Does alternator know how many amps to send to the Battery?

[daveb]

Originally Posted by xcnick

Looks like it just under 20 feet, back, over, down, back, up. I am on Amazon etc right now. 20 foot jumper cables with #2 wire is less than just one run of 20' of #2 wire. Seems nuts so I am still searching. I am looking to run this in a safer place than the original run by the exhaust manifold. Worth the money to have less connectors like you said.

Damn, if that was #10 I wonder what the voltage drop was? That's kinda in the red zone & couldn't pack too much at that distance.
Still I run way smaller than what the chart says to put in. So far I haven't had any issues but I don't run a constant 150 Amp load either. Still it never hurts to go slightly larger.

[Viva]

Originally Posted by daveb

Damn, if that was #10 I wonder what the voltage drop was? That's kinda in the red zone couldn't pack too much at that distance.

I had figured it out for #8, since that's what is in the '97 SMB (and might be what is in this '96, but I don't blame the owner for thinking it was #10 even if it is #8 - it looks darned skinny!) But let's calculate again for fun.

I think it's around a 40' round trip from the start battery to the aft end of the gaucho (on a V10 anyway). Let's give the benefit of the doubt and say 36'. My buddy's V-10 (in a different RV) often puts out 60 amps to the house bank, so we'll go with that (he has around a 130 amp alternator, IIRC, and says he has seen 90 amps but that would be rare).

Calculating the voltage drop for a 36' round trip run on #8 wire, 12 volts, 60 amps, copper conductor (I'll be nice and say not bundled), 75º ambient (167ºF), no conduit, comes out to 14% (ouch). If it were #10 that would be 22.3%!

OTOH, #6 is 8.8%
#4 is 5.5%
#2 is 3.5%
1/0 is 2.2%

If calculating the 150 amps of the V-10 startup (granted, it is only brief), then it calculates as follows:

#10 is 55.8% (ha ha)
#8 is 35%
#6 is 22.1%
#4 is 13.9%
#2 is 8.7%
1/0 is 5.5%

On my buddy's rig we did #2 because he wanted to be able to self jump start, and so we wanted to be able to comfortably fuse to 200 amps. Of course then too he gets the "better" voltage drop for the alternator charging as well. I think one could also just combine the batteries and wait a while, then uncombine and start (with smaller wire). I wish there were a way to wire it so that you could use the house bank without combining it to the "bad" start battery, but that doesn't seem practical when wanting to keep the Ford system stock (and I figure with big wire and the instantaneous jump start maybe the start battery won't draw down the house battery too much?).

For boat systems the ABYC recommends no more than 10% voltage drop for most things, and no more than 3% for critical systems (bilge pumps, instruments, etc.). Of course there are other systems for which reduced voltage drop is also desirable (solar springs to mind).

[xcnick]

Originally Posted by Viva

(I guess airplanes make boats look cheap, but I have never gotten into those...)

I don't know where you are, but I have a big crimper and could potentially make/send you a cable,

I am in Lake Tahoe. Just added that to the profile. I would love to work with someone. Mind if I sleep in your driveway. This forum is the only thing that keeps me from feeling like I am alone in this endeavor. The crimper would be great. So far my plan was to use a propane torch to solder the ends on.

The story of my life is playing way over my head. I am pretty good at it but it takes a lot of labor and advice like this. Basically $100 of labor to save $10. But I even do the airplane thing. I bought a $15000 dollar glider that 15 years later is now worth 20. Most of the people I fly with have $150,000 gliders that are worth 50,000 after 15 years. Don't even get me started on their RV's and that depreciation. $1500 DRZ400 rather than $8000 KTM, ski all winter on $400, $2,000 stand up jet ski rather than a $30,000 water ski boat that you end up driving instead of water skiing, $2000 MR2 rather than a Ferrari. Opps, that one didn't work, I'll quit while I am behind.

I bought this '96 Sportsmobile with 45000 miles for $9,500. This left me room to drop more into it which has been documented on this forum through my questions. But at first glace it would take $9,500 to do the electrical like I dream of and that doesn't make sense for something this old. The sportsmobile is making the wife extremely happy so I am under the gun to make it work well. The glider has only one seat. (The best part of a single seat airplane is the conversation.)

free web site mostly just for notes about my sportsmobile, but here it is:
https://sites.google.com/site/rvnotes4me/home

Trip Blog:
http://xcvan.blogspot.com/

[xcnick]

Originally Posted by Viva

OTOH, #6 is 8.8%
#4 is 5.5%
#2 is 3.5%
1/0 is 2.2%

If calculating the 150 amps of the V-10 startup (granted, it is only brief), then it calculates as follows:

#10 is 55.8% (ha ha)
#8 is 35%
#6 is 22.1%
#4 is 13.9%
#2 is 8.7%
1/0 is 5.5%

For boat systems the ABYC recommends no more than 10% voltage drop.

