On our Crown 34 we have a 2 grp 24 batteries, one a Trojan SCS150 deep cycle, the other a popular brand that is sold in local boating stores (sorry can't remember the name, only that mine is a "Gold Series"). I could not determine if the latter is a starting battery or not. It did not say deep cycle on it anywhere so I have to assume it is not a deep cycle. In any event, last fall I purchased a grp 27 deep cycle from WM (it was on sale for 80$) The case for the WM batt states it is a 90Ah with 715 MCA. The Trojan grp 24 currently on the boat has 100Ah and 600MCA. It appears to have some kind of date code stamped into it but I could not make any sense of it. So I interpret this to mean the the Trojan has more potential capacity. I was planning on pulling the Trojan and replacing it with my WM deep-cycle and buying another Trojan grp 27 SCS 150. Now I don't know what to do. I know I shouldn't mix batteries of unknown age. It seems ridiculous to pull the 100Ah Trojan bat and replace it with a 90Ah. On the other hand I have a very good quality grp 24 of unknown vintage and a pretty good quality new grp 27. Thoughts?
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More Info but...
David, We need more info regarding your AMPerage needs. What do you have onboard that consumes AMPs? I have a Starting and Deep Cycle battery with a 2 position selector switch. I was given a fairly new deep cycle battery that I was going to add but don't want to combine disimilar batteries as well. So I am planning on adding a 2nd selector switch (that I have already) to isolate the starting battery - my house will then run off either 1 or 2 or both deep cycles. Maybe this set-up will work for you?
David, We need more info regarding your AMPerage needs. What do you have onboard that consumes AMPs? I have a Starting and Deep Cycle battery with a 2 position selector switch. I was given a fairly new deep cycle battery that I was going to add but don't want to combine disimilar batteries as well. So I am planning on adding a 2nd selector switch (that I have already) to isolate the starting battery - my house will then run off either 1 or 2 or both deep cycles. Maybe this set-up will work for you?
The usual stuff
We have lights, stereo but no refrigeration or constant largepower drains. We like to hang on the hook for 2 or 3 days at a time and have access to shore power so re-charging is not a problem. My question is more about mixing batteries than the total capacity or the wiring of the combinations. In the end I want to have two house batteries and one starting. I plan on isolating the starting battery completely and only use it for starting if the house batts are totally drawn down. Obviously I want to avoid having a dead house bank and dead starting bank at the same time.
We have lights, stereo but no refrigeration or constant largepower drains. We like to hang on the hook for 2 or 3 days at a time and have access to shore power so re-charging is not a problem. My question is more about mixing batteries than the total capacity or the wiring of the combinations. In the end I want to have two house batteries and one starting. I plan on isolating the starting battery completely and only use it for starting if the house batts are totally drawn down. Obviously I want to avoid having a dead house bank and dead starting bank at the same time.
One solution would be
...to keep the Trojan AND the new battery and make them the house bank wired together ONLY AFTER equalizing the existing Trojan. Keep the Gold battery as a starting battery. It's simple, and has minimal fuss, also meets your idea of your use. Sure, you "shouldn't" mix batteries of different ages, but if you can equalize the old house battery first, then you should be fine. Other choice, if you don't want to do that, is chuck the old Trojan, buy another 90ah WM or equivalent to make up a new house bank. That would be the last choice, which is basically starting over.
The idea to separate them is another way to go, but that involves another switch and has the real downside of over utilizing single batteries, since the larger a house or any bank of batteries is, the longer those batteries will last. (See Calder). I wouldn't recommend it. Your boat, your choice. The other question is what are you doing for charging and how do you use your boat, which was important input Shorepower OK, but with your alternator, how do you charge your starting battery? Combiner, the switch, echo charge? When you marina hop that's one thing, but when you're hanging on the hook your two 100 ah batteries should be sufficient for what you describe your needs are for those 2 to 3 days since you don't have a fridge. Good luck, Stu
...to keep the Trojan AND the new battery and make them the house bank wired together ONLY AFTER equalizing the existing Trojan. Keep the Gold battery as a starting battery. It's simple, and has minimal fuss, also meets your idea of your use. Sure, you "shouldn't" mix batteries of different ages, but if you can equalize the old house battery first, then you should be fine. Other choice, if you don't want to do that, is chuck the old Trojan, buy another 90ah WM or equivalent to make up a new house bank. That would be the last choice, which is basically starting over.
