Any members who are knowledgable about solar?

[sailor55330]

So I need to get a better source of power to our dock to power the boat lift. Currently I'm running a generator to power the AC boat lift. I've got the permit to run 110 to the dock, but it's really not feasible due to cost. The cost of wire alone is over $3k due to the size needed for voltage drop due to distance (300ft).

SO, I need some advice. I'm thinking of going solar. I have a couple of options and while I understand the basics and confident I can install a system, I'm fuzzy on what the limitations of the system will be. Implementation is my strong suit, design is where I struggle.

My goals are:

1. Be able to run the lift probably a max of 4 times a day on a weekend, maybe once every other day during the week.
2. Run LED courtesy lights on the dock (at night only when we are down there)
3. Possibly have a USB charging station for phones
**Bonus would be to have a trickle charger for the boat.

The boat lift motor is simply a vacuum cleaner motor (Electrolux, 12amp) and the lift cycle takes about 4-5 minutes each lift).

My options are:

1. Set up a solar panel, inverter, and house bank (24v) to run all of this. Looking at a 2 bank battery system with around 200 AH of capacity
2. Replace my AC motor with a DC motor and run directly off the batteries. I would need to use DC lighting, obviously.

I have found a complete system that is "plug and play" that includes a 40w charger from a company called LakeLifter. They get good reviews and seem to build a good system--I've seen them in person.

What I don't know is would the 40w solar panel (you can get as small as 20w, 40w is the top) be enough to keep this system functioning on a busy weekend. I'm in Georgia, so a pretty good amount of sun with southern exposure. I've talked to the company and they claim a 2 battery set up will run the lift 6-8 times without needing to recharge, but obviously, you would be recharging constantly during the day. Most likely, my lift usage would be 2-3 times and the light for maybe 1-2 hrs.

It's all expensive, but solar is a fraction of the price of having 110AC put in (assuming you can find someone to do it---4 contractors out and so far, not one return quote as promised now 3 weeks later--all from highly reputable companies who specialize in this). So, I ask the group, does anyone have any electrical/solar knowledge? I don't know what size solar panel or battery bank is really needed. Also, AGM or Lithium ION? Not even sure if Lithium Ion will work with solar.

Help?

Thanks

[Titaniumboy]

I don’t know squat about solar, but are you sure about the voltage drop being a problem? After all the motor is only running for five minutes at a time, leaving plenty of time for the motor to cool off.

What gauge wire are you thinking you need? And even if voltage drop is a problem due to the long run, a buck/boost transformer (and smaller wire) could well be less expensive than 300 feet of larger wire.

Or maybe upsize the motor to a larger horsepower? Larger motors usually can handle lower voltage without excessive heating, especially for such a short time as five minutes.

[sailor55330]

The total run including from the panel to the dock is 420 ft. The wire is direct burial and I have been quotes #2 by one contractor and six gauge by another. Both recommend using aluminum wire and claim with that run on a 50 amp breaker the best you’ll deliver is 33 Amps at the pole. Third contractor said he would run 10 gauge copper but wasn’t sure what the voltage drop would be.

The cost would make your head spin

[Titaniumboy]

33 amps? I was thinking you only needed 12 amps for the lift.

Aluminum could be cheaper than copper right now? 420 feet of anything is going to be expensive. This long run of cable would really benefit from a buck/boost transformer or an autotransformer. Essentially instead of sending 120 volts down to the dock, you use the boost transformer or autotransformer to send 130 volts or 140 volts or whatever down to the dock, thereby mitigating any voltage drops.

I will try and run some voltage drop calculations later.

[sailor55330]

Appreciate the offer to calculate the voltage drop

As for the service, 50 amp service is what’s recommended around here should ever want to run shore power for a larger boat. Do it once basically

Your are correct on aluminum wire. Cheaper than copper. Was quoted $3100 for just the 2g aluminum.

So far no one has mentioned a booster and no one has provided anything in writing. Actually only one contractor has event officially quoted out of 4

[Titaniumboy]

Running 420 feet for 50 amps is a whole other ballgame than doing it for 12 amps.

[bruceb58]

200Ah of batteries seems like major overkill. You can have an inverter run the existing AC motor.

What do you think your total daily draw will be in watt hours?

