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-   -   Battery Isolators,Separators, and Switches? (https://www.sportsmobileforum.com/forums/f20/battery-isolators-separators-and-switches-7991.html)

TAlvarez 10-13-2014 07:59 PM

Re: Battery Isolators,Separators, and Switches?
 
Thanks everyone.
Did more research and am moving forward with the Grainger 2000W Pire Sine wave Inverter, Blue Sea separator, UB4D 200AH AGM battery, possibly two and 1 100watt+ solar panel. Should be plenty for my rig and the gear that I'll need to run.
Headed back to SMBW next month to have it all installed...

pbjosh 02-04-2015 03:28 PM

Re: Battery Isolators,Separators, and Switches?
 
Question for folks:

In the past I used a Surepower to combine house and starter batteries in a Tacoma. Wiring runs were short (just a couple feet), were double loomed, all terminals were booted, and I didn't use a fuse or breaker. I used 4ga and never had a problem. Truck is still going strong, somewhere in Panamá.

For our van I am using a Blue Sea 7622 so I can use the isolation circuits, the manual override, and the dash switch, since we have a much more involved electrical system. I am planning on 4GA wiring between my house batteries (LiFePo) and starter (regular old lead acid, new from prior owner so I left 'em in). I was planning a 100amp manual reset breaker in the circuit for charging, but time is here to mount it and I realize that if I need help starting or winching off the house battery (hopefully never), that breaker won't do. Of course there are a couple options. A shitty option is jumper cables to connect batteries. OK that's a terrible option, given that I already have wiring in place and getting to the house batteries is not that trivial, it requires pulling up the mattress and unscrewing a lexan panel. Realistically, we should never have a dead starter battery as I can trickle charge the start system from our solar when desired, and we have a 140A alternator and two starting batteries which should keep up with a 12k winch pretty well.

That said, I'd rather be able to start or winch with help from the house if necessary without shenanigans. But those are a lot of amps, even if only briefly over 4GA (about 10' run total). What do folks use for fusing / circuit protection that is good for 500A (for winching) or whatever realistic cranking amps are (probably 300-600?). A bussed block of auto-resetting circuit breakers? A monster breaker? The largest Blue Sea circuit breaker I see is 200A, with a 1 second ability to surge quite high (1200A) and about 10 seconds of 200% duty surge (400A). That is close on the starting but not quite on winching, but really I can't imagine winching with dead starting batteries and the van not running. That is highly improbable, and just plain dumb.

daveb 02-04-2015 04:00 PM

Re: Battery Isolators,Separators, and Switches?
 
Nothing is fused which haunted me over new years. But that said, a cold crank on a diesel might pull higher amps than what you can find in a fuse or breaker. And if you add too large of protection, you need to go with large wire so the protection trips before harm comes to the wire. That is my guess why manufactures don't fuse starting systems. My winch cable (#2 copper) was cut and spliced by Ford several years ago. They wrapped it with black tape which grounded out...the winch wire acted like a fuse but burned the Ford chassis starting harness and then those went up in flames. Nice job Ford :a7:


From the distance that most house systems are away from the winch, I'd guess 2/0 or larger would be what's needed if the starting batteries were dead for winching. As soon as you combine the two systems, the dead batteries also suck up the house reserves trying to recharge them. That pulls the voltage down even more. Not good on the winch motor.
They shouldn't give the idea that the house batteries can be used by themselves to start the engine... more that it assists the starting batteries if they need a little boost. There is a reason why Ford uses larger starting buss wire especially with batteries so far from the engine.

You could incorporate a high amp switch with larger buss and a smaller parallel fused charging circuit. Close the switch only when needed in an emergency. Sorry but sometimes the KISS phrase comes in there when we try to over engineer something. But you're going into a different environment and might need something out of the ordinary.

pbjosh 02-04-2015 04:51 PM

Re: Battery Isolators,Separators, and Switches?
 
Yeah the idea of a separate switched starting system came to my mind, but I would run out of room on two different electrical posts where things hub. The last thing I want to do is find room for and mount buss bars at this point, especially in the crowded engine bay near my starting battery. Pfffffftttt.... :)

I honestly can't imagine winching off the house, really I just can't. I'm sure there's a possible situation but in every case I can think of there is a better solution.

