Here's another thought, more geared towards the gentleman in .eu who was looking at running a bunch of 2 volt batteries in series, and home charging it.
I have done this in the past, and although it isn't the best method, since your going to use 2 volt batteries, you can still accomplish this and stay within the realm of 16 volts.
Take 2 of those 2 volt batteries and run them in series, creating 1X 4 volt cell.
Connect that in series, neg from the new bank to + on the car battery, and run your amp from the + side of the new battery bank. From vehicle ground to amplifier B+, you will see app 16 volts.
Now, the trick is here...
Take ONLY the B+ out from the ALTERNATOR (I always disconnect the vehicle CHARGE lead at the alternator, then run a dedicated lead from the alt to the battery stack), and connect it as well to the top of the battery stack (to the 16 volt side).
Since the cars electronics will all still see 12 volts, and the alternator will have to produce 18 volts to charge the 16 volt system, everything charges nicely.
I also think it is best to take and run a relay / solenoid setup to disconnect the extra 4 volt stack when not being used, to prevent overcharging. Usually 10 to 45 minutes of charging while driving around is sufficient. Just use a solenoid to disconnect the B+ from the alt to the top of the 16 volt stack to the + / - junction of the 12 and 4 volt batteries.
This works well in systems where you can't install a second alternator. Your car works fine, the amp works fine, everything charges nicely, BUT, you don't get something for nothing. Your alternator is usually running > manuf ratings, and you won't see rated Aout at 18 volts.... Expect about 20 percent less... Or even less efficiency. Still, makes it easy to run increased collector voltage cheaply.
--Toll_Free
