We have a Freedom 10 charger/inverter. We get no noise
in invert mode so that has not been a problem for us. However in charger
mode we get a hum on the DC so is only a problem in the marina. Our radios, etc all have their DC sourced from a bus in the main DC panel so not individually cabled back to the batteries.
This hum (which sounds like 50Hz or second harmonic of) only affects the VHF
(Icom IC-M502) and SSB
(Icom IC-M802) radios and nothing else and on those the hum feeds through into the transmitted signal as well as being audible on receive. It probably affects the AM/FM radio
but is not noticed because of the strong signal strengths in the marina overcome it. Is easy to determine that it is on the DC and is the charger
as is still on the radios when disconnect the antennas and the hum increases in strength with the charge rate.
We did have some hum on our TV when in 12v mode (it is a 230/12v one) but that was from an earth loop so a different matter. We have no problem with our instruments (all Autohelm/Raymarine) or anything else.
For the VHF I found that one of the noise filters sold for automobile audio systems killed it dead. They are a 3 wire passive combination of big inductor and capacitor and cheap
. Trikky Dikky used to sell them but no longer now as far as I know. While a 5A one of those would probably be ok rating wise I found that the voltage drop across the one I tried was high (forgotten what) so I installed a 30A one and that was fine and carry a spare in case of failure.
For the SSB
if I use it in the marina, which is not often because of so much other noise in the area, I just turn the charger off. I did try making a filter but because of the low frequency of the hum, the high current
and the need to minimise voltage drop the inductor was just going to be too big. As it is not a problem when off shore power
with no charging
I have not really worried about it any more. The VHF I did because it was easy and cheap
I suspect that one of the same filters would sort the problem with the instruments too, if their problem is also due to the hum. I carry a 5A one just in case of need for something I might install that gets affected. Whether it will sort any noise problem you may have in invert mode I don't know but suspect so.
I am on the boat at the moment so is a bit slow surfing but when I get home tonight I'll have a hunt on the internet
and see if I can give you some links to the types of filters I mean.