The really low wattage panels, i.e., under 50 watts won't really charge a battery they will maintain the battery at charged level.New C22 owner here. Looking to setup my factory electrical system with a trickle charger and solar panel. Also like to install a battery switch. Any helpful suggestions/resources etc are appreciated.
Am planning on starting out small and see how it goes. Just average list of accessories for coastal cruises, nothing crazy (Ipad & IPhones , Bluetooth speaker obviously). Would like to be able to spend 5 day’s on it comfortably without having access to a chord. I haven’t had a chance to do much research yet but am mechanically inclined and will do everything myself. Just looking for a good place to start and build from others experiences.The really low wattage panels, i.e., under 50 watts won't really charge a battery they will maintain the battery at charged level.
A 50w panel with a good controller will provide about 4 amps of charging current, just barely enough to recharge a Group 24 FLA battery over the course of a week.
The better answer depends on what you kind of electrical devices you have and how much electricity you use. Without that information, it is hard to give any more than a very general answer.
On average a decent quality solar panel will produce about 3 times its nominal rating in power per day. Bright sunny days in the summer will be a little higher, gray overcast rainy days, much lower. A 50 watt panel will produce about 150 watt hours (or 12.5 amp hours), a 100 watt panel will produce about 300 watts (25 ah).Am planning on starting out small and see how it goes. Just average list of accessories for coastal cruises, nothing crazy (Ipad & IPhones , Bluetooth speaker obviously). Would like to be able to spend 5 day’s on it comfortably without having access to a chord. I haven’t had a chance to do much research yet but am mechanically inclined and will do everything myself. Just looking for a good place to start and build from others experiences.
Great information, thank you! Do you have a website you can recommend for learning/calculating and were is great place to shop Solar/Marine electrical systems/supplies?On average a decent quality solar panel will produce about 3 times its nominal rating in power per day. Bright sunny days in the summer will be a little higher, gray overcast rainy days, much lower. A 50 watt panel will produce about 150 watt hours (or 12.5 amp hours), a 100 watt panel will produce about 300 watts (25 ah).
Calculate the energy you'll consume charging the phone, lights, etc. This will tell you how much power you need to generate.
Generally, Group 24 batteries have about a 70 ah capacity with only 35 ah of useable capacity when brand new.
Now it is just a numbers game, can you produce and store enough electricity for your needs? There are 2 options, vary the usage or increase charging. Just to make things more exciting there is 15-20% inefficiency when charging lead acid batteries, take out 10 ah and you need to put back 12.
Now this is a tough question. Most of what is written online is for larger systems for cruising boats with high output alternators and larger solar arrays. The principals are the same, just the scaling is different for your application.Great information, thank you! Do you have a website you can recommend for learning/calculating and were is great place to shop Solar/Marine electrical systems/supplies?
on everything @dlochner said.Great information, thank you! Do you have a website you can recommend for learning/calculating and were is great place to shop Solar/Marine electrical systems/supplies?
Great information!! I will check them out, thank you for your time!on everything @dlochner said.
Copying / adapting from some of my previous notes:
- Start by reading through @Maine Sail's articles at MarineHowTo.com. He recommends some good quality crimp tools at reasonable prices.
- If you go no further in your reading, remember: fuses and breakers are there to protect the wire and prevent fires.
- I believe ABYC calls for a battery to be fused within 7" of the positive terminal - the easiest way is with a terminal block fuse block right on the battery.
- The solar panel side of your charge controller is much more flexible - the panel output current is limited (e.g. ~8A for a 100w panel). So with any reasonable wire size, you don't need to fuse the wires from the panel to the controller. The battery -> controller wiring must be fused.
- Blue Sea Systems is top-notch (bus bars, breaker panels, etc.)
- Custom Cable USA(formerly GenuineDealz) carries high-quality wire, heat-shrink connectors, etc. Reasonably priced, and they ship quickly. Stock up on crimp connectors, so you have the right parts on hand. Just buy the 25-packs of all the common sizes.
- They will make custom cables too - e.g., if you need battery cables and don't want to spring for battery-lug crimpers.
Noted, very true, thank you!Just an FYI, you have to produce power for your usage plus battery self discharge.
So how much is lead acid battery self discharge? These guys Battery 101 Three Things Need Know Lead Acid Batteries | Northeast Battery Blog. say its 5 percent per month. If the battery capacity is 100 amp hours, that is 5 amp hours per month or 0.16 amp hours per day. Using the numbers previously given here (50W panel produces 12.5 AH per day), only 0.64 watts of solar is all that is needed to keep up with a 100ah battery daily self discharge. If you have two batteries, only 1.3 watts of the solar keeps up with self discharge. The rest you get to use.
My advice.. install a simple battery monitor when you add solar. This gives you net amp hours in/ out of the battery. I have done this with a trailerable sailboat with typical low power loads and have tried 10, 20, 30, 40 watt panels on one week trips. Im always watching energy in and out of the battery and found that 20 watt was threshold, 30 watts works fine and you will have some power to spare with 40 watts. This assumes you dont have any unusual high power demands such as a fridge or you are using a laptop for 5 hours each day.
You are likely to start a one week trip fully charged and dont need to finish a one week trip fully charged. Its just fine to be down by 30 amp hours at the end of the trip. These are trailerable boats, your not living on it full time.
I don't know if they are any better now, but I had a very disappointing experience with a battery monitor and solar. You see, the monitor, a Victron BMV-600, couldn't tell the difference between the sun going down and the batteries coming to full charge. As the sun went down the current would drop off gradually, and the Victron algorithm took this to mean the batteries were coming to full charge. When it reached about 3% of capacity it declared the batts full, and set the stored energy to 100%. And, this was usually not the case. So it was just about useless as a gauge of available capacity.My advice.. install a simple battery monitor when you add solar.
Nice! It looks like you are using roughly the same panel mounting arrangement we are, but with bigger panels! Any difficulty keeping those 50W panels in the up position?I'm running 2 Renogy 50W square panels and a Renogy charge controller.