Simple electrical system with solar for recharge

[bigjer40]

Hello all,

I have downsized to a 1998 Seaward Fox 19' Catboat. It is wired for running lights, anchor light, tiller pilot, depth finder, and a few 12v sockets. The only thing I want to add is a stereo and speakers. It does not have shore power and the 3hp Yamaha two-stroke isn't set up to charge the battery. It has a battery box and all the wiring is there.

What power we will use:
running lights/anchor light
stereo
tiller pilot
cabin light at night
charge ipad/iphones
depth finder

I read the main page for systems but honestly it was over my head. I don't intend to install shore power or use the outboard. I am hoping to run these items (obviously not all will be used at the same time) off a deep cycle battery and recharge with a light weight soft solar panel. By soft I mean the folding ones versus the rigid ones mounted on the boat. My boat really doesn't have room for that. West Marine sells little 3w flexible panel for like $30.

Is this possible? My trailer sailor will not be parked at my house, so I would like to have to keep from dragging the battery home every time I use it. One thing I did pick up from the articles is that I shouldn't deplete the battery further than 50%. so I am wondering if I am listening to tunes and the depth finder is on and a phone is charging, would a 3w panel be adequate to minimize the draw???

Any advice would be so much appreciated. I know it is desired for guys to do their own research and I tried but this stuff reads like blah blah blah to me. Watts, volts, amp hours etc etc etc. If you don't mind sharing your expertise for a very simple system, I would be grateful!

[CharlzO]

The main thing, will be how much of each, and how often you use them. Switching to LED bulbs for lighting will help immensely on your demand of the battery. 3 watts is not much at all in the grand scheme of things, and you can really find much better deals out for not too much more money. The big thing to remember, is the wattage on the panel ratings don't take into consideration any shading, or not-quite-optimum conditions. For example, a 2.2 watt panel on Defender, is rated to charge 4 AA batteries, in full sun, in 7 hours. You're charging a much bigger battery.

Also, how often are you on the boat? A small panel might not be able to keep you topped off if you're out every day, but if it's something where it'll have a chance to charge up over a week or two between outings, it might be doable. How often are you on it, and how often are you out overnights/dark for the lights to come into play? I assume you're looking more to use the panel as a charging system mostly after you've drawn the battery down with use, rather than using it to try to keep up with the usage as you go?

[bigjer40]

Originally Posted by CharlzO

The main thing, will be how much of each, and how often you use them. Switching to LED bulbs for lighting will help immensely on your demand of the battery. 3 watts is not much at all in the grand scheme of things, and you can really find much better deals out for not too much more money. The big thing to remember, is the wattage on the panel ratings don't take into consideration any shading, or not-quite-optimum conditions. For example, a 2.2 watt panel on Defender, is rated to charge 4 AA batteries, in full sun, in 7 hours. You're charging a much bigger battery.

Also, how often are you on the boat? A small panel might not be able to keep you topped off if you're out every day, but if it's something where it'll have a chance to charge up over a week or two between outings, it might be doable. How often are you on it, and how often are you out overnights/dark for the lights to come into play? I assume you're looking more to use the panel as a charging system mostly after you've drawn the battery down with use, rather than using it to try to keep up with the usage as you go?

Thanks Charlz,
Our last boat was a 27 footer with inboard diesel and shore power. We did a couple 5-7 day trips per summer. Lots of day sails, and a couple weekends and never had to worry about our power usage. We will still use this boat the same (a few week long summer trips, lots of weekends, and lots of after work or day sails). We have one cabin light inside we would use but may use a lantern.

Night time use : anchor light, little cabin light, and charge a phone or two.

Day time: stereo is almost always on, depth finder is usually on and I predict this boat will have us hopefuls sailing lots of new to us areas, and occasional tiller pilot.

I am hoping to find a system that with this usage in mind, prolongs or negates some of the use and recharges while we are off the boat. Maybe even adding a two battery system with a switch where the panel charges the battery that is not being used? I do have a battery gauge, so when one gets to 50% I switch to the other battery? Two batteries would also help distribute the weight better on my little boat (the current battery box is midship starboard side of the keel. I hope that answered your questions.

[gts1544]

bigjer40,
While I am no expert, it is my understanding that those small solar panels are basically "trickle" chargers, with just enough power, under optimum conditions, to overcome the battery's internal discharge, plus put a little charge into it over time. A battery will discharge due to its own internal resistance over time.

Additionally, solar panels, by virtue of the way that the cells are wired together, are very susceptible to any shading, which will dramatically cut their output. About the best that you can expect, over a 24 hour period, is maybe 30% of rated output.

