Charging issues

[phil2]

Been working on the new boat. Seems like house battery is dead 9 volts or so.  I have shore power with a adapter for a regular lead cord. Light for charger comes on cycles then goes green charged. Have 2 sets of wires one going to a isulater other to battery switch. Does the charger need full 30a to work? Or will regular lead be fine? Lost with it isulater should put power to that side once below 12 volts charges when running mains but not shore power. 

[rolmops]

You only need a trickle charger to keep your battery charged. 30 amps is only used for a quick burst of power. When the charger cycles between charging and green, it means that the battery is fully charged. But if you only have nine volts even when the battery seems fully charged. there is something wrong with the battery. If you are lucky it is just low water level in some of the cells, but it is a bad idea to count on luck when you are out on the water, so replacement with a new battery would be the smart thing to do.

[phil2]

Just was looking at manuals says once under 10 volts or over 13 charger it wont charge . sounds dumb to me.

[tech2526]

unfortunately at 9 volts that battery is bad

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[Shakemsam]

Place a reliable stand alone charger on the battery in question for a 24hr period. Not a trickle charger! 10 amp is good.. Then check the voltage drop under load. Better yet, remove the batt and have it tested. 

[phil2]

Thanks guys prob end up replacing it lasted a long time one ride lol. Brand new in September. Obviously faulty.