Thread: Main battery recommendations

Hello, been lurking here for a wile, excellent site, good info, did a search and did not find anything on this but maybe I did not know what to look for

I am going to build a carputer in the near future I have no specifics yet except I am hoping to use a DC to DC power supply, taking DC source to AC and then back to DC for the carputer sounds inefficient to me as there are losses at each step but DC>DC does not allow for much of a drop in source voltage

I am lucky that the victim auto can hold 2 full size batteries under the hood, I want to have one solely for starting, and one aux battery to safely provide power to the carputer & audio equip wile the engine if off and during crank.

I understand that NiCad’s have a flat discharge curve, in that the voltage does not start to drop off until the near the end of the battery’s charge, this sounds useful for a carputer where it is trying to regulate 12v from a 12v source, but as I understand NiCad’s would not be appropriate in an auto environment, they should not be charged by constant voltage like a alternator puts out, have memory problems if not fully discharged, are expensive, ect ect

Main question: Are there differences between the available lead acid batteries that would give one a higher percentage of it’s AH at sufficient voltage to run a carputer? That would have a flatter discharge curve than other lead acid batteries?

Right now I am looking at Hawker Odyssey 1200 or 1700, they are expensive but if they will do better at this task that would be ok with me. the other features of these batteries are nice but not really needed for this app, if not I will just use a quality liquid type deep cycle

I am also trying to find out witch batteries have the best AH that will fit in my vehicle as this should allow for longer run times but I am having a hard time finding full specs for specific batteries, many companies just have marketing BS on their websites no real specifications