also is it possible to add more money to an open channel later? I treid doing this in Zap wallet and it didn't seem to work
If you've sent enough funds and your channel tab shows "
can receive x.xx BTC",
you can use "
submarine swap" to increase your lightning funds up to the available inbound capacity.
To perform "
swap" in Electrum, click the "
swap" button and click the lightning logo or the BTC logo to switch them,
then fill-in the on-chain funds that you want to add to your lightning funds and complete the transaction.
Note: that will require an on-chain transaction and third-party service fee so it's not-so-different from opening a channel, moreover, it's more expensive.