I have been using 2 Group 24 wet cell batteries in my 1985 Catalina 30 and despite best efforts at keeping the batteries filled with distilled water continually find that they are down by several quarts after being charged with a Truecharge 10 for a month or more. I am considering switching to 2 Group 24 or Group 27 AGM batteries. Those of you that have AGM batteries on a Catalina 30, do you use Group 24 or 27? When leaving the boat for several weeks, do you keep the battery charger on or leave it off becasue of the low discharge rate of AGM batteries? Given that AGM batteries are sealed, any thought on doing away with the plastic battery box to make room for the larger Group 27's in the battery well, assuming that they are still strapped down? Thanks!
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AGM is the way to go
We upgraded from Interstate wet cells to Lifeline AGM on our C-310 when our charger died and resulted in a damaged battery. Our boat uses 2 - 4D batteries, so the initial cost increase was uncomfortable, but the AGM has much better performance, including the low self-discharge you referred, more amp hours available, and not to mention the low maintenance. We did not get the new charger installed for 3 weeks and the batteries lost very little voltage, since all we were operating during this time was the automatic bilge pump and ocassional usage of cabin lights. As to the correct size of batteries, research the manufacturer websites/literature and focus on amp hour ratings for house batteries and on both cold cranking and marine cranking amps for starting batteries.
We upgraded from Interstate wet cells to Lifeline AGM on our C-310 when our charger died and resulted in a damaged battery. Our boat uses 2 - 4D batteries, so the initial cost increase was uncomfortable, but the AGM has much better performance, including the low self-discharge you referred, more amp hours available, and not to mention the low maintenance. We did not get the new charger installed for 3 weeks and the batteries lost very little voltage, since all we were operating during this time was the automatic bilge pump and ocassional usage of cabin lights. As to the correct size of batteries, research the manufacturer websites/literature and focus on amp hour ratings for house batteries and on both cold cranking and marine cranking amps for starting batteries.
Battery water usage.
Batteries that require quarts of water per month sound unusual to me, unless they are being very heavily charged. If they are primarily on a float charge of about 13 volts they should use very little water. I saw this link over on the "Ask All Sailors" forum. It was very informative. The following short quote comparing AGM's to wet cell batteries reaffirmed my decision to stick with the wet cell for now, because I have no problem with maintaining and charging my batteries frequently, and I only need to add water twice a year. Many others would prefer the convenience of AGM’s. "Even with all the advantages listed above, there is still a place for the standard flooded deep cycle battery. AGM's will cost 2 to 3 times as much as flooded batteries of the same capacity. In many installations, where the batteries are set in an area where you don't have to worry about fumes or leakage, a standard or industrial deep cycle is a better economic choice. AGM batteries main advantages are no maintenance, completely sealed against fumes, Hydrogen, or leakage, non-spilling even if they are broken, and can survive most freezes. Not everyone needs these features."
Batteries that require quarts of water per month sound unusual to me, unless they are being very heavily charged. If they are primarily on a float charge of about 13 volts they should use very little water. I saw this link over on the "Ask All Sailors" forum. It was very informative. The following short quote comparing AGM's to wet cell batteries reaffirmed my decision to stick with the wet cell for now, because I have no problem with maintaining and charging my batteries frequently, and I only need to add water twice a year. Many others would prefer the convenience of AGM’s. "Even with all the advantages listed above, there is still a place for the standard flooded deep cycle battery. AGM's will cost 2 to 3 times as much as flooded batteries of the same capacity. In many installations, where the batteries are set in an area where you don't have to worry about fumes or leakage, a standard or industrial deep cycle is a better economic choice. AGM batteries main advantages are no maintenance, completely sealed against fumes, Hydrogen, or leakage, non-spilling even if they are broken, and can survive most freezes. Not everyone needs these features."
Thanks, Jon
Thanks for the input, Jon. Like you, I decided to try wet cells since I thought I would be able to check and maintain them. I have a Truecharge 10 with a trickle charge so overcharging shouldn't be a problem but I still seem to have to refill more than seems right. I've been using the deep cycles in tandem as a starting battery and maybe that's part of the issue. I will probably switch to AGM's for the peace of mind.
