Please explain this no crank no start

Question

hyundai coupe 2l 2006.

Car was idle for a while then sent for a service and in addition to service garage said battery was drained so they changed it.

After taking the car back I noticed the car would constantly not start(no crank or start) though when I used a battery jump starter it would then crank and start. Eventually I noticed the negative terminal on the battery was too small for the clamp and the connections were really loose, you could easily turn it back and forward, so it seemed like the battery was never recharging properly hence all the no crank no start except with the jump starter.

Garage then put a bolt in between the terminal and clamp and i drove it for the day and it seemed to be ok. However I then left car parked up for a few months after which it was a no crank no start again. At this point i thought maybe i just should have got a battery with terminals that fit and the loose connection and screwdriver workaround was the reason the battery kept draining.

Today I bought a correct fitting battery. While installing it I was stupid enough to connect the positive battery terminal to the negative cable and saw a spark and even a little clear water on battery which I wiped away. Completed battery installation correctly but now I was still getting a no crank or start but repeat key turns it would get it to start. Everytime i switched ignition off I would have to repeat key turns to get it on. however by end of today it wasnt starting at all regardless of repeat turns.

At this point I checked the battery with multimeter it seemed to be fine. When turning the key I noticed strong clicking sound in fuse box and switched main and start relays at which point i was now getting a crank but no start. So seems the main relay was gone and having replaced it all is fine now.

1. Does it sound like that main relay was bad all along and was the cause of all the no crank and no starts? If so why did using the jump starter get the car to run on those occasions?

2. When I installed the new battery as I said I connected the postive terminal to negative car cable, saw sparks and water coming out. Would this have caused the main relay to get damaged and so everything prior would have been due to the loose connection and bolt set up?

Just wondering if I damaged the main relay with my poor installation or do these symptoms suggest it was bad all along and I never needed a new battery?

3. the car runs fine after changing the main relay but as i saw sparks and a little water should i be concerned the battery is damaged in any way or is that very unlikely?

Thanks

Answer 1

Does it sound like that main relay was bad all along and was the cause of all the no crank and no starts? If so why did using the jump starter get the car to run on those occasions?

No. It sounds like you had a loose connection at the battery post, which sometimes would not allow you to crank the engine. Once the battery pack (or starter pack or whatever you were using) was attached, you had good power and the car could start.

When I installed the new battery as I said I connected the postive terminal to negative car cable, saw sparks and water coming out. Would this have caused the main relay to get damaged and so everything prior would have been due to the loose connection and bolt set up?

Yes. Absolutely.

the car runs fine after changing the main relay but as i saw sparks and a little water should i be concerned the battery is damaged in any way or is that very unlikely?

More than likely you didn't do the battery or your car any favors. I'd suggest if it is running and charging fine now, you escaped the wrath of the battery gods. Your car & battery live on.