Chinook RV Forum

It is currently September 20th, 2017, 10:11 am

All times are UTC - 8 hours




Post new topic Reply to topic  [ 60 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6  Next
Author Message
PostPosted: August 31st, 2017, 1:53 pm 
Offline

Joined: August 14th, 2017, 6:52 am
Posts: 37
K-

What converter do you have?


Top
 Profile  
Reply with quote  
background-color: #C1CAD2
 

PostPosted: August 31st, 2017, 2:08 pm 
Offline
User avatar

Joined: July 31st, 2014, 1:01 am
Posts: 1828
Location: 1999 Concourse
reddingnative wrote:
As to why you have to have your house power switch turned on for the shore power to work, I'm not sure. I'm going to double check my switch and make sure what I told you is correct.


I'm not sure if this will apply to your generation. But, it may since you mention a "store" switch. My generation (which has/had more stuff, such as LVD etc. nevertheless) still used the "store" switch. Here is why that has to be on:

Well, to work backwards because I think it will be easier to describe, what I have now (and this is typical on boats, which is my background), is bus bars that organize the main power at the house batteries. Essentially, a cable goes from the house battery to the bus bar, and then all the other cables go from there. So it's an organizational scheme. Also keeps a bunch of terminals from collecting on the battery, plus gives room for fusing etc.

Okay, ramble ramble, but the point is that from that positive bus bar, I have one cable going to the charger, and another (separate) cable going to the fuse block for my house loads. Or you could say it in the other direction: One cable goes from the charger (shore/gen) to my house battery bank, and ANOTHER cable goes from the fuse block (loads) to the house battery bank. Thus charging and using power can happen simultaneously, or either one can happen without the other. Sounds logical, right? I think it is. (Another cable brings in solar, another cable goes to the inverter, etc.)

But the way Chinook did it* is to use ONE cable to carry BOTH the loads and the charging. So only one positive cable (not two separate ones like in my scheme I outlined above) goes from the charger to the batteries, and the SAME cable carries the power from the batteries back to the loads.

The "store" switch is mostly like a main battery switch. So when you turn it off, you disconnect the loads from the battery, which is the intention (although it leaves a few loads connected by design). But, since that SAME wire also carries charging to the batteries from the charger, oops, you just cut off your ability to charge the batteries. At least in my era Chinook, there was an idiot buzzer in the cab overhead to let you know you might want to turn the "store" switch back on again if charging was applied. (The maintenance solar that Chinook put in bypassed this by running directly to the house battery post.)

To be fair to Chinook, I think this design is pretty well encouraged (insisted upon?) by the Brown Box power center that is ubiquitous to many RV's. At least if I remember correctly, there was only one place for "main" wires to come in, hence the same wires carry charging and loads. (I now have a separate charger and load center, and tossed the brown box, so I can't look at it to be sure).

_________________
1999 Concourse


Top
 Profile  
Reply with quote  
PostPosted: August 31st, 2017, 4:44 pm 
Offline
User avatar

Joined: October 20th, 2015, 6:57 am
Posts: 526
Location: Northern NJ
reddingnative wrote:
As to why you have to have your house power switch turned on for the shore power to work, I'm not sure. I'm going to double check my switch and make sure what I told you is correct.


Oh, I already know why. In my case, Chinook connected the (under stove in my year) converter (which I've updated to a Progressive Dynamics 9245 with Charge Wizard) directly forward to the underhood house battery and that's it.

The cable from the battery back to the house fuse center is separate.

So I can disable power to the house with my dash switch, yet the converter continues to charge the house battery, the same as solar does. No "please unstore" alarm needed.

_________________
1994 Concourse, wood & heated tile floor, tin ceiling, custom lighting


Top
 Profile  
Reply with quote  
PostPosted: August 31st, 2017, 5:17 pm 
Offline

Joined: August 14th, 2017, 6:52 am
Posts: 37
Blue~Go wrote:
reddingnative wrote:
As to why you have to have your house power switch turned on for the shore power to work, I'm not sure. I'm going to double check my switch and make sure what I told you is correct.


I'm not sure if this will apply to your generation. But, it may since you mention a "store" switch. My generation (which has/had more stuff, such as LVD etc. nevertheless) still used the "store" switch. Here is why that has to be on:

Well, to work backwards because I think it will be easier to describe, what I have now (and this is typical on boats, which is my background), is bus bars that organize the main power at the house batteries. Essentially, a cable goes from the house battery to the bus bar, and then all the other cables go from there. So it's an organizational scheme. Also keeps a bunch of terminals from collecting on the battery, plus gives room for fusing etc.

