So that means the 'coin' can only breakdown smaller and smaller? is there a way to combine them again? to cut down the size of transaction
Yes. It is possible to consolidate multiple outputs into one single output simply by sending the highest amount of coins that you can using the smallest number of involved outputs. In order to help you visualize it, consider 10 separate outputs of 1 coin each.
1+1+1+1+1+1+1+1+1+1 <-- outputs before consolidating
Let's assume (for this example only) that consolidating 5 outputs into one is the optimal choice.
(1+1+1+1+1) => consolidated into (5)
(1+1+1+1+1) => consolidated into (5)
So now we have two outputs of 5 coins each.
We can further consolidate those two into a single output of 10 coins if we want to later on.
So how do we do that? Well, if you are familiar with the console commands for the Bitcoin Core client, then you can manually handpick the outputs that you want to tap into.
This might be outdated, but it's a good enough step-by-step guide for a good method of consolidating outputs. Just replace any outdated commands with the updated ones if any.
Do not play around with this or you might LOSE some coins. Try it with low-value altcoins if you really are inclined to do so.I'm not familiar with every Bitcoin client in existence, but I believe that some clients automatically provide users with the optimal selection of outputs in transactions as far as transaction size is concerned. Only consider consolidating outputs if absolutely necessary. Also note that consolidating outputs haphazardly might end up costing you more in transaction fees than just sending coins as you need them.
I do NOT recommend beginners messing around with raw transactions or output consolidation. I don't even do it myself. It's easier to just not deal with dust transactions at all or let exchanges handle the consolidation for me.
I know about the different transactions not adding up to 1 total , but why would bitcoin-QT say it is too large .
The amount may be (relatively) small, but you have a lot of dust outputs. Your 5 BTC transaction involved 232 outputs - primarily dust outputs -- and had a transaction size of 41685 bytes. 232 is a huge number of outputs for a single transaction.
I am doing a small transaction here . What if I would want to buy an airplane or an expensive car with my BTC and all my incoming transactions are coming from my online store which all have small transaction amounts .
I will have to go make thousand transactions of 1 BTC to the seller ? This can't be right .
I understand what you mean, but that's just how Bitcoin works. Hopefully, users more knowledgeable than I am can give you some advice regarding this.
So you think sweeping my paper wallet will not have this problem of "transaction too large" in the future , because it only has 2 inputs ?
Yeah, that's fine.
Transaction ID cf784d45981d21dd57e7c5439b3736ce274ef158e476a4050aaef4512807d5ee-000
Blockchain.info says that that transaction has over 250 inputs. After seeing the 232 outputs of your 5 BTC transaction, I'm gonna assume that your 30 BTC transaction has over 1500 outputs. Nodes are prolly rejecting that transaction due to the large number of outputs.