I am fairly sure of the answer, but I've learned to ask the question anyway. I just bought this boat, so I know nothing about this boat's electrical history. 1. Boat has an old SeaHunter charger in the engine compartment. From what I've read, this will take 110 shorepower and charge the 12V batteries and keep them charged up by trickle charge when they are fully charged. 2. Boat has two 12V batteries. If I've read the model number correctly, they are 8Ds. It does list them as "Marine" and "Heavy Duty", so I am going to assume they are Deep Cycle. With nothing turned on in the boat, voltmeter in the panel reads about 12.3 volts. 3. There is an outboard on transom (ODay 28) which is an electric crank. When we try to start the engine, there barely seems to be enough juice to turn it over. And when we do, the voltmeter in the panel reads well below 12V; seems like once I saw it dip to 7V. 4. A hydrometer in each cell showed that one cell out of 6 in BOTH batteries was dead. 5. We disconnected the shore power and connected batteries to a new battery charger. The charger showed first battery at 17% charge (!!!!), so I set it at a 2amp charge speed and left it overnight. The next morning it read 100%, and so did the other. I'm betting they are wired in parallel for that reason. 6. When we tried to start the outboard, it just barely turned over. I am betting that both of these batteries are toast and will have to be replaced. Can anyone out there suggest something different? Is there any other way to test batteries and see if they are repairable/chargeable?
Is my battery dead (failed) or not?
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good bet
From your description, number 4 is the killer. Simply charging a dead cell isn't going to bring it back and may cause more problems if you're not careful. You could try equalizing the batteries but that too may be problematic.If you do, the voltage reading immediately after will be meaningless - wait a few hours to get a true resting voltage and recheck with a hydrometer. In all likelihood, the batteries are toast and I'd suggest you not replace them with similar sized batteries unless you drastically increase the charging system or risk slowly killing the new ones too. The good news is you bought a good boat
From your description, number 4 is the killer. Simply charging a dead cell isn't going to bring it back and may cause more problems if you're not careful. You could try equalizing the batteries but that too may be problematic.If you do, the voltage reading immediately after will be meaningless - wait a few hours to get a true resting voltage and recheck with a hydrometer. In all likelihood, the batteries are toast and I'd suggest you not replace them with similar sized batteries unless you drastically increase the charging system or risk slowly killing the new ones too. The good news is you bought a good boat
Time to by new batteries
Your charger shoud put out at least 13.5 volts. And fully charged batteries should read 12.6 volts. What the hydrometer should show is consistancy. Any reading on one cell exceptionally high or low is suspect. Just by two new batteries.
Your charger shoud put out at least 13.5 volts. And fully charged batteries should read 12.6 volts. What the hydrometer should show is consistancy. Any reading on one cell exceptionally high or low is suspect. Just by two new batteries.
Before you go out and buy
some batterys take a battery and a set of jumper cables to your existing batterys and see how the motor starts,if it has the same symptoms then check your starter and all connections that are associated with the starter. You do need to replace those batterys at some point if you find the problem with the starter or cables that will buy you some time
some batterys take a battery and a set of jumper cables to your existing batterys and see how the motor starts,if it has the same symptoms then check your starter and all connections that are associated with the starter. You do need to replace those batterys at some point if you find the problem with the starter or cables that will buy you some time
Thats all she wrote
If you recheck your results in #4 and get the same answer, those batteries are toast.
If you recheck your results in #4 and get the same answer, those batteries are toast.