Okay, ramble ramble, but the point is that from that positive bus bar, I have one cable going to the charger, and another (separate) cable going to the fuse block for my house loads. Or you could say it in the other direction: One cable goes from the charger (shore/gen) to my house battery bank, and ANOTHER cable goes from the fuse block (loads) to the house battery bank. Thus charging and using power can happen simultaneously, or either one can happen without the other. Sounds logical, right? I think it is. (Another cable brings in solar, another cable goes to the inverter, etc.)

But the way Chinook did it* is to use ONE cable to carry BOTH the loads and the charging. So only one positive cable (not two separate ones like in my scheme I outlined above) goes from the charger to the batteries, and the SAME cable carries the power from the batteries back to the loads.

The "store" switch is mostly like a main battery switch. So when you turn it off, you disconnect the loads from the battery, which is the intention (although it leaves a few loads connected by design). But, since that SAME wire also carries charging to the batteries from the charger, oops, you just cut off your ability to charge the batteries. At least in my era Chinook, there was an idiot buzzer in the cab overhead to let you know you might want to turn the "store" switch back on again if charging was applied. (The maintenance solar that Chinook put in bypassed this by running directly to the house battery post.)

To be fair to Chinook, I think this design is pretty well encouraged (insisted upon?) by the Brown Box power center that is ubiquitous to many RV's. At least if I remember correctly, there was only one place for "main" wires to come in, hence the same wires carry charging and loads. (I now have a separate charger and load center, and tossed the brown box, so I can't look at it to be sure).


Blue-Go, thanks so much for the detailed responses, I'm learning so much here. I have to double check my house switch and see if the the same as K's.

So, I posted a pic of the fuse you suggested and also do you make your own wire runs or do you order them pre-made? I don't have the tools for wire that large and my local Interstate Battery dealer can do it. Just need to compare online pricing to them for the wiring I need.

Thanks


Top
 Profile  
Reply with quote  
PostPosted: August 31st, 2017, 8:56 pm 
Offline

Joined: August 14th, 2017, 6:52 am
Posts: 37
kdarling wrote:
reddingnative wrote:
As to why you have to have your house power switch turned on for the shore power to work, I'm not sure. I'm going to double check my switch and make sure what I told you is correct.


Oh, I already know why. In my case, Chinook connected the (under stove in my year) converter (which I've updated to a Progressive Dynamics 9245 with Charge Wizard) directly forward to the underhood house battery and that's it.

The cable from the battery back to the house fuse center is separate.

So I can disable power to the house with my dash switch, yet the converter continues to charge the house battery, the same as solar does. No "please unstore" alarm needed.


So, given the fact that the house switch has 14 gauge wires attached, what is that switch controlling to allow current to and from the converter to the house battery which is a much larger gauge wire.?


Top
 Profile  
Reply with quote  
PostPosted: September 1st, 2017, 11:40 am 
Offline
User avatar

Joined: July 31st, 2014, 1:01 am
Posts: 1828
Location: 1999 Concourse
Kdarling: I figured yours might be different, but maybe the explanation will help someone else. It seems like Chinook was in an experimental/settling period (and I don't mean that in a bad way) in the mid-90's, so some details are not the same on various years or from year to year in that period. Then in '97 (I think) it more or less stabilized (with a few minor changes and then some fusing changes in the mid-2000's).

Anyway, it's always good to look things over as by now previous owners could have done things.

reddingnative: Yes that photo you posted is the fuse holder and fuse I meant. I like them for a few reasons:

1) They go right on the battery post, so there is NO unprotected wire.
2) No need to find a place to mount some other fuse holder.
3) No need to make up short "jumper" wires to go between the batt and some other fuse holder.
4) 10,000 amp AIC rating (see more on this below if interested).

Sometimes you can't use them though. Either if there is not enough height, or if you need a higher AIC rating (again, see below if interested). I could see it would be close between my start battery and the hood, but how close? I mounted the fuse/holder, put the little red cap on it, then stuck some putty on the top and made a cone that stuck up about 1/2". Closed the hood, re-opened it, and my putty cone was intact, so I knew I had the clearance (yay!). My gen van has the start battery on the passenger side at the front (also the hood is fiberglass, not metal, but I still didn't want them making contact). This is with the official Group 65 size Ford start battery.

