I'm in the process of ordering a new 30' boat. Our club doesn't have electricity at the dock so battery configuration and charging will be important. The boat will have a lot of electronic options - full instruments, plotter, stereo, refrigerator, fans, lights etc. and I want to get the best option to address battery capacity. I will be using the boat for 90% day cruising and 10% overnighting. I would like to run the engine as little as possible. The normal battery configuration for the boat is two batteries, one for the engine and one house (I don't know the sizes). The boat comes with a 30 amp battery charger that I could use at the service dock and I believe an 80 amp alternator. I was wondering what the best battery configuration would be. It has been suggested to me that I order 4 golf cart batteries in addition to the engine battery. Obviously I don't have a strong background in electronics and I would appreciate receiving advice on this matter over and above what the sales person is recommending . Gary
New boat battery configuration
- Thread starter GKuffner
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Design an electrical SYSTEM
not just a battery configuration 1. Without power at the dock you're gonna need a way to INPUT amps, so either solar or an upgraded alternator/regulator or both. The 80 amp alternator needs an external regulator if it is to do any good. Learn about "tapering" chargers. 2. Do an energy budget - you'll find that your fridge will most likely be your biggest daily energy user. 3. Maximize your house bank, 4 T-105s is a VERY good way to do that and still save your back when you have to move the batteries
Buy Nigel Calder's Boatowner's Manual or another excellent boating electrical book by Don Casey and start learning. Read a lot about combiners, echo chargers, relays, solenoids and 1-2-B switches. What ever you buy you can modify (i.e., fix from the bare bones basics). Try www.amplepower.com for battery info, download the ample power primer. Check out independent electrical systems, like Jack Rabbit Marine. Read this: http://www.c34.org/projects/projects-electrical-system-upgrade-2.html And after all that, if you can answer the question: "Why is it better to have the alternator output avoid the 1-2-B switch?", you will have arrived. Really, there's lots of information out there, but YOU have to design an electrical SYSTEM that will work for the way you intend to use the boat, which you have described very well, BTW.
not just a battery configuration 1. Without power at the dock you're gonna need a way to INPUT amps, so either solar or an upgraded alternator/regulator or both. The 80 amp alternator needs an external regulator if it is to do any good. Learn about "tapering" chargers. 2. Do an energy budget - you'll find that your fridge will most likely be your biggest daily energy user. 3. Maximize your house bank, 4 T-105s is a VERY good way to do that and still save your back when you have to move the batteries
Buy Nigel Calder's Boatowner's Manual or another excellent boating electrical book by Don Casey and start learning. Read a lot about combiners, echo chargers, relays, solenoids and 1-2-B switches. What ever you buy you can modify (i.e., fix from the bare bones basics). Try www.amplepower.com for battery info, download the ample power primer. Check out independent electrical systems, like Jack Rabbit Marine. Read this: http://www.c34.org/projects/projects-electrical-system-upgrade-2.html And after all that, if you can answer the question: "Why is it better to have the alternator output avoid the 1-2-B switch?", you will have arrived. Really, there's lots of information out there, but YOU have to design an electrical SYSTEM that will work for the way you intend to use the boat, which you have described very well, BTW.
Uh, Don, that's NOT what I said
Given the fact that he's going to be away from a shorepower connection, he needs BOTH the biggest house bank he can get (for many reasons: battery longevity, length of stay without recharge, etc.) AND needs to be able to recharge as soon as possible (large alternator with proper regulation) AND long term when he's not at the boat (solar - size depends on the electrical system configuration and how he uses the boat - if he's a live aboard, or almost one, he could ignore the alternator and buy large solar). There are choices, and Gary's right that two batteries won't hack it. He's also being sent in the right direction by his dealer with the (4) Trojans, best bang for the buck per amp in quality I've found. He's well defined his cruising / boat use goals and potential habits. But, he could get (2) 105s with the same daily draw and identical charging system (whatever that is) and still be disappointed. The largest house bank money can afford will always result in a happy boater unless the boat is a marina hopper in which case it makes NO difference. My point is, Don, it's most importantly NOT an "either OR choice" (battery) OR (charging), it's the need to design a BALANCED SYSTEM.