Thanks, 6 might be enough

[Viva]

Originally Posted by Viva

I don't know where you are, but I have a big crimper and could potentially make/send you a cable,

Originally Posted by xcnick

I am in Lake Tahoe. Just added that to the profile. I would love to work with someone. Mind if I sleep in your driveway. This forum is the only thing that keeps me from feeling like I am alone in this endeavor. The crimper would be great. So far my plan was to use a propane torch to solder the ends on.

Ooh, nice area! Going up 395 (and offshoots) is one of my all-time favorite drives. I totally hear you about working with someone. I often end up doing projects alone, and so many times another pair of hands (or another brain to noodle with) would be so great. Or just the camaraderie even if the other person were only working on their own project but side-by-side. I'm actually out "on the road" in AZ right now, so no driveway, sadly (or you'd be welcome). I do have my crimper along though

I met up with Scalf77 when I was up in Oregon, and he helped me out with "visualizing" quite a few electrical details that I wasn't entirely sure of, plus showed me how he did the "non-heated-vents" mod (on my list). It's great that there are so many knowledgeable and helpful folks here.

Originally Posted by xcnick

I bought this '96 Sportsmobile with 45000 miles for $9,500. This left me room to drop more into it which has been documented on this forum through my questions. But at first glace it would take $9,500 to do the electrical like I dream of and that doesn't make sense for something this old.

Ooh, nice buy. And low miles! Mine had the same stripes but in teal (whee!) I hear you on the project costs though. My '97 was also a "deal" (but had nearly 100k on it and needed tires), and my mission statement for it was "for ONCE in your life just buy something and USE it, without taking ages tearing it completely down and re-doing it, For Pete's Sake." I mostly held to that, although of course I did maintenance, tires, spark plugs, etc. Ironically, a friend of mine bought it from me and then this winter came down to AZ where we just spent a few weeks doing some of the projects I had really wanted to do on it (300 watts solar, MPPT controller, 250 ah of AGM house batteries, battery monitor, re-vamped DC distribution system). Now he can run the fridge full time whereas I had to either plug in or keep a move on (always driving to charge from alternator - through that #8 wire, LOL, good thing I never looked to see how small it was -- kind of knew I shouldn't look too closely). Funny thing is that now the SMB it has 140k on it and my buddy didn't deem it "unworthy." But I know what you mean: That can be one of the irritations of having an older rig, i.e. deciding that things "aren't worth it" and so going without them. Of course it is a real consideration.

I/buddy haven't added up exact figures, and I did have a lot of the "nickel and dime" stuff (tools, wire, lugs and ring crimps, shrink tubing, cushion clamps, stainless fasteners, etc.) left over from another project, and I'd say the project materials that he did have to buy ran somewhere around $3,000 or so (labor was free ) By the way, I asked him and he said it was fine for me to discuss the project/details here on the forum. Here's how I get that figure, just off the top of my head. I may be forgetting something.

Three 100-watt panels, shipped: $450
Blue Sky MPPT controller (25 amp), with built in shunt/battery monitor/remote display: ~$500
Aluminum angles and etc for roof mounting, plus paying shop to cut and polish them: $100
Blue Sea Cable Clam: $25
Blue Sea On/Off switch (to shut solar panels "off"): $25
Two Lifeline GPL 31XT batteries, shipped: $750
Bus bars, fuse holders, fuses, breaker, etc.: ~$400
Blue Sea fuse block = ~$50
8' #4 cable (I didn't have any of this size): ~$25

A Blue Sea 7622 would have added around $200 to the project, and wire/lugs would also have been a chunk, if we hadn't had "stock" lying around. Also this SMB is still fairly simple, with no Inverter or related systems.

But yeah, it took time and money. The nice thing was that the learning curve was small having just done a similar project on another friend's (non SMB) RV.

