<p>Any additional funding transactions would not be covered by older commitment transactions which can result in the loss of funds. Older commitment transactions will not contain inputs that spend from the new funding transaction. The funds sent in the second funding transaction require B to sign a spending transaction, and if B refuses, then A has no way to get those funds back should an older commitment transaction be broadcast.</p>

CC BY-SA 3.0
2018-01-02T21:19:18.603Z
2018-04-20T23:12:28.967Z
2018-04-20T23:12:28.967Z
Ava Chow
<p>The total <strong>capacity</strong> of a channel cannot be increased since the funds are held in a single UTXO (unspent transaction output). What can be done, however, is to rebalance the channel from within the Lightning Network itself, so A can use it again.</p>

<p>Let's assume the balance of the channel is now <code>0 BTC</code> for <strong>A</strong> and <code>2 BTC</code> for <strong>B</strong>, so <strong>A</strong> cannot send payments through the channel anymore. That makes <strong>A</strong> want to fund the channel so he can spend more.</p>

<p><strong>A</strong> can do this by asking a payment to be sent to him through LN that will effectively re-balance the channel to (say) <code>1 BTC</code> for <strong>A</strong> and <code>1 BTC</code> for <strong>B</strong>. This funding payment needs to originate from another Lightning node, for instance a Lightning-enabled exchange where <strong>A</strong> pays fiat (or other crypto) and gets <code>1 BTC</code> sent to his Lightning node.</p>

CC BY-SA 3.0
2018-04-20T23:13:23.090Z
This answer could be more helpful if it would address the main question of the asker, which is why it's impossible to increase the capacity of a channel.
Murch
CC BY-SA 3.0
2018-04-24T16:22:04.757Z
@onysseus - "The total capacity of a channel cannot be increased since the funds are held in a single UTXO" - For the UTXO, are both the Source and Target address on the Main Blockchain? Where is the UTXO stored? In a Wallet? Also, does this mean that when A opens a channel to B, A has to make sure it a high amount (ex: 5 BTC) just so that he/she will ~have the capability~ to "refill" the channel to this level (5BTC and not 1BTC)?
Casey Harrils
CC BY-SA 3.0
2018-01-10T15:04:05.983Z
2018-04-23T13:19:01.963Z
2018-04-23T13:19:01.963Z
Lucian Boca
<p>There is a way to increase the capacity of the payment channel. <a href="https://github.com/litexnetwork/papers/blob/master/FundCasc.pdf" rel="nofollow noreferrer">Dynamic Channel Deposit and Withdraw for Lightning Networks</a>
<a href="https://i.sstatic.net/IVyyc.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/IVyyc.png" alt="The FundCasc Splice-in"></a></p>

<p>If A want to add 0.5 BTC to the channel, he can propose to create a new funding transaction which spent the old funding and another UTXO from A. The new Funding transaction can be created by following steps.</p>

<ol>
<li>Creating a new Funding Transaction</li>
<li>Creating a pair of new Commitment Transactions (C2a and C2b), containing the corresponding RD2a and RD2b</li>
<li>Signing the new Commitment Transactions</li>
<li>Exchanging signatures for new Commitment Transactions</li>
<li>Signing a new Funding Transaction</li>
<li>Exchanging signatures for the new Funding Transaction</li>
<li>Broadcasting the new Funding Transaction</li>
</ol>

CC BY-SA 4.0
2018-05-09T14:26:25.643Z
2018-05-09T14:32:18.960Z
2018-05-09T14:32:18.960Z
johnson zhang
<p>If A and B have a Lightning Network channel，it was opened with a funding transaction (say, 1BTC from both sides for 2BTC total).  After A has spent some time transacting with B, the balance of the balance of the channel will be spent and then the channel will be closed with a confirmation transaction. Why doesn't the Lightning Network support additional funding transactions within this existing channel so that A and B can continue use this channel for transactions?</p>