Looks like it's new battery time :-(
If nothing else kills them, all lead-acid batteries eventually suffer a shorted cell. This happens because every time they are charged, some of the material of the positive plate gets sloughed off and falls to the bottom of the cell. It accumulates there and when it gets high enough to touch the positive and negative plate, that's all she wrote! 2 8D cells (they are about the size of 2 auto batteries combined) in your boat would be a LOT of battery power! If you analyze your battery drain and boat use, you might find you can get by very well with 2 Group 27 or 24 (about the size of auto batteries). Eliminating half the batteries will also eliminate about half the weight... an 8D weighs about 130 pounds. 2 factors to consider are whether the outboard has an alternator and/or a rope pull for backup starting. A hydrometer is almost useless (except as Landsend mentioned to check for consistency, or to check the electrolyte for stratification that would require an equalizing charge) if you don't have a baseline measurement - you're just doing a messy equivalent of checking the voltage. Be sure to take the old batteries with you - you'll get something as trade-in (I got $7 from Sears for a Group 24) and it solves the 'What do I do with these hunks of lead and acid?' problem. Definitely check the output of the charger when there are no batteries or loads connected. As mentioned above, it should read between 12.8 and 13.8 volts... some of that depends on what type of charger it is - I'm assuming a 'dumb' float charger. If so, and if it is the only source of charging for your batteries, you might do well to invest in a modern 'smart' charger. Your new batteries will last longer if they are treated well. Cheers, Bob s/v X SAIL R 8
If nothing else kills them, all lead-acid batteries eventually suffer a shorted cell. This happens because every time they are charged, some of the material of the positive plate gets sloughed off and falls to the bottom of the cell. It accumulates there and when it gets high enough to touch the positive and negative plate, that's all she wrote! 2 8D cells (they are about the size of 2 auto batteries combined) in your boat would be a LOT of battery power! If you analyze your battery drain and boat use, you might find you can get by very well with 2 Group 27 or 24 (about the size of auto batteries). Eliminating half the batteries will also eliminate about half the weight... an 8D weighs about 130 pounds. 2 factors to consider are whether the outboard has an alternator and/or a rope pull for backup starting. A hydrometer is almost useless (except as Landsend mentioned to check for consistency, or to check the electrolyte for stratification that would require an equalizing charge) if you don't have a baseline measurement - you're just doing a messy equivalent of checking the voltage. Be sure to take the old batteries with you - you'll get something as trade-in (I got $7 from Sears for a Group 24) and it solves the 'What do I do with these hunks of lead and acid?' problem. Definitely check the output of the charger when there are no batteries or loads connected. As mentioned above, it should read between 12.8 and 13.8 volts... some of that depends on what type of charger it is - I'm assuming a 'dumb' float charger. If so, and if it is the only source of charging for your batteries, you might do well to invest in a modern 'smart' charger. Your new batteries will last longer if they are treated well. Cheers, Bob s/v X SAIL R 8
Equalize
Before you discard the batteries, you could equalize them to shake off the deposits that accumulate on the plates. The one cell may be shorted internally and equalization may remove the fault or it MAY NOT. If your charger has an equalization function, it won't cost anything to try. Jim
Before you discard the batteries, you could equalize them to shake off the deposits that accumulate on the plates. The one cell may be shorted internally and equalization may remove the fault or it MAY NOT. If your charger has an equalization function, it won't cost anything to try. Jim
2A?
There seems to be a general agreement. FWIW: At a 2 Amp charge-rate, you’d need nearly a week to fully recharge a pair of depleted 8D’s, which would measure approximately 21"L x 10" W, and weigh about 161#.
There seems to be a general agreement. FWIW: At a 2 Amp charge-rate, you’d need nearly a week to fully recharge a pair of depleted 8D’s, which would measure approximately 21"L x 10" W, and weigh about 161#.
So if I replace them with 6V golf cart batteries?
That would mean 4 6V (two in parallel for motor and two in parallel for house bank). Right? And where does one find 6V golf cart batteries, and this doesn't sound cheap. One other thing. Does anybody know how to test if my battery charger is still working? Thanks again. p.s. BTW, the outboard has a pull chord emergency crank.
That would mean 4 6V (two in parallel for motor and two in parallel for house bank). Right? And where does one find 6V golf cart batteries, and this doesn't sound cheap. One other thing. Does anybody know how to test if my battery charger is still working? Thanks again. p.s. BTW, the outboard has a pull chord emergency crank.
Don't know how close you are but...
These are tojan battery distributors in Alabama. I paid $65 a battery for mine two years ago. They weight 70lbs a piece so be ready for where you place them. The boat WILL tilt to that side....
Jim S/V Java
These are tojan battery distributors in Alabama. I paid $65 a battery for mine two years ago. They weight 70lbs a piece so be ready for where you place them. The boat WILL tilt to that side....
