Here's one for the electric gurus. I have two 8D batteries for house use. 432 A/Hs of available power. with a separate engine start battery. For a long time I've suspected I'm not getting the proper performance from the house bank. Last weekend at the island the house bank went down to 12.14 volts at only 150 A/Hs used. I think I should be able to go to at least 216 A/Hs down, (50% of capacity) before the voltage falls that far. It seems I'm carrying a lot of weight but not getting the benefits of the two batteries. Thoughts? Thanks, Larry W.
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Steve
Age?
The first thing that comes to mind is the question...How old are they? The capacity will drop with age. Second thing is are you sure that you are fully charging them? If you are going through a battery bank combiner or if you don't have remote sensing on the alternator, you may not be getting a full charge. I don't know if you wanted question instead of answers, but it is a start. Steve
The first thing that comes to mind is the question...How old are they? The capacity will drop with age. Second thing is are you sure that you are fully charging them? If you are going through a battery bank combiner or if you don't have remote sensing on the alternator, you may not be getting a full charge. I don't know if you wanted question instead of answers, but it is a start. Steve
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Les Murray
What do you have for monitoring and charging?
Larry, Do you have any way of monitoring usage such as a Link 10? This way you can see exactly what you are using and how much you have left. Also, how are you charging these batteries? Do you have a smart regulator and high output alternator? Finally, what type of batteries are these? Do you have lead-acid or gel technologies? Gel and AGM batteries last longer, can take more deep cycle discharges, and self-discharge at lower rates. Let me know what you've got. I just went through this whole process of upgrading my electical system. Les Murray s/v Ceilidh '86 C-36 #560
Larry, Do you have any way of monitoring usage such as a Link 10? This way you can see exactly what you are using and how much you have left. Also, how are you charging these batteries? Do you have a smart regulator and high output alternator? Finally, what type of batteries are these? Do you have lead-acid or gel technologies? Gel and AGM batteries last longer, can take more deep cycle discharges, and self-discharge at lower rates. Let me know what you've got. I just went through this whole process of upgrading my electical system. Les Murray s/v Ceilidh '86 C-36 #560
switch to 6 volts.
Larry: Your batteries could be on their way out. What type of batteries are you presently using (flooded, gel, agm)? If you are using flooded (wet cells), you could install 4 6V batteries in the place of these 8D's can get more capacity with less weight. If you are using Gels, they can also be swapped too. If you are using AGM's it looks like you may be stuck with 12V batteries. I would have your batteries tested and see what you are dealing with before you do anything.
Larry: Your batteries could be on their way out. What type of batteries are you presently using (flooded, gel, agm)? If you are using flooded (wet cells), you could install 4 6V batteries in the place of these 8D's can get more capacity with less weight. If you are using Gels, they can also be swapped too. If you are using AGM's it looks like you may be stuck with 12V batteries. I would have your batteries tested and see what you are dealing with before you do anything.
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Tom
Are you SURE you are actually charging them all
the way up. How are you charging the batteries?. Do you have a good quality 3 stage (4 stage) marine charger ? Is it adequate to the task. Are you plugged into the dock at all times. Have you EVER equalized these batteries? How old are the batteries?.....Have you let them sit over an extended period of time w/o a charger?......When you measured that Voltage was there ANY load on the batteries at that time. We would need these answers before we know if they are really bad or not.
the way up. How are you charging the batteries?. Do you have a good quality 3 stage (4 stage) marine charger ? Is it adequate to the task. Are you plugged into the dock at all times. Have you EVER equalized these batteries? How old are the batteries?.....Have you let them sit over an extended period of time w/o a charger?......When you measured that Voltage was there ANY load on the batteries at that time. We would need these answers before we know if they are really bad or not.
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Don
It's not that simple
I fully agree with the other posts. It is not unusual for a serviceable battery to lose 20% of it's rated capacity. IF you started with a fully charged battery and you checked voltage with all load removed (and stabilized for 5 minutes) at the 50% mark, then 175 amps would be normal.
I fully agree with the other posts. It is not unusual for a serviceable battery to lose 20% of it's rated capacity. IF you started with a fully charged battery and you checked voltage with all load removed (and stabilized for 5 minutes) at the 50% mark, then 175 amps would be normal.
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Norm Freedman
Equalize?
How long has it been since you equalized them (assuming lead acid batteries)? This may very well help.
How long has it been since you equalized them (assuming lead acid batteries)? This may very well help.
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rp
Equalize? how do you do it??
I've read about it in Calders, but there isn't any real clear cut instructions. How do you do it, and what equipment is needed?? I have two 4D batteries, wet cell. Rp
I've read about it in Calders, but there isn't any real clear cut instructions. How do you do it, and what equipment is needed?? I have two 4D batteries, wet cell. Rp
Smart Charger will equalize!
The smart chargers such as Statpower (now Xantrex) have the ability to equalize flooded batteries. Be sure that you DO NOT use this technique on AGM or Gel Cells.
