Because someone emailed me to ask about how I was getting along with having
330 AH golf cart wetcells paralleled with the red AGM starting batteries in
my stepvan's diesel V-8 I thought I'd answer to the newsgroup, too, with my
personal experience.

Since November of 2002, I have had two 6V 330AH golf cart batteries
powering my work bench and a 500W Tripplite inverter in my 1998 Union City
Body/Chevy stepvan. The van came with two paralleled AGM starting
batteries, brand new complements of the taxpayers from its former owner,
the USAF. To separate the batteries when the van is parked for long
periods, while allowing me to crank the diesel if these odd batteries
failed, I added a simple 350A single-pole on-off switch from Guest?...it's
a boat battery switch.

For a while, every time I started the truck, I'd switch the switch to on
after the truck started and switch the switch off when I stopped the truck
engine because of all the scaremongering about parallelling AGM and wet
batteries I'd read and heard from all over. After a while, after I'd
forgotten to switch the switch and nothing untoward happened (no blast,
fire, dead batteries, molten cabling, etc.) many times, I opened the switch
one day and put a DC ammeter across the switch so I could see all this
dastardly current that would flow from AGM super batteries to my trusty old
wetcells with the big, thick plates. Curiously, the ammeter read zero. I
couldn't get any cross-battery current until I got down to the 29.99
MILLIAMP range when I measured a tiny 18ma flowing from the nasty old golf
cart batteries actually CHARGING the supercells, against everything that's
Holy!

Well, the switch is ON, tonight, just like it is every night, now. Nothing
melted. All the batteries are still perfect. I'd switch it off if I were
going away for a few days to months, just for safety. But, against all the
hype and bull****, paralleled, they are just fine....(c;

Your reporter in the kevlar vest,
Larry