Recommend a 100 watt Solar Setup for my C-22

Davidasailor26 · Jan 2, 2026

Carl Wonderful said:
I have 1 brand new, good quality regular Lead acid car battery right now

Car batteries are not really the best for what you’re looking to do. Car batteries are designed to give a relatively high amperage for a short period of time, like you need for starting a car engine. They aren’t designed for giving low amperage over a long period of time, and they don’t tolerate being deeply discharged very well at all. You’re much better off with a proper deep cycle lead acid battery, or better yet a LiFePO4 lithium battery.

Carl Wonderful said:
-An inverter would be nice.

Consider what you really want the inverter to and whether you could do the same thing with just 12V connections. Many things, like charging electronics, are doable with just 12V, and skipping the inverter saves complexity and cost.

Carl Wonderful said:
-Also like the charge controller option to see how many Volts I'm at.

The de facto standard for this is a Victron Smart Shunt. This tracks voltage and the amps in and out of the battery to give a more accurate state of charge than voltage alone. The smart shunt has Bluetooth so you can see the data from your phone without needing to wire an additional display.

dlochner · Jan 2, 2026

Carl Wonderful said:
-Also like the charge controller option to see how many Volts I'm at.

A Victron Smart Controller with Blue Tooth will provide the info you want and is programmable. Coupled with the Victron Smart Shunt you can have all the information you need on the phone.

Carl Wonderful said:
I have 1 brand new, good quality regular Lead acid car battery right now...but nothing else. I would be open to getting another battery in the near future.

Consider buying a medium grade (i.e. not the cheapest) LiFePO battery. A 100 amphour battery will give you plenty of power for a few days especially with some solar charging. Many LFP batteries now have Bluetooth so you can directly monitor the battery's condition.

DanMaine · Jan 2, 2026

I put the victron thing on my sailboat with lead/acid batteries. 'Nothing fancy and I don't use much electricity and it has been just great.

jssailem · Jan 2, 2026

In the stated price range of $300-400, you should be able to get a good solar kit that will provide at least 10 years of constant service. Renology is one brand to check out. They have been around for a few years. Look at the warranty for an idea as to the manufacturer's belief that their system will serve you for a specified period of time. Note that not all the components will last the same time frame. The panels are likely to have the longest warranty, 20plus years.

Factors that shorten life: Extreme heat/cold, poor installation (e.g., shading, bad wiring), lack of cleaning, or deep battery discharges. Proper mounting, ventilation, and occasional maintenance (e.g., checking connections) can push these toward the upper end of usable years of service.

The "Car Battery" may be the weakest component. It is not designed to provide energy in the way you suggest using it. You would be better off with a deep-cycle lead-acid or a LiFePO4 battery as @Davidasailor26 suggests.

In choosing a system, make sure that the charging controller is designed to meet the needs of the battery type you choose.

Develop an energy use plan. A list of the ways of use and amounts of power you want to draw from the battery. Think of the battery as your vehicle's fuel tank. Then start adding up the ways you will use the fuel. (i.e. Charge Phone 2 hours 2 amps)

Good luck. Winter is a great time to do this planning.

Project_Mayhem · Jan 2, 2026

Both Morningstar and Victron make good charge controllers. Morningstar can be found for a very low price. I had a Morningstar 6amp controller with a 100w Renogy panel on a pair of lead acid batteries that were 7+ years old. I used the boat as a day sailor and never ran out of power. The hardest part will be mounting the panel. You might consider two smaller ones as they are easier to mount

ShawnL · Jan 2, 2026

I'm not sure where you're planning on putting the solar panel, but I have a 100W on my (74) '22 and the Renology panel I bought fits really well in the triangle between my forward shrouds and the v-berth hatch. It's at a bit of an angle -- 30 degrees or so, which isn't ideal, but it still seems to work just fine there, and I don't have to move it when I sail.

walt · Jan 2, 2026

Another point...

100 watts with good sun/ very little shading is way overkill if you dont have a fridge and likely not enough if you ever put in a fridge.

Partial shade (from anything.. ropes, masts, booms), will significantly cut back on the power the panel puts out.

Its ballpark that you can put the 100 watts panel in a location that gets a lot of on and off get shading.. or you can put in about half that power panel in a very good location like off the stern pulpit and end up with the same useful power output. I prefer the smaller panel but in a very good location that gets very little shading.

BarryL · Jan 2, 2026

Hello,

What do you use the battery to power? Do you know how many watts or amps you use each day? Have you calculated your energy budget per day?

On my boat I use around
5 amps / hour for the fridge
3 amps / hour for the electronics (chart plotter, instrument displayed, AIS Transponder)
2 amps / hour for misc. stuff like water pumps, lights, listening to music

When sailing i basically use 10 amps / hour or 240 amps per day. When at anchor it's 1/2 that. When in a marina I don't know what it is because I'll be connected to shore power and running air conditioners, water heater, battery charger, etc.

If I needed solar to make 240 amps I would need (240amps X 12 volts =) 2880 watts. To generate that much power would need 400 watts X 7 hours.

I hope your power requirements are a lot less. But determine how much power you need and then set up the solar.

Good luck,
Barry

Project_Mayhem · Jan 2, 2026

Get a good, brand name controller (not Renogy) and save on the panel. Your batteries, and insurance company, will thank you. There's been reports of Renogy controllers catching on fire. Stick with Morningstar or Victron

Johann · Jan 2, 2026

Carl Wonderful said:
Can I get a decent full kit setup for around $300 to $400? Or will I just end up with junk that I'll need to replace in a year or two?