As far as starting, I imagine we'd just combine for a while to let the house bring up the starting batteries then try turning over again, while still combined. FWIW the LiFePo batteries can deliver basically as much current as your wiring and protection solenoids allow. For us, that is limited to about 500-600A for brief periods by the wiring sizes and solenoids employed, as we don't anticipate using over 100A ever, really. But if you have LiFePo, one thing to keep in mind in designing things is that they are able to discharge at over 10,000A when shorted, so it would be fully possible to start off them if we had engineered for it.

I guess I am perhaps overthinking it. Maybe I'll stay with the 100A breaker, or maybe I'll go to a 200A just for a bit of peace of mind, though I would probably want 2GA or 1/0 to match to a 200A breaker and I'm not sure I really need/want that...

Thanks for the thoughts daveb!

Viva 02-04-2015 05:37 PM

Re: Battery Isolators,Separators, and Switches?
 
I'm just re-wiring some things on my rig. A couple of concepts that you may already totally have a handle on (if so, pardon!). Plus, I'm an amateur, so take anything I say with that in mind.

One is that you fuse for the wire. There are "ampacity charts" (for example, ABYC puts one out) that tell you how much the wire can take (and specifies whether it is solo or bundled, in engine room or not [heat]). If you find you can't fuse a wire high enough for your load, then that's your signal to go up in wire size.

With that "combiner" wire you have two big things: One is the draw for the starter motor (if you are going to use it to "jump yourself,") and the other is the alternator output to charge the house bank. On the starter motor for the V-10 (my engine), I think it draws about 180 amps or so (not counting momentary inrush current). Then there is a 130 amp alternator, although I doubt that much would ever be going back to the house bank since the Ford engine takes some of it.

I have some 1/0 wire, so that's what I'm using. That can be fused to 242 amps in engine spaces (with 105ºC rated wire) (you can "overrate the fuse" in some cases, but I'm going to stick with straight ratings), so I'm going to start with a 225 amp fuse on the start battery wire (that goes to house bank), but could move to 250 if necessary.

Then you also want a fuse on the other end of the wire (by the house bank).

There is one more concept to know about, which is AIC, or "ampere interrupt capacity." Essentially if the fuse doesn't have a high enough AIC rating, it can simply melt/fail instead of doing its job. This is not about the fuse size, but about the fuse "strength," if you will.

ABYC (agency that does voluntary standards for boats - well respected) has recently refined their methods for determining needed AIC rating. Problem was that with bigger and more powerful house banks, standard rules of thumb were not enough anymore. If your battery's mfgr. specifies a short circuit number, then you can use that to determine AIC. A Blue Sea MRBF is rated around 10,000 AIC at 12 volts, IIRC. I am fine with the 10,000 AIC of the Blue Sea MRBF for my start battery, and the holder is super handy as it can go right at the battery post (I used a marine adapter stud clamp to convert the automotive post to a stud and then put ring terminals on all of the wiring).

OTOH, with my house bank (3 Lifeline Group 31's), I need more - can't remember the exact figure but somewhere between 15,000 and 18,000 AIC. This put me into a Class T fuse for my house battery bank, on the 2/0 wire coming from the interconnects to the positive bus. The 1/0 run up to the start battery is still fine with the fuse amperage I have for the Class T, so I don't need to fuse that wire separately on the house bank end (normally you have to re-fuse a wire whenever it goes down in size).

Since #4 (presuming non-bundled but in engine spaces - which I think starts at 86º or so) is rated for only 136 amps, that might be tight on fusing (although I believe you are allowed to go 50% over, I never feel like that's so great).

At any rate, maybe that gives you some ideas. Hopefully I haven't misspoken anywhere -- been a month or so since I designed my system. Plus.... not a pro.

daveb 02-04-2015 06:11 PM

Re: Battery Isolators,Separators, and Switches?
 
