TrueGS300

I am getting back into my GS build after a long break. Unfortunately my battery is toast and won't take a charge. I have relocated mine to the trunk and always felt that the crank was too weak, and also due to my build/tune it takes a bit of cranking to get the engine fired up. I was always dealing with a weak or insufficient crank even with a new battery. I am considering putting the highest cca battery I can find in, or maybe even dual batteries for the capacity to crank for a long time, or if the car sits for a while. I was running a Deka Intimidator AGM 850cca and it was not as sufficient as I hoped. I am thinking two Optima "yellow tops" for their deep cycle and high cca. I have a high amp DC alternator installed too, so plenty of power to keep the system charged.
I hate the idea of the weight of two batteries, but at least they will be over the rear wheels. And with a 800hp goal I probably don't need to worry as much about weight as I have in the past with most my builds anyways. Looking for suggestions or ideas of how to best upgrade my cranking power. Any reason the car would not like dual batteries? Or is there a good single battery that is up to snuff? I am running huge 0 gauge wires. So I don't feel like it's lacking in other ways. I may also benefit form a upgraded reduction starter if they make them for this car. Ideas welcome.

dwoods801

I also relocated my battery to the trunk. You have to remember that with DC, direct current, you lose amperage thru the cables, that’s why it feels weak. One the main reasons I wanted to relocate my battery was specifically so I can use a larger battery to increase the power for my stereo. So you want use the largest battery possible, either budget wise or whatever will fit in your mounting location? Any car that came with the battery in the trunk, like all Mercedes and BMW, use a Group H, you can get an H5, H6, H7, H8 and H9. I am running an H9, it’s rated at 900CCA, about the maximum output possible on a 12V battery. That’s what comes in all full-size German sedans. But its actually than a stock GS needs, you could probably go with an H7. It’s highly recommended that you get an AGM Battery, they won’t splash with battery acid if you ever get rear ended or something and bad luck makes it a nightmare. Also all H Series batteries have are built with a breather port so you can vent outside of the trunk which will help avoid some other possible issues like fumes building up in the car while you’re driving