probably just. My marina is very sheltered from

On the sailing side, I did get to actually sail with both sails this trip, so that was nice. After a 17 year absence, it's coming back to me.

As always - Perseveranti!

 

[SparkyGage]

FINALLY! Good wind for sailing and the gates of hell stayed closed! We've had a dearth of wind in the Ouachita's this summer, but last night was really nice and my wife and I had a nice sail. The battery and motor works great and I'm about to mount bus bars and quick connects because I'm happy with the setup.

Discovered the indicator lights for the battery meter on the trolling motor DO actually work. I wear Rx sunglasses, but yesterday we stayed out for the sunset and came back after dusk. After switching to regular lenses TADA the meter magically works. Seems my polarized lenses filter out green LEDs.

Now I just need to finish the shop portion of this project. And finish the interior of the boat. And put the wood back on. And...... (*sigh*)

 

[SparkyGage]

I added a circuit diagram and will add photos when it cools off and I can take some decent photos of the install.

 

[yabert]

I added a circuit diagram and will add photos when it cools off and I can take some decent photos of the install.

I will be interest to know how well the small 24V motor propel your quite heavy boat.
Like knowing the top speed with head wind and down wind.
Thanks

 

[SparkyGage]

I will be interest to know how well the small 24V motor propel your quite heavy boat.
Like knowing the top speed with head wind and down wind.
Thanks

Probably 5MPH

Mine is a low speed situation on a freshwater lake. I'm estimating that I am not exceeding 5mph based on my wake alone, but I am not having any difficulty maneuvering out of the slip in sub 10mph winds (Arkansas has been pretty calm this summer and I doubt we've has a single wind advisory this season - excluding storms). From my slip, to the mouth of the inlet, and on to the lake is 2.85 miles according to Google Earth. It takes me between 45-60min to get there depending on speed setting and wind. I'm using 2-3 out of 5 mostly once out of the docks, but as I learn the battery and system, I expect to be running on 4/5ths routinely by the next trip or so. So 5mph is probably it - maybe 6 in a tailwind.

Head winds haven't been a problem, and I routinely have a headwind leaving or entering the channel to the marina. With my sails stowed, I don't feel it too bad. Cross winds are typically more my concern because of emergency maneuverability, both in the docks and in coves. We have a lot of underwater obstacles on this lake and at times the choke point of the channel is only 50 yards wide during low water.

This is NOT the setup I would want for running around the lake under power all day, but for the entrance and exit to the lake, it is proving to be adequate for my needs. I would also say that this is probably the SMALLEST unit I would recommend for a boat this size. 86lb thrust is the theoretical equivalent of 1.5HP from what I'm reading and it feels like it.

If I upgrade, I will look seriously at a Minn Kota 110lb thrust 36v motor using 3 12v batteries in series.

Hope this helps.

 

[yabert]

Thanks for the details. That seem fine.
I also look for higher power motor, but for me 36V is a big NO as it don't fit with any 24V or 48V standard devices/battery.
Fortunately, it seem that 48V outboard motor start to be available decent price.

 

[SparkyGage]

Latest Trip with 4 adults (total boat weight above 3600lbs with crew and gear)

Battery capacity: According the manual for the iPowerQueen 25.6v 100Ah LFP battery, capacity is as follows -
27.0V - 100%
26.8V - 99%
26.6V - 90%
26.4V - 70%
26.2V - 40%
26.0V - 30%
25.8V - 20%
25.6V - 10%
21.6V - 1%

So this trip, we ran 54 minutes from the slip to the mouth of the lake where we catch a reliable wind. (I have a "Sailing" playlist that helps me track time). This 2.8mile run up the inlet on setting 3(ie half throttle) with what I consider to be a "full load" means we were traveling 3-4mph. Coming back in we used setting 3&4 for roughly the same distance. This morning the charger indicated 26.3v when I connected it. My next trip I will check V before and after with a couple of my meters and see what they tell me. But based on these numbers I'm seeing a "safe" 10 mile range with this setup.

Starlight Cruising - While the motoring is slow for sure, all the guests, and my wife especially, like the fact that we can talk above the noise. No yelling except in the strongest winds. Most of the trips this year have been Sunday afternoon cruises to watch the sun set, then star gaze on the return trip. There is minimal traffic at these times and the water gets like glass in the cove our marina is in.

End of summer considerations - I may buy a different footprint battery next year and keep this one as the backup if I plan a several day trip. I'm thinking this more about the logistics of where it fits in my boat and 3 50Ah batteries in parallel might work better for me, as well as, theoretically give me 50% more "safe" range. Also be easier to handle getting on and off the boat as I can move each single handed (this battery lifting is giving me a workout - i'm only taking the lead one back and forth as needed for charging.) I am also considering buying another motor and breaking it down so if this one dies (or the prop gets damaged) I have a spare. Other than the pole/shaft, it would fit into a 2/1.5/.5 plastic tub which is the same size as my mess kit.

Goals met so far - 1)No one has died. 2)My wife still likes going. 3) I can be leaving the slip within 30 minutes of arriving (including a quick wipe down and clearing the cobwebs) and usually have things ready to leave within 30 minutes of return. 4)I feel safe getting out on the lake knowing I have enough juice to get back if I run out of wind -the biggest hesitation compared to an outboard gas motor.

Now I just have to get this shed power finished. Could have used it during a couple of power outages this summer. - Perseveranti!

 

[sunshine_eggo]

Technically, I think goals #2 and #1 are out of order based on priorities...

Be aware that those voltages are for resting. Under load or charge they are different. Cut any load or charge, wait about 5 minutes and then compare the resting voltage to the chart.

 

[SparkyGage]

Technically, I think goals #2 and #1 are out of order based on priorities...

Be aware that those voltages are for resting. Under load or charge they are different. Cut any load or charge, wait about 5 minutes and then compare the resting voltage to the chart.

Ah, priorities.....

My charger does an initial 10 second "cold read" on the battery before it start's charging - that's where I was getting my 26.3v from, but I want to test with my "good" meter and my meter I keep in the go bag as well as that's usually the one I have with me on the boat.

 

[SparkyGage]

One more followup today: I just charged the battery and I had the charger where I could watch it and before it reached "full" it said that it had put 58Ah of juice in it. Sooo... that means I used about 60% capacity. Need to keep that in mind on my next trip.