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PostPosted: September 23rd, 2017, 11:13 am 
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Location: 1999 Concourse
Hi Reddingnative,

I'm camped in a place with no cell signal, so only getting online occasionally until I move someplace else.

I enjoyed reading your thought process and solution for mounting the switch. Very nicely done!

I imagine your Ford start battery is different from mine (cause mine is 97-newer which has a different engine and the start battery on the passenger side), but the way Ford did the battery cables on mine was .... well, they weren't just cables, but instead, "harnesses." i.e. more complicated and more expensive ;)

On the negative side, there are/were two cables that terminated in a "double schnozzle" at the battery post. One of the cables (long one) went down under the rig to the starter (which is under the cab a ways), and the other went about a foot into the front corner near the headlight and was the chassis ground.

The positive setup was similar, with two cables merging into one at the post.

I ended up cutting both of those off and putting regular ring terminals on, then using the post-to-marine-terminal posts. I also upsized the negative to chassis ground since it was now part of my combiner loop (had to bed a 10mm wrench to get in there - they must have done that prior to building the front end :? ). I also found a break in the insulation and a very green section of wire down by the starter where they had "bent" the wire. That's when I found out about "harnesses" as opposed to cables because my first thought was to replace the cable. I looked up the replacement "cable" to see what it was like and found a huge, multi-headed harness instead :shock: Not only complicated and expensive, but it would have had the same geometry in the "bad spot" that led to the problem. So instead I cut off the bad section and used a heavy crimper and FTZ butt to add on a new section including the ring terminal to the starter. I eliminated the sharp bend that had caused the problem. Much faster starting after that!

I did a similar thing on the positive side because Chinook had two MORE wires added to the Ford double schnozzle, and it wasn't pretty. So now I have two Ford rings on the marine post, plus the combiner wire on the MRBF. The fourth wire "went away" as it was the generator start which I moved back to the house bank.

Okay, that got a little off track. Back on, I have really enjoyed reading your write-up. You didn't let any confusion stop you and it looks like you are doing a very tidy job with quality components. NIce!

Oh and yes, while Blue Sea makes many of their own components, in other cases they use industry standard parts (Contura, the fuses that go in many of their components, etc.). That can be good to know, as you found.

BG

PS: I've never had any photos come up sideways, so I'm not sure why that happens.

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PostPosted: September 24th, 2017, 8:18 pm 
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BG-

Appreciate your feedback! I'm loving that 7622 already and the remote is a must IMO. Thanks for the suggestions. The terminal fuses are great and installed in just a few minutes.

I found another spot to ground the engine battery on the engine block on the driver side. It still required 7 feet of 1/0 cable, but it's solid now. I left the existing ford negative battery cable in place, it has that primary, very small gauge wire, going to the engine block and a smaller, short chassis ground wire married to it at the battery terminal. Is there an issue with leaving those ground wires in place?

On another note, while looking for a spot for the new 1/0 negative cable I just installed, I discovered melted wire loom on both sides of engine exhaust manifolds where Chinook ran their wiring back to the house as it passed by the manifolds. The wiring itself was ok, but the loom was trashed. About 3 feet on the driver side and 2 feet on the passenger side. The ford OEM wiring for the chassis had a special wrap to protect it from the heat. The Chinook wiring was secured to the OEM wiring. I had some special wrap and covered those damaged areas.

Thanks again.

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1995 Ford E350 Chassis, 7.5L 460


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PostPosted: September 25th, 2017, 2:09 pm 
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Location: 1999 Concourse
Good eye catching those melted spots. Mine didn't have those, but then Chinook had put the battery combiner way over on the fender, so they had no reason to "cut it close" on that route.

I'm not sure if your "combiner loop" is the same as mine, but here is how I figured it: I have, IIRC, a 225 amp fuse on the positive terminal of the Ford start battery on the 1/0 wire that I ran back to the house battery (combiner loop). Okay, all good. That covers the starter current if I self jump start, and also the 1/0 wire can be safely fused that high. But what about the negative half of that loop? Well, I have a 1/0 negative wire from the house bank to the chassis, then I think we can assume the chassis is at least as good as a 1/0 wire. But then how does that loop get from the chassis to the Ford start battery to complete the loop? In my case it was through the Ford stock wire that went from the Ford negative terminal to the chassis. That was a 4AWG wire. NOT covered by a 225 amp fuse. So my whole loop was no longer 225-amp-fuse-worthy. Hence I replaced that wire with a larger one. Your loop may be somewhat different (?), but that's how mine went.

BTW, it's great to hear that you like the 7622 and found the MRBFs easy to use.

BG

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PostPosted: September 25th, 2017, 6:45 pm 
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BG-

Ok, so I fused at 250 amps, sounds like should have been 225 amps? Not sure why I choose 250 amps.

In checking the repair records from previous owner, the engine battery negative cable was replaced but it is way undersized. The larger wire is grounded to the engine block and I can't get to the bolt. The smaller wire combined with that primary wire at the negative post is grounded to the chassis next to the engine battery.

So, I just need to run a short 1/0 ground cable to the chassis, get a different negative terminal connector and eliminate that the existing undersized ground cable.

Thanks

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1995 Ford E350 Chassis, 7.5L 460


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PostPosted: September 27th, 2017, 7:34 am 
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BG-

I ran a short 1/0 cable to a chassis ground bolt in front of the engine battery and removed the OEM ground wire that connected to engine block and chassis ground by battery.

