Mercedes Battery Isolator

kmccann · 06-24-2005, 04:21 AM

I've decided that I want to install a battery isolator with my carputer but I have run into a problem. There are two wires connected to the (+) terminal (duh), a 0 gauge and a 4 guage. I assumed that the 0 gauge wire connects to the alternater and the 4 gauge powers stuff in the car. (Perhaps my assumptions are part of the confusion, but the battery is in the trunk and the alternater is wedged in the engine pretty good, so I am trying to avoid major engine deconstruction.) However, when I attach the 0 gauge wire the the alternater post (leaving the 4 gauge wire attached to the battery) and the battery to its proper post, the car does not start. I also tried the same thing with the 0 gauge and the 4 gauge wire switched with no success. It seems that unless both wires are connected to the battery, the car will not start. Could anyone offer some explaination as to what I could do? Or even better, is there anyone who has installed a battery isolator in a Mercedes who could give me some ideas? Thanks a lot!

dan__wright · 06-24-2005, 04:35 AM

you will need both wires, ones for the alternator / starter motor, and the other one is for the cars electronics, including the ignition system.

RoyN · 06-24-2005, 04:41 AM

i assume you are putting an isolator between 2 bats right?

I'd just leave the original setup, and setup the additional battery, with isolator in between, and setup the carpc to the second battery...

it would keep the carpc and its battery isolated, and keep the 0 and 6ga wires where they originally were meant to be...

unless I misunderstood everything you said!

kmccann · 06-24-2005, 04:53 AM

dan:

i will need both wires where? connected to the "alternater post" on the battery isolator? i never tried that...it would be nice if it was that easy.

Roy:

yes, i am going to use two batteries. and the setup you described is what i am attempting to acomplish. my problem (i believe) is determining what wire is connecting the original battery to the alternater. i can't just leave everything else as is because then the original battery would still be connected to the alternater as well as the "alternater post" on the isolator. that would cause the 2nd battery to draw power from the first battery through the isolator when the alternater is not running (atleast from what i understand).

thanks for the quick responces.

RoyN · 06-24-2005, 05:01 AM

Oh, yeah... I was thinking more of a tank circuit that would merely run both bats in paralel when the car is on and isolate when the car is off...

From what I can gather the Starter and Alternator would be on the same Gauge 0 wire... however, I would refer you either to benzworld.org or some other forum, and ask around... or maybe a local car shop can help?

kmccann · 06-24-2005, 05:02 AM

ill try that. thanks.

dan__wright · 06-24-2005, 05:10 AM

you you want to run all your cars electronics off the second bat or just your carPC?

kmccann · 06-24-2005, 05:12 AM

well, im thinking just the carpc. but i am also putting in a new head unit which i would like on the 2nd battery, but i could just run a new wire for that. so, just the carpc on the 2nd battery.

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