I'm a 12V novice. I've read the 12V Bible and "Sailboat Electrics Simplified", but I have a question that's really not covered in the books. I want to install a small solar powered system on my boat to power VHF, running lights, etc. I have no engine, no alternator - this will be a solar-only system. In the books, they talk about "grounding" your 12V system by running a cable from the negative bus bar to the engine block. Since I don't have an engine, what should I do? My ODay 22 has an encapsulated keel (no exposed keel bolt to ground to either). Again, I'm new to this, so sorry if I missed something obvious! Thanks for your help.
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A thought
Ed, The easest way to set the neg. side up is to make a neg bus bar and have all equipment (loads) attached to it. This bus bar is normally a insulated (plastic) block about 1 in to 3 in wide, 6 to 10 in long with a conductor strip (metal) strip running down the middle if the block, the strip has screws that you can attach terminals to. Run your neg side of your battery to the strip and attach all loads (neg side) to that same strip. In short, (no pun intended) electricaly-loads are attached , NEG side to the neg side of the battery. As an added safety feature, you can add a large fuse (50 AMP normal if running a less than 10 HP electric start outboard the size of this fuse would depent on how much current, amps, if all the load were on at once) between the neg side of the battery to the bus bar. Remember to fuse all loads on the positive side to EACH load (light, motor etc.) according to the amount of current that the wire to that load can handle. MY 6 cents worth
Ed, The easest way to set the neg. side up is to make a neg bus bar and have all equipment (loads) attached to it. This bus bar is normally a insulated (plastic) block about 1 in to 3 in wide, 6 to 10 in long with a conductor strip (metal) strip running down the middle if the block, the strip has screws that you can attach terminals to. Run your neg side of your battery to the strip and attach all loads (neg side) to that same strip. In short, (no pun intended) electricaly-loads are attached , NEG side to the neg side of the battery. As an added safety feature, you can add a large fuse (50 AMP normal if running a less than 10 HP electric start outboard the size of this fuse would depent on how much current, amps, if all the load were on at once) between the neg side of the battery to the bus bar. Remember to fuse all loads on the positive side to EACH load (light, motor etc.) according to the amount of current that the wire to that load can handle. MY 6 cents worth
One ground connection per device
The goal is to have everything use the same ground point. This is the ideal, but due to things like resistance within wires, it is not real world. The best you can do is to have one ground point for the entire boat and have one connection from each piece of powered equipment go directly to that one point. The copper bar is a great approach. Multiple ground points will result in current flow from one ground point to another within a piece of equipment. These currents are typically very low, but will produce strange symptoms in some gear, especially sensitive meters. The thing to be careful about is when a piece of equipment has a negative power connection that is internally connected to a metal case. Make sure the case does not provide an alternate path to ground. Good luck
The goal is to have everything use the same ground point. This is the ideal, but due to things like resistance within wires, it is not real world. The best you can do is to have one ground point for the entire boat and have one connection from each piece of powered equipment go directly to that one point. The copper bar is a great approach. Multiple ground points will result in current flow from one ground point to another within a piece of equipment. These currents are typically very low, but will produce strange symptoms in some gear, especially sensitive meters. The thing to be careful about is when a piece of equipment has a negative power connection that is internally connected to a metal case. Make sure the case does not provide an alternate path to ground. Good luck
For Your Needs
A brass or stainless bolt may suffice for the negative bus just put a ring terminal on each of your negative leads and run them back to the bolt. This will work well for nav lights, interior lights, a VHF, depth sounder, bilge pump, and a radio. When you get much beyond these few simple gadgets it is time to go get that bus bar.
A brass or stainless bolt may suffice for the negative bus just put a ring terminal on each of your negative leads and run them back to the bolt. This will work well for nav lights, interior lights, a VHF, depth sounder, bilge pump, and a radio. When you get much beyond these few simple gadgets it is time to go get that bus bar.
