Which battery is best?

[w8n4ya]

Hello forum members & MB experts,

I have a pretty simple question. Since Mercedes-Benz does not make car batteries, which battery either OEM (mine says "Made in China" or aftermarket is best?

I have read much about Optima batteries (although I can't seem to find the right size on their website for the R-129 SL500). Other forum members have success with Interstate batteries.

I have a 1997 SL500 that is having a battery drainage issue. I bought a Battery Tender Plus to keep it float charged. Well, the red charging light never turns green - even after 12 hours of connection, and the unit itself gets pretty warm to the touch.

Yesterday morning, the battery was drained so much overnight that I had to use a jump box to start it. Does the Battery Tender Plus first drain the battery and then charge it? Or does it start charging once its hooked up? what's taking the process so long? Is it the mere size of the MB OEM battery?

Now for those who charge or cut off the battery power while the car is stored, how do you reset the convertible on a 1997+ model? Doesn't it lock out after the voltage drop?

Thanks in advance for any assistance.

[BoomInTheTrunk]

are you charging with the battery still hooked up to the car. if you are you might have a short in the electrical of the car causing the battery to drain. Now if the battery is out and wont hold a charge than the battery is toast.

[TheDon]

get the white one from the dealership for added concourse points

[iwrock]

I think I have an Interstate in my SL600. I dont know for sure, but I can check for you after work... It does an excellent job of firing the car every time...



I do want to get an optoma next time it dies...

[tecqboy]

The 1 amp battery tender should charge your battery even if the battery is still connected to the vehicle. No, it does not discharge the battery first, as some nicad battery chargers do. ( Ni cad batteries are a very special case ).
If your battery is 5 years old or more, than it's probbably time for a new one. 5 years on an auto battery is a considered good service life. Optima batteries are great, but as you discovered, they don't have one for our vehicles. You can still use one, but you'll have to figure out which size will fit the space and how to mount it. I got my last battery at Sears and it was made in USA by Johnson Controls.

Now, if the battery is going dead when it shouldn't, you have a current drain issue. These cars are known to have some problems here. Number 1, the trunk lamp stays on after the trunk is closed; caused by a bad switch. Number 2, the motor in the power antenna runs although the antenna is down. Number 3, the anti theft alarm and remote door locking circuits cause the vacuum pump to run when it shouldn't.

[rfpmoxie]

I have had great luck with Duralast. Coincidentally, the battery for the '90 300SL is the same as the battery for my '84 300D. Both are Duralast. I use a battery tender in the winter and, yes, 3 times now in 4 years, I've had a battery with 9 Volts or less that wouldn't start my car (at home, fortunately). The battery tender has re-charged the battery and all is fine. Also, my belief is that 14 hours is not excessive as it depends on how "uncharged" your battery is. A multimeter reveals much. Good luck, Ron

[Seon]

I'd suggest finding what is causing your battery to drain. Might be a bigger problem later

[Bob G]

I have a 1968 280SL and have always used CTEK 3300 battery trickle charger. A couple of months ago I noticed a headlight and side market light out this caused the trickle charger to remain in the orange charge mode. Once these two light bulbs were replaced it went to green.
I would have to say you have a parasitic drain somewere. start pulling fuses andd check which fuses remain hot like the ignition. could be something as simple as my problem.
good luck
Bob Geco
1968 280SL 1992 300E sportline

[Carlos Serrano]

I replace the original with an AC Delco 4 years ago and still as good as the day I bought it. About $75.00 if I recall correctly

[lynns]

Originally Posted by w8n4ya

I have a 1997 SL500 that is having a battery drainage issue.

Please read What to do with an R129 dead battery.

[compress ignite]

This is the best battery...Warranty,Service Life,Charge Retention rates,CCA.
No Liquid to Leak, AGM type(Absorbed Glass Mat).

You will CRY at the price.

[Lexxani]

Originally Posted by rfpmoxie

I have had great luck with Duralast. Coincidentally, the battery for the '90 300SL is the same as the battery for my '84 300D. Both are Duralast. I use a battery tender in the winter and, yes, 3 times now in 4 years, I've had a battery with 9 Volts or less that wouldn't start my car (at home, fortunately). The battery tender has re-charged the battery and all is fine. Also, my belief is that 14 hours is not excessive as it depends on how "uncharged" your battery is. A multimeter reveals much. Good luck, Ron

I have duralast gold batteries in both my cars, theres autozones everywhere and the prices on their batteries are excellent. I'd only get the gold series though as the other two lines are cheaper and dont have as many cold cranking amps. . .I buy them for these facts as well as the warranty. . .

I had a battery I purchased from AAA, when it died, what a PITA to get it replaced, stick with a battery you can get serviced everywhere.

[brt]

for various reasons, mb does NOT recommend using a conventional lead-acid battery (which is what you'll get if you buy a battery from napa, autozone, etc.) for use as an electronics consumer battery in the trunk. mb only recommends an agm (absorbent glass mat) battery for use in this application.

for any who are interested in saving some money on this, go to http://www.eastpenn-deka.com/ZipSearch.aspx?pageid=843

type in your zip code and you will find a local outlet for the deka 9agm48 battery, which my local deka warehouse guy says is an oem replacement that they sell to mercedes dealers. the cost to me was about $154, which compares to $253 at two mb dealers in my area and $283 at a third dealer. it is an agm battery (like the oem varta) and fits perfectly.

[lynns]

My 2000 SL R129 has one conventional lead-acid battery on the right side of the trunk. Do you believe that I would have ANY type of problem replacing my battery with a Deka AGM Eurpean Performance Battery for $145.00 ?

Is an "Absorbant Glass Mat" battery also known as a "Fleece" battery?

Date: May 2001
Order No.: P-SI-54.10/53
Supersedes:
Group: 54
SUBJECT: ALL M-B MODELS NEW “FLEECE” BATTERY
New Fleece technology batteries have been phased into production as of the 1st quarter of 2001.
These new Fleece batteries are identified externally as follows:
• Black battery housing
• Identification note: VRLA Battery
• Non-removable battery covers

CONSTRUCTION OF THE BATTERY

A special woven fabric (Fleece) is used in the battery cells.
The fleece (V, Figure 2) retains the liquid sulfuric acid much like a sponge, which results in the following advantages:

• Greater battery Cycle capability, which means longer battery life.
• Improved cold start properties.
• Virtually no acid leakage if battery housing is damaged.
• Improved deep discharge durability.
• Absolutely maintenance-free.

[brt]

i had an r129 car and i replaced the original battery with one from autozone which worked perfectly for the 3 remaining years that i owned the car. this battery was a conventional lead-acid version that i believe had an outlet for a venting hose. it was way cheaper than the one from the dealer. in the newer sl's, mb specifies the use of an agm battery. in the older cars it apparently didn't matter. why would you spend $50-$75 more to get a battery that you don't need?

i don't know if a "fleece" battery is the same as an agm, but it sounds similar.