I think that you will have to determine how you are going to use your "simple" electrical system. Are you going to operate off of a fully charged, capable, deep cycle battery and allow the solar to recharge it when not in use or are you looking for a solar setup that will replace your usage on a daily basis while embarked? In any event, be sure to buy a large enough battery with sufficient capacity to cover your needs, with a charging system capable of recharging it with your time frame. I hope that this helps! gts1544 - George

[CharlzO]

Stereo is going to be the biggest culprit. If it's almost always on during the day, you can expect it will likely drain that battery a ways. Think about how long you would feel comfortable in a car with the radio on, before you reach for the key to make sure it starts. Slightly different batteries and whatnot, but I can't even make it through a drive-in movie without starting the car to be safe lol.

You did identify the one main issue with your first post though, and that is space on the boat. Short of adding a bimini arch over the very back (if you google search 'Seaward Fox 19', I saw a few that did it), and used that as a mount for flexible panels on top, that might work to give you enough room to get enough wattage on them. Otherwise, the only two places are really the top of the companionway cover, and the very front deck in front of the mast. Of course, the sliding hatch would possibly suffer from shade a lot more than the bow. Perhaps two panels, one in each, and wired together.

Also, with what you'll be running, you'll need a panel(s) that will adequately recharge. It might not keep up completely, but enough wattage should at least help. But I would also look into at least a basic charge controller on the chance that they do fill the battery up, you don't want to have to worry about going over. Hard to say if it's needed based on how much it actually draws on the battery, but better safe than sorry.

I'm not sure on the math, to be honest, but you'll likely want something like 20 watts or so. People will say to run the batteries with how you'll use it, and measure to see how much drop over a typical day, and then size your panels based on what it'll take to offset and recharge. Just gonna be tricky with limited space.

[bigjer40]

Mine has the Bimini as well. If you found the one on yacht world you saw my boat. The cabin trunk forward is prime real estate on a little boat. Might have to go with the Bimini. I started to look into a portable stereo as well since it would be my biggest drain. It's almost like time has stood still with portable radios. I thought for sure you would be able to plug in MP3 players and they wouldn't be using 6 batteries but that doesn't seem to be the case in 2014.

[Boulter]

Originally Posted by CharlzO

Also, with what you'll be running, you'll need a panel(s) that will adequately recharge. It might not keep up completely, but enough wattage should at least help. But I would also look into at least a basic charge controller on the chance that they do fill the battery up, you don't want to have to worry about going over. Hard to say if it's needed based on how much it actually draws on the battery, but better safe than sorry.

I'm not sure on the math, to be honest, but you'll likely want something like 20 watts or so. People will say to run the batteries with how you'll use it, and measure to see how much drop over a typical day, and then size your panels based on what it'll take to offset and recharge. Just gonna be tricky with limited space.

I have almost the exact same situation in my Sandpiper 565. I don't yet have a solar panel installed, but I own a 15 W panel scavenged off my Ontario 32 which I will eventually mount off the pushpit somehow.

I would say that a 20W panel is on the lower limit of what might work given 2 or 3 days usage, then away 4 or 5 days. I was thinking about 40W myself in the long term to cruise in perpetuity, but my boat usually comes home to shore power after 3 to 5 day outings, so I am just looking to extend the number of days out, not necessarily keep the batteries full up. I figure I already have the panel, might as well use it and see how it goes.

I already have LED anchor and running lights, so these loads are not a dominant factor. I think the biggest load will be the Simrad TP32 tiller pilot if and when I run it hours a day.

To give you some very rough ideas:

I assume your battery is 100Ah, of which 50Ah is usable (to 50% DoD)

Sound system 12 volt 1/2 Amp 12 hours a day uses 6Ah/day, so if it were your only load, could run about 8 days with no additional charge.

Your VHF in receive 12 volt, 1/4 Amp 12 hours a day uses 3 Ah/day , so if it were the only load, could run about 16 days with no additional charge.

Incandescent anchor light 0.8 Amps 8 hours/day uses about 6Ah/day so again about 8 days if the only load. An LED unit would be about 5 times this or 40 days.

If you can provide the raw current draw figures from your equipment documentation, and estimate number of hours usage per day for each load, I can do up the calculations for you in a speadsheet. This is something I intend to do more formally for my boat, so really no more work to plug in your figures into a template.

Contact me by PM if this is of interest.

Another thought I just had. If you are only out a few days at a time, there is a good chance you don't need a permanently mounted panel. Buy some big panel, say 80 watts and store it in your vehicle while out sailing. Then drop it into your cockpit and plug it in when you go home. This idea of coarse assumes nobody will steal it, not that a few screws will stop anyone if it is permanently mounted.

Boulter

[bigjer40]

Thanks Boulter! Just bringing her home today. Gonna clean her up and start sail with no power for the holiday weekend and then figure out what I am going to do. Thanks for the offer with the spreadsheet. Will most likely take you up on it. The way you explained it made sense to me. I am thinking I will just go with a handheld VHF on this boat. Still hoping to find a decent portable radio as well. That would really simplify things.

