Equity = sum of all open positions (negative and positive) during an open period. This will constantly change throughout the period and gives live update to what the account stands at.
Balance = is the figure after the trades are closed for the investment period. This only changes whenever there is a deposit, withdrawal, or a position being closed.
These two terms and figures are often mixed up. The difference is that the balance will not include any un-finalised transactions (e.g. open positions). For instance, the balance may show $25000 but because there’s a couple of $100 positions that are currently sitting in the positive and not being closed off, the equity is sitting at 25200 (25000+2*100).