Just to battery
Ed, You wrote: "I want to install a small solar powered system on my boat to power VHF, running lights, etc. I have no engine, no alternator - this will be a solar-only system." Keep it simple. The ONLY ground you have on your boat is the negative on the battery (ies?). Even if you had an engine and alternator, when installing a solar panel, you'd connect it (the "other" lead) to the negative, which essentially simply connects the negative from the battery to the engine. It's all one big, same thing. Just follow the solar panel manufacturer's instructions, positive to positive, negative to negative at the battery with the in-line fuse that comes with the panel. No big deal, no extra buses or anything are required. Stu
Ed, You wrote: "I want to install a small solar powered system on my boat to power VHF, running lights, etc. I have no engine, no alternator - this will be a solar-only system." Keep it simple. The ONLY ground you have on your boat is the negative on the battery (ies?). Even if you had an engine and alternator, when installing a solar panel, you'd connect it (the "other" lead) to the negative, which essentially simply connects the negative from the battery to the engine. It's all one big, same thing. Just follow the solar panel manufacturer's instructions, positive to positive, negative to negative at the battery with the in-line fuse that comes with the panel. No big deal, no extra buses or anything are required. Stu
Solar System & Grounding
Ed --- Four points: 1. By "Solar only" you just meant there was no engine-driven source of charging current for the battery, right? In other words, you intend to have a battery in the system & use the solar panel(s) to keep it charged. I don't think a solar panel alone will fill your needs very well. 2. The "Ground Bus" should be connected to the battery negative (-) terminal with a short, heavy wire. As others mentioned, the various systems that you are powering should all bring their negative leads back to that bus. And, if there are more than three systems, use an actual bus with multiple tie points rather than a single stud. 3. The battery positive (+) terminal should be connected to a distribution panel with a short, heavy wire. A "Master on/off" switch should be wired between the battery and distribution panel. The distribution panel should have fuses or circuit breakers and an on/off switch for each circuit you are powering. The fuses/CBs should be sized to less than the maximum current-carrying capacity of the distribution WIRE in that circuit (in case there is a dead-short, the wire won't overheat and burn up). 4. The solar panel should connect to the battery directly (before, not through, the Master On/Off switch) to ensure it charges whenever possible. You might need a charge regulator to control the charging rate. Also, ensure there is a series diode & fuse in the positive solar panel-to-battery circuit; both should be sized to carry the maximum charging current. The fuse should be close to the battery (protects the boat from high-current shorts); the diode should be close to the solar panel (protects the panel from reverse-current battery drain). Good luck --RonD
Ed --- Four points: 1. By "Solar only" you just meant there was no engine-driven source of charging current for the battery, right? In other words, you intend to have a battery in the system & use the solar panel(s) to keep it charged. I don't think a solar panel alone will fill your needs very well. 2. The "Ground Bus" should be connected to the battery negative (-) terminal with a short, heavy wire. As others mentioned, the various systems that you are powering should all bring their negative leads back to that bus. And, if there are more than three systems, use an actual bus with multiple tie points rather than a single stud. 3. The battery positive (+) terminal should be connected to a distribution panel with a short, heavy wire. A "Master on/off" switch should be wired between the battery and distribution panel. The distribution panel should have fuses or circuit breakers and an on/off switch for each circuit you are powering. The fuses/CBs should be sized to less than the maximum current-carrying capacity of the distribution WIRE in that circuit (in case there is a dead-short, the wire won't overheat and burn up). 4. The solar panel should connect to the battery directly (before, not through, the Master On/Off switch) to ensure it charges whenever possible. You might need a charge regulator to control the charging rate. Also, ensure there is a series diode & fuse in the positive solar panel-to-battery circuit; both should be sized to carry the maximum charging current. The fuse should be close to the battery (protects the boat from high-current shorts); the diode should be close to the solar panel (protects the panel from reverse-current battery drain). Good luck --RonD
not enough?
thanks for the input everyone. Ron - you mentioned that the solar panel on its own might not be sufficient for me. If I just plan on VHF, GPS, and depth sounder(3-5x a week for a couple of hours) with occasional running lights 1x a week for a couple of hours, I calculated the amp hours and thought I'd be OK with solar power only. Am I missing something? I'm not going on any extended cruises. Thanks again
thanks for the input everyone. Ron - you mentioned that the solar panel on its own might not be sufficient for me. If I just plan on VHF, GPS, and depth sounder(3-5x a week for a couple of hours) with occasional running lights 1x a week for a couple of hours, I calculated the amp hours and thought I'd be OK with solar power only. Am I missing something? I'm not going on any extended cruises. Thanks again
Enough Solar?