Okay so let me see if I can finish what I started yesterday, but then stupidly lost before posting :x

So we were talking about why does the wire size need to be bigger (to be safe/proper). Well obviously you CAN get away with what's there, as these rigs have been around for years. But, it's taking a risk. Basically in order to make it work, they had to leave the wires completely unfused (no OCP, no fuse/breaker). If there is ever a short, thousands of amps can be instantly unleashed from the battery(s) (many more than the number of usable amps it stores), and clearly that would not have a pleasing result. Or they can get too warm and smolder. Or nothing could happen, but then I wear a seatbelt and chances are I won't get in an accident on most trips. But if I do, I want it on.

So, every wire size and temp rating (both of these are on the wire, boat wire is generally 105ºC, and so is most of the wire Chinook used) has an "ampacity rating." This is how many amps can safely pass through the wire without it overheating or etc. There are some factors that lower the rating, such as being in an engine space (heat), or being bundled with other wires (again, heat).

So let's take 8AWG wire, for example (such as you have on one leg of your "circle" that's going to include the two batteries, and the 7622. 8AWG (presuming it is rated 105ºC; ampacity would be lower if it's rated 90ºC or below), not bundled (I'll assume), and in an engine space. I look this up on an ampacity table and see that it's rated to be fused (or breakered) to 68 amps. BUT, your alternator (estimating here) can put out more than 100 amps. And your starter (again estimating based on my V-10) can draw 220 amps. So if you put a 65 amp fuse on that 8AWG wire, it's going to blow every time you drive, and every time you self-jump start. Obviously that can't work. So the circuit is therefore un-protected.

Again, obviously these rigs aren't burning down right and left, but some RV's do have electrical fires. For me, it's one thing to go along with original equipment, knowing that it's not really correct but most likely nothing will happen. I can do that some. But to go in and change/re-wire a circuit and leave it like that? That I can't do. If I'm going to go in and work on it, then I'm going to bring it up to safe standards.

So let's see what size wire/cable you'd want. I'm going to lay out the example with the figures for my engine/starter because I don't know what they are for yours (presuming you have the 460 or...? I have the V-10 that came along in 1997). So, my starter can draw from 130-220 amps (there can be an inrush current of up to 800 amps, but this is not counted when figuring out OCP, because it's only for milliseconds). Therefore, I'd like to be able to fuse to at least 225 amps, maybe 250. So I go to my ampacity chart again....

I see that 2AWG/105ºC wire in an engine space, not bundled, can be fused to 178 amps. 1AWG to 208 amps and 1/0 to 242 amps. 2/0 can go up to 280 amps. At this point 1/0 looks like a good choice, but wait, there's more :)

Next I circle around and look at voltage drop. Voltage drop is more of a factor the lower the nominal voltage of a system is. So with a 120 volt house system, it's not much of a factor. You can go 50 or 100 feet from the power source to the load with relatively small wire. And on a larger scale, this is why long-distance power transmission lines are super high voltage. There is less loss. But we are at the bottom rung with only 12 volts. Even 15 feet is a loooong distance if we're talking about a higher amperage circuit (such as your alternator or starter draw). So we balance the amount of voltage drop we are willing to tolerate with the size of the wire we are willing to tolerate. Sure, you could run fire-hose sized wire, but no-one's going to do that. The shorter the wire run the better.

So actually in your case, the ampacity is probably the driving factor and not voltage drop, because your wire run is relatively short, with both your start and house batteries under the hood. In my case, voltage drop was the "stronger" factor, because it's between 15-20 feet from the start battery to the house bank in my Chinook (in around 1997 they moved the house bank to the area under the water heater near the head of the couch, plus the start batter is on the passenger side, so it's a long trip). In your case we can check the voltage drop calculator, but ampacity will almost certainly be your factor.

So from what I listed above, it looks like 1/0 wire would be the way to go. And it would be great. But let's say you don't want to spring for that, or you don't have space, or etc. Well there is an allowance that you can (maybe it's not best, but you can) go up to 50% over the fuse rating if you have to. So you could use 2AWG. The 1/0 is a shoe-in if you want to use it (again, estimating your starter draw and alternator output), but let's say you want to run 2AWG through the theoretical paces:

2AWG in an engine space (presuming you get 105ºC rated wire - more on that below) is rated to 178 amps. 50% more is 267 amps and you are looking to fuse at 225 amps, so you can get by on this level. Now let's look at voltage drop. I'm guessing you don't have a full length negative wire, but instead use chassis grounds (negative wire from each battery goes to frame or other connected metal piece). That makes it a little harder to calculate, as who knows what size "wire" that corresponds to, but let's run it presuming it's all 2AWG. So if I were to run a wire from side to side (actually my combiner wire does cross over), it'd go back to the firewall, over the air cleaner area by the rear hood joint, and then back to the other battery. So let's say ten feet. That's twenty feet round trip. Okay, off to the calculator...

