How to Bump Channel Opening Fee Higher in Thunderhub

I made a noob mistake and put too low of a fee rate on my first ever channel opening transaction, to Start9 HQ. It is showing in Mempool as an RBF so that’s good. Can someone please direct me on how to bump up my fee by RBF?

Transaction ID 8b58ddc2f531f90d1666a8ffa48c6e26675d1e29e5e9c867f5bac813d357f18e


I’m not sure that Thunderhub has a channel opening bump fee feature, I’ve searched their documentation but it’s not mentioned as something that has been added recently.

This leaves you with two ways to bump the fee (you don’t really bump it, it’s a CPFP, but LND calls it a fee bump)

  1. Command line - Bumping fee for lightning channel open -

  2. Ride the Lightning (recommended)

RTL is the lightning node UI that we’re supporting in the Start9 marketplace. It does happen to have a fee bump feature.

If you install and open it, configure it to connect to your LND service, you’ll find your channel open in Pending. Next to the channel there’ll be a little button with some drop down options, one of which will be to bump the fee.

Now, something you’ll need to know.

If you open a 500,000 sat channel with a 1,000,000 sat UTXO, depending on the fee you’ll have a TX with an one output of 500,000 (the channel) and another with some 495,000 (the change) and perhaps a fee of 5000 in my example. The first of those outputs will probably be the fee and will be called output #0, the second will be output #1, the channel open, and the third will be #2 your change.

So back in RTL, when you click on bump fee… it’ll ask you for the change output number (which you should now know). It’ll also ask you for the new fee.

(Since you posted it, I’ll assume you don’t care if the community sees your TX)

Something else you’ll need to know.

With a CPFP you are not setting a new fee on the old TX, as you would with a RBF. Instead you are spending your change in a way that will be profitable for a miner to mine, but in order to pick up the change spend, which comes after the first TX you made that you want to speed up, the miner will need to mine both. This means the fee for the second TX, the change spend, needs to be high enough to cover the NEW transaction and make that profitable, AS WELL AS make up for the shortfall in the first transaction fee.

So the second TX fee should be much much higher than the current recommended fee. Perhaps twice, or a bit more? If you make a mistake again, it starts getting very expensive.

Hope this makes sense!

I’ll likely go through the exercise just so I can do it for others, but what will be the outcome if I just let this one sit and it goes stale and I just reopen another channel and don’t be a noob this time and pick a reasonable fee? It was mostly just not understanding the UI in Thunderhub. I thought I was setting fees for interacting with my node, not the fee for establishing the channel. Since I know full well what variance from the mempool average fee is depending on one’s time preference.

Thanks again for your help. I’m really striving to gain the knowledge that will allow me to help vendors in my area accept Lightning payments for goods and services. :call_me_hand:t4:

Lightning implementations tend to ignore channel opens after a certain period of time, then not respect the channel open. But the TX could sit in the mempool for longer, and could confirm anyway, leading to you need to force close the channel, a TX that could then also get stuck. Meanwhile your node will remember the TX and hold those funds forever hostage. Should you force it to forget the opening, because you assume it’ll never confirm, and then it does confirm, then those funds are in trouble.

Basically it’s better to be proactive with these types of things. Lightning calls for more proactivity in general.

Copy that. I have RTL ready to go. I will go through the excercise. I just have to come back later before my wife asks for a divorce lol. Thanks again. I will let you know how it goes. PS I am on nostr at:


1 Like

I can see the part of the transaction that represents the change. On the line in RTL bump fee that says “Index for Change Output” what kind of value goes on that line? In mempool I don’t know what the index of the change is. Thanks.

The output is indeed output #2. But I can’t just seem to use the numeral 2 on the “Index for change output” line on the fee bump utility in RTL

OK I entered “1” and it took the change.

The child transaction is 8b58ddc2f531f90d1666a8ffa48c6e26675d1e29e5e9c867f5bac813d357f18e

It is showing due for confirmation in 10 minutes or so. Sorry for the spam I am just so stoked to have learned this.


Great, hopefully it will confirm soon.

BTW, the way to identify the change output is to know how big the channel you opened was, find that one, then choose the other.

Cha-ching. It worked. And, living dangerously as usual the effective fee rate for the remainder to go to the channel ended up being .8 sats/vb higher than what Mempool is currently showing as high priority. And I am getting a divorce.

Now I just have to figure out how to get someone to open up a channel to me for some inbound liquidity I guess. Peace brother.

I think the best way is to find some one you know and trust, but there are lots of liquidity services out there if you do a search. Or you can go to Plebnets TG Telegram: Contact @plebnet But be selective. I have had some bad experiences with some peers.

Ok thanks. PS do the sats showing on both the Lightning side and On-chain side of my channel both count towards the available liquidity or is there a reason I should even have it weighted more to one side or the other? My goal of course is to just do a small scale test of having someone accept a payment for something and having it route through my node.

On-chain is not considered part of liquidity. Channel liquidity is either local (your spendable balance), or remote (your receivable balance).