Quote:

Originally Posted by pbjosh
Yeah the idea of a separate switched starting system came to my mind, but I would run out of room on two different electrical posts where things hub. The last thing I want to do is find room for and mount buss bars at this point, especially in the crowded engine bay near my starting battery. Pfffffftttt.... :)

I honestly can't imagine winching off the house, really I just can't. I'm sure there's a possible situation but in every case I can think of there is a better solution.

As far as starting, I imagine we'd just combine for a while to let the house bring up the starting batteries then try turning over again, while still combined. FWIW the LiFePo batteries can deliver basically as much current as your wiring and protection solenoids allow. For us, that is limited to about 500-600A for brief periods by the wiring sizes and solenoids employed, as we don't anticipate using over 100A ever, really. But if you have LiFePo, one thing to keep in mind in designing things is that they are able to discharge at over 10,000A when shorted, so it would be fully possible to start off them if we had engineered for it.

I guess I am perhaps overthinking it. Maybe I'll stay with the 100A breaker, or maybe I'll go to a 200A just for a bit of peace of mind, though I would probably want 2GA or 1/0 to match to a 200A breaker and I'm not sure I really need/want that...

Thanks for the thoughts daveb!

I didn't ask but there is a hell of a difference starting a diesel over a gas engine. I just assume you have a diesel as your planning an out of US trip. I'm not sure exactly what the amperage rating for a hard cold start on a diesel with low starting batteries (400+ amps). The main thing is in a pinch you don't need a fuse melting out if your life depends on a quick judgement to get your vehicle out of harms way. I've had two electrical incidents and both were from poor installation tactics done by people other than me. Not that I can't FU but none of the SMB's coming out of the factory provide fused battery components unless things have changed over the year. It's a rare occurrence IMO. Now fusing is a good idea in some cases and I'd hate to hear by not doing so that you lost your van due to fire but YMMV. Viva's point is solid and probably a good idea but I'm not fusing mine...yet :b1:

On another note I'd suggest strapping down the chassis batteries if they are mounted to the frame like mine. I was horrified to find the battery boxes stressing where they bolt up. It wouldn't have been long before they dropped on their own. Too much off roading I guess. I really doubt the Ford engineers figured somebody would stick such a heavy off road conversion under the body. I plan to redesign or reinforce the way the batteries are held in place. I've already put heavy straps around my house batteries.

Viva 02-04-2015 07:39 PM

Re: Battery Isolators,Separators, and Switches?
 
I hear you on "letting sleeping dogs lie," and I have done that for awhile too. In my case I needed to do some upgrades to the stock house system, and I didn't want to actively put things back as they were without adding the fuses and upgrading the wiring. Adding the fusing was relatively painless once I figured out what I needed. The one gotcha would be if the wiring was too small to properly fuse (I up-sized).

I mentioned this above, but to elaborate slightly, I put "marine post" adapters on the Ford start battery automotive posts (this is a V-10). These are just lead battery clamps that have studs on them that take ring terminals and then a nut. I followed what I am used to which is 3/8" stud on positive and 5/16" on negative. Quite a few people make them; I have one FTZ and one Ancor (just happened that way due to stock levels, etc.)

So now I had posts. I don't know if there have been changes, but my 1998 chassis had a Ford battery cable harness with "built in" combination lug/clamps that went on the automotive post. The added wire for the run back to the house was sort of wedged in, and not looking super slick. On the positive side of the start battery, I cut the Ford lug/clamp off and put on a tinned copper lug that slips over the marine post. I also put a Blue Sea 5191 MRBF fuse terminal on the new marine post, along with a Blue Sea 5188 225 amp MRBF (fuse). This has 10,000 AIC so is good for my start battery (Odyssey Group 65 AGM).

At the house bank end, I used a Blue Sea Class T Fuse holder (Blue Sea 5502), because it has an AIC rating of 20,000 (I needed around 15,000, so the MRBF was not enough for the three Lifeline Group 31's). I used a 225 amp Class T Fuse in it, and installed it just as the positive cable comes off the battery bank (recommended within 7").

I couldn't get the Blue Sea photos to upload (too large I think), but these part numbers can easily be looked up at www.bluesea.com.

