Hi,

I love both backtrader and ccxt so I'm really pleased that this is happening :)
For IB and other feeds, setting historical=True gives the following behaviour (taken from the docs):

The data feed will make multiple requests if the requested duration is larger than the one allowed by IB given the
timeframe/compression chosen for the data.

But it appears that CCXT feeds are only making one request. Eg:

hist_start_date = datetime.utcnow() - timedelta(days=50)
data_min = bt.feeds.CCXT(exchange="gdax", symbol="BTC/USD", name="btc_usd_min",
                         timeframe=bt.TimeFrame.Minutes, fromdate=hist_start_date, historical=True)

This only returns the first 200 minutes, starting from 50 days ago. I may have completely misunderstood what's occurring, but I'd love to help out so feel free to point me in the right direction :)