The idea to separate them is another way to go, but that involves another switch and has the real downside of over utilizing single batteries, since the larger a house or any bank of batteries is, the longer those batteries will last. (See Calder). I wouldn't recommend it. Your boat, your choice. The other question is what are you doing for charging and how do you use your boat, which was important input Shorepower OK, but with your alternator, how do you charge your starting battery? Combiner, the switch, echo charge? When you marina hop that's one thing, but when you're hanging on the hook your two 100 ah batteries should be sufficient for what you describe your needs are for those 2 to 3 days since you don't have a fridge. Good luck, StuI plan to use a combiner
to charge all three batts. I was looking at the Xantrex Truecharge 10TB but it is not able to equalize. The next step up is the Truecharge 20 which can equalize but is over twice the cost of the 10TB. I have read so many conflicting opinions if equalizing extends the life span of a battery that I really have no idea what to think.
to charge all three batts. I was looking at the Xantrex Truecharge 10TB but it is not able to equalize. The next step up is the Truecharge 20 which can equalize but is over twice the cost of the 10TB. I have read so many conflicting opinions if equalizing extends the life span of a battery that I really have no idea what to think.
Was the old set up working for you?
If it was working for you and the batteries were holding good charges, Why not leave it alone until something quites working so good then put the WM battery in position,or purchase a second WM battery and put them into service together. Just a thought.. r.w.landau
If it was working for you and the batteries were holding good charges, Why not leave it alone until something quites working so good then put the WM battery in position,or purchase a second WM battery and put them into service together. Just a thought.. r.w.landau
Yes and no...
The boat is relatively new to us (Sept. 2004) so we have not had tremendous opportunity to cruise it over night on the hook. So far we have spent a total 3 nights on her all with shore power. I have a 10A portable charger that I use when I have shore power but I never leave it connected if I am not on the boat. This past weekend I unravelled the mystery of which battery was connected to which position on the batter switch and discovered that the voltmeter was reading the opposite battery from the switch. So long story made slightly shorter... I now have confidence that I am discharging my house battery when in position 1 and my starter in position 2. Basically I am looking for more capacity as we are planning extended cruising this summer not all of which will be on docks with power. I have a 55A alternator with an external regulator so charging under power shouldn't be an issue.
The boat is relatively new to us (Sept. 2004) so we have not had tremendous opportunity to cruise it over night on the hook. So far we have spent a total 3 nights on her all with shore power. I have a 10A portable charger that I use when I have shore power but I never leave it connected if I am not on the boat. This past weekend I unravelled the mystery of which battery was connected to which position on the batter switch and discovered that the voltmeter was reading the opposite battery from the switch. So long story made slightly shorter... I now have confidence that I am discharging my house battery when in position 1 and my starter in position 2. Basically I am looking for more capacity as we are planning extended cruising this summer not all of which will be on docks with power. I have a 55A alternator with an external regulator so charging under power shouldn't be an issue.
OK, so now...
it's time for you to buy Nigel Calder's Boatowner's Manual for Mechanical and Electrical Systems or something close to it. Other choice is to view all the articles on Sailnet, because it's all been written about before in books and articles. Look up energy budgets, too. David, you have a basic case of the basics. You're asking us what battery to use, when you're still doing your homework on your boat (which is great, by the way). You do an energy budget, you figure out your use, which you may have done already and then install 3 to 4 times that capacity in your house bank and separate your start battery, just like you're doing. The combiner is a great idea. Unless you have a smart regulator, your OEM alternator will not provide you with much input. This is another LOOOOONG basic that's been written about by all of us, and by the experts. Go for it, find it and enjoy. Sources include jackrabbitmarine, Ample Power, [all www.xxx.com] and anything else you can Google on electrical systems for boats, batteries, solar power, alternators, etc. Balmar has a good website, so does Xantrex. Try West Marine advisors, in the catalog or on their website. You're dealing with basic boat system electrical design for your intended use. There is no one right answer. The 10 amp charger is too small for your boat's electrical system, I feel, my personal observation. Get a permanently mounted 20 amp or larger charger. You'll be glad you did: it cuts charging time, especially, as you say, that you don't leave your boat plugged in (which is a good idea). I really don't think we can help you any more to chose what specific batteries you end up putting in your boat, you've got some good opinions. Your choice, at least you've got the hardware. You do NOT have a DILEMMA - you DO have a CHOICE. Happy research. All the best, Stu
it's time for you to buy Nigel Calder's Boatowner's Manual for Mechanical and Electrical Systems or something close to it. Other choice is to view all the articles on Sailnet, because it's all been written about before in books and articles. Look up energy budgets, too. David, you have a basic case of the basics. You're asking us what battery to use, when you're still doing your homework on your boat (which is great, by the way). You do an energy budget, you figure out your use, which you may have done already and then install 3 to 4 times that capacity in your house bank and separate your start battery, just like you're doing. The combiner is a great idea. Unless you have a smart regulator, your OEM alternator will not provide you with much input. This is another LOOOOONG basic that's been written about by all of us, and by the experts. Go for it, find it and enjoy. Sources include jackrabbitmarine, Ample Power, [all www.xxx.com] and anything else you can Google on electrical systems for boats, batteries, solar power, alternators, etc. Balmar has a good website, so does Xantrex. Try West Marine advisors, in the catalog or on their website. You're dealing with basic boat system electrical design for your intended use. There is no one right answer. The 10 amp charger is too small for your boat's electrical system, I feel, my personal observation. Get a permanently mounted 20 amp or larger charger. You'll be glad you did: it cuts charging time, especially, as you say, that you don't leave your boat plugged in (which is a good idea). I really don't think we can help you any more to chose what specific batteries you end up putting in your boat, you've got some good opinions. Your choice, at least you've got the hardware.
