My truck charging current to batterys, measured.

[kcmusa]

I have a pair of group 24 12v battery's (thats all that will fit in the space)
I ran them down to 80%, put a dc amp meter on the line and found my truck started at 25 amps charging current then settled to a 22 amp rate. Very happy with that rate to the battery's.

[CC75]

Wow, 22 amps down that tiny wire. I would expect around 5amps. I am surprised that your truck would be willing to push that much current to the trailer.

[kcmusa]

I was surprised also. Guess a plug for Chevy. Lol

[Skyliner]

I've seen as high as 40 amps charging while I tow but that was from the solar panels on the roof ;-)