Well, maybe not. As I think about it, that's not all of the wires. Because there is likely a 4AWG wire leading off to the starter for the starting circuit. But, you have 6.5% voltage drop on just the combiner circuit if the starter is drawing 200 amps. Then you'd have say another 6% on the starter wire if it's 6' one-way and 4AWG. This is probably just fine for your jump starting circuit. Motors have a guideline of staying under 10% voltage drop, but this is close and it's only your jump start circuit.

For charging (from alternator to house bank as you drive), the less voltage drop the better, because to a charging battery, tenths of a volt are a big deal. I'd say under 1% is fabulous, under 2% is good, and over 3% is meh.

Using 60 amps as the number going from your start/alternator to your house bank (I use that as it's the most I've seen on any regular basis going from my alternator to my house bank - if you have more it'd likely be brief, is my guess), then you are at 1.9% voltage drop. This is very good for charging.

So, upshot is that this is what I would do:

1) Get an MRBF holder and fuse for the positive post of each battery. If you can find out the draw of your starter that would be great for deciding on fuse size.

2) Run 2AWG minimum, 1AWG better, 1/0AWG best for the whole "circle" from battery to battery through the 7622 (this would include the two short negative leads to ground that I presume go off of each battery)

3) Put the 7622 someplace along the positive cable run - best is the least water and least heat location.

4) Then hook up the smaller wires for the control of the 7622.

As far as making cables, that is a good question. I had cables made for me a number of times in the past, and each time there was some issue. Either they were the wrong length, the crimp was bad, I had made a length mistake, or etc. So, since I knew I'd be doing a bunch of work (and working on friends' projects), I bought a big crimper and laid in a stock of wire/lugs/etc. But not everyone wants or needs to do that. I'd be happy to make up cables for a fellow Chinooker, but I'm off Chinooking and not with my big tools at the moment.

However, there is another option. There is a company called genuinedealz.com (I know, kind of cheesy name but they seem like a good company, have been around awhile, etc.). They sell boat cable and lugs (I have bought FTZ lugs from them), and they will also make custom cables. I had never bought any of the custom cables (since I can make my own), but as it happens I'm helping a friend with a big electrical project, and so since the big tools are not here, he decided to order custom cables from genuinedealz. I actually planned the cables and placed the order, and I can say that their web interface for making up the cables is really good. You "build" each cable and can see it laid out on the screen. Easy and clear. I have not seen the cables yet as they just arrived yesterday (they ship VERY quickly and free shipping via USPS), but my friend said they look really good. I'll add some info here if anything changes once I have seen them.

It's still nice to make your own if you have the tools, Sometimes (especially on larger diameter shorter cables) the orientation of the lugs really matters (and you can get that "just so"), plus you can easily add labels with clear shrink, but being able to order the custom cables for a smaller job is really sweet, IMO.

They use UL rated boat cable (so it will be tinned, finely stranded copper, 105ºC rated). The heat shrink is adhesive (good). www.genuinedealz.com Again, I'll report back within a day or so if I see anything to not recommend the cables once I've worked with them on my friend's rig.

BG

*Oh I said I'd say something about AIC rating if you are interested (and still awake... :lol: ). AIC stands for Ampere Interrupt Capacity. For example, a typical ATO/ATC type blade fuse has a 1,000 amp AIC rating. This isn't the fusing rating (that would be like 15 amp, 30 amp, etc.), but is how many amps the fuse body or holder itself can withstand before it just fails and melts or blows apart or etc. The fuse does you no good if the holder just melts together after all. So let's look at a single Group 27 (common size) battery. I'm using the specs for a Lifeline brand battery since they publish them. The short circuit amp rating of their Group 27 is 3,374 amps. Meaning that in a short circuit situation that many amps can be released all at once (yikes!). So an ATO/ATC fuse, with a 1,000 amp rating, would be destroyed, and that destruction might not break the circuit, so you'd have a pickle on your hands (maybe a burning pickle).

The MRBF, on the other hand, is rated to 10,000 amps AIC. So you can see you have a comfortable margin. There are some other types rated at 5,000 AIC, which you could also use, but they are not as convenient as the MRBF, since it sits right on the battery post.

For another example, my friend's new house bank is two batteries, size 6CT for a 300 amp hour capacity. BUT, the number of amps that could be released in a short circuit is 5,658 per battery, or 11,316 amps for the pair. So the MRBF does not have a high enough AIC Rating (too bad, as they are so convenient!). Thus he had to go to a Class T fuse (bulkier, less convenient, and more expensive) because they have a 20,000 amp AIC rating.