You do NOT have a DILEMMA - you DO have a CHOICE. Happy research. All the best, Stu
David,
You do realize that if you use 100Amps overnight you will have to run your engine 3 hours to get it back to about 80-85% of a full charge? Unfortunately amps add up quick on a boat. Just the refrigeration can take 50 amps over night. David, I don't know how much you know so I am starting with basics because even if you know this someone else that is reading this is starting with basics. If you have a 100 amp battery and you want it to live through the summer, you only want to discharge it about 50% before recharging it. Yes, there are times when you may discharge it more but keep them to a minimum. Fully charge the battery at every reasonable opportunity ( at the dock). This will help the battery life. While you are on the hook you might not be able to charge it beyond 85%. By the way, if that charger is an automotive charger, it can be very dangerious on the boat. I would suggest an onboard charger designed for marine use. A 55 amp or larger alternator might be a good investment if you plan on spending alot of time on the hook. It would cut your engine run time almost in half especially if you are planning to double your house battery amperage. So I don't know if this has helped. Is this info what are looking for? r.w.landau
You do realize that if you use 100Amps overnight you will have to run your engine 3 hours to get it back to about 80-85% of a full charge? Unfortunately amps add up quick on a boat. Just the refrigeration can take 50 amps over night. David, I don't know how much you know so I am starting with basics because even if you know this someone else that is reading this is starting with basics. If you have a 100 amp battery and you want it to live through the summer, you only want to discharge it about 50% before recharging it. Yes, there are times when you may discharge it more but keep them to a minimum. Fully charge the battery at every reasonable opportunity ( at the dock). This will help the battery life. While you are on the hook you might not be able to charge it beyond 85%. By the way, if that charger is an automotive charger, it can be very dangerious on the boat. I would suggest an onboard charger designed for marine use. A 55 amp or larger alternator might be a good investment if you plan on spending alot of time on the hook. It would cut your engine run time almost in half especially if you are planning to double your house battery amperage. So I don't know if this has helped. Is this info what are looking for? r.w.landau
Excellent info folks
Thank you so much for your insightful replies. Iplan on doing a bunch more research before I commit to anything. One comment above caught my eye... "Get a permanently mounted 20 amp or larger charger. You'll be glad you did: it cuts charging time, especially, as you say, that you don't leave your boat plugged in (which is a good idea)." Does this mean even with a permanently mounter charger like a Xantrex Truecharge 20 it should not be left plugged in if we are not on board? I thought one of the advantages of a three stage charger was that you could leave it plugged in and it won't over charge your batteries.
Thank you so much for your insightful replies. Iplan on doing a bunch more research before I commit to anything. One comment above caught my eye... "Get a permanently mounted 20 amp or larger charger. You'll be glad you did: it cuts charging time, especially, as you say, that you don't leave your boat plugged in (which is a good idea)." Does this mean even with a permanently mounter charger like a Xantrex Truecharge 20 it should not be left plugged in if we are not on board? I thought one of the advantages of a three stage charger was that you could leave it plugged in and it won't over charge your batteries.
Stay Plugged In
Keep your boat plugged in, it will keep your batteries topped off. Yes, there is an increased risk of fire if you keep your boat plugged in at the dock, but there is also an increased risk of fire at your house if you don't throw the main breaker to the off position when you leave the house to go to the boat for the weekend. Many boats have refrigiration, air conditioning, heating, dehumidifiers on them, and if they aren't plugged in at the dock, then either the batteries will be dead when you get to the boat, or else the boat will unnecessarily be subjected to humididy, heat, or cold. I know of no one who unplugs their boat - sailboat or power boat - when they leave the dock.
Keep your boat plugged in, it will keep your batteries topped off. Yes, there is an increased risk of fire if you keep your boat plugged in at the dock, but there is also an increased risk of fire at your house if you don't throw the main breaker to the off position when you leave the house to go to the boat for the weekend. Many boats have refrigiration, air conditioning, heating, dehumidifiers on them, and if they aren't plugged in at the dock, then either the batteries will be dead when you get to the boat, or else the boat will unnecessarily be subjected to humididy, heat, or cold. I know of no one who unplugs their boat - sailboat or power boat - when they leave the dock.
