voltage drop after battery isolator

If the voltage on the wire is only 6.8, that means whatever you are using to power that wire, can not handle the current demands of the coil.  You need to not turn it on again.  Find a new power source to trigger the pac-200

Agreed. As I wrote before, disconnect the present 6.8V to the PAC-200 and jumper the +126V from the main battery (ie, its heavy contact). If that does not energise the PAC200 & connect its heavy terminals, then it is faulty. (Assuming the PAC2-- ground and battery grounds are the same.) The voltage of the second battery has no relevance (other than the spark/explosion risk I wrote before if it is that flat). Even if it is a voltage sensing isolator, they usually only sense the main/primary battery voltage. Very few sense the secondary battery voltage - that is usually only done when the user wants to charge the secondary battery from another charger and hence also charge the primary battery (thru the isolator). And if it is simply a PAC-200, I wonder why anyone would suspect it isn't a PAC-200? And if it is a PAC200, the charging has nothing to do with it. It simply needs 12V (or 10V whatever) to energise it. If your alternator cannot maintain its output at reasonable RPM, then you may have a undersized alternator (or the dc-dc converter from the Prius main battery - ie, the x00V bank). But I see nothing that suggests that.

ok i got my batttery back but it has been raining all day so i havent been able to put it in. but from the recent posts im understanding that getting it charged doesnt matter. so hopefully tomoro is nice so i can put the battery in then run jump a wire from the main 12v to the acc slot on the isolator. hopefully that works, i too think thats what the problem is. i will update once i do that. then my new task will be to find a 12v switched that i can tap into to run to the isolator. thanks for all the help

Or have that audio-on power a smaller relay that supplies 12V to the PAC-200. That's if it is simply the PAC-200 taking too much current from the original switch/control. Normally battery isolators are powered from the charge lamp (as per the UIBI) else smart, intelligent, voltage sensing etc battery isolators if you don't have a charge light or similar circuit available. When isolators are controlled by ignition switches (IGN or ACC) or HUs & amps, the risk is forgetting to turn them off....

ok sorry between work and the rain i havent got a chance before now to test it. so i ran a wire from the + terminal on the main battery to the acc terminal on the pac200 and turned the car on. i got over 13v on both terminals(big terminals) of the isolator. so that acc wire is the problem. i tested it at the jl amp as well and the amp seems to run fine even know the remote wire is only 6.8v. but now i need to find a new 12v switched that is actually 12v to run to my jl amp and the isolator. it started raining again while i was testing everythign so i guess i shall try to find a better 12v switched another day. right now the remote is off the 12v switched from the factory jbl amp. im guna try to find a 12v switched in the trunk so that i dont have to go tearing apart my dash and running the wire etc.

ok update****** so the rain was off and on so i took a chance to get this done. the remote wire that tapped into my factory amp an went to my amp and isolator...... i disconnected it from the factory amp wire and extended it an ran it to the 12v socket in the center counsel(which is switched). after testing the connector i then connected the remote wire to the switched wire on the socket. i turned the car on and everythign at the isolator was perfect and everythign works great. Thank you guys soo much! :)