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Someone with an electrical engineering background needs to set me straight. Wind Horse is charging two group 27s with a 6 watt Seimans solar panel. For the past year this has been effective for keeping the batteies at 12.8 volts or better. Recently I'm finding that the afternoon voltages are around 12.75 and the early morning voltages around 12.4. The bilge pump is not cycling during the night and the battery switch is off. The batteries are less than two years old. I'm guess that the diodes have failed and the solar panel is 'back flowing' power during the darkness hours but that failure seem premature. I am considering disconnecting the cable between the battery and the main switch to see if there is a power leak in the switch. Before I crawl into the engine compartment and begin taking things apart does anyone have another suggestion?
Mike M
SV Wind Horse
#375
Galveston, Tx
Mike M
SV Wind Horse
#375
Galveston, Tx
Offline
Are you sure that your afternoon measurement is not just the surface charge that's present on any recharged battery? One tract I read said that the surface charge can last up to 12 hr, but went on to say that you can dissipate it and get a true reading (in a car) by leaving the headlights on for 5 or 10 minutes. Before you do anything dramatic, you might try comparing your morning reading with a no-surface-charge reading.
Also, one of the club's chief mechanics recently told me that published numbers for battery charge are all taken in ideal circumstances - in use and with a year or so on them, batteries will always deliver less than ideal voltages.
David Weatherston
Towser, Toronto
C&C 27 Mk IV
David Weatherston
Towser, Toronto
C&C 27 Mk IV
Offline
Thanks David, I did consider the surface charge issue and began testing only after disconnecting the solar panel and waiting several minutes. I will try and put a load on the batteries as you suggest and see if that changes the test results. I guess that it is time to get out the hygrometer and check the specific gravity.
Mike M
SV Wind Horse
#375
Galveston, Tx
Mike M
SV Wind Horse
#375
Galveston, Tx
Offline