Given the fact that he's going to be away from a shorepower connection, he needs BOTH the biggest house bank he can get (for many reasons: battery longevity, length of stay without recharge, etc.) AND needs to be able to recharge as soon as possible (large alternator with proper regulation) AND long term when he's not at the boat (solar - size depends on the electrical system configuration and how he uses the boat - if he's a live aboard, or almost one, he could ignore the alternator and buy large solar). There are choices, and Gary's right that two batteries won't hack it. He's also being sent in the right direction by his dealer with the (4) Trojans, best bang for the buck per amp in quality I've found. He's well defined his cruising / boat use goals and potential habits. But, he could get (2) 105s with the same daily draw and identical charging system (whatever that is) and still be disappointed. The largest house bank money can afford will always result in a happy boater unless the boat is a marina hopper in which case it makes NO difference. My point is, Don, it's most importantly NOT an "either OR choice" (battery) OR (charging), it's the need to design a BALANCED SYSTEM.
Boat power usage
You have described the problem, now you need to asses the production and storage issues. I have an excel spreadsheet that takes a lot of the number crunching out of it. email me at roosaw@verizon.net if you want a copy with instructions.
You have described the problem, now you need to asses the production and storage issues. I have an excel spreadsheet that takes a lot of the number crunching out of it. email me at roosaw@verizon.net if you want a copy with instructions.
You have a path for a power hungry boat.
You have several choices all of which will still require you to recharge the batteries. Where can you get power for your charging needs? 1.From the engine driven alternator. 2.From solar panels. 3.From the commercial grid. Determine how much you can get for each source and budget accordingly.
You have several choices all of which will still require you to recharge the batteries. Where can you get power for your charging needs? 1.From the engine driven alternator. 2.From solar panels. 3.From the commercial grid. Determine how much you can get for each source and budget accordingly.
I would suggest installing a Link/2 type system
I think a "power" monitoring system a really good investment. I find I check mine all the time. I would list my Link/2 system as one of the top 5 additions to my boat. I find it an indespensible when I am "off the grid" (no 115 VAC power) You can get really sophisticated ones and "single bank" systems like the Link/2 for a reasonable price. These type devices will let you know how many Amp/Hours you are using and how many amp/hours you are taking in at anytime and how much you are "down" (think of it as a energy Flow meter & fuel gauge for your batteries). Like was explained before you need to look at your boat as a system, but a device like this will help you know if you need to make adjustments to your "energy-battery system". It will show in short time if your "goes-into" batteries is not keeping up with your "take-out-of" battery per day. Also like suggested below, since you won't be plugged into power at the dock a few solar panels might be a good idea.
I think a "power" monitoring system a really good investment. I find I check mine all the time. I would list my Link/2 system as one of the top 5 additions to my boat. I find it an indespensible when I am "off the grid" (no 115 VAC power) You can get really sophisticated ones and "single bank" systems like the Link/2 for a reasonable price. These type devices will let you know how many Amp/Hours you are using and how many amp/hours you are taking in at anytime and how much you are "down" (think of it as a energy Flow meter & fuel gauge for your batteries). Like was explained before you need to look at your boat as a system, but a device like this will help you know if you need to make adjustments to your "energy-battery system". It will show in short time if your "goes-into" batteries is not keeping up with your "take-out-of" battery per day. Also like suggested below, since you won't be plugged into power at the dock a few solar panels might be a good idea.
Don't forget wind generation
Dollars per watt engine driven alternators are the cheapest and solar is the most expensive. Wind comes in somewhere in the middle. As long as you are not in a snug anchorage and not going down wind a wind generator can be working for you. If you have a 200 AH/day habit then all you are really talking about is 8ish amps continuous output. Realistically, that is a constant wind of 14-16 knots. Solar has to do all its work during the day and so has to have a greater capacity (22ish amps max). Provided you don't mind the noise and have a way to dump the load (heat water?) when the wind gets up for a while wind can work too. Actually when you sit down and crunch all the possibilities (owner preference being the most important BTW) you have to also know: Speed of the boat going down wind The average time you want to spend between recharges and total AH draw for that time Where you are going to be doing your sailing and the wind/sun available there. The total volume of space you can devote to batteries (bigger is better for a number of reasons)(6 volt golf cart are the best for most of the same reasons) How long do you leave the boat unattended and what are the loads during that time. A bigger battery bank (more AH) is always a better idea for a cruiser. A day sailer WO/shore power would appear to have many of the same requirements.
Dollars per watt engine driven alternators are the cheapest and solar is the most expensive. Wind comes in somewhere in the middle. As long as you are not in a snug anchorage and not going down wind a wind generator can be working for you. If you have a 200 AH/day habit then all you are really talking about is 8ish amps continuous output. Realistically, that is a constant wind of 14-16 knots. Solar has to do all its work during the day and so has to have a greater capacity (22ish amps max). Provided you don't mind the noise and have a way to dump the load (heat water?) when the wind gets up for a while wind can work too. Actually when you sit down and crunch all the possibilities (owner preference being the most important BTW) you have to also know: Speed of the boat going down wind The average time you want to spend between recharges and total AH draw for that time Where you are going to be doing your sailing and the wind/sun available there. The total volume of space you can devote to batteries (bigger is better for a number of reasons)(6 volt golf cart are the best for most of the same reasons) How long do you leave the boat unattended and what are the loads during that time. A bigger battery bank (more AH) is always a better idea for a cruiser. A day sailer WO/shore power would appear to have many of the same requirements.