Thanks for the input, Jon. Like you, I decided to try wet cells since I thought I would be able to check and maintain them. I have a Truecharge 10 with a trickle charge so overcharging shouldn't be a problem but I still seem to have to refill more than seems right. I've been using the deep cycles in tandem as a starting battery and maybe that's part of the issue. I will probably switch to AGM's for the peace of mind.
AGM or Wet
I have three 27 wet batts, two under the nav center and one under the aft berth. I have to add water once maybe twice a year, a total of aprox 1 qt over all. We use the boat 40 weekend per year and turn the charger off when we close up. Returning on friday afternoon I will turn the charger on and leave it on until we cut lines Saturday morning. I find know problems with wet batteries and seldom hear of any. On the other hand I have heard serveral complaints regarding AGM types short life is a common complaint that I has been reported. If you go to AGM type remember to flip the switch on your TrueCharger to accomidate the different charging format that they require. Fair winds!
I have three 27 wet batts, two under the nav center and one under the aft berth. I have to add water once maybe twice a year, a total of aprox 1 qt over all. We use the boat 40 weekend per year and turn the charger off when we close up. Returning on friday afternoon I will turn the charger on and leave it on until we cut lines Saturday morning. I find know problems with wet batteries and seldom hear of any. On the other hand I have heard serveral complaints regarding AGM types short life is a common complaint that I has been reported. If you go to AGM type remember to flip the switch on your TrueCharger to accomidate the different charging format that they require. Fair winds!
Something else is wrong
David, I'd suggest staying with 'wet cells' as the ROI of AGM's isn't there, but it's a personal decision, so whatever. However, something else is wrong with your electrical charging system or the usage thereof that if not corrected may kill any new batteries too. In my 1988 Catalina 30 (battery location slightly different than yours) and even at 6+ years old, with a TrueCharge 20 AMP charger, my two Exide series 27 batteries never used that much water. Here's a few ideas to consider. I will presume that both batteries are behind the louvered doors of the nav station (which is below and inboard of the electrical panel), underneath the pull-out shelf/tray. Further presume you have charger model TC10TB. Is the charger mounted where the temperature around it closely approximates the temperature location of the batteries? Is the charger's temperature selection slide switch in the correct setting for the air temp around the batteries (don't think your charger has this switch, but mine did, so just in case)? Is the charger mounted where acid fumes will not affect/ruin it (i.e. NOT above the batteries)? Is the wiring between the charger and the batteries correct (i.e. TWO 10-12 gauge positive wires to each battery's positive terminal, with a 8-10 gauge negative wire to one battery's negative terminal, with a large (0-2 gauge battery cable) between both negative battery terminals). Is the charger NOT connected to the batteries through a battery isolater (causing a voltage drop and charger to overcharge as it will not sense the correct battery voltage)? Is the main battery selection switch (on the main electrical panel) set to 1 or 2 or OFF (AND NOT both/all) while charging? Are both batteries the same age, amperage, chemistry? Is the charger's battery type selector switch set to 'F'? Was the charger installed years after the batteries were installed and as such the batteries are badly 'sulfated' (which will cause excessive overcharging)? Have you ruled-out a faulty charger by checking the battery voltage during the chargers different cycles to verify the voltage at the battery terminal is correct (i.e. no more than 14.4 volts)? Is your boating area extremely warm and the absense of a temperature compensation switch/sensor causing too high a charging voltage (i.e. should you have selected the Truecharge 20 which has a manual temperature switch and the ability to accept input from a remote temperature sensor at the battery)? Is the charger's A/C wiring correct and not backwards (black=positive, white=neutral, green=saftey ground to casing)? Is shorepower wiring correct and not reverse-polarity'd? Is the charger connected via a very long extension cord which is causing a voltage drop (instead of hard-wired to the A/C side of the panel and receiving shore-power via a properly sized for the length, shore-power cord)? Have you checked to assure the charger is receiving 120 vAC? Is one of the alternator's diodes shot allowing current to drain to ground, thereby causing the charger to never think the battery is charged? Are you leaving the charger connected when away and the shorepower is being periodically interrupted (e.g. daily) causing the charger to start its charging cycle too often? Ok, that's my 'up to midnight' brain dump of thoughts to help you out... hope this helps...