I would go with:
Victron SmartSolar 75/10 MPPT - $65
(be sure to get the SmartSolar… it has Bluetooth)
Victron Smart Battery Sense - $40
(this will provide the MPPT (and you!) with battery voltage and temperature so it can adjust the charging)
Victron Phoenix 250W inverter - $100
100W Solar panel that fits your space… probably $70-120]

So I think for $300-400 you can have a nice, quality setup.

Project_Mayhem · Jan 2, 2026

Don't forget to budget for mounting hardware.

Two Renogy 50w panels - $90/pair
Morningstar Sunsaver Duo w/display - $115
30' cable and Y Splitter - $45
Controller to battery cables and fuse - $30
Total for Electronics: $280

I used BougeRV brand cables from amazon. It was good quality pure copper but not tinned. Zero issues in the 4-5 years I used it on Lake Michigan. You don't need 10awg cabling for 100w of solar. I had a 6a controller with my 100w panel.

The SunSaver Duo charge controller is capable of handling two batteries so you can use your car battery for engine starting or as a backup. It has more stats than most of Morningstar's controllers which only show low, medium and high

My last boat , which had the solar, relied solely upon the solar. I disconnected the tiny alternator in the outboard as I didn't want unregulated power to be dumped into the batteries which could possibly overcharge them

dlochner · Jan 2, 2026

Carl Wonderful said:
I didn't realize a car battery was so inefficient when it comes to solar.

Car batteries, which are usually flooded lead acid (FLA) or absorbed glass mat (AGM) are inefficient for any deep cycle use. They work well in cars because a car needs a battery that can provide a lot of power in a very short time (250 amps for about 10 seconds), which really amounts to very little power overall, and can be brought back to a full charge in a short time. This is not how batteries are usually used on a boat. On a boat there is typically a low power drain for a very long time (for example 5 amps for 8 hours). That takes a much longer time recharge. Charging LA batteries is also inefficient, there is a 15-20% loss of energy in the charging process. In simpler terms, if 20 amphours are used it takes about 24 amphours to bring it back to a full charge.

Lithium batteries are more efficient, there is less power loss in the charging cycle and have a longer life (number of charge/discharge cycles) than LA batteries. They do have some special charging requirements and require charging sources that can meet those requirements. The upfront costs are higher for a LFP battery installation, however, the long term costs are much less. Properly maintained LFP batteries can last 10 or more years, LA batteries have a much shorter life, may be 5-6 good years if they are treated well.

JBP-PA · Saturday at 7:51 AM

Carl Wonderful said:
Thanks for all the good info. I'll have to look into those brands!

I didn't realize a car battery was so inefficient when it comes to solar. Good to know... but stinks I cant use that new battery.

I do not intend to use bluetooth because I plan to put my phone AWAY when I go on the boat, lol. I also don't even have smartphone really, I would love to see all the important info displayed on the controller itself if possible.

A car battery can work, it's just not very good for this. If you don't have any way to return it or use it for another purpose, you can use it for a while. A simple volt meter can give you an approximate charge level for lead batteries. The Victron Smart Shunt is great, but pretty pricey, and requires a smartphone.

Alas, phones are pretty essential now. If you are talking to the coast guard, they often ask to switch to your cell phone. Unless you get the Victron Cerbo with the GX touch display, all their stuff uses your phone for the display. A phone is also a cheap chart plotter. You can get a smartphone pretty cheap by choosing a model that is a few years old.

JBP-PA · Saturday at 8:13 AM

I've used one of these cheaper battery monitors for years before I got the Victron one. Still use it actually, when I don't want to fuss with my phone. I have the hall effect one, but I don't see it anymore.

https://a.co/d/fIgS4FI

jssailem · Saturday at 8:31 AM

JBP-PA said:
A car battery can work,

As has been stated, the nature of the electrical power demands of a car is different from a boat. Car batteries in a boat have a shorter life span. Car Batteries support high power needs for short time periods, then recharge. It is related to their internal components. Deep-cycle batteries, preferred for boat usage, are designed to supply lower power loads over longer periods.

Since you have the hardware, design your system for long-term usage, but power it with the current hardware until the batteries are consumed. This could provide you with 1-2 years of sailing experience and let the industry continue to develop. In 2 years, there will likely be a whole new level of options. You will be better prepared with your sailing and boat knowledge.

Stu Jackson · Saturday at 9:41 AM

Carl Wonderful said:
I didn't realize a car battery was so inefficient when it comes to solar. Good to know... but stinks I cant use that new battery.

You should get to know this website, too, and start to "study up!" about boat electrical systems.

What is a Deep Cycle Battery? - Marine How To

Light Cycle vs. Deeper Cycle NOTE: This article deals with FLOODED marine batteries, not AGM or GEL batteries. The Problem: The problem, as I see it, is one of dishonest marketing where multiple battery types wear the same clothes (sticker) and will perform differently when

marinehowto.com

Yup, winter's a good time to read, read, read...

Lazy1 · Saturday at 7:08 PM

I have had the following on mine for 5 years and have never had to charge the battery any other way and all the parts are now 5 years old and still going strong.

Victron SmartSolar 75/10 MPPT
Interstate standard 80-100ah fla
2x 30 watt panels mounted on each side of the pushpit

runs fish finder, raymarine st2000 and keeps ipad charged running navionics

Project_Mayhem · Sunday at 8:44 AM

If treated properly, a deep cycle can easily last 8 years on a sailboat.

I'd pput that new car battery in your car, use the old car battery as a backup in the boat and buy a new deep cycle as the primary battery. You will need a dual or two separate solar charge controllers as the batteries will have different charge characteristics, capacities, age, etc

Recommend a 100 watt Solar Setup for my C-22

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SBO Weather and Forecasting Forum Jim & John

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SBO Weather and Forecasting Forum Jim & John

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