the wait to start is just due to the amount of power the grid heater draws. the reason your voltage and check engine light are on is because the grid heater still cycles till your temp gets up there enough. I don't remember where the temp is pulled or what temp is used. I currently run 2 yellow tops and they work great. I ran Dekka's but they vent so bad it made a huge mess. NHRDA had a coupon in their membership package and I got both batteries for $204 shipped to me so if you know anyone that joined but didn't buy batteries now is a good time to ask.

 

My batteries died in my truck on my pops last week on a cold morning in VA and he was able to jump it at get down to the local interstate battery dealer 2 batteries taxes and all out the door 130 for 2 new batteries... That beats just about every parts store in town from what pop says by around 50 bucks... Just a heads up sorry I don't have any more details about the batteries but I'm deployed and thats all the info I have from pop... Hope this helps you save some money...

 

To the best of my knowledge, Optima does not make a battery with CCA that high. Matter of fact, Optima's actually have a lower CCA's than regular cell batteries. Their CA's are decent but we're all caring about the CCA's, not the CA's. Optima's just have a great reputation for reliability in harsh jarring situations because of the gell cells where lead/water cells can break. Plus Optima's can be mounted in any position for certain applications.

You DO NOT need a deep cycle battery. Deep cycle batteries have solid cells with low cranking amps but those solid cells can be drained and recharged many times over without much cell deterioration. Automotive batteries have a grid type cell that disperses energy much more quickly so cranking amps are higher but draining them will cause the girds to deteriorate and fall apart. A couple discharges can destroy an automotive battery. Marine batteries are a cross between the two. Marine batteries have a cell design that is a combination of automotive type and deep cell type so that they retain some of the CA's but still have the ability to discharge more often without failure. The amount of time it takes to discharge a deep cell and marine battery is called reserve time. Reserve time is important to RVers and people who run accessories in their vehicles while the engine isn't running. The longer the reserve, the longer you can run accessories without fully draining the battery. Reserves are also determined by amp's per reserve time. This is obviously how much amperage the battery will maintain during the reserve time.

The reason you want batteries in top condition in the Cummins is because when the grids do cycle before startup, they draw a tremendous amount of energy. If both girds are running, they can pull up to 180 amps, and over a couple thousand watts. And also, after the engine does start, the grids will continue to cycle pulling more energy than the alternator can sustain so the batteries will be further depleted until the grids stop or you go faster than 17-20 mph. Matter of fact, the colder the outside temps, the longer the grid heater will cycle pre-startup. So one thing to be careful of is if you live in an area that gets around 0* or less then its advised to let the engine run for a decent period after starting so that the charging system has a chance to recoup the battery level otherwise if you do to many engine on/off short trips then the battery level will not have a chance to build back up and eventually fatigue the batteries.

 

I have been doing the duralast gold thing for3 years and every year running the grid heater(wait to start) destroys my batteries but I just bring them back I was getting sick of the batteries always going dead... so I disconnected the electrical connections to the grid heater it starts 1000 times better even in the cold. Having more power n a faster crank speed lights it right off. Just telling my findings.... disconnect your grid heater n if your engine is not trashed it will start much better!

 

I didn't see anyone answer your question about your voltage fluctuation. It is perfectly normal, the fluctuation is caused by the heater grid cycling on and off in cold weather. It draws a good bit of juice from the batteries.

 

I just bought two new batteries myself yesterday I bought 850 cca ac delco batteries because I'm a gm mechanic and it was just easy to get them from work they have a 4 year warranty on them they were reasonably priced I paid 100 a piece for them optimas don't have a great warranty on them and are also with my discount trough work were 170 bucks a pop and the voltage deal I agree with bowling its normal and if your batteries are weak your gonna notice a higher drop in cold weather