1. If you have an HD wallet (not account... no idea why he saying account. Bitcoins aren't banks) any address that receives funds can combine that with any other address within your HD wallet.
I said "account" because Mycelium supports multiple BIP44 "accounts" within your HD wallet...
https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki#accountSo, your point #1 is not necessarily true... if you create multiple "accounts" in your Mycelium HD Wallet... you CANNOT use coins contained in an address that is in Account 1 with coins from an address that is in Account 2.
Example: 1bitcoin(...) and 1B1tCoiN(...) both receive 0.01BTC each. You can make one transaction for 0.02BTC (minus fees) assuming that 1B1tCoiN(...) was a change address in your BIP32 HD wallet. If two seperate addresses recieve the funds they can't be spent in one transaction on mycelium. There my be a way in core but I'm not sure as that's too technical for me.
Also... your example here is wrong... as long as all the addresses are in the same "Account"... it makes no difference if they are change addresses or "separate addresses" (not even sure what you mean by that??)... if you have coins in the same account, you can spend them together in one transaction.
2. If you have 30 different change addresses, any address within your HD account that receives funds can be spend in one transaction. If every address had 0.001BTC you could spend 0.03BTC all in one transaction.
I'm not sure where you got the idea that only coins in "change" addresses can be spent together? Perhaps you don't understand what a change address actually is and/or how they work and what their function is?
You're saying that
bitcoins have accounts and in the same post saying I don't know what I'm talking about. Hahaha
. I don't care about mycelium terminology, I'm talking about bitcoin terminology.
Let me break this down for you: when you spend on one address and your funds are sent to that 'new address' that was generated, that's your
change address. Get it? You send another tx? Oh look another
change address where your change goes into (such wow. So currency.). The first address in your
BIP32 hierarchical deterministic wallet is just an address and the rest are at one point change addresses. Did I dumb that down enough for you? Let's try an example: If you have 100 addresses in your HD wallet, at one point 99 of those were used as change addresses. It's not magic, or my imagination.
It's how HD wallets work.Ya you can have multiple HD wallets. Those can't be spent in the same transaction. That was pretty self explanatory but again I'll
really break it down for you.
TL;DR: anything within an HD wallet can be spent together. Any other HD wallet (or any other type of wallet) would need to be spent separately in mycelium.
Also, bitcoins don't have accounts nor will they ever. Stop using fiat terms on a bitcoin forum.