Jim S/V JavaDisconnect the output wires -
this can be done either at the charger or the batteries. I favor the charger end for several reasons that I enumerated in a recent thread. Measure across the + & - output terminals on the terminal block on the charger. You should read between 12.8 & 13.8 volts. Anything higher or lower needs to be looked at closer. Have you analyzed your electrical needs while sailing? Sure seems like a lot of batteries to me.... but I've got 2 Group 24s and a Group 8 on my 31' Hunter If you buy 4 6v batteries, you will end up with even more Amp Hours, because all the 6v I have seen are pretty heavy-duty. Dem golfers, dey need good 'celleration, after all ;D And before you buy 6v batteries, make sure they fit wherever you have your current batteries..... they tend to be different sizes. Cheers, Bob s/v X SAIL R 8
this can be done either at the charger or the batteries. I favor the charger end for several reasons that I enumerated in a recent thread. Measure across the + & - output terminals on the terminal block on the charger. You should read between 12.8 & 13.8 volts. Anything higher or lower needs to be looked at closer. Have you analyzed your electrical needs while sailing? Sure seems like a lot of batteries to me.... but I've got 2 Group 24s and a Group 8 on my 31' Hunter
If you buy 4 6v batteries, you will end up with even more Amp Hours, because all the 6v I have seen are pretty heavy-duty. Dem golfers, dey need good 'celleration, after all ;D And before you buy 6v batteries, make sure they fit wherever you have your current batteries..... they tend to be different sizes. Cheers, Bob s/v X SAIL R 8For a boat that size...
4 golf carts is way overkill unless you are running a 12volt refer!!! Keep it simple and use a group 27 for your starter and then consider 2-6volt golf cart batteries for your "house" bank. Hell, to sail on Lake Guntersville, 2 group 27's would probably be fine. The 6volts don't parallel, they go in series to combine for 12 volts. Series= 6volt #1, positive lead to "house" positive, negative lead to positive lead on 6volt #2. Negative lead on 6volt #2 to "house" ground (or negative buss bar ground). You should just use a standard 1-2-All-Off switch. 1 for start, 2 for house. Battery charger? Go with the best "smart" charger you can afford. Great deals to be found on the web.
4 golf carts is way overkill unless you are running a 12volt refer!!! Keep it simple and use a group 27 for your starter and then consider 2-6volt golf cart batteries for your "house" bank. Hell, to sail on Lake Guntersville, 2 group 27's would probably be fine. The 6volts don't parallel, they go in series to combine for 12 volts. Series= 6volt #1, positive lead to "house" positive, negative lead to positive lead on 6volt #2. Negative lead on 6volt #2 to "house" ground (or negative buss bar ground). You should just use a standard 1-2-All-Off switch. 1 for start, 2 for house. Battery charger? Go with the best "smart" charger you can afford. Great deals to be found on the web.
Charger should put out at least 13.5 V
is just plain WRONG. Please go to www.amplepower.com and download and READ the Ample Power Primer. Stu PS or go to West Marine and read their catalog in the electrical section or on line on their Advisor's. Learning is hard - there's so much out there and so little being read...
is just plain WRONG. Please go to www.amplepower.com and download and READ the Ample Power Primer. Stu PS or go to West Marine and read their catalog in the electrical section or on line on their Advisor's. Learning is hard - there's so much out there and so little being read...
Do you really need a dedicated starting battery?
I am in the process of designing an electrical system for my boat. The engine I have is a 15hp Saildrive. I started it in the shop with the battery from my riding tractor. It is a small garden tractor battery and it had plenty of power to start that engine. So I feel with such a small amp draw, a dedicated starting battery is just not warranted. I am installing a pair of Grp. 24's and I'll start the engine with one of those. Dedicated starting batteries are a great idea if you have no way to start the engine should the battery go dead. You have a starter rope so that's not the case, skip the starting battery. Just my two cents. Dan
I am in the process of designing an electrical system for my boat. The engine I have is a 15hp Saildrive. I started it in the shop with the battery from my riding tractor. It is a small garden tractor battery and it had plenty of power to start that engine. So I feel with such a small amp draw, a dedicated starting battery is just not warranted. I am installing a pair of Grp. 24's and I'll start the engine with one of those. Dedicated starting batteries are a great idea if you have no way to start the engine should the battery go dead. You have a starter rope so that's not the case, skip the starting battery. Just my two cents. Dan
Hold up
I just went through this with mine.Yes A small riding lawnmower battery started it just fine.However when hooked to an amp meter I drew 40 amps and this was only for a 7.5 horse.I tried pull starting it and the compression is so high it almost pulled my arm out of the socket.So before you say you could just put a rope on it try first.Now picture doing it in the dark rain with serious waves.
I just went through this with mine.Yes A small riding lawnmower battery started it just fine.However when hooked to an amp meter I drew 40 amps and this was only for a 7.5 horse.I tried pull starting it and the compression is so high it almost pulled my arm out of the socket.So before you say you could just put a rope on it try first.Now picture doing it in the dark rain with serious waves.