CC BY-SA 3.0
2017-11-25T06:19:01.983Z
Not sure what you mean by "when A translate some time with B, the balance of A is will be spend all" - can you explain? I assume though when you say translate you mean transact, but it still doesn't make much sense.
Highly Irregular
CC BY-SA 3.0
2017-11-27T05:05:26.580Z
I think the question is clear in the title, related: https://bitcoin.stackexchange.com/questions/57897/is-it-possible-to-add-funds-to-an-already-open-lightning-network-channel
meshcollider
<lightning-network><ln-channel-balance-management><ln-splicing>
Why can't lightning network channels increase balances？
user17314
# Why can't lightning network channels increase balances？

(Asked by: username_0 on 2017-11-24)

If A and B have a Lightning Network channel，it was opened with a funding transaction (say, 1BTC from both sides for 2BTC total). After A has spent some time transacting with B, the balance of the balance of the channel will be spent and then the channel will be closed with a confirmation transaction. Why doesn't the Lightning Network support additional funding transactions within this existing channel so that A and B can continue use this channel for transactions?

**Tags:** lightning-network, ln-channel-balance-management, ln-splicing

> **Comments:**
> **username_1**: Not sure what you mean by "when A translate some time with B, the balance of A is will be spend all" - can you explain? I assume though when you say translate you mean transact, but it still doesn't make much sense.  
> **username_2**: I think the question is clear in the title, related: https://bitcoin.stackexchange.com/questions/57897/is-it-possible-to-add-funds-to-an-already-open-lightning-network-channel  

---

## 3 answers

### Answer by username_3 on 2018-01-02. Score: 3

Any additional funding transactions would not be covered by older commitment transactions which can result in the loss of funds. Older commitment transactions will not contain inputs that spend from the new funding transaction. The funds sent in the second funding transaction require B to sign a spending transaction, and if B refuses, then A has no way to get those funds back should an older commitment transaction be broadcast.


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### Answer by username_4 on 2018-01-10. Score: 1

The total **capacity** of a channel cannot be increased since the funds are held in a single UTXO (unspent transaction output). What can be done, however, is to rebalance the channel from within the Lightning Network itself, so A can use it again.

Let's assume the balance of the channel is now `0 BTC` for **A** and `2 BTC` for **B**, so **A** cannot send payments through the channel anymore. That makes **A** want to fund the channel so he can spend more.

**A** can do this by asking a payment to be sent to him through LN that will effectively re-balance the channel to (say) `1 BTC` for **A** and `1 BTC` for **B**. This funding payment needs to originate from another Lightning node, for instance a Lightning-enabled exchange where **A** pays fiat (or other crypto) and gets `1 BTC` sent to his Lightning node.

> **Comments:**
> **username_5**: This answer could be more helpful if it would address the main question of the asker, which is why it's impossible to increase the capacity of a channel.  
> **username_6**: @onysseus - "The total capacity of a channel cannot be increased since the funds are held in a single UTXO" - For the UTXO, are both the Source and Target address on the Main Blockchain? Where is the UTXO stored? In a Wallet? Also, does this mean that when A opens a channel to B, A has to make sure it a high amount (ex: 5 BTC) just so that he/she will ~have the capability~ to "refill" the channel to this level (5BTC and not 1BTC)?  

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### Answer by username_7 on 2018-05-09. Score: 0

There is a way to increase the capacity of the payment channel. [Dynamic Channel Deposit and Withdraw for Lightning Networks](https://github.com/litexnetwork/papers/blob/master/FundCasc.pdf)
[![The FundCasc Splice-in](https://i.sstatic.net/IVyyc.png)](https://i.sstatic.net/IVyyc.png)

If A want to add 0.5 BTC to the channel, he can propose to create a new funding transaction which spent the old funding and another UTXO from A. The new Funding transaction can be created by following steps.

1. Creating a new Funding Transaction
2. Creating a pair of new Commitment Transactions (C2a and C2b), containing the corresponding RD2a and RD2b
3. Signing the new Commitment Transactions
4. Exchanging signatures for new Commitment Transactions
5. Signing a new Funding Transaction
6. Exchanging signatures for the new Funding Transaction
7. Broadcasting the new Funding Transaction


---

