650cca vs 850cca group 65 battery

Daniel McCurdy

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So my batteries are just shot it starts fine when its warm outside but if it drops below 40 the batteries drop to around 12.3-12.4 volt and have no power. The cheaper batteries are only 650cca would 2 of these work good to get the big 7.3 cranking fast enough to start or should i pay the extra and get the 850cca batteries, all group 65.
 

ROCK HARVEY

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I bought the 750cca everstart plus at Walmart, and they crank my engine over fast. I also replaced/upgraded the starter at the same time though. Unless your batteries are old, I would test for voltage drop at the starter before you replace the batteries. Your batteries might be fine, but your cables might not be letting them get full power to the starter.
 

Daniel McCurdy

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With the cables disconected the batteries at the post are only reading 12.3 volts. The batteries are around 3 years old
 

Daniel McCurdy

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main problem is im very limited on money right now so the 60$ walmart value battery is looking very good but it only has 650cca
 

Booyah45828

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Then buy what you can.

FWIW, I know of guys that buy and use batteries from the junkyard. They typically get them for 20 bucks. If you can get a good pair of them from something that was wrecked, you might be better off there then spending over 120 at walmart.
 

Brian VT

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Another option is if you have an Interstate Battery store near you.
Ask for a "blemish". They usually keep them in the back. They have no label on them and are cheaper than the "normal" ones but the ones I've bought are all still in use (and it's been quite a while since I bought any).
 

captain720

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So will 2 of the 650cca batteries will spin it over plenty fast enough, thats the main question here.
If it’s over 32 degrees all the time than you should be able to barely get away with that. If you see the teens regularly you will have to have 750s or better and once it hits the negatives your really going to need some batteries. It comes down to where you live more than anything.
 

Daniel McCurdy

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theres been a few times in just the past few weeks it was around 0-5 degrees for a few days but that was kinda a fluke thing. It does get around 20-25 regularly though
 

chillman88

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So will 2 of the 650cca batteries will spin it over plenty fast enough, thats the main question here.

I'm pretty sure that's the same ones I've been running in my F250 for a few years. I'll have to double check. My truck had no trouble starting in winter with one single 1000cca battery so as long as everything is in good shape you really should be fine. When it'll come bite you is if you have air intrusion issues or something else that makes you have to fight it to start.
 

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If they're only dropping to 12.3 when cranking, sounds like you have something else wrong, like a bad ground, tired starter, ect.. Most auto parts shops will test batteries for free. Maybe have them tested before replacing them?
 
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