I own a 1991 Hunter 28 with the standard 18 hp Yanmar engine. This boat came (used)equipped with two group 24 dual purpose batteries batteries and a Perko selector switch. These batteries have been in the boat for 4 years and one of them is no longer holding a charge so I am looking at replacing one or both of them. I sail both daytime and evening and spend short weekends on the boat. Unless the wind dies I rarely have the motor on for more than 30 minutes at a time. MY question concerns my next selection of batteries to best fid my sailing style. Some say I should get one starting and one deep cycle, while other advice says to get two dual purpose batteries. The dual purpose batteries have served me well and have the advantage of both good starting and house function. Should I stay with them? Having a starting battery may be good for starting, but how good would it be for my house functions if my secondary deep cycle cycle battery died during the night? Also how effective would the deep cycle battery in starting my Yanmer if the starting battery lost its charge during the night? Thanx, Bob
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Two deep cycles
Bob: I suggest that you go with two deep cycles. If you have a charger aboard they should be fine even with your short motoring periods. We have had this setup since new and there is always plenty of starting power for the diesel. The diesel only needs enough power to spin the engine. I have started our diesel with bad batteries by just decompressing the engine and getting it spinning, then release the levers one at a time. I would suggest that you move up to a larger size battery as room permits. Group 27 or 31 or even 6 volts. Read what you can in the archives too.
Bob: I suggest that you go with two deep cycles. If you have a charger aboard they should be fine even with your short motoring periods. We have had this setup since new and there is always plenty of starting power for the diesel. The diesel only needs enough power to spin the engine. I have started our diesel with bad batteries by just decompressing the engine and getting it spinning, then release the levers one at a time. I would suggest that you move up to a larger size battery as room permits. Group 27 or 31 or even 6 volts. Read what you can in the archives too.
Solar Panel
A while after I bought our boat I had similar problems and discussed this with a long-time sailor at work. I wanted to get new batteries and asked him for advice and he offered to buy my old ones. Well, this guy pinched a penny so hard I know there must be a catch. After doing a lot of checking I figured out I probably hadn’t been running the engine long enough to properly charge the batteries. There are several issues that prevent the batteries from lasting as long as they should or providing as much of a charge as they should. 1. Running time: "Rarely run the engine (read 'charge') for more than thirty minutes." With the yanmar alternator and "one-step" regulator the batteries don get a really GOOD charge. They get charged, yes, but not a good one. The initial input may not be enough to churn the battery acid to prevent sulfating. Second, "rarely more than thirty minutes" is seldom going to be long enough to top off the batteries. A fix for the later would be to add a solar panel to the system, even a small one, to top of the batteries between uses. 2. Alternator: A three-step regulator and alternator set-up would help to get more of a charge into the batteries when you do run the engine but I don't know if this option is available with the Yanmar alternator. Going to a better alternator with three-step regulator may be too costly; however, it is removable if you sell the boat. 3. Sulfating: This could be shortening the life span of the batteries as much as anything. 4. Battery charger: consider adding a battery charger to top the batteries off when you're at the dock, something with three-step/multi-step capability.
A while after I bought our boat I had similar problems and discussed this with a long-time sailor at work. I wanted to get new batteries and asked him for advice and he offered to buy my old ones. Well, this guy pinched a penny so hard I know there must be a catch. After doing a lot of checking I figured out I probably hadn’t been running the engine long enough to properly charge the batteries. There are several issues that prevent the batteries from lasting as long as they should or providing as much of a charge as they should. 1. Running time: "Rarely run the engine (read 'charge') for more than thirty minutes." With the yanmar alternator and "one-step" regulator the batteries don get a really GOOD charge. They get charged, yes, but not a good one. The initial input may not be enough to churn the battery acid to prevent sulfating. Second, "rarely more than thirty minutes" is seldom going to be long enough to top off the batteries. A fix for the later would be to add a solar panel to the system, even a small one, to top of the batteries between uses. 2. Alternator: A three-step regulator and alternator set-up would help to get more of a charge into the batteries when you do run the engine but I don't know if this option is available with the Yanmar alternator. Going to a better alternator with three-step regulator may be too costly; however, it is removable if you sell the boat. 3. Sulfating: This could be shortening the life span of the batteries as much as anything. 4. Battery charger: consider adding a battery charger to top the batteries off when you're at the dock, something with three-step/multi-step capability.
Agree
I agree with everything that has been said so far. On our 290 we went a bit further than Steve, as we have 3 Group 27 AGM's. We have no problem with power, even when out for a few days and running the refrigerator. Dan Jonas (S/V Feije)
I agree with everything that has been said so far. On our 290 we went a bit further than Steve, as we have 3 Group 27 AGM's. We have no problem with power, even when out for a few days and running the refrigerator. Dan Jonas (S/V Feije)
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