You you have a place that recycles batteries you could just take it to them and drop it off. Otherwise you need to wire up some kind of load to the main battery wires. I use a small 30mm fan and an LED w/a resistor. You can use an automotive light bulb also as others have mentioned. Anything that will get the pack down to 2V or less. Those light bulbs get very hot just FYI.
Once they puff its time to get rid of them. They may work for awhile like that but they become more of a fire hazard and without even knowing the history of this one Id ditch it.
If you're discharging it to get rid of it you dont worry about the balance plug. Just discharge it via the main batt leads. It doesn't need to be even.
THIS is the cheapest lipo charger Id recommend to anyone.
Yes, you can bind the new receiver to the transmitter.
If you're using a 5000mAh or larger battery then anything 30C or higher will be fine for this application.
This lipos are stupidly expensive especially for no name brand batts. I would not buy these. Id look for something off of Hobbyking or Amazon. Turnigy, Zippy, Zeee, Hoovo, HRB, POW Power, etc. If you find something on one of those two websites thats not one of these post it up here and we can give ya an opinion on it.
https://northeastmodelcentre.co.uk/...shop-only/lipo/voltz-5000-mah-7-4v-lipo-pack/
None of these ESCs are suitable.
Just FYI, The nominal voltage for a lipo is 3.7V/C so if a lipo doesn't say 2S specifically on it it will say what the voltage is. So a 7.4V lipo is a 2S. 3S would be 11.1V, 4S would be 14.8V and so on.
This ESC is about the same spec and quality as the one that was in it. Will it work? Probably but
THIS is a waaaaaay better ESC. Granted its twice the price but its five times better than the other ESC.
Something else to take in to consideration. If you do end up getting deeper into electrics you're probably gonna want a
Programming box for your ESC to make it way easier to program. Well if you stick with the same manufacturer of ESC then you'll only need one programming box. Hobbywing is a known good budget brand.
Just do what ya can when ya can. I understand that nitro is your main thing and you dont want to spend a lot of electric not knowing if youll like it or not but theres certain lines you dont really want to dip under imo. Worst case scenario put it on the back burner and buy one piece at a time until you have everything to start the project. Most nitro guys end up loving electrics as well as nitros so you probably end up liking both.
As for the existing ESC, plug the battery in to it and see if it will even turn on. If you get leds flashing then you could try replacing the melted wires and connector and give it a shot. Worst case scenario you fry a £12 receiver but thats a third of the price of a 120A hobbywing ESC so thats all on you my man. Theres no way to know what will happen.