A float charge is normally 12.8 to 13.2 volts
and I gave it another half volt because all this is pretty imprecise and you don't have to buy a new charger because the voltage is a little high. D, you'll probably do better if you use both batteries in parallel to start the engine.... spreads the large current draw out a bit, less stress on either battery. Stu, Amplepower has lots of good stuff, but I find their information on float charge voltage a bit vague: "Depending on the type of battery, (liquid, gel), and the age of the battery, 13.4 - 13.8 Volts is appropriate as a float voltage." Any voltage higher than the full-charged, open circuit voltage (typically 12.6 - 12.8) but not high enough to cause the batteries to gas (overcharge) is OK. Higher is not more advantageous at all. All for tonight.... sailing for lobsters tomorrow. Cheers, Bob s/v X SAIL R 8
and I gave it another half volt because all this is pretty imprecise and you don't have to buy a new charger because the voltage is a little high. D, you'll probably do better if you use both batteries in parallel to start the engine.... spreads the large current draw out a bit, less stress on either battery. Stu, Amplepower has lots of good stuff, but I find their information on float charge voltage a bit vague: "Depending on the type of battery, (liquid, gel), and the age of the battery, 13.4 - 13.8 Volts is appropriate as a float voltage." Any voltage higher than the full-charged, open circuit voltage (typically 12.6 - 12.8) but not high enough to cause the batteries to gas (overcharge) is OK. Higher is not more advantageous at all. All for tonight.... sailing for lobsters tomorrow. Cheers, Bob s/v X SAIL R 8
Re: Hold Up
I wasn't saying that a starting battery is a waste of money. I was getting at the fact that with small outboards, they could be started with the house bank off the deep cycles. I hope to never have to pull start mine *yks Dan
I wasn't saying that a starting battery is a waste of money. I was getting at the fact that with small outboards, they could be started with the house bank off the deep cycles. I hope to never have to pull start mine *yks Dan
Using a hyrometer
Take it to a parts store or Walmart and have them Load test it and stop screwing around. As to Hydrometer a fully charged cell will be 1250 temp. corrected all 6 cells should read the same if you see a big difference,or the fluid is black you have a bad cell. The battery is junk and you have to buy a new one. you loose a cell one of 3 ways Lose of active material from the plate settling in the bottom of the case and Shorting out the cell, Treeing ( minieral deposits building up on the plate and poking a hole through the seprator or the weld that attaches the plate to the strap breaking. A fully charged battery will have a voltage of about 12.6 ( Again this is temp corrected) After chagring you have to knock off the surface charge. Turn on all of your lights for about 15 Min, turn them off and check the voltage should be 12.6. Talk about over kill to start 7Hp engine with an8D's 8D's were used to be used to start 350 Hp diesel engines. Walmarts Cheapest lawn and garden battery will do just fine They start 20 Hp lawn mowers all the time. Only if you spend a lot of time on your boat at night away from shore power would you ever need an 8D a group 24 deepcycle is a 80amp hour battery (4 amps continuious for 20 hours) a 27 is a 105 ( better than 5 amps for 20 hours) Car batteries last 2 to 3 years in Kansas. When i need a battery for my boat, I buy a battery for one of my cars( The oldest) and put the used battery in the boat. I am never stranded in the winter because of a bad battery in the car. Unless you spend a lot of time on the water at night, With a recoil start out board, I don't even understand why you would need 2 batteries on the boat much less 2 8D's.
Take it to a parts store or Walmart and have them Load test it and stop screwing around. As to Hydrometer a fully charged cell will be 1250 temp. corrected all 6 cells should read the same if you see a big difference,or the fluid is black you have a bad cell. The battery is junk and you have to buy a new one. you loose a cell one of 3 ways Lose of active material from the plate settling in the bottom of the case and Shorting out the cell, Treeing ( minieral deposits building up on the plate and poking a hole through the seprator or the weld that attaches the plate to the strap breaking. A fully charged battery will have a voltage of about 12.6 ( Again this is temp corrected) After chagring you have to knock off the surface charge. Turn on all of your lights for about 15 Min, turn them off and check the voltage should be 12.6. Talk about over kill to start 7Hp engine with an8D's 8D's were used to be used to start 350 Hp diesel engines. Walmarts Cheapest lawn and garden battery will do just fine They start 20 Hp lawn mowers all the time. Only if you spend a lot of time on your boat at night away from shore power would you ever need an 8D a group 24 deepcycle is a 80amp hour battery (4 amps continuious for 20 hours) a 27 is a 105 ( better than 5 amps for 20 hours) Car batteries last 2 to 3 years in Kansas. When i need a battery for my boat, I buy a battery for one of my cars( The oldest) and put the used battery in the boat. I am never stranded in the winter because of a bad battery in the car. Unless you spend a lot of time on the water at night, With a recoil start out board, I don't even understand why you would need 2 batteries on the boat much less 2 8D's.
