Battery/charging/starter cables
- Thread starter shanemac
- Start date
ebsprintin
surviving member
I just got around to making my own cable to by-pass the problematic cable harness. I consider it a semi permanent fix. My cable is only a direct connection between the alternator and battery. I used #2 AWG welding cable with crimped connectors and bolted inline 300 amp ATM fuse. I left the original cable inplace and used it as a route to tie my cable to. I disconnected the existing cable at the alternator and insulated that end to keep it from grounding to anything. The alternator end of my by-pass cable is the only connector outside in the out-of-doors, the fuse holder is in the battery box. For the alternator end I crimped on the ring connector with a hammer crimper. I used liquid electrical tape to seal the connector/cable connection then heat shrunk the connection with heavy duty, waterproof heat shrink. The cable follows the cable harness under the transmission, passes the starter connection and then runs back to the battery box. I used regular heat shrink for the inside connections; otherwise, the inside connections are crimped and sealed the same as the outside connection. I get a solid 14.0 V. Cost of parts is less than $30.
If this repair/mod holds up, I'll eventually remove the old cable and replace the atm fuse with a fusible link.
eb
If this repair/mod holds up, I'll eventually remove the old cable and replace the atm fuse with a fusible link.
eb
sprintguy
16+ yrs Master Commercial technician
Guys : take a look at the last picture of post #1 , I see this condition with all the ones I put cables in.
Notice how the cable from the battery is laid over the P/S rack (gear) and then criss/crossed over the cable that goes to the alternator. The added stress on the cable joint (splice) connector , and the engine heat , cause the shrink tubing to get bridle and then split (because of stress). This allows moisture to enter the cable joint and wire itself, then you get a failure (prematurely).
When you install the new cable run the cable that goes to the battery - behind the one that goes to the alternator, then using the new bracket that comes on the new cable (you may have to cut the cable tie to reposition) secure the cable to the engine , were the bracket to the alternator cable is bolted to the block by the bell housing, then run back to the frame rail to the battery (the way it was before). Do not cross over the P/S rack (gear)
Carl
Notice how the cable from the battery is laid over the P/S rack (gear) and then criss/crossed over the cable that goes to the alternator. The added stress on the cable joint (splice) connector , and the engine heat , cause the shrink tubing to get bridle and then split (because of stress). This allows moisture to enter the cable joint and wire itself, then you get a failure (prematurely).
When you install the new cable run the cable that goes to the battery - behind the one that goes to the alternator, then using the new bracket that comes on the new cable (you may have to cut the cable tie to reposition) secure the cable to the engine , were the bracket to the alternator cable is bolted to the block by the bell housing, then run back to the frame rail to the battery (the way it was before). Do not cross over the P/S rack (gear)
Carl
jdcaples
Not Suitable w/220v Gen
Thanks, Carl.
I've ordered a new cable because I have found a 1+ volt drop between the alternator (14.1 v) and the battery posts (12.8v). After considering replacing the entire OEM solution - you've given me cause to consider keeping the OEM solution.
You've given me cause to consider keeping the OEM solution in the long run... it still seems like a fragile solution to me, however.
What the h*ll does the 300 amp fuse do, anyway? Protect me from mixing up the red (+) and the black (-) from one another while jump starting?!?!? If I blow that, I'm an idiot that deserves what I get from not understanding + from - . . .
-Jon
jdcaples
Not Suitable w/220v Gen
Before I replaced the battery cable, I recorded:
14.1 v at the alternator
13.5 v at the starter
and
13.2 v at the battery
As it got worse, I saw 12.4 at the battery.
I have replaced the cable.
Now I'm seeing this:
My new battery cable is installed. I now have 14.4 v coming off the alternator and 14.3 v at the battery terminals. Both my battery charger/tester, my hand-held fluke tester and Chrysler's StarMOBILE scan tool using StarMOBILE desktop client and WiTECH softwrare agree with these metrics.
It takes less than 5 minutes at idle for my battery tester to tell me the battery's at 100% charge.
Interesting metrics:
Turn on the heated glass and the voltage at the battery drops 0.2 v.
Turn off the heated glass,
then turn on the seat warmers, the xenon headlamps to bright, roll the windows up and down, run the wipers and turn on all the interior lights and the voltage drops 0.1 v.
I'm going to ask again: What does that in line fuse do?
Here's another question:
The factory cable is stranded copper, looking like 2 gauge to my untrained, uneducated eye.