The smart chargers such as Statpower (now Xantrex) have the ability to equalize flooded batteries. Be sure that you DO NOT use this technique on AGM or Gel Cells.
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John Buckham
Charge!
When the charger is on the battery terminal voltage of the batteries should rise to 13.2 to 13.8 volts. If not check your charger. If you do, charge the bank until the batteries begin to gas (bubble)(assuming you have flooded batteries)) then using a battery hydrometer check the specific gravity of the electrolyte in each cell. This will provide you with a clear picture of the condtion of each cell in the battery. If you find the cells have somewhat uneven readings try to equlize the battery by intentionally overcharging for 6 hours by running the chargers voltage up to at least 14 volts, but not higher then 15 volts. This will overcharge the good cells, but hopefully allow the cells that are less charged to come up. After the six hours are up cut the juice completely and let the battery cool for several hours (overnight is good) and retake the specific gravity readings, if the equilazation took the cell readings should be closer to each other. Chargers, the new “smart chagers” may have this function invoked by pressing a recessed button, some chargers have a knob to set charge rate – and some have nothing and can’t do this. If you’ve got sealed batteries (AGM etc) don’t try to equilize as overcharging will damage this type of battery. Good Luck.
When the charger is on the battery terminal voltage of the batteries should rise to 13.2 to 13.8 volts. If not check your charger. If you do, charge the bank until the batteries begin to gas (bubble)(assuming you have flooded batteries)) then using a battery hydrometer check the specific gravity of the electrolyte in each cell. This will provide you with a clear picture of the condtion of each cell in the battery. If you find the cells have somewhat uneven readings try to equlize the battery by intentionally overcharging for 6 hours by running the chargers voltage up to at least 14 volts, but not higher then 15 volts. This will overcharge the good cells, but hopefully allow the cells that are less charged to come up. After the six hours are up cut the juice completely and let the battery cool for several hours (overnight is good) and retake the specific gravity readings, if the equilazation took the cell readings should be closer to each other. Chargers, the new “smart chagers” may have this function invoked by pressing a recessed button, some chargers have a knob to set charge rate – and some have nothing and can’t do this. If you’ve got sealed batteries (AGM etc) don’t try to equilize as overcharging will damage this type of battery. Good Luck.
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R.W.Landau
Larry,
I did not read the other posts so if this has been stated ....Forget it. Batteries discharge differently according to the the way they are drained. If you drain 150 amps in 6 hours, It is alot different than drawing 150 amps over 12 hours. The batteries like it slow. The slower the batteries are drained the more amp/hours you will get out of them. That is why 2 6 volt batteries work better than one 12 volt battery of the same size. It dosen't see the draw as being as fast as the single battery.( the size of the cells are larger) A fully charged 12 volt wet cell battery should be fully charged at about 12.72 volts after 4 to 6 hour rest after charging. Sometimes you have to get to know your charger. I know that when my charger reaches 13.4 volts that after a 4 to 6 hours rest, they read 12.72 volts.(fully charged) Every battery is different. hope this helped! r.w.landau
I did not read the other posts so if this has been stated ....Forget it. Batteries discharge differently according to the the way they are drained. If you drain 150 amps in 6 hours, It is alot different than drawing 150 amps over 12 hours. The batteries like it slow. The slower the batteries are drained the more amp/hours you will get out of them. That is why 2 6 volt batteries work better than one 12 volt battery of the same size. It dosen't see the draw as being as fast as the single battery.( the size of the cells are larger) A fully charged 12 volt wet cell battery should be fully charged at about 12.72 volts after 4 to 6 hour rest after charging. Sometimes you have to get to know your charger. I know that when my charger reaches 13.4 volts that after a 4 to 6 hours rest, they read 12.72 volts.(fully charged) Every battery is different. hope this helped! r.w.landau
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larry w.
Batteries, additional info
Thanks to all who responded; I guess I should have included all this relevant info in the original post. I stay plugged into a shore charger, Xantrex three-stage that tops them up completely. On board I have a Balmar 115 amp alternator than can push 90 amps at 14.4 volts, regulated by an AmpHour+ three stage smart charger with a digital display that shows voltage, amp/hours and amp flow, positive when charging, negative when drawing. I'm sure the batteries are fully charged when I leave the dock and that they are being charged as fast as they can accept when the alternator is turning. I just think they go down too far, too fast and am not getting the full benefit of that large bank. More thoughts? Thanks, Larry W.
Thanks to all who responded; I guess I should have included all this relevant info in the original post. I stay plugged into a shore charger, Xantrex three-stage that tops them up completely. On board I have a Balmar 115 amp alternator than can push 90 amps at 14.4 volts, regulated by an AmpHour+ three stage smart charger with a digital display that shows voltage, amp/hours and amp flow, positive when charging, negative when drawing. I'm sure the batteries are fully charged when I leave the dock and that they are being charged as fast as they can accept when the alternator is turning. I just think they go down too far, too fast and am not getting the full benefit of that large bank. More thoughts? Thanks, Larry W.
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