As background, I have a 200AH lithium battery setup in my trailer with 700W of solar and a 2000W inverter. I designed the system and installed myself.

[Krob1114]

How about a Honda generator for maybe $1200?

[sailor55330]

200Ah of batteries seems like major overkill. You can have an inverter run the existing AC motor.

What do you think your total daily draw will be in watt hours?

As background, I have a 200AH lithium battery setup in my trailer with 700W of solar and a 2000W inverter. I designed the system and installed myself.

That's the big question as I don't really know, nor do I know how to figure it out. Here's what I do know-

If I go with the AC motor and inverter, then the motor draws 12amps (vacuum cleaner motor)
If I go with a DC motor and no inverter, the motor is listed as an 1800w motor.

Figure 3 LED floods @ 10w each, running for up to 2 hours a day.

No clue how to figure out consumption.....As I said, I'm good with installation/implementation, but clueless on design.

[jhnmdahl]

40W feels small, but you're only drawing high current for short periods of time so it may be enough. For reference, a typical current-gen full-size residential panel (a single panel is maybe 40"x67") in the 350W range.

Math is fairly straightforward - 40W for an hour is 40 Watt-hours replenishment. Watts are Volts times current (Amps) for instantaneous calculation, or Watt-hours or Amp-hours for capacity and draw. So, 40 Watt-hours divided by 12 Volts (e.g., to recharge a 12V battery) is 40/12 or 3.3 Amp-hours of battery replenishment per hour. If everything is 12V, you can simply choose between adding up Amps or Watts to determine capacity, charging rate, and draw.

[kbloom72]

I run my boat lift and dock lights (LED) off of 2 12v batteries with a 20w-24v charging kit. It works without any issues. I use the lift at least 8-10 times a week in the summer.

[sailor55330]

How about a Honda generator for maybe $1200?

I do have a generator, but the Army Core of Engineers has some really "unique" rules regarding the use of generators. They don't prohibit you from using a generator, but you aren't supposed to store a generator on the dock and you aren't supposed to store anything with fuel on core property (lake and surrounding shore is core property). If caught, it's a fineable offence and potentially could result in your dock permit being revoked (think fuel spill) and then your property value loses about 40% immediately (dock permits are printed gold here). Are they out looking for violations daily, probably not, but it only takes 1 ranger having a bad day... There are documented cases of fines and permit suspensions/revokes throughout the years.

Not worth the risk to me.

Heaven help you if you cut down/trim a tree on core property

[sailor55330]

.

[sailor55330]

I run my boat lift and dock lights (LED) off of 2 12v batteries with a 20w-24v charging kit. It works without any issues. I use the lift at least 8-10 times a week in the summer.

Thank you--that is a similar system to what I am considering, but wasn't sure whether to go with a 20w or 40w panel. Sounds like 20w works well, so 40w it is (using BBP"s engine analysis here---Captain Overkill has arrived)

Are you using deep cycle batteries?

[sailor55330]

40W feels small, but you're only drawing high current for short periods of time so it may be enough. For reference, a typical current-gen full-size residential panel (a single panel is maybe 40"x67") in the 350W range.

Math is fairly straightforward - 40W for an hour is 40 Watt-hours replenishment. Watts are Volts times current (Amps) for instantaneous calculation, or Watt-hours or Amp-hours for capacity and draw. So, 40 Watt-hours divided by 12 Volts (e.g., to recharge a 12V battery) is 40/12 or 3.3 Amp-hours of battery replenishment per hour. If everything is 12V, you can simply choose between adding up Amps or Watts to determine capacity, charging rate, and draw.

Thank you JHN-

So, now my ignorance is showing because I really understand nothing you posted---watts vs volts vs amps vs current loses me.

if I stay with 110 and an inverter, then it's a 12amp motor that will run for about 5-6 minutes a cycle. Would that be about 1.2amps of power?

If I go with a DC motor, it's rated at 1800w, which would be about 150w to run for a 5 minute cycle?

What does going to a 24v system do vs 12 volt. It sounds like a 40w panel would provide a charge rate of about 1.6 amp-hours (40/24)?

In other words, a 40w panel should replenish a single use of the lift in about 2 hours?

So frustrating because I can see exactly how to wire it in my head and how to install it, but I am lost on the capacity/calculations.

I really appreciate the help.