Republican presidential nominee John McCain doubled his travel expenditures in August and increased his payroll and his media spending from the previous month while enjoying his biggest fundraising stretch of the campaign.

McCain reported raising $47.5 million in August, with more than $9 million coming in the three days after he announced his selection of Alaska Gov. Sarah Palin as his running mate, according to a report filed late Friday with the Federal Election Commission.

Overall, McCain spent nearly $41 million in August — his most exorbitant month so far, but still shy of Democratic rival Barack Obama’s whopping $55 million in August expenditures.

McCain spent about $23 million in advertising, his highest as he jockeyed for position against Obama in battleground states. McCain increased his staff spending, building up a payroll of nearly $1.2 million. He also spent more than $3 million on travel, at least twice as much as what he spent in July.

Obama had not yet filed his FEC report. It is due at midnight Saturday. But his campaign has announced he raised $66 million in August, a record for a presidential campaign

McCain has chosen to accept $84 million in public funds to spend from September until the Nov. 4 election. That means he can no longer raise private money for his campaign. Obama, who has set fundraising records, has decided to continue raising private funds for the general election in hopes of surpassing McCain.

The money race is an important element at this stage of the contest, as both campaigns are seeking to influence voters with ads and to build sizable ground organizations to register and mobilize voters in more than a dozen battleground states. The campaigns are especially aware of mail-in or absentee voting schedules in some of those states and are spending money to get as many early votes as they possibly can.

McCain also filed a report for the general election — McCain-Palin 2008. In addition, he raised money for a general election compliance fund — an account that he can only use to pay for legal and accounting expenses.

McCain used the compliance fund to lend McCain-Palin 2008 a net $4.7 million for the general election. Such a loan is permissible because the campaign could not raise private money after Sept. 1, but was not entitled to receive the public funds until after McCain officially received the nomination on Sept. 5. That money was used to pay in advance for advertising aired during the first week of September and must be repaid with the $84 million in public funds.

Both candidates are also helping their respective national parties raise money. The parties can spend money on behalf of their presidential candidates — up to $19 million can be coordinated with the campaigns, other funds can be used to pay for get out the vote efforts, for hybrid ads that mention the presidential candidate, or independent expenditures that help the candidates but cannot be coordinated with the presidential campaigns.

The McCain campaign ended August with $27 million in the bank. It has since transferred about $18 million to the Republican National Committee and about $9 million to various state Republican committees, party and campaign officials said.

The RNC has said it had $76 million in the bank at the beginning of September before obtaining the McCain camp’s leftover cash. The Democratic National Committee has said it had $17.5 million cash on hand at the end of August and Obama’s campaign has said he would report $77 million cash on hand.

That means both campaigns were roughly on even footing, putting a burden on Obama and the DNC to surpass McCain’s $84 million in public funds and any major contributions raised by the RNC.

Obama reported raising more than $9 million for his campaign and the Democratic Party this week in Hollywood. He also reported raising $10 million online for his campaign in less than 24 hours earlier this month after Palin gave her acceptance speech at the Republican National Convention.

Overall, Obama has raised more than $440 million for his presidential campaign, an unprecedented amount. The campaign said it has more than 2.5 million donors. McCain has raised $210 million.