Viva

PS: I also found that where the Ford battery harness negative lead curves around to attach to the starter underneath the van, the black insulation had split at the apex of the curve and the exposed wire was a bit green. I cut off that section and spliced on a new piece of tinned #4 (it's originally #4), with new heat shrink, etc. Actually the inside of the wire wasn't hideous, but I couldn't tell until after I cut it off and opened it up. OTOH, it was not that great looking and who wants "green wire" in the starting system.

pbjosh 02-04-2015 08:00 PM

Re: Battery Isolators,Separators, and Switches?
 
Yeah I have the 7.3. I'm fairly certain I'm going to let it go at the 100 amp breaker near the main starting battery, as that is better sized for the 4GA, but I might get a ~200A, still mulling. I don't have a breaker/fuse between my 7622 and my house battery, but that run is about 4.5 feet of 4ga that is mounted to our non-conductive walls with little stick down mounts and zip tie, and runs straight to the main power pole of our battery protection solenoids. If the shit hits the fan and I need to jump myself I'll move the mattress and the bed platform, take the cover off the electronics and use jumper cables. Gack. Should never happen, fingers crossed.

On the battery mounting, I bent and welded up a box out of .060 5052 sheet. Then welded on feet and built straps that hold the batteries in. It's lined with automotive carpet. Box is held to the floor with 6 x #10 stainless sheet metal screws and to the wall with a couple more via another mounting strap. They are mounted inside the van, not under. I don't think they are going anywhere. All of the electrical stuff (protection solenoids, electrical mgmt computer (from an electric car to manage the solenoids and the LiFePo batteries), a 12-24V DC stepup converter, a marine fuseblock, a large fuse for our inverter, and a solenoid for switching the stepup converter, are mounted in a box that has a screw on lexan cover.

The messy part, for me, is how close my electrical stuff is to my plumbing. I am fitting a very well fit sheet of komatex (PVC board, sort of like a substitute for plywood, more flexible, easier to work, a bit less strength, waterproof and most importantly for me, DOES NOT MOLD!) between the electrical side and the pressurized plumbing side as a splash guard. The non pressurized side of the water supply, coming from the tank, does run under the electronics, but they are protected from beneath and are off the floor in case of flood, and there are only two pex crimps anywhere near the electronics. I hemmed and hawed a lot over placement of things and decided to do this, as we have decided for the fulltime in place bed and maximum possible storage, which shrinks down the systems space...

I uploaded a couple images to imgur quicklike but the 1024 pixel restriction is killing me here. Sorry they aren't inline, follow the links!

Here is the box on top of the batteries. 54lbs for 200AH (180 usable). Battery cost was about $1200 but there are some other additional costs in the mgmt systems ($500+), the solenoids are pricey and there is some logic to avoid wrecking the batteries with over/undercharge.

https://i.imgur.com/hjQ2FvL.jpg

Here is the box installed, I welded some 1/8 6061-T6 bar stock onto the box and tapped 8x32 threads into it, then secured the straps with 3 x 1/4" 8x32 stainless machine screws on each side of each strap. Used the same trick on my strapping for my water tank, which gave me a jenga-esque securing system for the water tank that can be disassembled in place to get the tank out without pulling tons of other stuff, but lets the tanks be as large as possible for the space it is in, if that makes sense.

https://i.imgur.com/uKxPiiP.jpg

Here's the system board installed, but missing a lot of the connections. The box is built of 1/2" Komatex put together with Weld-on PVC cement (forget the Weld-on number at the moment) and brass screws. A lexan cover screws on to the front. One (vacuum side, non-pressurized) PEX pipe runs underneath all that but again it's the non-pressurized side and the box is pretty well protected from below, and the batteries and electronics are all 2" off the floor, and there will be a very well fitted splash guard between all this and the wet bits.

https://i.imgur.com/hNmGcvT.jpg

Anyways this has next to nothing to do with the thread on battery separators or my original question, but there you go :)

