"Transaction too large"-Error when sending Coins
When i try to send coins to another wallet i receive the message "Transaction too large" but it's only 300 coins... What's wrong?
This is because there are too many transactions being pulled together to make the transaction. This happens because that 300 coins is probably composed of 1000+ transactions. The best way around it is send a few series to yourself. If 100 coins is a low enough number of transactions; then send yourself 100, then 200, then 300 and it will cut it down. IF you go into "Settings->Options-> Wallet" and enable "coin control features", then you will have a "coin control" button on your send screen. From this screen select a few transactions (~100) and transfer the Coins to another own Address. Do it twice until you don't have thousends of Transactions in your active Adresses. We recommend to do this regular if you are running a Masternode.
Every transaction that is pieced together to get the total coins for a new transaction has a size associated with it; that size seems to be 78 bytes of overhead and then 148 bytes per transaction; so if you're collecting up 10 masternode rewards, it's going to be 148 x 10+78 = 1556 bytes; 100 masternode rewards will end up being 148 x 100+78 = 14878 bytes. The limit (defined by MAX_STANDARD_TX_SIZE) is 100k. This means you're pretty much limited to pulling together 675 rewards into a single transaction. So to extrapolate that to even more useful information: If you have a Full Masternode, your rewards are 0.6 coins each. So 675 rewards, to stay under the 100k limit, is 405 coins. If your stash is from Medium Masternode earnings; the limit is hit at 243 coins. A light masternode: 81 coins.
The Magic of Auto Combining Rewards describes a way to automatically combine masternode rewards into larger transactions, allowing for this Transaction Too Large error to be virtually eliminated.
Thanks for CaveSpectre for this Perfect Answer! :)