PS: One more thing on the MRBF. If you only have "automotive" terminals on your batteries (the thick posts that are like 5/8" in diameter and not threaded), then you will want to get some marine terminal adapters (these give you a threaded post you can put a MRBF or other lug on such as those you'd get from genuinedealz). Here is one example, although there are also fancier ones:

https://www.amazon.com/Ancor-260325-Ele ... r+terminal

Just don't use the wing nuts (a big no-no) but use lock washers and nuts instead. These are typically a 3/8" post for the positive and a 5/16" post for the negative. It's usually this way on boats to avoid confusion. So that's something to keep in mind if ordering cables with lugs on the end.

I went to these adapters and an MRBF for my start battery (house battery already has marine posts).

PPS: Usual caveat that I'm not a professional electrician, electricity can be dangerous, etc.

_________________
1999 Concourse


Top
 Profile  
Reply with quote  
PostPosted: September 1st, 2017, 4:51 pm 
Offline

Joined: August 14th, 2017, 6:52 am
Posts: 37
Blue~Go wrote:
Kdarling: I figured yours might be different, but maybe the explanation will help someone else. It seems like Chinook was in an experimental/settling period (and I don't mean that in a bad way) in the mid-90's, so some details are not the same on various years or from year to year in that period. Then in '97 (I think) it more or less stabilized (with a few minor changes and then some fusing changes in the mid-2000's).

Anyway, it's always good to look things over as by now previous owners could have done things.

reddingnative: Yes that photo you posted is the fuse holder and fuse I meant. I like them for a few reasons:

1) They go right on the battery post, so there is NO unprotected wire.
2) No need to find a place to mount some other fuse holder.
3) No need to make up short "jumper" wires to go between the batt and some other fuse holder.
4) 10,000 amp AIC rating (see more on this below if interested).

Sometimes you can't use them though. Either if there is not enough height, or if you need a higher AIC rating (again, see below if interested). I could see it would be close between my start battery and the hood, but how close? I mounted the fuse/holder, put the little red cap on it, then stuck some putty on the top and made a cone that stuck up about 1/2". Closed the hood, re-opened it, and my putty cone was intact, so I knew I had the clearance (yay!). My gen van has the start battery on the passenger side at the front (also the hood is fiberglass, not metal, but I still didn't want them making contact). This is with the official Group 65 size Ford start battery.

Okay so let me see if I can finish what I started yesterday, but then stupidly lost before posting :x

So we were talking about why does the wire size need to be bigger (to be safe/proper). Well obviously you CAN get away with what's there, as these rigs have been around for years. But, it's taking a risk. Basically in order to make it work, they had to leave the wires completely unfused (no OCP, no fuse/breaker). If there is ever a short, thousands of amps can be instantly unleashed from the battery(s) (many more than the number of usable amps it stores), and clearly that would not have a pleasing result. Or they can get too warm and smolder. Or nothing could happen, but then I wear a seatbelt and chances are I won't get in an accident on most trips. But if I do, I want it on.

So, every wire size and temp rating (both of these are on the wire, boat wire is generally 105ºC, and so is most of the wire Chinook used) has an "ampacity rating." This is how many amps can safely pass through the wire without it overheating or etc. There are some factors that lower the rating, such as being in an engine space (heat), or being bundled with other wires (again, heat).

So let's take 8AWG wire, for example (such as you have on one leg of your "circle" that's going to include the two batteries, and the 7622. 8AWG (presuming it is rated 105ºC; ampacity would be lower if it's rated 90ºC or below), not bundled (I'll assume), and in an engine space. I look this up on an ampacity table and see that it's rated to be fused (or breakered) to 68 amps. BUT, your alternator (estimating here) can put out more than 100 amps. And your starter (again estimating based on my V-10) can draw 220 amps. So if you put a 65 amp fuse on that 8AWG wire, it's going to blow every time you drive, and every time you self-jump start. Obviously that can't work. So the circuit is therefore un-protected.

Again, obviously these rigs aren't burning down right and left, but some RV's do have electrical fires. For me, it's one thing to go along with original equipment, knowing that it's not really correct but most likely nothing will happen. I can do that some. But to go in and change/re-wire a circuit and leave it like that? That I can't do. If I'm going to go in and work on it, then I'm going to bring it up to safe standards.