David, I'd suggest staying with 'wet cells' as the ROI of AGM's isn't there, but it's a personal decision, so whatever. However, something else is wrong with your electrical charging system or the usage thereof that if not corrected may kill any new batteries too. In my 1988 Catalina 30 (battery location slightly different than yours) and even at 6+ years old, with a TrueCharge 20 AMP charger, my two Exide series 27 batteries never used that much water. Here's a few ideas to consider. I will presume that both batteries are behind the louvered doors of the nav station (which is below and inboard of the electrical panel), underneath the pull-out shelf/tray. Further presume you have charger model TC10TB. Is the charger mounted where the temperature around it closely approximates the temperature location of the batteries? Is the charger's temperature selection slide switch in the correct setting for the air temp around the batteries (don't think your charger has this switch, but mine did, so just in case)? Is the charger mounted where acid fumes will not affect/ruin it (i.e. NOT above the batteries)? Is the wiring between the charger and the batteries correct (i.e. TWO 10-12 gauge positive wires to each battery's positive terminal, with a 8-10 gauge negative wire to one battery's negative terminal, with a large (0-2 gauge battery cable) between both negative battery terminals). Is the charger NOT connected to the batteries through a battery isolater (causing a voltage drop and charger to overcharge as it will not sense the correct battery voltage)? Is the main battery selection switch (on the main electrical panel) set to 1 or 2 or OFF (AND NOT both/all) while charging? Are both batteries the same age, amperage, chemistry? Is the charger's battery type selector switch set to 'F'? Was the charger installed years after the batteries were installed and as such the batteries are badly 'sulfated' (which will cause excessive overcharging)? Have you ruled-out a faulty charger by checking the battery voltage during the chargers different cycles to verify the voltage at the battery terminal is correct (i.e. no more than 14.4 volts)? Is your boating area extremely warm and the absense of a temperature compensation switch/sensor causing too high a charging voltage (i.e. should you have selected the Truecharge 20 which has a manual temperature switch and the ability to accept input from a remote temperature sensor at the battery)? Is the charger's A/C wiring correct and not backwards (black=positive, white=neutral, green=saftey ground to casing)? Is shorepower wiring correct and not reverse-polarity'd? Is the charger connected via a very long extension cord which is causing a voltage drop (instead of hard-wired to the A/C side of the panel and receiving shore-power via a properly sized for the length, shore-power cord)? Have you checked to assure the charger is receiving 120 vAC? Is one of the alternator's diodes shot allowing current to drain to ground, thereby causing the charger to never think the battery is charged? Are you leaving the charger connected when away and the shorepower is being periodically interrupted (e.g. daily) causing the charger to start its charging cycle too often? Ok, that's my 'up to midnight' brain dump of thoughts to help you out... hope this helps...
Bill N- good ideas
Bill N- those are all excellent suggestions and I can see that my work is cut out for me this weekend. You're right; if the problem is in the charging system then it makes no difference if the batteries are flooded or AGM.
Bill N- those are all excellent suggestions and I can see that my work is cut out for me this weekend. You're right; if the problem is in the charging system then it makes no difference if the batteries are flooded or AGM.
Battery problem solved
After checking the TrueCharge 10 to make sure it was operating properly and again losing far too much water in just one week, I determined that battery 1 was not holding a charge and probably had a damaged cell. As a result, the charger never read the battery as "charged" and kept charging at the buld level which resulted in excess water consumption. Also my error in using 2 Group 24 Sears deep-cycles as starting bank; my guess is the battereis were damaged by the starting loads after 1 year. Switched to West Marine Dual-Purpose 650's today and now able to start with either battery. Will check water usage next weekend but looks like problem is solved.
After checking the TrueCharge 10 to make sure it was operating properly and again losing far too much water in just one week, I determined that battery 1 was not holding a charge and probably had a damaged cell. As a result, the charger never read the battery as "charged" and kept charging at the buld level which resulted in excess water consumption. Also my error in using 2 Group 24 Sears deep-cycles as starting bank; my guess is the battereis were damaged by the starting loads after 1 year. Switched to West Marine Dual-Purpose 650's today and now able to start with either battery. Will check water usage next weekend but looks like problem is solved.
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