Half a dozen Sanders delegates spoke to about 300 demonstrators gathered at a plaza near City Hall, about 4 miles from the convention site, for daylong rallies and speeches.
Erika Onsrud, an at-large delegate from Minnesota, told the crowd they need to continue to fight. Amid cheers, she exhorted them: "Stay awake!"
Other delegates acknowledged that Sanders' loss was disappointing but told the crowd they can create change themselves without the Democratic Party and the mainstream media, contending the media contributed to a rigged election.
A few blocks away, police detained 10 protesters at Comcast's corporate headquarters for holding a sit-in accusing the cable giant and NBC owner of not reporting the truth. Officers zip-tied them and briefly closed the 975-foot skyscraper to all but Comcast employees. The demonstrators were ticketed and released.
Another group of about a dozen anti-Israel demonstrators protested at a hotel where a number of delegations to the four-day convention were staying. They called for a free Palestine.
The absence of marches was a marked change from earlier in the week, with some Sanders supporters saying their comrades seemed fatigued and frustrated.
Thousands of activists have taken to the streets during the convention to voice support for Sanders and his liberal agenda. On Tuesday night, the "Bernie or bust" brigades watched in dismay as Hillary Clinton became the first woman nominated for president by a major political party.
Demonstrator Shannon Morgan said she is fatigued by political frustration, long days and hot pavement that burned through the soles of her Vans and scorched the bottom of her feet.
The 45-year-old from Long Island, New York, described herself as an anarchist socialist and said she cannot understand why Sanders supporters are still singing and cheering.
"I don't believe in burning things down," she said, but added that it is frustrating "to see them still happy and not storm the convention center and sit in."
The longstanding bitterness between Sanders' supporters and Clinton's seemed to grow worse over the past few days after a trove of hacked emails showed that officials at the Democratic National Committee played favorites during the primaries and sought to undermine Sanders' campaign.
Sanders had urged supporters Monday to fall in line behind Clinton for the good of the country. But many were unmoved.
Thousands gathered in the streets outside the convention at the Wells Fargo Center on Tuesday night, and some tried to scale the 8-foot walls around a restricted zone. Police and the Secret Service arrested four protesters.
As of midday Wednesday, only about 75 people were at the nearby park that has become a base for the protesters.
Jennifer Hall, 47, flew into Philadelphia from California on Wednesday and said her fellow Sanders supporters seemed tired. She said she came to "comfort the heartbroken, mourn with the mourners and help sustain the effort" fighting against two-party politics.
"We can all cry and keep going," she said.