So let's see what size wire/cable you'd want. I'm going to lay out the example with the figures for my engine/starter because I don't know what they are for yours (presuming you have the 460 or...? I have the V-10 that came along in 1997). So, my starter can draw from 130-220 amps (there can be an inrush current of up to 800 amps, but this is not counted when figuring out OCP, because it's only for milliseconds). Therefore, I'd like to be able to fuse to at least 225 amps, maybe 250. So I go to my ampacity chart again....

I see that 2AWG/105ºC wire in an engine space, not bundled, can be fused to 178 amps. 1AWG to 208 amps and 1/0 to 242 amps. 2/0 can go up to 280 amps. At this point 1/0 looks like a good choice, but wait, there's more :)

Next I circle around and look at voltage drop. Voltage drop is more of a factor the lower the nominal voltage of a system is. So with a 120 volt house system, it's not much of a factor. You can go 50 or 100 feet from the power source to the load with relatively small wire. And on a larger scale, this is why long-distance power transmission lines are super high voltage. There is less loss. But we are at the bottom rung with only 12 volts. Even 15 feet is a loooong distance if we're talking about a higher amperage circuit (such as your alternator or starter draw). So we balance the amount of voltage drop we are willing to tolerate with the size of the wire we are willing to tolerate. Sure, you could run fire-hose sized wire, but no-one's going to do that. The shorter the wire run the better.

So actually in your case, the ampacity is probably the driving factor and not voltage drop, because your wire run is relatively short, with both your start and house batteries under the hood. In my case, voltage drop was the "stronger" factor, because it's between 15-20 feet from the start battery to the house bank in my Chinook (in around 1997 they moved the house bank to the area under the water heater near the head of the couch, plus the start batter is on the passenger side, so it's a long trip). In your case we can check the voltage drop calculator, but ampacity will almost certainly be your factor.

So from what I listed above, it looks like 1/0 wire would be the way to go. And it would be great. But let's say you don't want to spring for that, or you don't have space, or etc. Well there is an allowance that you can (maybe it's not best, but you can) go up to 50% over the fuse rating if you have to. So you could use 2AWG. The 1/0 is a shoe-in if you want to use it (again, estimating your starter draw and alternator output), but let's say you want to run 2AWG through the theoretical paces:

2AWG in an engine space (presuming you get 105ºC rated wire - more on that below) is rated to 178 amps. 50% more is 267 amps and you are looking to fuse at 225 amps, so you can get by on this level. Now let's look at voltage drop. I'm guessing you don't have a full length negative wire, but instead use chassis grounds (negative wire from each battery goes to frame or other connected metal piece). That makes it a little harder to calculate, as who knows what size "wire" that corresponds to, but let's run it presuming it's all 2AWG. So if I were to run a wire from side to side (actually my combiner wire does cross over), it'd go back to the firewall, over the air cleaner area by the rear hood joint, and then back to the other battery. So let's say ten feet. That's twenty feet round trip. Okay, off to the calculator...

Well, maybe not. As I think about it, that's not all of the wires. Because there is likely a 4AWG wire leading off to the starter for the starting circuit. But, you have 6.5% voltage drop on just the combiner circuit if the starter is drawing 200 amps. Then you'd have say another 6% on the starter wire if it's 6' one-way and 4AWG. This is probably just fine for your jump starting circuit. Motors have a guideline of staying under 10% voltage drop, but this is close and it's only your jump start circuit.

For charging (from alternator to house bank as you drive), the less voltage drop the better, because to a charging battery, tenths of a volt are a big deal. I'd say under 1% is fabulous, under 2% is good, and over 3% is meh.

Using 60 amps as the number going from your start/alternator to your house bank (I use that as it's the most I've seen on any regular basis going from my alternator to my house bank - if you have more it'd likely be brief, is my guess), then you are at 1.9% voltage drop. This is very good for charging.

So, upshot is that this is what I would do:

1) Get an MRBF holder and fuse for the positive post of each battery. If you can find out the draw of your starter that would be great for deciding on fuse size.

2) Run 2AWG minimum, 1AWG better, 1/0AWG best for the whole "circle" from battery to battery through the 7622 (this would include the two short negative leads to ground that I presume go off of each battery)

3) Put the 7622 someplace along the positive cable run - best is the least water and least heat location.

4) Then hook up the smaller wires for the control of the 7622.

As far as making cables, that is a good question. I had cables made for me a number of times in the past, and each time there was some issue. Either they were the wrong length, the crimp was bad, I had made a length mistake, or etc. So, since I knew I'd be doing a bunch of work (and working on friends' projects), I bought a big crimper and laid in a stock of wire/lugs/etc. But not everyone wants or needs to do that. I'd be happy to make up cables for a fellow Chinooker, but I'm off Chinooking and not with my big tools at the moment.

