Question About Wiring Upgrade for New 150amp Alternator - Page 2 - PeachParts Mercedes-Benz Forum

funola · #16 02-24-2009, 09:03 PM

The Autozone battery should be called Duracrap. I bought one in Oct and it does not have a lot of reserve. It's really light, should be much heavier for 900 CCA. Also a lot of money (about $90 now). I was able to get all of my money back and went to Walmart and bought one for $64. The Walmart battery feels heavier and comes with a 2 year free replacement warranty. I'll have to see how it holds up.

Quote:

Originally Posted by Graplr

Battery is less than two months old. I would assume that the battery did not fully recharge and thus having trouble starting, but there may be a new battery drain that has developed. The battery is the Duralast from Autozone. Don't recall the specs offhand but I believe it is the DL-49?? I know the problem doesn't lie in the battery itself. Hopefully the new alternator fixes it, if not there is obvioulsy a newly developed short somewhere.

Okay, looks like 2 guage it is.

FI, I know you upgraded the starter wiring, do you think it would help at all in (cold) starts? How about the ground strap? Well I'm at it, if it is beneficial, I might as well do it all.

Graplr · #17 02-25-2009, 11:19 AM

Quote:

Originally Posted by funola

The Autozone battery should be called Duracrap. I bought one in Oct and it does not have a lot of reserve. It's really light, should be much heavier for 900 CCA. Also a lot of money (about $90 now). I was able to get all of my money back and went to Walmart and bought one for $64. The Walmart battery feels heavier and comes with a 2 year free replacement warranty. I'll have to see how it holds up.

The Duralast has a free 2 year replacement as well.

Graplr · #18 02-27-2009, 09:34 AM

Quick Update-

I received the alternator yesterday. I put it on last night. It was pretty straightforward. The hardest part ended up being the new wiring. It bolted in and the belts went on fairly simple. It came with a double pulley on it already. As others have stated, the Eagle Auto guy was helpful and he has sent me a couple messages making sure I got it and that it is working.

I bought 2 premade 2 gauge cables. The first runs from the alternator to the battery positive terminal. I also spliced the old wires to the alternator and hooked them up as well so they still go to the junction box. Then I figured while I was at it I might as well upgrade the wiring to the starter. I added a 2 gauge wire from the starter to the positive battery terminal so I have as much current as possible going to the starter. Overkill I know, we will see if it makes a difference.

Now really the only thing left to do is add a cable from the engine to the negative battery terminal to make sure the engine is grounded as best as possible. Again, overkill.

I got 14.1 volts at idle with nothing turned on. I didn't check it with everything running.

Thanks for your help.

vstech · #19 02-27-2009, 09:47 AM

Quote:

Originally Posted by Graplr

The Duralast has a free 2 year replacement as well.

yeah, but the walmart batterys have a 3 year replacement warranty!
how many times in that 3 years you will have to use the warranty is up to debate... bummer.
what walmart battery are you using?
I could only find group 39 batteries that fit in the MB spot... kinda dinky IMHO...
the larger batteries from walmart are too tall and have the terminals on the wrong side...

funola · #20 02-27-2009, 09:49 AM

I don't like the ground strap either. I got stranded for a day after doing a bunch of 0-60 time trials. Starter clicked but no start. Battery was good. Turned out the bell housing bolt for the ground strap worked itself loose enough to not provide enough current to the starter. There was only one bolt on the starter, and one other bell housing bolt of the wrong size and that was loose, the other engine to transmission bolts were missing. This was probably from the shoddy work of the place that rebuilt the transmission (PO did that)..Point of all this is if the ground strap went from the starter direct to the battery, I wouldn't have been stranded.

Quote:

Originally Posted by vstech

Yeah, I would upgrade the ground wire from the battery to the body and put a nice ground strap THERE to the engine. I don't like the way MB puts the ground to the body, then another strap somewhere else to the engine. I want TOTAL ground connectivity through the copper to the engine!
obviously, MB's design is adequate for their oe wiring, but for the upgrade, I'd upgrade it all.
and while I agree a short distance makes it fine for lower capacity wire, I would want 0 or better for 150A... it gets MIGHTY hot near the turbo, and heat lower's a conductor's capacity...