I've been hibernating from the RC hobby and inching my way back to the track.
I've got my SCT and buggy's tuned and almost ready. I have 3 trucks and 2 buggys (with shorty batteries) and misc rc's using lipo's with 4mm.
My trucks need new batteries which i was going to purchase SMC's

I am seeing that the new standard is 5mm.
Do i bite the '5mm bullet' and solder new bullets to charger balance board and trucks/buggys/car leads to 5mm?

If that is the case, what do i do with my old batteries?
Granted they are about 4 years old but holding up well.

If i need to convert are there any recommendations on which bullets to get?
I will be needing a min of 30.

Thanks

These are popular sellers for us, once they are on your ESC you can use either 4mm or 5mm terminal batteries:

HobbyStar 4mm to 5mm Low-Profile Bullet Connectors, 10pk | RCJuice

https://www.amainhobbies.com/protek-...tk-5005/p14566

I run these and don't have any issues. No need to solder anything.

I used 4mm to 5mm adapters that came with my Turnigy Graphene pack a little over a year ago and they worked great until one day I had intermittent issues with my ESC randomly shutting off. I had learned that my negative lead had become de-soldered over time so I re-soldered it and was good for about 5 min before the negative wire de-soldered itself again... which I re-soldered a second time and once again it became de-soldered. At that point I swapped out a fresh set of 5mm bullets and the pack ran fine the rest of the day. After closer inspection I could see that the 4mm to 5mm adapter had signs of oxidized corrosion on both sides of the adapter and it needed to be replaced. Unfortunately for me, the excess heat from the added resistance from the worn connector caused premature swelling of my pack and I decided to discard it.

If I were to use 4mm to 5mm adapters again in the future, I would probably get into the habit of replacing them every 6 months or so.

No need to replace that often...just clean them periodically with contact cleaner/motor spray. If they become loose fitting, spread them apart a little with exacto/knife.

the gold plated finish was scrapped away, the connectors definitely needed to be replaced, I foolishly didn't do a proper job inspecting them like I should've

Thanks for suggestions on the adapters but im thinking it may be best to succumb to change and just swap everything over 5mm. I just hope that when i finish they dont decide to go to something new like 5.5mm.

I think that's a good option. I tried the 4mm-5mm adapters and just didn't like having that extra connection and the fact that the plug would stick higher out of the battery than normal.

Agreed, im just not a fan of having something "extra" in the loop that may go wrong although im not a fan of soldering about 20 terminals on hot days but what are you going to do.

I had the same thing happen using the Protek adapters. I will try the cleaning with motor spray and see if that works. I might try the 5mm with the 4mm bullet as mentioned in another reply, that way I'm not constantly pulling the 4mm bullet out and wearing out the inside of an adapter. Or I'll use my 5mm batteries on one vehicle and the 4mm on my other vehicle.