Battery power

1,000 cold cranking amps is way more than necessary for your van. That would be a typical battery for starting a diesel engine on a cold day. Your starter motor draws around 250 amps to get started, and once it is spinning, that drops to as low as 100 amps. That is all that will be drawn from the battery, regardless of how much current it is capable of supplying.

As all batteries age, the lead flakes off the plates, and that reduces how long it can crank the engine, or run the radio with the engine off. You will not get longer life from a battery that starts out with a higher cold cranking amp rating. Imagine if you placed an ice cube on the sidewalk on a hot summer day, and it melted in five minutes. Buying a larger battery is like putting two ice cubes on the sidewalk. You will still have only water in five minutes, not ten minutes.

Also be aware that the lead that flakes off the plates collects in the bottom of the case. When that builds up high enough, it shorts that cell, then the battery must be replaced. To get that really high cold cranking amps, the manufacturer has to put in more plates in each cell, or larger plates. That reduces the amount of room for that debris to collect, so that battery could fail sooner. This is why truck batteries often only have a three-year warranty instead of a five-year warranty. The added vibration helps that lead flake off faster, so the manufacturer knows it is going to fail sooner.

Batteries seems to be one place where the car manufacturers do not "cheap-out" and put in the cheapest battery they can find. My 1980 Volare came with a puny 325 CCA battery that cranked the engine just fine. It lasted for five years, and I only replaced it because that is the typical life expectancy for a battery. My 2014 Ram truck came with a substantial 850 CCA battery. I let it freeze last winter from lack of driving the truck. Replaced it with a smaller "reconditioned" 750 CCA battery that will run my laptop and power inverter for over two hours, then still start the engine.

What might be more important to you is the "reserve capacity". That refers to the number of minutes it can supply a specified amount of current. That, along with the CCA rating, are good numbers to use when comparing batteries to each other.

Unless you have some unusual need for such a huge battery, it does not make good economic sense to buy more than you need. You will not get a faster cranking speed or longer battery life. What you might get is the ability to crank the engine for many more minutes, but the days of flooded and cold carbureted engines is long gone. Since the early 1990's, no engine I am aware of takes more than a few seconds of cranking to start unless there is some other problem.

Here are links to some related articles that might give you more information:

https://www.2carpros.com/articles/car-battery-load-test

https://www.2carpros.com/articles/how-to-replace-a-car-battery

No. You would be wasting your money by buying more battery than you will ever need or use. You would not buy two batteries to do the job of one.

Vans like ours typically call for about a 550 to 650 CCA. If it makes you feel better, it's common now to find 750 and even 800 - 825 CCA replacement batteries. For the average customer, the higher numbers provide the illusion that "more is better" in some way. What I would do is look at the CCA rating of the original battery, then buy a replacement that's the same size, plus or minus around 100 CCA. Slightly smaller will do the job just fine, and slightly larger will not cost too much more money.

Remember, there is always a trade-off to fit everything into a package that fits under the hood. The trade-off for a significantly larger CCA rating is a shorter life expectancy and a shorter reserve capacity.