Let's just hope I can stay out of airplanes

PS: If you really do want to use #6 wire, I can simply make you up one and send it if you let me know the length and what size ring terminals you want on each end. I'd probably go to larger wire, but even #6 is a lot bigger than #8 (or 10!). I don't have #4 on hand. Might have enough #2 but not sure. It would probably have to be black vs. red (I always end up with extra black wire due to the runs with chassis grounds only needing red!). In #6 I could dig up red, I believe.

Thanks for the links to your travels, etc. Going to go check them out.

[boywonder]

Viva: That wiring to the fuse block looks great.......what are you using for labeling the wires? Clear heat shrink from Mcmaster over some generic labels as mentioned in the terminal thread?


viewtopic.php?f=14&t=15568

are those crimp-n-seal terminals?


....looks like we are also using the same water pump.........

[xcnick]

Originally Posted by boywonder

Viva: That wiring to the fuse block looks great

Yes, I am intimidated. I doubt I will be posting pictures when I am done now I have seen this.

Viva, glad Scalff77 or Greg helped you. He was a big help posting the pdf of the isolator manual, thank you. I am glad to have that. I can't take anything apart right now because I am one phone call away from having to drive up to Beaverton. Greg you got your ears on?

I better quit begging for driveways or I will have you all at once in my Tahoe driveway.





But Oregon has gone a little nuts, no more Walmart camping in Cornelius, no camping at Government Camp rest area. I am lucky, my cousin gives me a driveway in Scappoose.

But for now I just sit on the computer while I wait for the phone to ring and plan this electrical thing. It might be a month before I can go at this project.

nick

[Viva]

For labeling I use "extra sticky" TZ tape in a P-touch labeler (can look up actual tape part number later). So I write what I want on the label and print it out on the spot. Then over that I use non-adhesive, clear olefin shrink tubing from McMaster-Carr for insurance (on the labels).

The smaller crimps (#22-#10) are FTZ "crimp 'n' seal" (they include adhesive heat shrink) and the big lugs are FTZ tinned copper (with separate heat shrink in the form of FTZ Dual Wall heat shrink).

Pump is the ShurFlo 4008 (which I guess you can see). The original 1997 water pump started cycling last spring and I was totally worried about some of the (pb) tubing springing a leak inside the walls (had been in 28º weather just before it started). First thing I did was replace the grey valve under the couch (the one that changes from city water to allowing you to fill the tank) as I had read it was vulnerable to freezing. That didn't fix it. Uh-oh. So then I replaced the pump, just because it was 15 years old and was much easier than potentially fixing pipes inside walls. Thankfully that fixed the cycling problem. Whew! So the wall pipes were fine. However it is the current owner (my buddy) who put in the soft hose arrangement. It's much quieter now, although I'm not 100% sure whether that is the new pump, or the "soft" mounting (used to be the rigid pipes went right to the pump) because I had already "moved out" and was in the process of selling it when the pump was changed (I left the hard pipes in that case). And now two variables have been changed. At any rate it is much quieter than with the original pump/piping.

[Viva]

Wow those rowing shells look neato! I used to row "back in the day," but although I loved the teamwork and I love rowing, I was never really into the racing aspect (which is what it was all about). That was just the only way to have enough regular practice to get out and row well, and plus we used club boats. But boats you own and can take out yourself when and where you want? That looks SUPER fun. What kind are they? Those pics with the shells (and bikes) have me all fired up with ideas!

I understand about not wanting to tear into it if you might be heading out on a trip. It's not that easy to do piecemeal.

PS: I bet your install would (will) also look great. It's really pretty easy to make it look organized when you start out with nice, Blue Sea components, wire/labels, good parts, etc.

What you can't see is that the bottom of the compartment is not so neat looking, because a bunch of AC wires run through it and can't really be moved (they come in from "the hole in the wall" and run to the AC breaker box across the compartment). I'll ask my buddy if he can take some photos to show the rest of it.

BTW the "skinny" wire running down/left across the battery is the temperature sense wire for the solar controller - we didn't run #14 battery jumpers! The temp sense wire allows the controller to adjust the voltage for the actual temperature at the battery. Reason is that the voltage is very specific, and is set for 77º. Any amount cooler than that the voltage is raised automatically; if hotter the voltage is toned down. This keeps the batteries happier. The temperature sense is on the battery deemed likely to get warmer.

[xcnick]

Rowing shell is not for racing, open water type. http://maasboats.com/shells-2/aero/