Nigel Calder's book
To reiterate one point from the first post: get Nigel Calder's "Boatowners' Mechanical and Electrical Manual" (see link). It is an excellent resource. The chapters on electrical systems address how to create a balanced electrical system. They also describe how to set up your alternator and regulator to get maximum charging as appropriate for your batteries so you don't have to run the engine needlessly, in addition to covering some of the other charging options.
To reiterate one point from the first post: get Nigel Calder's "Boatowners' Mechanical and Electrical Manual" (see link). It is an excellent resource. The chapters on electrical systems address how to create a balanced electrical system. They also describe how to set up your alternator and regulator to get maximum charging as appropriate for your batteries so you don't have to run the engine needlessly, in addition to covering some of the other charging options.
Some more resources
1. Calder's book is very, very good. If you can, get the second edition (maybe for less$$) because it is printed in a more traditional style and covers the basics better than the 25th century 3rd Edition. 2. See our discussion about wind generators, specifically Reply #14 here: http://c34.org/bbs/index.php?topic=1563.0 You're perfectly welcome to peruse or join our C34 Message Board and search around to find information on your topic. I agree conceptually with getting the Link. Most do it first, we have left it to last because I can do the amp hours use on our boat in my head (re: Bill Roosa's post #4). Four days at anchor, still working with a 390 ah house bank by turning the fridge off overnight! 3. Not mentioned by anyone, it's not "electronics" you're working with here, it is basic 12V (and 120V) electricity. Pretty straightforward if you trace and keep track of your wiring and connections. 4. Size of boat doesn't matter, and what you're working on is perfectly reasonable for a boat of medium to large size for the equipment that you are intending to support. Most of us with boats in that size range are facing the very same issues, and they have, in most part, with proper planning and research and "homework" on the part of the skippers, worked out just fine. You've received some very good input here to a well presented question. Thanks.
1. Calder's book is very, very good. If you can, get the second edition (maybe for less$$) because it is printed in a more traditional style and covers the basics better than the 25th century 3rd Edition. 2. See our discussion about wind generators, specifically Reply #14 here: http://c34.org/bbs/index.php?topic=1563.0 You're perfectly welcome to peruse or join our C34 Message Board and search around to find information on your topic. I agree conceptually with getting the Link. Most do it first, we have left it to last because I can do the amp hours use on our boat in my head (re: Bill Roosa's post #4). Four days at anchor, still working with a 390 ah house bank by turning the fridge off overnight!
3. Not mentioned by anyone, it's not "electronics" you're working with here, it is basic 12V (and 120V) electricity. Pretty straightforward if you trace and keep track of your wiring and connections. 4. Size of boat doesn't matter, and what you're working on is perfectly reasonable for a boat of medium to large size for the equipment that you are intending to support. Most of us with boats in that size range are facing the very same issues, and they have, in most part, with proper planning and research and "homework" on the part of the skippers, worked out just fine. You've received some very good input here to a well presented question. Thanks.New boat battery configuration - Thanks
Thanks to all those who responded to my questions with such great information and advice. Sailing is broadening my experiences in ways I never expected when I took up the sport 4 years ago. Gary
Thanks to all those who responded to my questions with such great information and advice. Sailing is broadening my experiences in ways I never expected when I took up the sport 4 years ago. Gary
One additioonal comment...
You might consider getting a Honda2000 or similar generator. 1. It is under $1k and you hav no further upgrades to make. 2. It can charge your batteries using your existing charge...with no "no-load" charging wear on your engine. 3. It gives you an alternative way to start your boat if you drain your batteries too far. 4. It gives you AC power on th boat for a variety of other needs/wants and is useful off th boa as well. Downside is noise...about 58 decibels which is actually pretty quiet for a generator...and not as bad as running most engines!
You might consider getting a Honda2000 or similar generator. 1. It is under $1k and you hav no further upgrades to make. 2. It can charge your batteries using your existing charge...with no "no-load" charging wear on your engine. 3. It gives you an alternative way to start your boat if you drain your batteries too far. 4. It gives you AC power on th boat for a variety of other needs/wants and is useful off th boa as well. Downside is noise...about 58 decibels which is actually pretty quiet for a generator...and not as bad as running most engines!
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