Batteries

[Tom]

I have 4 batteries in two sets. I change my batt switch from 1 to 2 every now and then just to use both sets. I am on shore power all the time except once or twice a week that I go out sailing for the day. After sailing for the day and listening to the radio and using the depth sounder I have no juice left to start the motor. I bought the boat with these batteries so I'm not sure how old they are. When I check the volts they are are at full charge for all four. But when I go to start the motor I get nothing. Should I not use starting batteries for everyday 12 volt use? Do I need four new batteries or two? I would hate to replace the two only to have the other two drag down the new ones. I haven't checked each cell yet but I'm going to do this tommorow. Maybe this will tell me if I have one or two bad cells in each battery and that I do need four. Anyway thanks for any help.

 

[Jeff Walker]

Something doesn't seem right

Tom, The small load of the radio and other instruments should not dis-charge your batteries after one day. You said you have 4 batteries so I assume you have two sets of 6 volt batteries in series to create 12 volts. You can add up the power consumption of your instruments but unless you're running a refrigerator, I doubt you're above 6 to 8 amps per hour. Assuming you have 100 amp/hours of useable power (leaving at least 50% of amp-hours unused), 8 hours of sailing should leave you plenty amps to start. Deep cycle 6 volt batteries are not good at providing cranking amps and this may be part of the problem. You might add a Group 27 starting/storage 12 volt battery and isolate it for starting only.What I did is purchase a small solar panel which provides enough power to run the VHF and instruments even when the batteries are turned to "off". I just move it around to a sunny spot while I'm sailing or when I'm anchored and so far have had no starting problems using my 2 Group 27 (105 amp-hour) 12 volt batteries. Good luck,Jeff

 

[Don Hall]

Battery Cables?

I had a similar problem with my '87 C-30. It turned out to be a loose batery cable lug at the starter. It was so loose that it just slipped off in my hand when I removed the cable I had replaced everything else in the battery & charging system before finding the real problem. So check your cables.Secondly, I highly recommend that you buy at least one new battery and make it your dedicated engine starting battery. You can parallel the others for "house". I put in a Heart Echo Charge (West Marine or Jack Rabbit Marine) unit that charged the engine whenever there was a charging current to the house bank. There are other makes as well. Good luck.