Worth a rebuilt hybrid battery?

I'm in a pickle.
Prius 2005 with nearly 400,000 km (~250,000 miles)
Second time I get the infamous red triangle. Four years ago I got code P0A80 and changed the hybrid battery myself (after reading lots on PriusChat ... thank you!). All fixed.
Last week an independent vendor told me he had a spare hybrid battery so I drove 60 km (~40 miles) to be told he didn't have one (geez ....).
He read the codes and told me this :
P3000, cell #8 is bad. There was errors for the ABS brakes and ECUs but he didn't give them to me. He reset the error codes.
At that moment my car started to have "hiccups". It tries to charge the hybrid battery for 1-2 seconds and then stops. The vendor told me it's the first time he's seen this.

At that point I disconnected the (small, 12v) battery for 10 minutes to reset the system hoping the hiccups would stop. Didn't help.

Since the vendor didn't have a replacement hybrid battery I drove back home. Fan on the batteries was on all the time until the car just stopped charging the hybrid battery. Nearly all the 60 kms back were without battery assistance. I live way up so I had to do some "sporty" driving.

The car's pretty rusty and I dont have enough money to afford a more recent one (and the prices are just ridiculous anyways).

So the question is : do you think changing the hybrid battery is a waste of money?
Now I don't have a properly working car so I'm kinda backed into a corner.

I've ordered an ODBII reader so I'll update this article with more info when I get some.

I'm pretty good around computers so last time I changed the Hybrid battery it was a cinch. Hopefully this time it's as easy although that bad luck with that vendor didn't help.

 

TLR : It was a swap from a Prius with a dead display, was told it was the original battery.

Long form : First time I had the red triangle of death I was lucky. My neighbor had an identical Prius but it's display electronics was dead (no display whatsoever yet the car worked). The good news was that the hybrid battery was fine (it was made in the Philippines and was never replaced if that makes any difference). Bought the car for 500$ C (a deal!). Wound up swapping the battery by myself.
I don't know what the KM on that battery was since the car's display was shot.
What I know is that when I put the battery in, my car I was at ~280,000 km. I'm now at ~400,000 km.
A pretty good deal.
BTW, I wound up exchanging my neighbor's Prius (with my old battery) for four cords of wood. Worth about 400$ C
I can't complain

Now you tell me new batteries are in great shortage. I'm guessing from my experience, rebuilt are also rare. I have little to no interest in combining two batteries to make a good one since I don't have the equipment to balance the batteries out (and test things out proper).

The mechanical parts of the car are working A1 except for the check engine light. Also the 12v battery is, at rest, is a teeny bit below specs.

For the rest, the car feels like it's 17 yo LOL

 

Thank you so much for your reply!
Buying an individual module was part of my possible scenarios.
That's assuming there's no more gremlins lurking around P3000 could mean a broken ICU or - I'm thinking - corroded battery harnesses
Do you know if I need any special equipment to change the module or is a regular battery tester good enough to test the other modules?

 

Note : The first time I replaced the hybrid battery, all the bolts holding the battery together had corrosion on them. Cleaning the didn't seem to help.

 

Thanks for the info. Makes perfect sense. I'm getting my ODB2 scanner any minute now and I'll know more about the codes (I'll post them here).
A local used hybrid battery vendor told me he believes all the codes are caused by my bad battery module.
Apart from a check engine light everything else was perfect before (well apart from the part where the car is turning into a rust bucket LOL).

 

Been there, done that! So far, cars don't run away fearing for their demise when I try to get in so I'm good.

 

I'm waiting for a replacement hybrid battery as we speak.
I've got a quote for a replacement module for #8 that's apparently shot in my case.
I've taken the whole battery apart before (not the one I have now but the previous one) and I've got a multimeter so in theory I'm good to go if I can't find a rebuilt hybrid battery.
I had a RC Model battery charger four years ago but I lent it and the person broke it.
Note: Last time I took a hybrid battery apart, there was a lot of deposits on the connectors on the side of the battery modules. Where we live there's a lot of humidity (but it's not sea water, thank god).
UPDATE
Got my ODBII reader, works fine but there was no codes; had to unplug the 12v battery when I went to the battery vendor this week, the car was acting weird trying to recharge the hybrid battery. Good news : no new codes since.
My car however still has a red triangle and has the ABS light on.
Intuition tells me changing the hybrid battery will fix the issue although it's bad news if there's shortages on that front.