Why can't we just put a straight, well-sealed, non-fused, stranded-copper cable from the alternator to the starter and put another non-fused, stranded-copper cable continuing on towards the starter battery?
Alternatively, why can't there just be one cable with a crimped on lug to attach to the starter as the cable makes it way from the alternator to the battery?
-Jon
PS: I'll bring the cable to the 6th Annual NorthWest SprinterFest in Tualatin, OR in April. Bring test tools and we can perform an autopsy.
14.1 v at the alternator
13.5 v at the starter
and
13.2 v at the battery
As it got worse, I saw 12.4 at the battery.
I have replaced the cable.
Now I'm seeing this:
My new battery cable is installed. I now have 14.4 v coming off the alternator and 14.3 v at the battery terminals. Both my battery charger/tester, my hand-held fluke tester and Chrysler's StarMOBILE scan tool using StarMOBILE desktop client and WiTECH softwrare agree with these metrics.
It takes less than 5 minutes at idle for my battery tester to tell me the battery's at 100% charge.
Interesting metrics:
Turn on the heated glass and the voltage at the battery drops 0.2 v.
Turn off the heated glass,
then turn on the seat warmers, the xenon headlamps to bright, roll the windows up and down, run the wipers and turn on all the interior lights and the voltage drops 0.1 v.
I'm going to ask again: What does that in line fuse do?
Here's another question:
The factory cable is stranded copper, looking like 2 gauge to my untrained, uneducated eye.
Why can't we just put a straight, well-sealed, non-fused, stranded-copper cable from the alternator to the starter and put another non-fused, stranded-copper cable continuing on towards the starter battery?
Alternatively, why can't there just be one cable with a crimped on lug to attach to the starter as the cable makes it way from the alternator to the battery?
-Jon
PS: I'll bring the cable to the 6th Annual NorthWest SprinterFest in Tualatin, OR in April. Bring test tools and we can perform an autopsy.
Jon,
I've wondered too, your exact questions. Why not replace the battery cabling with something that it is not prone to trouble and readily available, and why the resister/fuse/whatever is inline? My "harness" was replaced at a Chrysler dealer last year and the tech said he disected the original cable to find no issues. The new harness resolved my issues. Starting to get somewhat different starting issues but have not crawled under to troubleshoot yet. Should be 65 degrees tomorrow so sounds like no excuses.
I've wondered too, your exact questions. Why not replace the battery cabling with something that it is not prone to trouble and readily available, and why the resister/fuse/whatever is inline? My "harness" was replaced at a Chrysler dealer last year and the tech said he disected the original cable to find no issues. The new harness resolved my issues. Starting to get somewhat different starting issues but have not crawled under to troubleshoot yet. Should be 65 degrees tomorrow so sounds like no excuses.
folzag
Member
I would need to see the schematic to be 100% certain, but with that caveat there are only two things it can possibly do: to protect the alternator from a) a short to ground at the battery or jumper post (I would think the alternator should have its own internal protection circuitry... or, perhaps not) b) an over-voltage (24V) jump start. Either one of these I think has a negligible chance of happening for almost anyone reading this forum. Certainly for anyone that has the wherewithal to replace the cable on their own.
Absolutely no reason I can think of. If my Sprinter develops this problem that is what I intend to do. That said, fusible links are a standard component in vehicle electrical system design. They aren't infallible though, and can fail when they shouldn't.
I think a crimp in the middle of the cable would be tough to properly accomplish mechanically. I don't know if they even make connectors that are made to crimp mid-cable. Seems like it would have a tendency to come loose, assuming you even could get it to fit up against the starter post, which I doubt you could.
-Allan
jdcaples
Not Suitable w/220v Gen
I think it's a 300amp fused link in the cable. I know for a fact that MB sells it seperately. I also know for a fact it sits between the alternator and the starter.
I agree that it might be tough to get a mechanically sound connection with three terminals between the battery, the starter and the alternator. The post would likely accomodate thicker lugs than stock.
Mostly I'm ticked because it's a sucky weak design with no excuse that anyone I've spoken with is able justify.
-Jon
I agree that it might be tough to get a mechanically sound connection with three terminals between the battery, the starter and the alternator. The post would likely accomodate thicker lugs than stock.
Mostly I'm ticked because it's a sucky weak design with no excuse that anyone I've spoken with is able justify.
-Jon
piper1
Resident Oil Nerd.