Ed: re/your question to Ron about solar, I use a 10 watt flexible panel on my C22, with a similar electric load to that you describe, hooked to a good sized "deep cycle" battery. It works fine for my use. One tip though, is I do check voltage often with a little digital voltmeter that I purchased at a discount auto store; usually it stays above 13v. We do have lot's of sun out West, but I suspect if we had several days with dark clouds or if we didn't keep the panel oriented toward the sun adequately, that we could run short of volts. Dick
Ed: re/your question to Ron about solar, I use a 10 watt flexible panel on my C22, with a similar electric load to that you describe, hooked to a good sized "deep cycle" battery. It works fine for my use. One tip though, is I do check voltage often with a little digital voltmeter that I purchased at a discount auto store; usually it stays above 13v. We do have lot's of sun out West, but I suspect if we had several days with dark clouds or if we didn't keep the panel oriented toward the sun adequately, that we could run short of volts. Dick
Solar/Battery Combo
As much as we wish for sunny days and fair winds, the weather doesn't always cooperate. Sometimes we even run a bit past sunset... You'll want the power reserve from a good battery to carry you through those conditions -- especially for VHF operation. Consider an emergency situation where you expect to rely on that radio to call for help. Operating your running lights from solar panels is sort of an oxymoron.
As much as we wish for sunny days and fair winds, the weather doesn't always cooperate. Sometimes we even run a bit past sunset... You'll want the power reserve from a good battery to carry you through those conditions -- especially for VHF operation. Consider an emergency situation where you expect to rely on that radio to call for help. Operating your running lights from solar panels is sort of an oxymoron.
battery
Sorry, Ron. I thought it was implied that I was actually going to use the solar panel to charge a battery. Sorry for the confusion - by "solar only", I meant no alternator charging the battery. Thanks
Sorry, Ron. I thought it was implied that I was actually going to use the solar panel to charge a battery. Sorry for the confusion - by "solar only", I meant no alternator charging the battery. Thanks
similiar setup
My venture has running lights, vhf, etc. with one deep cycle battery running it all. I don't have an alternator charging it. I have been looking at solar too, but since I only daysail I've said to heck with it so far. Never run the battery down too far. Of course I keep a battery charger on it as needed at home.
My venture has running lights, vhf, etc. with one deep cycle battery running it all. I don't have an alternator charging it. I have been looking at solar too, but since I only daysail I've said to heck with it so far. Never run the battery down too far. Of course I keep a battery charger on it as needed at home.
Excellent point Brian
A 10W panel is enough for a daysailer who uses the running lights for an hour or two after sunset. If you use more power or run the lights longer, you need more grunt. The problem is the time it takes for a low power solar panel to restore the charge. If you draw the battery down too far (past 50% of its rated capacity) the battery takes so long to recharge it may become "sulfated". If this happens the battery has to be replaced. The solution is either a higher power solar panel (at least 30W, and you'll need a charge regulator as well) or have a regular plug-in charger as a backup. Those little 2kVA Honda generators are kinda neat too. Peter H23 "Raven"
A 10W panel is enough for a daysailer who uses the running lights for an hour or two after sunset. If you use more power or run the lights longer, you need more grunt. The problem is the time it takes for a low power solar panel to restore the charge. If you draw the battery down too far (past 50% of its rated capacity) the battery takes so long to recharge it may become "sulfated". If this happens the battery has to be replaced. The solution is either a higher power solar panel (at least 30W, and you'll need a charge regulator as well) or have a regular plug-in charger as a backup. Those little 2kVA Honda generators are kinda neat too. Peter H23 "Raven"
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