yes - the jump when turning on the lights shouldn't be more than just a jump, down and back, that's just the delay in the regulation reacting to the current draw change .... if it's acting a bit different since changing the alternator it's likely the regulator [internal] or alternator itself being a bit different .... a good auto electric shop [or maybe the store you bought the alt from] can check the system under all conditions to see if it's working properly, and maybe adjust it if necessary

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics