Dual battery
 

How many early first gen. guys have put dual batteries in their 12 valve? My 89 only has one, not sure how will start when it10 degrees outside.

I'm just guessing, since my 89 also has only one battery, that with the gear down starter and the grid heaters along with the block heater that you won't have any problems at 10 deg. F. I never did when I lived in KS. My truck always lit on the first cylinder to turn over. Still does here in balmy SoCal FWIW.

Edwin

10 degrees is too cold for human habitation. Although the truck may start I don't think you would be able to get me to start at 10 degrees. I would move to where it's warmer. [laugh]

If the battery is in good shape and the right size [not a car battery] it will start fine.

No need for two honestly, just make sure you run a deep cycle battery and make sure it's marine grade. Many times we have guys cranking the crap out the the cummins 12 valvers until the leads get hot or melt. They kill the starting battery because the engine was sitting in -25F weather with a major wind chill.

Deep cycle is made for powering things up which you want when you need to hit the grid heaters/glow plugs a few times. We ended up replacing all of our starting batteries with deep cycle, they just don't die.

Still with one battery on each of my cummins trucks. Less trouble from them than any other diesel I've had that came with 2 batts from the factory.

And less batteries to buy ;)

I have 2 in mine, but the second one is to run the winch and a power inverter. They are isolated from each other and the starting battery system is unchanged. It starts real nice on the frigid 40 degree winter mornings here in Phoenix...Mark

This was my experience also. I would say that running synthetic 5w40 does much more for cold weather starting than a second battery. I also have had bad experiences with parallel battery systems in heavy trucks/equipment. Batteries in parallel just haven't lasted very long for me.

If you want it to spin real fast for a second or two, hook them up in series and jamb 24 volts into it, that should be quite a show...Mark

Between the extra connections/cables to compromise, and one dying battery straining/killing the other... I've found this tendency also.

Used to work on old Kenworth trucks, they had a series parallel switch on the starting syst. 24V starting then kicks back to 12 volt syst. for all else.

Thank you ALL for the info. One big one it is! Odyssey AGM battery maybe, steep $299.00 price though

The Only Reason the Second gen's have 2 batteries are they have More Computer Junk to run. So 1 run's the Junk the Other start's the engine .These truck's were designed to start fine in cold weather when plugged in .Doesn't mean you can't run to Batteries but IMO no need for Over Kill unless you run a really good system and want some Extra boost .

I've had 2 1st gens. 1 with a single battery and 1 with duals. Neither gave me trouble starting in the cold. By cold I mean 0*F or colder (+10* is t-shirt weather). I've fired up a 1st gen at -45*F without it being plugged in after a 12 hr shift when the breaker blew on the outlet at work.

The biggest thing that helps in cold weather starting is a TIGHT fuel system. A LP piston lift pump is a nice addition too as it helps push the cold/thick fuel through the filters better.

Same here but at -35. As long as it had been driven within 12 hours it never hesitated to start without being plugged in at those temps.