Replacing Auxiliary attery
Thread Starter
Member
Joined: Oct 2009
Posts: 79
Likes: 5
From: PA
S550 4MATIC W221, W222, Lotus Elise
Replacing Auxiliary attery
It's time to replace the auxiliary battery in the trunk.
1. Bought "AutoCraft Platinum AGM Battery, Group Size H8, 900 CCA" from advance auto parts online. This is the exact matching AGM battery with OEM
2. Asked store to test and all good with 1000CCA
3. To keep electricity on while doing replacement, I use jump start cable to connect auxiliary battery with another car. This way you don't have to reset anything
4. Take out a floor board that close to the vertical board in the trunk.
5. Pulling the left lower bottom the vertical board and take out the board from left side. You will see the battery on the right.
6. Making sure to attach an air hose on the right top on the battery and plug the left air hole on battery.
7. The rest is the same as to replace any battery. Took me 30min. to complete.
Done.
1. Bought "AutoCraft Platinum AGM Battery, Group Size H8, 900 CCA" from advance auto parts online. This is the exact matching AGM battery with OEM
2. Asked store to test and all good with 1000CCA
3. To keep electricity on while doing replacement, I use jump start cable to connect auxiliary battery with another car. This way you don't have to reset anything
4. Take out a floor board that close to the vertical board in the trunk.
5. Pulling the left lower bottom the vertical board and take out the board from left side. You will see the battery on the right.
6. Making sure to attach an air hose on the right top on the battery and plug the left air hole on battery.
7. The rest is the same as to replace any battery. Took me 30min. to complete.
Done.
Last edited by mb1000; Apr 7, 2016 at 01:12 PM.
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Joined: Nov 2014
Posts: 4,242
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From: Chicago burbs
2015 S550
No need to hook up a battery charger or tender when you replace the aux battery. You don't lose any of the presets or other settings in the car when you replace it. Those will maintain power off the starter battery when you're replacing the aux.
Thread Starter
Member
Joined: Oct 2009
Posts: 79
Likes: 5
From: PA
S550 4MATIC W221, W222, Lotus Elise
Thread Starter
Member
Joined: Oct 2009
Posts: 79
Likes: 5
From: PA
S550 4MATIC W221, W222, Lotus Elise
Dave, do you know where soes the transmission get the power, from start battery or consumer battery?
After replaced the consumer battery, shifts seem to be better.
thanks
Last edited by mb1000; Apr 7, 2016 at 02:32 PM.