However, there is another option. There is a company called genuinedealz.com (I know, kind of cheesy name but they seem like a good company, have been around awhile, etc.). They sell boat cable and lugs (I have bought FTZ lugs from them), and they will also make custom cables. I had never bought any of the custom cables (since I can make my own), but as it happens I'm helping a friend with a big electrical project, and so since the big tools are not here, he decided to order custom cables from genuinedealz. I actually planned the cables and placed the order, and I can say that their web interface for making up the cables is really good. You "build" each cable and can see it laid out on the screen. Easy and clear. I have not seen the cables yet as they just arrived yesterday (they ship VERY quickly and free shipping via USPS), but my friend said they look really good. I'll add some info here if anything changes once I have seen them.

It's still nice to make your own if you have the tools, Sometimes (especially on larger diameter shorter cables) the orientation of the lugs really matters (and you can get that "just so"), plus you can easily add labels with clear shrink, but being able to order the custom cables for a smaller job is really sweet, IMO.

They use UL rated boat cable (so it will be tinned, finely stranded copper, 105ºC rated). The heat shrink is adhesive (good). http://www.genuinedealz.com Again, I'll report back within a day or so if I see anything to not recommend the cables once I've worked with them on my friend's rig.

BG

*Oh I said I'd say something about AIC rating if you are interested (and still awake... :lol: ). AIC stands for Ampere Interrupt Capacity. For example, a typical ATO/ATC type blade fuse has a 1,000 amp AIC rating. This isn't the fusing rating (that would be like 15 amp, 30 amp, etc.), but is how many amps the fuse body or holder itself can withstand before it just fails and melts or blows apart or etc. The fuse does you no good if the holder just melts together after all. So let's look at a single Group 27 (common size) battery. I'm using the specs for a Lifeline brand battery since they publish them. The short circuit amp rating of their Group 27 is 3,374 amps. Meaning that in a short circuit situation that many amps can be released all at once (yikes!). So an ATO/ATC fuse, with a 1,000 amp rating, would be destroyed, and that destruction might not break the circuit, so you'd have a pickle on your hands (maybe a burning pickle).

The MRBF, on the other hand, is rated to 10,000 amps AIC. So you can see you have a comfortable margin. There are some other types rated at 5,000 AIC, which you could also use, but they are not as convenient as the MRBF, since it sits right on the battery post.

For another example, my friend's new house bank is two batteries, size 6CT for a 300 amp hour capacity. BUT, the number of amps that could be released in a short circuit is 5,658 per battery, or 11,316 amps for the pair. So the MRBF does not have a high enough AIC Rating (too bad, as they are so convenient!). Thus he had to go to a Class T fuse (bulkier, less convenient, and more expensive) because they have a 20,000 amp AIC rating.

PS: One more thing on the MRBF. If you only have "automotive" terminals on your batteries (the thick posts that are like 5/8" in diameter and not threaded), then you will want to get some marine terminal adapters (these give you a threaded post you can put a MRBF or other lug on such as those you'd get from genuinedealz). Here is one example, although there are also fancier ones:

https://www.amazon.com/Ancor-260325-Ele ... r+terminal

Just don't use the wing nuts (a big no-no) but use lock washers and nuts instead. These are typically a 3/8" post for the positive and a 5/16" post for the negative. It's usually this way on boats to avoid confusion. So that's something to keep in mind if ordering cables with lugs on the end.

I went to these adapters and an MRBF for my start battery (house battery already has marine posts).

PPS: Usual caveat that I'm not a professional electrician, electricity can be dangerous, etc.


Blue-Go-
I read your post and will re-read it several more times, very helpful. Thank-you!

In researching the specifications for my starter, I found a Ford Service advisory regarding starting problems associated with some diesel engines with batteries remotely located. In this particular case the diesel engine starter was drawing up to 900 amps and they had received customer complaints of engines not starting due to incorrect wire sizing. Their advisement was exactly as you are suggesting and it stated that vehicles with gasoline engines should follow the same guidelines.

So, really all I need to do is mount the 7622 in place of the existing emergency start solenoid and increase the gauge of my wiring as you suggested. I have all the correct mounting terminals you mentioned.

The 8ga wiring attached to the house battery is the run from the house battery to the house solenoid and on back to the converter. All the other wiring connecting the engine and house batteries is 4ga.

So I have a question regarding these old school solenoids. How much power do they consume when turned on?