And thank you VIVA for the input. I have considered what you mention (more or less). I am only a very slight bit more cowboy in my way of doing things, in that I don't mind large currents through decent quality welding cable for brief periods (IE, if the situation arises, trying to jump start with cable that technically should be a gauge or two larger, where the ignition is only turned for a few seconds), but I really do like to try to build things that won't ever need to be repaired, serviced, or taken apart, at least within my abilities to forsee all possibilities, as limited as they are :)

If any of you have seen my solar thread, I pansied around and failed to drill through my roof all day long thinking about the variations of how to pass the panels' cables through the part of my poptop that is outside the poptop canvas. It's not rocket science but I'm trying to do it with the minimum of holes, minimum of profile of cables on the roof, and the ability to paint over all parts involved to make it less obvious.

Cheers anyways and thanks to all for all their thoughts on my various questions,

Josh

coyotearms 02-05-2015 11:21 AM

Re: Battery Isolators,Separators, and Switches?
 
Quote:

Originally Posted by pbjosh
Question for folks:
That said, I'd rather be able to start or winch with help from the house if necessary without shenanigans. But those are a lot of amps, even if only briefly over 4GA (about 10' run total). What do folks use for fusing / circuit protection that is good for 500A (for winching) or whatever realistic cranking amps are (probably 300-600?). A bussed block of auto-resetting circuit breakers? A monster breaker? The largest Blue Sea circuit breaker I see is 200A, with a 1 second ability to surge quite high (1200A) and about 10 seconds of 200% duty surge (400A). That is close on the starting but not quite on winching, but really I can't imagine winching with dead starting batteries and the van not running. That is highly improbable, and just plain dumb.

My "short" input given Viva's very detailed posts, is that my build came with #4 cables between house bank of three 90 AHr Dekka's, through a Sure Power and to the start bank, which in my case (diesel w/ start bank under chassis within about 4 ft of house bank). According to Sure Power install sheet #4 was appropriate. When I swapped out a dead Sure Power for the Blue Sea 7622, I considered upgrading the #4, but still felt it was appropriate for emergency engine starts so it is still #4. However, I added a Blue Sea MRBF battery terminal fuse block (P/N 2141) to that circuit and a 125 A fuse. After attempting to start the engine with a dead start bank due to a low-current short somewhere in the engine compartment (Ford's fault) I discovered that fuse was burned out. I replaced it with a 175 A one that I felt was as much as I wanted to trust the #4 cabling. That was two years ago, it has never burned out, but I have not had a serious start issue again. If that happened and the 175 A blew, I would upgrade the #4 cabling to whatever Ford uses between the starter bank and starter, upgrade the fusing for what currents expected, but would be assuming I would never winch (assuming it is connected to the start bank) without the engine running fast enough to ensure alternator can put out it's max. In that case the current draw if the house bank is pulled into the mix (probably only with dash switch connecting banks because battery voltage could be so low the isolator may not engage even with solar in the mix) would be only contributing along with the alternator and house bank as all are in parallel at that point. My last suggestion is to invest in a clamp-type ammeter, which is what I did (Craftsman Model # 82369 ~$60, AC/DC current up to 400 amps and replaces your multimeter too) to sort out such issues in the future. But remember given what I said about revving engine and pressing dash switch: never be sitting in your vehicle when winching---does complicate things doesn't it?

awiggin2 07-27-2015 11:07 PM

Re: Battery Isolators,Separators, and Switches?
 
I am a new sportsmobile owner and know very little about electrical systems. That said, I'm hoping the answer to my question does not leave me asking more questions.

I recently went camping and left my van parked for about 48 hours; fridge running the whole time and using the stereo occasionally (maybe 2 hrs/day). This amount power consumption concerned me, but I knew I had cables and a friend's diesel truck, so I viewed it more as an experiment. I left the 'radio switch' on the external/house battery the entire time, thinking if anything ran down it would be the house battery, not the van battery. To my surprise the van battery was dead, yet the fridge (the biggest power hog) was still going strong.

I've read most of the initial post, but I'm still confused as to why this happened and how to fix it. Apparently the refrigerator chewed through the van battery first and then moved onto the house battery. Why? (what good is a house battery if it is second in line to the van battery?)


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