Hi Guys,
Not sure if anyone out there can help me with this. Hopefully yes!
I just installed a new fixed VHF on my boat (Garmin IC 411)
I now noticed that when I i press the transmitter button to talk on the VHF my Voltage goes down to 10.8V/11V from the normal 12.2V. The change in Voltage can be seen on my Garmin GPS. Now is this normal??, do i need to worry that the GPS and other equipment won't function well when this happens or that my motor would not start someday when im out there?
I just charged the battery as i do at the beginning of every summer using a trickle charger and it shows Green on the indicator. This battery is approx 6/7 years old and is a Maintenance Free, Sealed Delphi Battery 12V 80Ah with the following specifications: CCA(-18 Degrees Celsius) BCI 800 IEC 480 DIN 440 EN 760.

can it be that this battery is near the end of its useful life??
I used other batteries to check if my battery is the problem, but the same happens.
I have Lights, Bilge pump, Shower, GPS, VHF and a Stereo on my 19.5 ft boat. Obviously these will never be on all at once. (just maybe the stereo, VHF and GPS). I know that its best to have two batteries, but I do not want my boat to get any heavier then it already is

Hope someone can help,
thanks,
Steve