Howdy
What type/brand of batteries are using?
DEFFINENTLY replace all your cables with either welding cable or high quality LARGE battery cable. Use industrial crimp connectors and lugs. They require a special tool, but most electrical shops have one and if you get all your cables cut and ready they can crimp on the connectors. Make sure you can seal the connectors as well.
In the USMC we found that the life of the batteries was increased by using a de-sulfication battery charger about every 4-6 months. Just hook it up and let it run the cycle for 24hr. It really seemed to help. Especially with the standard lead acid plate type of battery.
Depending on the environment that your batteries see, 4-5 years might be all you get. I typically replace mine at 5 years and move the old batteries to a less demanding job.
I have been using carquest AGM type in all my rigs for about 5 years and been very happy. I have also been very happy with Optima Red Top.
IMHO- stay with the two battery system. If you have good cables/connections, it will work fine.
Hope this helps....
1996 Chvy 3500 CCDWLB 6.5 Heathed, NO vac, marine injctrs, ARB bumper, BIG pipe, 3" lift, bright lights, bypass oil system.
1986 Chvy 6.2 M1009 blazer RAM AIR, Headers, Custom interior
2001 Chinook RV, V10 gas
1974 John Deere 1530 diesel tractor
1993 John Deere 455 Diesel lawn mower
1967 GTO, 1989 Honda Transalp
2009 VW Jetta TDI, flashed and piped, 6speed, fun car!
1998 6.5 suburban, stock, daughter's
1993 6.5 3500 CCSWLB GM8, Heathed, big exhaust, gauges, Son's
1984 6.2 ATS turbo 3500, SCDWLB - Son's
3 kids, 1 wife, 1 dog
Gunsmith, Tactics Instructor, Fabricator USMC 87-93 Semper Fi!