What gets me (and it's not just MB that does it), if that fuse link fails, the alternator will self destruct. An alternator spinning, that is energized, and has no output path (if that fuse/link blows) will fry itself in very short order (like in seconds). The cables I made do not have any fuse in them, to me, the risks out weighed the rewards.
It's one reason why big truck alternators are very commonly energized by the very same wire that they output to. If it fails, the alternator just shuts down.
It's one reason why big truck alternators are very commonly energized by the very same wire that they output to. If it fails, the alternator just shuts down.
folzag
Member
What I'm not sure about is whether the rest of the vehicle electrical system is connected at the battery end of the Y cable or the alternator end. It could make a difference as far as what is being protected, or not, against over-voltages or ground-shorts. I don't think it would change my opinion about leaving the fuse out of a replacement cable, but it would clarify the failure mode and what I'm risking.
As for it being a sucky weak design, yeah, I'd say the experimental evidence would make it hard to argue otherwise at this point. I think manufacturers should be on the hook for longer than the standard warranty for obvious design problems such as these. The question isn't whether it will fail, the question is when. About our only recompense is we aren't required to keep MB's sucky design. We are free to come up with our own and implement it however we choose.
-Allan
jdcaples
Not Suitable w/220v Gen
You're welcome for the metrics.
Did it go well? No, it didn't. I got part way though it - right to the precipice of no return - and between the cold, the wet, the neck pain, the scrapped knuckles and the mortal fear that I'd further trash the burned insulation (never jumped it, btw). After looking at it, considering buying a very small, stubby ratcheting box wrench and another one with a 90 degree pivoting head.
I ended up hiring a better wrench turner than myself who used the exact tools I considered buying one wet Saturday morning.
I well and truly hate that cable design.
-Jon
jdcaples
Not Suitable w/220v Gen
Here's a picture of the "Y" damage at the starter.
I have never jumped this vehicle.
I have never charged the the battery while connected to the vehicle.
Questions:
What caused this insulation failure?
Is the conductor's exposure is due to the insulation being degraded by thermo-expansion/contraction?
Here are some pictures with a few physical metrics:
Overall Length
Alternator to Starter cable run:
Cable OD (this is a few centimeters away from the connector's thicker (heat shrink?) insulation which is visible:
I forgot to copy the photo of the length of cable between the starter and the battery.
Generally speaking, I think the connectors are 3/4 of an inch in width.
McMaster-Carr didn't really have anything that spoke to me.
This website:
http://www.awcwire.com
has some products which are appealing because of the number of strands, the thermal tolerances etc.
What would you use to create a durable, home grown solution?
-Jon
I have never jumped this vehicle.
I have never charged the the battery while connected to the vehicle.
Questions:
What caused this insulation failure?
Is the conductor's exposure is due to the insulation being degraded by thermo-expansion/contraction?
Here are some pictures with a few physical metrics:
Overall Length
Alternator to Starter cable run:
Cable OD (this is a few centimeters away from the connector's thicker (heat shrink?) insulation which is visible:
I forgot to copy the photo of the length of cable between the starter and the battery.
Generally speaking, I think the connectors are 3/4 of an inch in width.
McMaster-Carr didn't really have anything that spoke to me.
This website:
http://www.awcwire.com
has some products which are appealing because of the number of strands, the thermal tolerances etc.
What would you use to create a durable, home grown solution?
-Jon
ebsprintin
surviving member
Jon,
I used welding cable, lugs, and the linked to crimper from Wind & Sun.
http://www.solar-electric.com/teluwiha.html
I'm still looking for a ring connector with a 90 degree bend for the connection at the alternator.
eb
I used welding cable, lugs, and the linked to crimper from Wind & Sun.
http://www.solar-electric.com/teluwiha.html
I'm still looking for a ring connector with a 90 degree bend for the connection at the alternator.
eb
Last edited:
piper1
Resident Oil Nerd.
http://www.phillipsind.com/flashmag/WebCatalog/WebCatalogMag1/
It will take a minute for the catalog to load eb. Look towards the back (pg 52 ish)
Am I still going to see you next week?
ebsprintin
surviving member
Looks like a lot of useful products. There seems to be only one size of 90 degree lug. Maybe I'll switch to the corresponding cable size. A larger cable can't hurt for that run between the alternator and battery. Besides, if I burn up the vehicle, I want it to go quickly.
Dave, I'm within one load of going out of service for next week. See you then.
eb
Dave, I'm within one load of going out of service for next week. See you then.
eb