Don't Stay Plugged In
David How's that for consistent opinions? You don't have a fridge. Why stay plugged in? Your house bank will self discharge about 2 to 5% during a week, so you'll lose 5 to 10 ah. Plug the boat into your new 20 A charger for the half an hour or so you're getting ready at the dock, OR use your engine to charge when motoring out, OR buy a solar panel to offset the self discharge OR (worst case) go plug it in the night before you leave. You're right that the new better battery chargers will not over-fry your batteries (you NEED to learn why - see, read and download the Ample Power Primer), but why bother? As a friend once said to me, the chances of frying everything on board from a dockside power problem is much higher than if you stay unplugged if you can. The analogy to homes is not unreasonable, but is simply not applicable because your boat's panel (single phase 30 A breaker) can get fried a lot quicker than your house because marina power isn't as consistent as your local power utility. We leave our boat unplugged with an 11 watt solar panel keeping the batteries topped off. We do not keep our fridge running when we're not there. Each area of the country, for obvious reasons, has different MOs. All the best, now go do some reading and ignore this board for a while Essentially what you're into is designing your boat's electrical system. Should be lots of fun, you're certainly on the right track. Stu
David How's that for consistent opinions? You don't have a fridge. Why stay plugged in? Your house bank will self discharge about 2 to 5% during a week, so you'll lose 5 to 10 ah. Plug the boat into your new 20 A charger for the half an hour or so you're getting ready at the dock, OR use your engine to charge when motoring out, OR buy a solar panel to offset the self discharge OR (worst case) go plug it in the night before you leave. You're right that the new better battery chargers will not over-fry your batteries (you NEED to learn why - see, read and download the Ample Power Primer), but why bother? As a friend once said to me, the chances of frying everything on board from a dockside power problem is much higher than if you stay unplugged if you can. The analogy to homes is not unreasonable, but is simply not applicable because your boat's panel (single phase 30 A breaker) can get fried a lot quicker than your house because marina power isn't as consistent as your local power utility. We leave our boat unplugged with an 11 watt solar panel keeping the batteries topped off. We do not keep our fridge running when we're not there. Each area of the country, for obvious reasons, has different MOs. All the best, now go do some reading and ignore this board for a while
Essentially what you're into is designing your boat's electrical system. Should be lots of fun, you're certainly on the right track. Stu
Don't Stay Plugged In (another reason)
Hello, Stu gave some excellent reasons to unplug the boat before you leave. Here's another: If the shore power system that you connect to isn't grounded perfectly (and few are), and / or if your boat isn't grounded perfectly, a lot of stray electrical current will leak into the water. A best, your zincs will need to be changed quickly. At worst, your prop, shaft, and other metal will quickly suffer from galvanic corrosion. I bet that if you motor for 10-15 minutes into and out of your dock, your batteries will get plenty of charge. Unlike most of the other posters, my opinion is that for a boat without refrig, radar, full screen chart plotters, etc., the engine driven alternator will easily keep the batteries charged. My boat is on a mooring, so I usually keep the batteries charged with the alternator. It's about .5 nm from my mooring to open water. Just running the engine for that short period of time was enough to keep my batteries charged all last year. When I did spend a night or two on board, I would try to run the engine a little longer, but I never used much electricity. On my boat, I have lights, waterpump, and that's about it. Barry Barry Lenoble Noble Prize, 1986 Newport 28 Mt. Sinai, NY
Hello, Stu gave some excellent reasons to unplug the boat before you leave. Here's another: If the shore power system that you connect to isn't grounded perfectly (and few are), and / or if your boat isn't grounded perfectly, a lot of stray electrical current will leak into the water. A best, your zincs will need to be changed quickly. At worst, your prop, shaft, and other metal will quickly suffer from galvanic corrosion. I bet that if you motor for 10-15 minutes into and out of your dock, your batteries will get plenty of charge. Unlike most of the other posters, my opinion is that for a boat without refrig, radar, full screen chart plotters, etc., the engine driven alternator will easily keep the batteries charged. My boat is on a mooring, so I usually keep the batteries charged with the alternator. It's about .5 nm from my mooring to open water. Just running the engine for that short period of time was enough to keep my batteries charged all last year. When I did spend a night or two on board, I would try to run the engine a little longer, but I never used much electricity. On my boat, I have lights, waterpump, and that's about it. Barry Barry Lenoble Noble Prize, 1986 Newport 28 Mt. Sinai, NY
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