Maybe. Probably. But I am never comfortable with doing this because the house voltage ranges from ~12-15V. This really shouldn't be a problem for a
charger and I think you will be fine, but I always install a 12V DC-DC converter when doing these things. These converters are inexpensive (<$20, and usually <$10) and provide me piece of mind.
Icom may even sell a DC
plug for your charger. Our Standard Horizon has that option.
Mark