Here is the layout-

258A alt regulated at 14.95v wired directly to factory starting battery.

Wire comes off of the starting battery and goes to the rear through solenoid then to 3 batts in the rear.

When the stereo system is ran at full tilt for about 2 minutes straight, at one time recently i got a rotten egg smell that came from inside the engine bay but only under high amperage demands.

Local Auto Zone fears that since the alt is ran to the starting battery first before it reaches the rear batts and amps is that it may be overcharging the starting battery.

We felt the terminals onthe starting batery and they were scorching hot.

So... for those who have setup high powered electrical systems before....

Is it ok if i run 1 cable from the alt to the starting battery then another cable off the same point from the alt to the rear battery bank?

If the amps pull excessive current, the alt should disperse that current only through the wire that is running to the rear right?

Does that sound like what i have to do?

i have mine from the alt to the front cell... then to the rear just like you have yours. i have never had that problem. on any of my cars.

well, i know i'm outputting more current than you are alternator-wise...

Even though i cant prove the smell came from the batt, i do know that the terminals were scorching hot and that leads me to believe probable cause of excessive current.

They told me that even if the batt is 100% charged, it can still be overcharged.

I thought overcharged was just too high of voltage but they're telling me it can\is overcharg(ed\ing) from excessive current as well.

I really need to find out for sure if thats what is goin on but all the shops are closed til monday. I gotta be bassless for a couple days to prevent possible battery failure.

perhaps you can run one wire off the alt for each cell you have.... but eitherway its still gonna over charge the one cell if the other two are low...

i thought this is why it was best to have all cells wired togather so that it sees one large cell in a way.. not three diffrent ones....

but your right you have a problem on your hands...

are all the batterys the same type. possible diffrent type battery under hood could be causing problem.

they are all AGM.

the 3 in the rear are all XS power batts. The bat up front is factory agm battery.

ALL 4 batts float at 13.0 with car off.

There is a solenoid in the rear which isolates the front batt from the rear.

dump that solenoid and try it.... thats where i had problems but mine was an issolator.

All are being charged off the same alt, so the starting battery should not be getting overcharged. If it is, then the other three are as well. That won't happen unless your regulator is bad either.

Rotten egg smell would be attributed to fuel. How is your vehicle running? Getting less mileage lately? I am suspecting a leaky exhaust system and an over-rich condition causing the smell.

I`m almost 99% sure that that smell is of hydrogen sulfide due to the battery being overcharged. If you battery is as hot as you say it is that means it`s a couple minutes from popping in your face. Not to mention the gases a battery emits can be fatal if you inhale them too much. I know this cause I was in mechanic school and I`ve seen plenty of battery`s blow up cause of irresponsible students that leave the chargers on high and forget about them...the car hood looked like a tent after the battery exploded.