you should not waste the time on downloading the 100GB data, you can dump your wallet and check the all the addresses for balance.
Try this command, it will help you to convert wallet into human readable form, to do that
Open Bitcoin-Qt and click help - Debug - console and use code
dumpwallet c:\walletdump.txt
If it is Encrypted then you can use this command to decrypt it for 3600 sec(6 min) then try the above command.
walletpassphrase yourpasswordhere 3600
After that Download a lightweight wallet like electrum
https://electrum.org/Click File --> New/Restore --> proceed further --> In place of Standard Wallet select Watch Bitcoin Addresses --> Paste all the addresses there
It will take you time to sort the file, you can use notepad++ or other applications to sort it.
After that, you are able to see all the addresses and their balance in Addresses tab. If not available then you can use CTRL + A or simply click the wallet dropdown and select addresses.
Let me know if you need further help.