Ocean rower Simon Chalk may be forced to turn off his steering at night as dense cloud cover means the batteries on board are not being charged.
Simon Chalk: Needs sunshine
Mr Chalk, 30, is attempting to row the Indian Ocean from Australia to Reunion Island.
He has an emergency battery so is still able to communicate, but in 58 days at sea this is the lowest he has been on power.
In the latest message on his website at BBC Devon Online, Mr Chalk also told how a shark swam under his boat and how the thought of decent food, a cold drink and a bed are keeping him going.
"I'm now fighting to get south but the storm's still blowing hard," said Mr Chalk, a property developer from Newton Abbot.
"But this is now day five of this bad weather.
"According to the weather router it may turn round tomorrow but what I really need is sunshine to get the batteries charged.
"It'll take four days to fully recharge from scratch, and that's with good sunshine," he said.
Mountainous seas and ferocious winds peaking at 130mph have pounded his 23ft vessel for most of the two months since he began his bid to become only the second person to cover the 3,478 miles to Reunion.
"Still, at least I'm making progress," said Mr Chalk
"Every mile counts."