FieroGT3800SCII

First - I searched, but did not find definitive answers to all my questions.

Are both batteries AGM from the factory? I know the auxiliary battery up front is but I wasn't sure about the main battery in the trunk.

What are the opinions of the batteries in Toadster's common replacement thread? I almost blindly bought both, but the Exide main battery only gets 2.9/5 stars which is not great as far as Amazon ratings go.

The thread I'm referring to is here:
https://mbworld.org/forums/w211-amg/...ne-thread.html

jcjmw

My main battery (in trunk) just got replaced. I just went down to autozone and got their best one with same crank power and reserve. It was under $200 vs dealer wanting $400 .

F1BHP

On the r230 the main battery in the trunk is agm and the starter battery under the bonnet is not.

poohlvhun

try advance auto and use their online coupon.
Their replacement battery is AGM.

poohlvhun

http://shop.advanceautoparts.com/p/a...chTerm=battery

slownrusty

I replaced both batteries this past summer with much smaller AGM batteries and saved about 45lbs.

FieroGT3800SCII

I'm hoping it lasts! I'm also going to check the auxiliary battery but those seem easier to find.

Toadster

parts thread has a link to the aux battery ~$65

cetialpha5

Wow, that's madness. Good luck with that setup. What's the mah rating of that replacement battery? My guess is that it will die sooner on you as you will have deeper discharges relative to the factory one. But I guess the weight savings and the price on the cheaper battery might balance some of that out.

Pepboys now has a 30% off code on orders over $150 and their battery is a Bosch at $200. After the promo30 code which is on their front page, it takes it down to $140. Advance Auto also has it for $174 and you can use a discount code that will take $50 off the battery (TRT30) so you're down to $124.

F1BHP

I replaced both mine with litiums with a total weight of 17lb. Not sure what the weight of the two stock batteries are. But probably saved over 60lb.
Anybody know the weights of the two batteries?

cetialpha5

Lithium I think requires a different type of charging than standard lead acid which is what these AGM batteries basically are. For the pepboys battery, the Bosch one is listed at 52 pounds and the Autocraft at Advance auto is 59.45 lbs. I guess that's probably why the Bosch is rated at 850 CCA whereas the Autocraft is 900 CCA.

F1BHP

Voltphreaks make lithium battery replacements that use the standard charging system.
How much does the starter battery weigh if the aux battery is 60lb?

cetialpha5

The main battery is about 60 pounds. If you follow one of the links to the aux battery, it is listed as 10.5 pounds with a shipping weight of 11 pounds. So you shaved off anywhere from 45 to 53 pounds. I think Lithium is also only good for 500-1000 charge cycles. How many years is it supposed to last? Some say AGM batteries can last anywhere from 8-10 years.

60nomad

That little battery is not 60lbs. I replaced both of mine and the big one felt like 60lbs...unless I am much stronger then I thought!


I just paid $140 for an interstate (my dealer cost) and I think I paid like $80 for the little benz battery at Mercedes, dealer cost. (I will need to check my receipt) I couldn't find that lil pos anywhere but then again...I didn't look too hard and wanted it asap. (Didn't 'need' it asap but thought it was causing some options not to work, which it was, but not for the things I wanted it to work for...lol)

60nomad

I would love to know how the lightweight batteries are working out because I was going to do it in my V but decided against after what I had heard about charging and other things. Also, how much were those??? Couldn't have been cheap from my last research about a year ago! When I heard and saw the prices...I decided that I would go 50lbs SLOWER!

F1BHP

I have been away while the car is being worked on so it will be a few more weeks until I find out how the lithiums have worked out. Price wise yes they are expensive voltphreaks gave me a good deal to show that it can work. The other way to look at it is that I have spent way more money tuning to save 50lb than I spent on the batteries.(carbon fiber seats)

60nomad

This is helpful! HOW MUCH??? lol


Don't mind me...just came home from a Xmas party...and a good one!

slownrusty

No luck or madness needed, I did my research and has worked flawlessly since the summer.

Weight of the stock battery:

cetialpha5

They do have a website. They're a bit up there. They have one on sale if it's still in stock at $850. Otherwise, they're $650, $900 and $1200. I suppose you could get away with using the $650 one for the aux battery and the $900 one for the main. Total weight on those two would be 8 pounds though and he mentions a total weight of 17 so it's unknown what combo was used.

You could also drive around without filling up the tank. Gas is about 6 pounds per gallon so not putting in that last 8 gallons at fill up will also save 48 pounds.

F1BHP

I used the VPH 900 and the VPR S40 and I can still run the car with half a tank and save another 50lb so not a great argument. Why do people always feel the need to make stupid comments when people are trying new things and trying to maximize performance with what they have. I am not spending your money.
I also mentioned I got a special price to fit these two batteries so I can report findings once tested.

cetialpha5

My previous post was aimed at 60Nomad who was not going to go with lithiums.

60nomad

I am a real race guy and applaud guys for doing things to make a car faster no matter what 'they' do at any cost but it is not for everyone! You are correct though, the gas thingy can be done by anyone, so not a very good point but I do not think he was digging towards you either. I seriously contemplated doing this about a year ago but the cost per advantage just didn't agree with me. Even still...I almost did it!


You're right on that...no lithiums for me! When you have saved 20lbs here, 5lbs there, 40lbs here etc...it adds up quick! If I cared a lot about weight in the E then I wouldn't have looked and got a loaded one! My car must be 200lbs heavier then a with much less options. Now my V is another story, Moonroof delete! Not many of those around!