you are right
There is so much to know, So much out there and so little read. missed one more ingedent there is So much BS propagated by those who present them selfs as "Expert" espicailly when it comes to batteries. "NEED TO EQUALIZE CHARGE ON BATTERIES TO PREVENT ACID sTRATIFICATION" You bet thats true if you have an industrial battery that is 6 feet tall not an issue on a 12 inch tall lead acid battery. Sells a lot of chargers and books Better for the seller than the boater. If continually charging is a good Idea, why do navy Submarines operate their batteries at a 5 amp Discharge (execpt when operating under the polar Ice cap)???? A battery has 3 enemies 1 HEAT 2 vibration 3 over charging. Charging a battery is like baking a cake When it is done, It's done baking a cake longer doesn't make it better neither does charging a battery after it is fully charged The West marine advisor discusses how a new set of batteries will solve a number of electrical problems. The only problem I am aware of that new batteries will solve is bad batteries. OR maybe a battery connection problem that was correct during the install process. And their discussion of benfits of a gel cell makes me sick Resists overcharing yet needs to be charged at 14.1 volts max Tolerates low temps A full chaged auto battery will not freeze until the temp is something like 140 degrees below 0 ( At one time they used a higher concentration of acid for batteries used in the extreme north) "a convetional wet cell requires continual maintance" What maintance??? I haven't added water to a battery in 20 years "Sustains damage if left discharged" They all do, the lead sulfate sets up and will not reverse) AS to the multi step battery chargers, Good for the Manufacture and retailer way over kill for the boater
There is so much to know, So much out there and so little read. missed one more ingedent there is So much BS propagated by those who present them selfs as "Expert" espicailly when it comes to batteries. "NEED TO EQUALIZE CHARGE ON BATTERIES TO PREVENT ACID sTRATIFICATION" You bet thats true if you have an industrial battery that is 6 feet tall not an issue on a 12 inch tall lead acid battery. Sells a lot of chargers and books Better for the seller than the boater. If continually charging is a good Idea, why do navy Submarines operate their batteries at a 5 amp Discharge (execpt when operating under the polar Ice cap)???? A battery has 3 enemies 1 HEAT 2 vibration 3 over charging. Charging a battery is like baking a cake When it is done, It's done baking a cake longer doesn't make it better neither does charging a battery after it is fully charged The West marine advisor discusses how a new set of batteries will solve a number of electrical problems. The only problem I am aware of that new batteries will solve is bad batteries. OR maybe a battery connection problem that was correct during the install process. And their discussion of benfits of a gel cell makes me sick Resists overcharing yet needs to be charged at 14.1 volts max Tolerates low temps A full chaged auto battery will not freeze until the temp is something like 140 degrees below 0 ( At one time they used a higher concentration of acid for batteries used in the extreme north) "a convetional wet cell requires continual maintance" What maintance??? I haven't added water to a battery in 20 years "Sustains damage if left discharged" They all do, the lead sulfate sets up and will not reverse) AS to the multi step battery chargers, Good for the Manufacture and retailer way over kill for the boater
jimq26...wow...lot of information
Boat was bought 2 months ago with outboard attached and 2 apparently failing batteries installed. I don't have much money and even less information, which is why I posted the question. I didn't want to throw away the batteries if they could be resurrected. Nor did I want to waste a lot of time. I know these batteries are overkill, but they are what I've got. I asked the question so that I could learn something. I am new to all of this, and the books I've read have been over my head. I appreciate the information. Thanks all the same.
Boat was bought 2 months ago with outboard attached and 2 apparently failing batteries installed. I don't have much money and even less information, which is why I posted the question. I didn't want to throw away the batteries if they could be resurrected. Nor did I want to waste a lot of time. I know these batteries are overkill, but they are what I've got. I asked the question so that I could learn something. I am new to all of this, and the books I've read have been over my head. I appreciate the information. Thanks all the same.
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