Hello Russ,Well, no one else has replied to your question, so I'll give it a try.
I know a little about Russco chargers.
So you're charging a 126 volt pack?
Are you aware your SC24-120 charger is for charging 132 and 144 packs ONLY? Read your manual.
Operating this charger into a 126 volt pack will over-current the charger. Your 11 amp output verifies this.
No wonder you're having problems! The charger has been mis-applied.
You can't blame the charger for that.
Almost miraculous that I appear to have found you here. Would love to get in touch with you. I joined this site to see if I could reach you here so hopefully it works. Hope all is well and I hope to hear from you.