With the recent activity regarding solar panels and house bank charging I've decided that my fall project needs to include a solar panel charging system for my single battery 1998 H240. I use the boat once or twice a week and generally don't even use the battery. I have installed a Humminbird Fishfinder for a depth guage and it would be nice to have it operational all the time. I did run out of juice on a recent trailer trip to Lake Michigan and ended up anchoring without a light one night. My house bank is a single deep cycle trolling motor battery that is installed behind the aft berth so it's a big pain crawling back there to pull out the battery to take home to charge (we're on the trailer in a dry dock)and then crawl back and remount. My questions regarding a solar charger are: 1. What equipment will I need to buy? Is it just a panel and some leads or is a regulator of some sort involved? 2. Do I need to worry about overcharging and boiling battery fluid over or any other types of spills in the boat? 3. What sort of panel should I buy? I'm interested in power output etc. 4. What is the life expectancy of a solar panel? Thanks for your input.
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Unisolar/flexcharge
I Have a 23ft San Juan. I installed a 42 watt panel behind mast and in front of companion way(the hatch slides under it). You will also need a voltage regulator (Flexcharge is good- they have a web site). Call jack rabbit marine they will sort you out and will match most any price you find on the net. My panel is the sort that works in partial shade; I think Unisolar. I love it; my bank always reads 14.25V when I arrive at the boat. I have a rutand 503 small wind charger going on next. Once in I am hoping to put in a small well insulated fridg.
I Have a 23ft San Juan. I installed a 42 watt panel behind mast and in front of companion way(the hatch slides under it). You will also need a voltage regulator (Flexcharge is good- they have a web site). Call jack rabbit marine they will sort you out and will match most any price you find on the net. My panel is the sort that works in partial shade; I think Unisolar. I love it; my bank always reads 14.25V when I arrive at the boat. I have a rutand 503 small wind charger going on next. Once in I am hoping to put in a small well insulated fridg.
Solar Works Great
We added a pair of flexible solar panels from Solar Electric when we went cruising this summer. They worked great! You need to do a "little engineering" before you buy. You can "trickle charge" without a regulator if the panel(s) output are only a couple of percent of your battery's capacity. Depending upon your battery, recharging may take up to a couple of weeks, depending upon the state of discharge. Larger capacity panels plus a regulator, of course, are going to cost a lot more. How dependant are you on your battery? And do you have the need to recharge quickly? You may want to go the regulator way if you use your stereo, VHF, lights a lot. Do an energy audit. Install a good quality volt meter and never discharge beyond 50% as this will prematurely wear out the battery. You don't have to worry about a properly installed "trickle" or regulated cooking your battery. Leave them on all the time at the dock and you'll never drag that battery home for a re-charge. They have diodes so they won't discharge at night or when it's clouldy. You biggest concern should be locking them down so they don't walk away at the dock. We bought two large sized flexible panels (we have a refrigerator) which we keep stored under some cushions when not in use. Exposure to UV will degrade the panels over time. Which means that after a year or so, their output will begin to drop, resulting in longer recharge cycles.
We added a pair of flexible solar panels from Solar Electric when we went cruising this summer. They worked great! You need to do a "little engineering" before you buy. You can "trickle charge" without a regulator if the panel(s) output are only a couple of percent of your battery's capacity. Depending upon your battery, recharging may take up to a couple of weeks, depending upon the state of discharge. Larger capacity panels plus a regulator, of course, are going to cost a lot more. How dependant are you on your battery? And do you have the need to recharge quickly? You may want to go the regulator way if you use your stereo, VHF, lights a lot. Do an energy audit. Install a good quality volt meter and never discharge beyond 50% as this will prematurely wear out the battery. You don't have to worry about a properly installed "trickle" or regulated cooking your battery. Leave them on all the time at the dock and you'll never drag that battery home for a re-charge. They have diodes so they won't discharge at night or when it's clouldy. You biggest concern should be locking them down so they don't walk away at the dock. We bought two large sized flexible panels (we have a refrigerator) which we keep stored under some cushions when not in use. Exposure to UV will degrade the panels over time. Which means that after a year or so, their output will begin to drop, resulting in longer recharge cycles.
Single Battery & Solar Panel
Tom If the output of the solar panel is more than 1 1/2 % of you total amp hours in your battery, you WILL need a regulator. Either get a small panel (which will only add a little bit of power to your battery, most likely offset the self discharge if you have a wet cell), or get a larger panel with a regulator, or get another battery to increase your electrical capacity and parallel them together with a larger panel. I've used the flexible Unisolar panels (USF-5 on our former C25, and a USF-11 on our C34) for the past 15 years. The first panel went south after three years and was replaced free of charge by Unisolar. The second one on the C25 is still in use by its new owner (12 years), and we've had the 11 on our 34 for four years, no problems. Read more about panels on the West Marine website, Advisors, and other reference sources.
Tom If the output of the solar panel is more than 1 1/2 % of you total amp hours in your battery, you WILL need a regulator. Either get a small panel (which will only add a little bit of power to your battery, most likely offset the self discharge if you have a wet cell), or get a larger panel with a regulator, or get another battery to increase your electrical capacity and parallel them together with a larger panel. I've used the flexible Unisolar panels (USF-5 on our former C25, and a USF-11 on our C34) for the past 15 years. The first panel went south after three years and was replaced free of charge by Unisolar. The second one on the C25 is still in use by its new owner (12 years), and we've had the 11 on our 34 for four years, no problems. Read more about panels on the West Marine website, Advisors, and other reference sources.
Excellent comments, by George! (no pun intended)
The energy audit is a great idea. Once it's done you'll have a good idea of how much electricity you typically use. Since you know how often you use the boat, you already know how much time you need to replace what you use each time. Just select a panel that will restore the charge within the required time. Bear in mind that indicated panel ratings are based on full, right-angle exposure to bright sunlight. Since most panels are fixed, you will only get the full rated power for an hour or two each day. You have to increase wattage if you need to be fully charged each time you go out. For a single battery, you probably won't need a regulator for panels less than 15W. I sail a lot at night (but rarely anchor out) and have a tillerpilot, depthsounder, VHF, GPS, cabin lights, stereo and Hella fan. I got a UniSolar 11W panel for my H23 four years ago and I haven't had to take the battery out of the boat since for a charge. However, I watch my electrical use like a hawk and make sure not to drop below the 50% level. Flexible panels are less efficient, but they deliver the rated power over a broader range of light conditions and are a lot less fragile than single-crystal, rigid panels. Happy charging! Peter
The energy audit is a great idea. Once it's done you'll have a good idea of how much electricity you typically use. Since you know how often you use the boat, you already know how much time you need to replace what you use each time. Just select a panel that will restore the charge within the required time. Bear in mind that indicated panel ratings are based on full, right-angle exposure to bright sunlight. Since most panels are fixed, you will only get the full rated power for an hour or two each day. You have to increase wattage if you need to be fully charged each time you go out. For a single battery, you probably won't need a regulator for panels less than 15W. I sail a lot at night (but rarely anchor out) and have a tillerpilot, depthsounder, VHF, GPS, cabin lights, stereo and Hella fan. I got a UniSolar 11W panel for my H23 four years ago and I haven't had to take the battery out of the boat since for a charge. However, I watch my electrical use like a hawk and make sure not to drop below the 50% level. Flexible panels are less efficient, but they deliver the rated power over a broader range of light conditions and are a lot less fragile than single-crystal, rigid panels. Happy charging! Peter
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