Thanks for all the information and links. Enjoy your Memorial Day-


Top
 Profile  
Reply with quote  
PostPosted: September 1st, 2017, 4:53 pm 
Offline

Joined: August 14th, 2017, 6:52 am
Posts: 37
kdarling wrote:
reddingnative wrote:
As to why you have to have your house power switch turned on for the shore power to work, I'm not sure. I'm going to double check my switch and make sure what I told you is correct.


Oh, I already know why. In my case, Chinook connected the (under stove in my year) converter (which I've updated to a Progressive Dynamics 9245 with Charge Wizard) directly forward to the underhood house battery and that's it.

The cable from the battery back to the house fuse center is separate.

So I can disable power to the house with my dash switch, yet the converter continues to charge the house battery, the same as solar does. No "please unstore" alarm needed.


Have a great Memorial Day, thanks for your help.


Top
 Profile  
Reply with quote  
PostPosted: September 1st, 2017, 7:57 pm 
Offline
User avatar

Joined: July 31st, 2014, 1:01 am
Posts: 1828
Location: 1999 Concourse
reddingnative,

Glad you may find the post useful. I know it's kind of a "wall of text."

reddingnative wrote:
In researching the specifications for my starter, I found a Ford Service advisory regarding starting problems associated with some diesel engines with batteries remotely located. In this particular case the diesel engine starter was drawing up to 900 amps and they had received customer complaints of engines not starting due to incorrect wire sizing. Their advisement was exactly as you are suggesting and it stated that vehicles with gasoline engines should follow the same guidelines.


Do you have a diesel? If so, yes I believe they may draw more. But I'm not sure. They do often have two start batteries though. OTOH, even the V-10 can take 800 amps of "inrush" current, but that's not really counted when selected wires or fusing, because it's only for an instant. So, do you have a diesel? If so, then maybe make an extra effort to find out the "normal" starter draw (vs. the inrush current). If you have a gas engine such as the 460, it may be similar to the V-10 but still great if you can find out specs.

reddingnative wrote:
So, really all I need to do is mount the 7622 in place of the existing emergency start solenoid and increase the gauge of my wiring as you suggested. I have all the correct mounting terminals you mentioned.


That's the basic setup, yes. And include the two chassis ground wires that are coming off the two negative terminals. As I think about it, I suppose technically you might want to upgrade the wires to the starter as well, but I did not. Mine are still the original 4 gauge. That said, the charging loop, which is what is in use most of the time (jump start is rare) are all upgraded and that loop is fused.

Then I believe the 7622 is going to have some small wires (and they may have you fuse the small ground wire with a blade fuse) that lead to the remote switch.

reddingnative wrote:
The 8ga wiring attached to the house battery is the run from the house battery to the house solenoid and on back to the converter. All the other wiring connecting the engine and house batteries is 4ga.


I must have missed something in the diagram then. In my notes where I (thought I) copied it down without all the other distractions, I didn't see a way for the "circle" to exist without running through the 8 AWG wire. Did I miss part of the circle?

reddingnative wrote:
So I have a question regarding these old school solenoids. How much power do they consume when turned on?

I don't remember for sure, but something like 1 or 1.5 amps comes to mind for some reason. I think they also induce some voltage drop. The 7622 is what they call "magnetic latching" so I don't think it uses any/much power. Also I don't believe it induces voltage drop in the same way. So a plus all the way around.

Good long weekend to you too!

BG

_________________
1999 Concourse


Top
 Profile  
Reply with quote  
PostPosted: September 2nd, 2017, 8:52 pm 
Offline

Joined: August 14th, 2017, 6:52 am
Posts: 37
Blue-Go-

I do not have a diesel, but that Ford service document suggested that gasoline engines follow the same wiring gauge as for diesel. I have 7.5 L 460 engine CA emissions.

I have 4 wires connected to the positive terminal of my house battery:

1- Primary 4ga. wire connected to the engine emergency start solenoid. (The circle)

1- 8ga wire with two in line 50amp self reset fuses connected to the house solenoid. (Part of the circle?)

1- Wire connected to the Store/In Use switch inside the cab mounted next to the momentary switch for combining both batteries. This wire provides power to turn the house solenoid on and off for use or for charging the house battery.

1- Wire from the solar control panel.

In regards to the power draw of the old school house solenoid, I'm thinking I might, at some point add a Blue Sea battery switch in place of this solenoid if it is more efficient.

Thanks again.


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 60 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6  Next

All times are UTC - 8 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Powered by phpBB® Forum Software © phpBB Group