This was talked about previously, but I wanted to add a little twist to it. What if (which I have done) crimped the wire already, would using solder be legal/make a better connection, OR would electrical tape over the crimp make a better connection?
Soldering an already crimped wire isn’t necessary, but it could add to the integrity of the connection. I do not know if it is legal or not. Electrical tape would not give you a better electrical connection, because it is not a conductor. Overall, the connection would be better being covered because it would have less of a chance of shorting out. Hopefully someone else can add to this to make it a more complete answer.
Any half decent inspector will make you tape exposed wire/connectors before they pass you.
Do yourself a favor and do it before the wire is on the robot where you can’t reach it to tape it
The EE who works with my team always has us put a little solder on the tip of the wire sticking out of the top of the lug we crimped.
Just a thought:
Electrical tape may be easier to handle and quicker to apply, but in the long run, I prefer heatshrink tubing - none of that sticky black residue or anything.
Sparks
This year, on our team we are making it mandatory that all wires be soldered to the terminals ( yes, ALL connectors) But since you cant get good access on the female spade terminals, we will use uninsulated ones and put heatshrink all the way down the connector.
For the past two years, we have had wiring trouble be it victors melting down, or battery terminals that weren’t crimped, just taped ( yes just taped :ahh: ) that will not happen this year.
We even purchased a 100/140 W soldering gun and a 40w soldering station, so no excuses for them this year. I might solder the battery lugs on with a propane torch myself though. 
The best thing to do is crimp the terminals, fill them with a little solder, and heat shrink the wire. It looks really neat.
Steve,
Soldering is legal. A correctly crimped connector when properly done makes an excellent connection, auto makers do it all the time. But when you are not sure of the crimp, soldering will give you extra confidance and slightly better resistance in the crimp area. Always follow up with a bare electrical connection with heatshrink or tape. If you need to open the connection then use tape. Tape over the crimp cannot provide enough extra pressure to tighten up the crimp so it does nothing but insulate the connection.
a correctly crimped wire does not need to be soldered. in fact in military work soldering the connectors is prohibited.
Thanks Al and everyone for the advice, just wanted to check to see if the soldering was legal or not, after a crimp is already in place and got my answer so thank you!
Anytime!