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Discussion Starter · #1 ·
My car is an '08 Elise SC with 35K on the clock.

I think my battery might be fading. It's the original 'Megatron' battery (had no idea Calvin Johnson had his own line of batteries). :)

- My voltmeter shows 12.6 plus after driving a bit (sitting in garage for 2 hours)
- Voltmeter shows 13.5ish after car running

However, when starting up the car, it takes a bit to crank. It does crank, but it's sluggish a bit. Yesterday, after sitting for about 6 hours, it struggled and didn't crank at first (did on the second try).

So, I'm assuming the battery is in fact start to go - 6 years of driving and 35k miles would make sense. However, the voltmeter has me perplexed.

Thoughts?
 

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Wow Such Admin
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Have you measured it while cranking? Just measuring voltage of a battery with the car off won't tell you much. It could read 12.6 volts but not have enough amperage to turn the starter and start the car. Get the battery tested, it is most likely bad.
 

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The short of it is that a lead-acid battery's unloaded voltage doesn't actually tell you much about how much current it can provide.

You can take the battery to a parts store and they'll usually have a tester which will test the internal resistance and possibly apply a simulated cranking load.

But, since it's clearly not working for you, just buy a new one! Six years seems about right for some batteries to start to go.
 

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Discussion Starter · #6 ·
Ok, I'll replace the battery.

Was thinking Optima RedTop 35. Worked fine in my prior car.

This one effectively appears to be the same battery that was in there. Did the job for 6 years. Thoughts on it?

It's $112 less 20% versus $195 for the Optima
 

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Discussion Starter · #8 ·
I do not recommend Optima's.
Test the battery voltage after it has been sitting for at least 12 hours.
Michael
I've read your threads through and through

What battery would you recommend that can be used with the oem bracket?

I want something with decent cca that's why that autozone
one or interstate looked interesting.

Want to be able to buy something locally and not deal with core exchange via shipping
 

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I've been using my Optima Red Top since 2007. Never had any problems, never need to trickle charge/top it off either, and I run my Chase Cam with the car off for ~30 hours per week.
I have heard numerous reports of bad batteries though, I guess I was lucky with mine as I have them in 3 vehicles with no issues. My Exige is the Daily Driver.

I was made fun of for having a full size Red Top at a Lotus meet, but the joke was reversed when I was the only one with a battery big enough to jump a seldom used Esprit. (I was the only one without jumper cables hehe)
 

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Batteries are made based on how you use them. A battery for a DD is not good for a once a month driver. Not sure what of the 35k you put on it so are you planning to DD this car? Optima batteries for DD is a good choice (unless there is some sort of major issue I'm not aware of) where Alien Motion is great for a Sunday spin especially with the charger that you can buy with it. IMO a Alien Motion is an over kill for a DD.
 

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Gamera The Atomic Turtle
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^yup. I have a 625 in my clam hinged car. Fine battery.
 
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