what size battery do i need?

[TheBar]

Make sure you don't buy a less powerful battery like a 525 CCA for a big V10 engine. I buy 800+ CCA with bigger reserve capacity batteries for large engines. I'm sure some will disagree and provide a mathematical formula or theorem to disprove this, but IMO if it starts out with more amps it will have more amps after 5 years. Which may be why I have good luck with batteries lasting a long time. I also see the bigger batteries like an H7 have more power and therefore will last longer. If they fit.

Since maintenance free batteries came out in the 70's I have never had one fail before it was 7-8 years old. But I do live in a more temperate climate and I do start every vehicle and let it recharge at least once a month. In a car I don't drive often I just replaced a Walmart brand battery that was 12 years old. Last fall it held a steady 12.4 volts and worked fine. When the temperature was in the single digits last winter it wouldn't turn over. After charging it would only hold 11.9 volts after 24 hours. It was done.

There are only a few battery manufacturers in the USA but they are sold under dozens of different brand names. So a Walmart battery may be the exact same battery as an Interstate.

 

[Mark_K5LXP]

Totally agree with TheBar, as a rule when I replace a starting battery I put in the biggest one that will fit in the tray. Even my 4 banger ranger has the same battery one finds in a V8 F150. It works out that of the several sizes that fit, the prices are all the same or very close. I wouldn't replace a working battery to upgrade but for the same money there's no reason not to get the bigger battery with more CCA and maybe get a little extra service life out of it.

Mark B.
Albuquerque, NM

 

[CharlesinGA]

The old calicum-lead maintenance free battery pioneered by Delco was a miracle. Yes, they lasted for 7-9 years. Then Delphi took them over and something happened, I got a couple of bad ones one right after the other, and they became difficult to locate a supplier for them, and I switched to AGM batteries. The old Delco batteries were the "green eye" ones with a green lens and a ball floating in it to tell you if it was charged. When I bought my 2003 RAM 2500 in March of 2018, it still had the original Damiler-Chrysler labeled batteries with 12/02 date code stickers on them. Hesitated cranking but it started. They were the Delco green eye batteries with a label over the "eye". I replaced them with a pair of Bosch AGM batteries, just now 6 years old. Somebody always had AGM batteries on sale, 25% off, but now you cannot find any sales on them at all. When I bought the Bosch's, Pep Boys had them on sale, thats why I ended up with them.

Charles

 

[Gary RV_Wizard]

Read "Good" v/s cheap batteries. .. I usually judge based on the warranty. But I do admit that's an assumption A battery warranted for 5 years is better than a 90 day type thinking

However I do admit I've gotten a lemon that way (It was, however, replaced under warranty and the replacement lasted several years)

Typically the battery with a longer warranty simply has the price increased to cover the cost of additional warranty replacements. A premium-price battery may have a more rugged case and internal structure, but the amount of lead and acid needed to produce a given amount of power is the same.

AGM batteries are more complex to produce than flooded cells, so they cost more. Whether they are "better" or not depends on how you measure value.

 

[Isaac-1]

I would tend to say that AGM's are better if you value reliability over bang for the buck.

 

[John From Detroit]

AGM batteries are more complex to produce than flooded cells, so they cost more. Whether they are "better" or not depends on how you measure value.

I agree with you on that... As for the rest.. I've never done an actual study so I can not be sure Never cut them open to see if perhaps but your words make sense To make a specific battery you need anode cathode and electrolytic with lead acid there are limits to the choices.. BUT the quality of all three may vary with the battery (More purity one would think lasts longer) and the lead is not pure but is an alloy... How well that's done may also make a difference.

But the amount of each in the case should be fairly constant from cheap to most expensive.

Still the one that died a week after it was put in... Well It had a LIFETIME warranty.. Don't get much longer than that. The 2nd replacement had a 5 year extended due to they no longer offered the lifetime (Wonder why) and that one lasted.. the life of the car. Car was about a year old when I put the first Lifetime in it.

 

[ennored]

What does your owner's manual say?

From a 2001 E350 manual: