Saving two Optima batteries...
Posted: Jun 15th, '10, 11:25
Some of you might remember that about a year ago I posted some info on the Optima AGM storage battery products. I had purchased a total of 6 of these to be installed as part of my upgrading the main 12 volt battery/power distribution system in my ’83 B33 FBC. I installed them in three banks of two batteries each, one bank for each engine starting and one bank for house power and generator starting.
Each battery bank also feeds a single bilge pump.. I have three bilge pumps, (forward, midships and aft), each drawing power from it’s own battery bank. I am not using the boat these days, because I am involved in a general rebuild and upgrading of almost every system, so the only load on these batteries are the bilge pumps. I had an older three bank battery charger online to keep the batteries fully charged. The charger is installed in the space forward on the engine room, where the holding tank and water tanks are located. “â€Out of sight.. out of mind!â€.
Last week I noticed there was a little more than normal amount of rainwater in the center bilge compartment. I also heard that the bilge pump for this area was running, but saw there was no water exiting the thru hull fitting. Strange. I also noticed that the light in the manual-off-auto switch panel for this pump was on, but dimmer than usual. Also strange. I suspected corroded wiring or a bad ground connection.
To make a long story short.. I found the online battery charger had died… probably weeks before, and apparently the midships bilge pump, in response to the heavy rains we had been having over the past several weeks had drawn so much power from it’s battery bank that the voltage from this bank had dropped so much that the pump had enough power to run, but at a reduced speed, which was not fast enough to lift the discharge water high enough to get over the high point in the discharge hose. This kept the pump running constantly, and drew the battery bank down even further.
After I figured this all out I took a voltmeter reading on the affected battery bank, and found 6.2 volts! Here I was with two almost new batteries so far discharged my portable battery charger would not recharge them.. instead it kept beeping a warning that the batteries were “faultyâ€, and would not accept a charge. The prospect of having to buy two new Optima AGM batteries for about $175 each was not pleasant, especially since these were essentially new. My local battery sales guy assured me the batteries were junk, and would not ever accept a charge. I was more than a little upset!
Out of despiration I called Optima, and spoke with one of their customer service people. He told me that there was a good chance to save the two batteries. What he suggested was to take one 6.2 volt Optima battery, and connect it in parallel to a good battery with normal 12+ volt output.. then attach the charger to the two batteries, and set the charger at 10 amps (the max for my portable charger) for a couple of hours. I did this and bingo.. the Optima read 11.9 volts. I reattached the portable charger for another couple of hours and reached 12.3 volts by the end of the day. I know that I might have shortened the life of these two batteries, and at present due to other things I can’t start the engine they serve to see how they respond to a load, but at least I feel I might have saved these batteries from premature death. I used the money I “saved†to buy a new charger and battery monitoring panel.
I post this with the expectation that someone else here might have a similar situation one day, and might recall and benefit from this trick.
Each battery bank also feeds a single bilge pump.. I have three bilge pumps, (forward, midships and aft), each drawing power from it’s own battery bank. I am not using the boat these days, because I am involved in a general rebuild and upgrading of almost every system, so the only load on these batteries are the bilge pumps. I had an older three bank battery charger online to keep the batteries fully charged. The charger is installed in the space forward on the engine room, where the holding tank and water tanks are located. “â€Out of sight.. out of mind!â€.
Last week I noticed there was a little more than normal amount of rainwater in the center bilge compartment. I also heard that the bilge pump for this area was running, but saw there was no water exiting the thru hull fitting. Strange. I also noticed that the light in the manual-off-auto switch panel for this pump was on, but dimmer than usual. Also strange. I suspected corroded wiring or a bad ground connection.
To make a long story short.. I found the online battery charger had died… probably weeks before, and apparently the midships bilge pump, in response to the heavy rains we had been having over the past several weeks had drawn so much power from it’s battery bank that the voltage from this bank had dropped so much that the pump had enough power to run, but at a reduced speed, which was not fast enough to lift the discharge water high enough to get over the high point in the discharge hose. This kept the pump running constantly, and drew the battery bank down even further.
After I figured this all out I took a voltmeter reading on the affected battery bank, and found 6.2 volts! Here I was with two almost new batteries so far discharged my portable battery charger would not recharge them.. instead it kept beeping a warning that the batteries were “faultyâ€, and would not accept a charge. The prospect of having to buy two new Optima AGM batteries for about $175 each was not pleasant, especially since these were essentially new. My local battery sales guy assured me the batteries were junk, and would not ever accept a charge. I was more than a little upset!
Out of despiration I called Optima, and spoke with one of their customer service people. He told me that there was a good chance to save the two batteries. What he suggested was to take one 6.2 volt Optima battery, and connect it in parallel to a good battery with normal 12+ volt output.. then attach the charger to the two batteries, and set the charger at 10 amps (the max for my portable charger) for a couple of hours. I did this and bingo.. the Optima read 11.9 volts. I reattached the portable charger for another couple of hours and reached 12.3 volts by the end of the day. I know that I might have shortened the life of these two batteries, and at present due to other things I can’t start the engine they serve to see how they respond to a load, but at least I feel I might have saved these batteries from premature death. I used the money I “saved†to buy a new charger and battery monitoring panel.
I post this with the expectation that someone else here might have a similar situation one day, and might recall and benefit from this trick.