Hi all,

I'm going to replace my battery pretty soon on my MCS - should I replace it with an OEM one as I see it has some funny stuff on the positive end or is it not really necessary and any car battery will do?

 

If you can find an Optima Red Top 34R it is a direct replacement, better technology and higher capacity.

There are a bunch of threads that list some other replacements but frankly there is nothing better than the Optima.

Rich

 

Thanks, I've found a local supplier. Will give them a ring.

 

+1

 

I got mine at Costco.

 

Response to my email from local supplier:
"We have the Optima RTC 4.2L Red top @ ###### (Around $300 US)." A bit steep IMO - largely due to our import taxes.

Is that the right one, what is the average price of one in the US?

I phoned BMW, they are going to charge me $200 for a new OEM battery.

I don't have any big sound systems etc other than stock Cooper S sound.

 

I think I paid about $130 for my red top.

 

Holy I hate our taxes...

Will the battery he is mentioning be the right size for my car?

 

The 34r is a direct replacement. Perfect fit and you won't need the vent although I left it in there just in case. And it is 800AHrs which is more than the OEM battery.

I have no idea what a Optima RTC 4.2L Red Top is. I see no reference to it on the Optima site.

Rich

 

Actually, the Optima 34R is 800 Cold-Cranking Amps (CCA), not 800 Amp-hours. Its capacity is only 50 Amp-hours. (Both the capacity and cold-cranking amp ratings are higher than the stock battery, though).

An 800 Amp-hour battery would pretty much fill your hatch!

 

He would have to import the battery as that is the only Optima they stock here I might go the OEM route, bit too much hassle for just a battery as I have nothing other than stock sound in my car.

Thanks again for all your time and effort, you guys have been great

 

I highly suggest you reconsider to the Red Top Optima, depending on cost effectiveness ofcourse. Id say that going to a red top is worth 140% of what it would cost to do stock, if you can get a red top shipped in that price, do it. maybe costco online? not sure what they have to offer you in South Africa...
Costco also offers a 3 year no questions asked replacement on your battery...i shorted mine and upgraded to a yellow top because I run tons of sound and video, only cost me 20 bucks for the upgrade

 

+1 on the Optima. I bought mine at Batteries Plus.

 

--I'm looking at an Optima Yellow Top D34/78. Going for $169 at Costco. I was surprised they had the yellows as they only carried reds before. I typically sit in my car and listen to the stereo with the engine off so I thought the yellow top would be better. Add to that I'm in the northeast where we've hit -10 degrees a few times already and winter has only just begun.

Anyone else have experience with this battery?

~p

 

I'd go with the red-top, as it is unlikely that you will run the battery down much unless you have a high-amperage aftermarket stereo.

BTW, while the Optima 34R is a perfect fit, you will need to shim it up about 1/2" to make the hold-down bar fit. You could either put something under the battery to raise it, or use a piece of wood about 1/2"x3/4"x6" to fit between the hold-down and the battery.

DO NOT just leave it sitting in there unsecured, as you wouldn't want to be in any accident where a forty pound battery came up and bounced around loose in the passenger compartment...

 

Thanks and nice tip on the fitment. I almost have 3 years on my OEM battery and so I guess I am much closer to the end of it's life than the beginning. The Optima red top sounds like a good selection.

Some here have also spoken highly of the Braille battery, which is a much smaller option. I think it is only 11 lbs, significantly smaller, I would expect less CCA and even more fitment issues than the Optima.

 

The Braille battery is also about half the capacity. Lower weight is nice, except that the MINI already has a strong front-wheel weight bias. And don't plan to use one in snow country.

But if you do use a mini-battery, you can remove the battery box and get a straight-through exhaust.

All of life is a series of engineering trade-offs...