The science of jump starting a diesel - Page 4 - PeachParts Mercedes-Benz Forum

winmutt · #46 12-07-2010, 02:44 PM

Quote:

Originally Posted by Fulcrum525

What I have-The $10 special jumper cables bought during an emergency some years ago.

What I need-BEEFY jumper cables and LOTS of power to supply them

I've jump started a number of cars with my own jumper cables before and they work like a charm every time. HOWEVER when it comes to the occasions when I need to jump start my own car? Forget those things are fricken hopeless. It's something that i've noticed on a few occasions and it happened again tonight. My car started perfectly fine on its own this morning without issue. Now today was pretty darn cold and the car sat in the parking lot for 10 hours without being run. I glowed twice but when I turned the key...barely a crank and I nnew instantly that the battery was dead. The lot attendant tried to help me jump it but the starter just couldn't get enough juice. Mercedes Roadside came out and with a starter battery and a set of monster cables....no surprise she fired right up.

I've got a Sears battery that should still be under warranty. Tomorrow i'm going to shoot over there and get it tested and possibly replaced....think i'll look around for a GOOD set of jumper cables while i'm there.

New battery? You almost certainly have a drain.... If you are on small cables just give the battery plenty of time to charge.

Fulcrum525 · #47 12-07-2010, 04:35 PM

Yep, new battery went in today. I didn't realize that the unit I had in place was 4 years old

(I thought it was only 3

) Makes sense though...last time I had battery issues I was dating Betsey...which was in 2006.

*sigh* where has my mind gone

compu_85 · #48 12-07-2010, 06:20 PM

Does the weather get very extreme in CT? I would expect a good battery to last more then 4 years. Moreso in a W126 since the battery isn't subjected to as much engine heat.

The OEM battery in my SDL is 5 years old, and as far as I can tell is perfect. I do leave it on a tender while the car is parked, though.

-J

Fulcrum525 · #49 12-08-2010, 08:43 PM

Quote:

Originally Posted by compu_85

Does the weather get very extreme in CT? I would expect a good battery to last more then 4 years. Moreso in a W126 since the battery isn't subjected to as much engine heat.

The OEM battery in my SDL is 5 years old, and as far as I can tell is perfect. I do leave it on a tender while the car is parked, though.

-J

It get's fairly cold which was definitely the case on Monday. I had jumped a number of cars over the 4 years I had that battery. It was just it's time to be replaced really.

speednjay · #50 12-08-2010, 09:21 PM

i carry a whole 2nd battery in the car.

although i dont live in the cold anymore..optima batteries work far better that acid filled batteries in the cold. never had a problem starting in any midwest winter with an optima.

Beastie · #51 12-08-2010, 09:44 PM

Okay
1.when I worked the night shift on 737's in between flights I made jumper cables for all my coworkers for Xmas one year. They worked great....... I never got around to making a good set for me so I found a good set not just a cheap set.
2. I had issues until I installed the correct battery in the car. You know the large monster one that looks like it belongs on excavation equiptment.
3. I have 2 jump boxes-One from &ostco about 15 years ago and check it every month to keep it charged. It still works and does start the diesel ( before the correct battery) The other is a name brand unit and also starts the diesel.
4. I guess if I were on a trip during the winter it would be prudent to bring one of my boxes along.

bdtsr · #52 12-08-2010, 09:49 PM

As far as dual batteries are concerned, look under the hood of any Ford, Chevy or Dodge diesel truck and tell me what you see...........two batteries! Even our 1981 Olds 98 diesel had two batteries. I was surprised when I got my '87 300D that it only had one battery. As long as the batteries are the same, there is not a problem. Look in almost any boat and you'll see two batteries per engine. More of a safety issue here though. The new AGM batteries are really good but expensive. I plan on updating my 300D to dual batteries in the trunk with a selector switch and battery boxes. The added weight over the rear wheels will help in the snow as well. As for daytime charging, there are some good solar panels that will help keep the battery topped off and don't require an extension cord.

speednjay · #53 12-08-2010, 09:53 PM

Quote:

Originally Posted by bdtsr

As far as dual batteries are concerned, look under the hood of any Ford, Chevy or Dodge diesel truck and tell me what you see...........two batteries! Even our 1981 Olds 98 diesel had two batteries. I was surprised when I got my '87 300D that it only had one battery. As long as the batteries are the same, there is not a problem. Look in almost any boat and you'll see two batteries per engine. More of a safety issue here though. The new AGM batteries are really good but expensive. I plan on updating my 300D to dual batteries in the trunk with a selector switch and battery boxes. The added weight over the rear wheels will help in the snow as well. As for daytime charging, there are some good solar panels that will help keep the battery topped off and don't require an extension cord.

jsut wire in a battery isolator and then dont even worry about the 2nd battery till you need it.

samboyellowsub · #54 12-08-2010, 10:10 PM

If the person that is jumping you off has a set of cheapo jumper cables and you have a set as well, then use them both in parallel. It has worked for me twice in the past when one set alone is too weak for the job.

vstech · #55 12-09-2010, 12:34 AM

Quote:

Originally Posted by bdtsr

As far as dual batteries are concerned, look under the hood of any Ford, Chevy or Dodge diesel truck and tell me what you see...........two batteries! Even our 1981 Olds 98 diesel had two batteries. I was surprised when I got my '87 300D that it only had one battery. As long as the batteries are the same, there is not a problem. Look in almost any boat and you'll see two batteries per engine. More of a safety issue here though. The new AGM batteries are really good but expensive. I plan on updating my 300D to dual batteries in the trunk with a selector switch and battery boxes. The added weight over the rear wheels will help in the snow as well. As for daytime charging, there are some good solar panels that will help keep the battery topped off and don't require an extension cord.

of course, those vehicles are v8 diesels, and the starter is even bigger than the one MB uses in our vehicles.
the inline 5 and 6cyl motors don't have nearly the size pistons that the chev/ford/international motors do, and they need more power to start the compression than we do.
6+liter motors have larger pistons and longer strokes than our 3 liter motors have. more compression needed.
a bigger or a pair of batteries is NOT needed. just a GOOD battery and GOOD connections.
that's all.

Beastie · #56 12-09-2010, 08:04 AM

Hey...... BDSTR you stole my thunder. I bought solar panels at Big Box and there were 2 in the box. They work great on a healthy battery to keep it fully charged. Also the point on the Olds diesel, same thing same engine on my Dad's
81' ? Olds Toronado Diesel, 2 batteries. Someone mentioned a 2nd battery in the trunk being an issue. My 92 500E has it there.

Brian Carlton · #57 12-09-2010, 08:43 AM

Quote:

Originally Posted by vstech

a bigger or a pair of batteries is NOT needed. just a GOOD battery and GOOD connections.
that's all.

About the only justification that you can use for two batteries is on an engine with high miles and lower compression. If you must crank it for 30-45 seconds at zero degrees, I then change my stance and suggest two batteries. One of them is probably not going to cut it, unless it's brand new.

vstech · #58 12-09-2010, 08:51 AM

Quote:

Originally Posted by Brian Carlton

About the only justification that you can use for two batteries is on an engine with high miles and lower compression. If you must crank it for 30-45 seconds at zero degrees, I then change my stance and suggest two batteries. One of them is probably not going to cut it, unless it's brand new.

hmmm.
if 30-45 second cranks are needed, I bet valve adjustment and GP work is needed too...

Brian Carlton · #59 12-09-2010, 09:00 AM

Quote:

Originally Posted by vstech

hmmm.
if 30-45 second cranks are needed, I bet valve adjustment and GP work is needed too...

Absolutely.

However, a battery is $100..........valves are $1000. by the time you're done (I'll not mention the time effort and commitment required to DIY).

vstech · #60 12-09-2010, 10:23 AM

acck! I said valve ADJUSTMENT! yeah, if the head needs to come off it's a bad thing.
my 400K+ 82 gets cranky when it's below 20 outside, but it starts fine with a good glow.
battery is going on it's third year... gotta get a new one in there. cables are pristine. chain is dead on. valves get adjusted every fall. block heater is dead... thinking about installing a hose mounted one, but it really doesn't get below 20 that often. this winter could be one of those though... 16 already this year.
I've got no glow plug light, so I must have a plug or two out, but it still starts for me. (bosch plugs are loosing their appeal for me, thinking of switching to a better brand)