[Adventurebound]

I quickly researched efficiency of solar cell pointing in different directions to the sun. Pointing away from the sun you can loose 40% efficiency. Add some cloud and you would be better off getting exercise on a bicycle driven generator.

[GrowleyMonster]

3w is barely enough for a trickle charge but it would work for that, probably without a controller.

It sounds like you should have about 100w of solar. Twice that would be super. 80w about the minimum.

Have you thought about a wind gen? They work great anchored or docked. On a reach, you could use it sailing. This is a doable home brew project. You will need a controller but that's not a very complicated thing. Or get a cheapie from Harbor Freight.

Often when the sun isn't shining, the wind is blowing, and vice versa. Just sayin.

[bigjer40]

Went into Best Buy today to research the stereo situation. They now have what are called Bluetooth portable speakers. They have one that is water resistant and will play for 6 hours on a charge. Plays via your smartphone or mp3 payer. Then will recharge that device when plugged in. It is also water resistant. There is also one by Bose that sounds pretty good considering it is portable and rechargeable. All for $199. At this time, it seems like a pretty good option.

[bigjer40]

Originally Posted by GrowleyMonster

3w is barely enough for a trickle charge but it would work for that, probably without a controller.

It sounds like you should have about 100w of solar. Twice that would be super. 80w about the minimum.

Have you thought about a wind gen? They work great anchored or docked. On a reach, you could use it sailing. This is a doable home brew project. You will need a controller but that's not a very complicated thing. Or get a cheapie from Harbor Freight.

Often when the sun isn't shining, the wind is blowing, and vice versa. Just sayin.

I thought about this, but am thinking more about transom mounted hydro charger. Since my boat is usually in the river with a decent current. Also, I wouldn't be as much set up and take down when trailering. Not to mention it really wouldn't look very good on my particular boat.

[Nicholson58]

Originally Posted by bigjer40

Hello all,

I have downsized to a 1998 Seaward Fox 19' Catboat. It is wired for running lights, anchor light, tiller pilot, depth finder, and a few 12v sockets. The only thing I want to add is a stereo and speakers. It does not have shore power and the 3hp Yamaha two-stroke isn't set up to charge the battery. It has a battery box and all the wiring is there.

What power we will use:
running lights/anchor light
stereo
tiller pilot
cabin light at night
charge ipad/iphones
depth finder

I read the main page for systems but honestly it was over my head. I don't intend to install shore power or use the outboard. I am hoping to run these items (obviously not all will be used at the same time) off a deep cycle battery and recharge with a light weight soft solar panel. By soft I mean the folding ones versus the rigid ones mounted on the boat. My boat really doesn't have room for that. West Marine sells little 3w flexible panel for like $30.

Is this possible? My trailer sailor will not be parked at my house, so I would like to have to keep from dragging the battery home every time I use it. One thing I did pick up from the articles is that I shouldn't deplete the battery further than 50%. so I am wondering if I am listening to tunes and the depth finder is on and a phone is charging, would a 3w panel be adequate to minimize the draw???

Any advice would be so much appreciated. I know it is desired for guys to do their own research and I tried but this stuff reads like blah blah blah to me. Watts, volts, amp hours etc etc etc. If you don't mind sharing your expertise for a very simple system, I would be grateful!

3 watt is extremely small. Volts X amps = watts. Easy to calculate backwards. There are solar panels you can get that can be cemented to the cabin top. Not cheap and a lot of work. Find panels on line. We$t'$ price can usually be beat by large margins. There are much larger folding soft panels as well.

You might consider replacing IC lights with LED replacements. Marinebeam Replacement LED bulbs for your existing boat fixtures Their PWM controllers make the most of small current.

Can you possibly find a tiller pilot that uses its own battery like a Torquedo? This way, you could recharge at home.

One method of using conventional panels is to mount one on each side rail with swing up capabilities. I have seen this done but on a boat with high freeboard. Modern rigid panels may have efficiency over 20%. We have 3 of these rated 220 watts each. A small version of one of these might be able to satisfy the need and also not take up too much space. Soft & thin film panels are different technology and are still in the 5% efficiency range.

We have a lot of small battery powered items. We use rechargeable LI size AA,C & D cells and take them home to recharge.

[darylat8750]

Most of the folks that put on wind generators then add solar say they wish they had just gone to solar first and not bothered with the wind...

[mcarling]

3W of solar might not be enough to overcome to the self-discharge of a deep cycle battery. Do yourself a big favor and get a LiFePO4 battery instead -- and a lot more than 3W of solar. One of these batteries, for example, would do:
Winston Battery Limited