So here are my circle distances: All cable is Southwire welding cable 1/0

Engine
- 1 foot from terminal fuse block on engine battery positive to 7622. (250 amp fuse)
- 7 feet from engine battery negative to engine block.
- 1 foot from engine battery negative to chassis ground.

House
- 5 feet from 7622 to terminal fuse block on house battery positive (250 amp fuse)
- 1 foot from house battery negative to chassis ground

Thanks

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1995 Ford E350 Chassis, 7.5L 460


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PostPosted: September 27th, 2017, 12:06 pm 
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Sounds like you did a nice, tidy job with robust materials. Good on you!

I don't have that longer ground to the engine block, but I do have a longer run to the starter (Ford stock). That's 4AWG but it's not in the combiner "loop" so it's separate. I did replace the negative jumper from Ford start to chassis like you did (that is in the loop).

I looked and I have a 200 amp fuse on mine. Basically might as well fuse as small as won't trip when jump starting (that's a higher load than alternator charging). My buddy with same engine tried a 175 amp fuse but that did blow (he only ran 2AWG wire so was trying to go with smaller fuse). I laid in 225 amp spares just in case the 200 wasn't enough, but so far it has been fine.

I don't know what the temperature rating of your cable is. Mine is marine cable rated at 105ºC, and that has an ampacity rating of 242 amps in an engine space (heat reduces the rating). If it were rated at 90ºC that would be reduced to 200 amps, and to 191 amps if it were rated 75ºC. I believe most wire should say along the side what the temperature rating is (but I have never used welding cable so no experience with it).

Since MRBF's aren't too pricy, you might try a 200 amp fuse and then self jump start. If it doesn't blow you can then use it. Or maybe a 225. Even with what you have now you are much MUCH better off than you were before (my stock wires in that loop were completely unfused - too small to be able to fuse is probably why). I don't know if you have the exact same starter on your engine as on the V10 (wouldn't be surprised but just don't know) so I don't know exactly how much it draws as compared to the V10.

I did my experimenting with the MRBF because on the other end (house bank) I have a Class T fuse (because the short circuit rating on my larger house bank is too large for the AIC rating on a MRBF) and I did NOT want to just buy a bunch of those to experiment (much more expensive fuses than MRBFs).

Anyway, now you are basically good to go, with a robust, modern system. And you will lose almost nothing to voltage drop when charging, plus you can self-jump start. Nice!

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PostPosted: September 27th, 2017, 10:09 pm 
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BG-

Ok, thanks. The Southwire welding cable is rated at 105C, 285 amps. So in the engine compartment you loose 15-20% of rating?

I'll get those other fuses. My starter is rated at 1.5kw which would be 125 amps.

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PostPosted: September 29th, 2017, 12:31 pm 
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I've never thought of it in strict percentages (I have a chart I go by), but yes, you lose ampacity in a few situations, all of which have to do with heat one way or another. Engine room is one case (I forget the exact temp, but it's not all that high), bundled is another case - the more wires in the bundle the more you lose (there is a factor you can apply for bundles of more wires than they mention in the set ratings, which are 3 or 5).

That sounds like an efficient starter. My buddy with my same engine/starter (V10) tried 175 amp fuse (since he only ran 2AWG wire), but that would blow. 200 has not blown on his or mine (I do carry a 225 as my spare). My starter is rated for 130-220 amps (quite a range). That would not be inrush as that's super quick.

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PostPosted: October 1st, 2017, 8:59 am 
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BG-

I think I noted incorrect amp draw for my starter. I have the 1995 E350 460 7.5L CI. I'm find specs, but they all note 1.5kw for power. I'm not sure where to look for the correct specs. I can't imagine it would be much different than yours, but not sure.

Safe Travels-

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PostPosted: October 1st, 2017, 9:48 am 
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I wasn't able to easily find it for my engine either. And I don't have an amp clamp to test it myself. But, I have a fraquaintence with an E-350/V10, and he had noted that it was 130-220 amps, with a maximum load of 800 amps. I believe the "maximum load" refers to inrush current, which we don't have to fuse for.

I don't remember for sure at the moment, but I think the alternator on my rig is 135 amps. Of course all of the amperage never makes it back to the house bank for charging (because the engine/accessories uses some for itself), but even if it did that would be below the starter draw, so that's the deciding factor.

To lend some credence to that figure, my buddy who first tried a 175 amp fuse on that combiner circuit, would blow it when self-jump starting. A 200 amp fuse solved that problem, so that's what I use (I have 225 amp spares, since they would still cover the wire, and since I wasn't totally sure 200 would do it, plus if the voltage is low, the amps could go up slightly). I haven't actually had to self-jump start (don't seem to have any parasitic loads on my start battery), but my buddy (2003 V10) had to do it quite a bit for awhile while he was chasing down a parasitic load on his start battery. The 200 amp fuse worked fine.

I suppose one thing you could do is look up a replacement starter for your unit vs. mine on an Internet parts house site. I wouldn't be entirely surprised if it's the same starter even with a different engine (but it might not be). You could also just buy some "sacrficial" fuses and see what blows and what doesn't (I know, that's a bit crude, but it would be certain and the MRBFs are not super expensive.

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