Shouldn't be a problem.
I run my FF, GPS, VHF and 200W 4 speaker CD stereo with Ipod all at the same time.
Never had an issue even when running on one, but most times I run on both batteries to keep them charged.
~..~..~.. ><((((º>
Things done at the last possible minute are done with the greatest possible information. Procrastination is, therefore, the most efficient means of doing things.