Battery sizing

SnowyOwl

SnowyOwl

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Finland
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1994 Ford Thunderbird LX 4.6
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I'm about to replace the battery on my Bird. The only group 65 sized battery I can find from the whole country is rated 85Ah capacity and 800A CCA. On a quick check, many other size 65 batteries are significantly smaller in terms of capacity and CCA. Shall I encounter problems with the 85 Ah / 800 A one, is it possible that it's too "big"?

I would assume that cars of this age aren't too picky about the battery specs...
 
Those ratings are the max the battery can supply, The started, car, etc will only draw what it needs. The only problem I could see is if the battery is severely drained it could put strain on the alternator to charge it up. But you shouldn’t be draining a starter battery anyway.
 
SnowyOwl said:
I'm about to replace the battery on my Bird. The only group 65 sized battery I can find from the whole country is rated 85Ah capacity and 800A CCA. On a quick check, many other size 65 batteries are significantly smaller in terms of capacity and CCA. Shall I encounter problems with the 85 Ah / 800 A one, is it possible that it's too "big"?

I would assume that cars of this age aren't too picky about the battery specs...
Click to expand...
Our cars aren't picky but Kidd-7 is right, the CCA is simply the amount of current the battery can supply at -17.8 C° (0 F°) which is really the only time peak current is demanded. Funny enough, in Canada all our group size 65 batteries are rated at 850 CCA which is what I have so absolutely no worries about your battery being too big.
 
Any group 65 should be fine for a cold climate. I actully run a 58 in mine which is the smaller Ford size, it's a direct fit replacement. I believe that some V6 model years came with a 58 from the factory
 
No that would not be "too big" or too powerful if that is your concern. Will be beneficial in the cold climate.
 
Group 58 is what I’ll run when the Optima goes, keep in mind that’s what 4.6 Mustangs were equipped with from the factory, there’s no electrical load ours have that they don’t’. Plus they’re nearly 20lbs lighter than the 65.
 
Yeah. It was the physical dimensions of the battery what I wanted to be precisely correct, as I got a remark about the battery being loose on the yearly safety inspection. (The current battery is euro sized and too small for the stock clamps to keep in position). And I wanted to avoid crafting a custom battery holder as well, due to engine bay aesthetics.

Got the "new" battery yesterday. "New" in quotes because the battery had been sitting on the store's shelf for two years, although still seems to have ~12V of voltage left.. So perhaps they've charged it a few times. Gotta charge it with a "smart charger" before installing and see if it's any good or not.
 
Batteries sulfate when sitting, and it's hard to remove, and it shows up as 'high internal resistance', which means it runs the stereo, but not the starter.
If I had the cash, I'd go for li-ion. The one I looked at had a built-in charger to keep it happy.It was almost $500, but no sulfation.
 
Grog6 said:
Batteries sulfate when sitting, and it's hard to remove, and it shows up as 'high internal resistance', which means it runs the stereo, but not the starter.
If I had the cash, I'd go for li-ion. The one I looked at had a built-in charger to keep it happy.It was almost $500, but no sulfation.
Click to expand...
These so called "smart battery chargers" advertise that they're able to recognize the sulfation and fix it somehow. I'll try to charge the battery tomorrow, let's see what the charger says.
 
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