Mystery electrical system problem - not sure how to proceed.

Thanks again. I knew how the switch worked, but I wasn't sure if the drawing was showing that - now I see it.

Now just to satisfy my own curiosity I will have to see how I did ground the trim tab relay - with the HPU wire or separately (HPU wire may have been a bit short.... I can't remember because I changed the relay location after I figured out a better place for it (back when I was putting it in). I believe it's all the same electrically though. That will be tomorrow in warmer daylight.

Good suggestion on the diagram and Blue Sea - I'll see if I can e-mail a copy to the tech person for when we talk - that should be a lot better than trying to "tell" how it is. I'm really curious to hear their thoughts.

At this point it would be "easy" if it were just a defective part (although finding it.... not so much!).

Sunbeam

PS: Hmm, I found something interesting. Thing is, I keep thinking it's *much* more likely that some mistake was made than it is for the ACR itself to be defective. So I read the directions for the installation of the ACR just now again. But this time something jumped out at me:

Minimum connections for operation:

• Connect one battery bank to stud terminal A.
• Connect the other battery bank to stud terminal B.
• Connect the quick connect terminal marked GND (ground) to the DC system ground through a ten to fifteen amp in-line fuse to prevent fault currents from flowing in this wire.

I will have to look in the morning, but I think I may not have an inline fuse in the ground connection wire. I have a feeling it is connected directly to the negative bus. I didn't wire that part, so I'm not positive, but I can't "see" an inline fuse there in my mind. I don't know exactly what "fault currents" are, but.... maybe they are what is causing my problem?

Heck, who am I kidding. There is no way I can sleep wondering about that! :dons jacket and headlamp to go look now:

PPS: Just checked: no inline fuse. So maybe "fault currents" are what is causing the ACR to blow fuses when it clicks over into "isolate" mode? That would be a simple fix (which of course I will do anyway, since it's required). Ironically, when I first sea-trialed the boat after all the work, the battery wasn't charging at all (which I could see by looking at the battery monitor). Turns out the ground wire (the very same one!) was connected to the wrong terminal on the ACR. I switched that and it worked fine for the first three weeks of this trip, then the "mystery" started. Now I can't wait for morning so I can ask first my buddy (who is much more electrically inclined than me) - and then perhaps Blue Sea - if the lack of inline fuse is an obvious cause of the issue.

Then I'll see about properly wiring up the optional starting isolation.
 
Excellent. Now that the circuit diagram is drawn up, and everybody's on the same page, we can try to noodle through what might be happening to pop that 30A fuse in the SafetyHub. So far, I don't have a good theory, but I'll sleep on it and maybe something will come to me. (The ACR is certainly suspect at this point, but I'm not convinced that it's the problem.)

In the mean time, I have some thoughts brewing about the overall system layout. With the way everything appears to be wired, I have some concern about the circuit(s) running from the switch to the house loads (through the positive bus). If the switch were ever set to 'combine' (or if there was ever a problem with the ACR :shock: ), there would be no fuse protecting the wires to the trim tabs, or to the distribution block at the helm. They would be connected directly to both the start battery, and to the motor(s) - either of which could end up pumping some serious amperage through those wires if there were ever a short to ground in those circuits.

Just something else to consider...
 
Did you happen to see my PS about the ACR ground not having an inline fuse? I don't completely understand how "fault currents" would affect things, but I now wonder if that is the problem.

AK Angler":39pdxvqe said:
In the mean time, I have some thoughts brewing about the overall system layout. With the way everything appears to be wired, I have some concern about the circuit(s) running from the switch to the house loads (through the positive bus). If the switch were ever set to 'combine' (or if there was ever a problem with the ACR :shock: ), there would be no fuse protecting the wires to the trim tabs, or to the distribution block at the helm.
Click to expand...

Hmmm, that doesn't sound good. I take it this is regardless of the inline fuse in the positive wire to the trim tab relay? (20 amp, as suggested by Bennett.) And of course there is no separate fuse (well, except the one we put in now for testing) on that helm feed wire. I was thinking it was protected by the main fuse, but maybe with the "Combine" function these things are negated?

Is what you are saying that when combining the fuses don't really work as they should because the engine(s) and their outputs could then be connected to these things? That means the amperage could overwhelm the fuses (?)

Since I can't sleep anyway, I think I will go read the instruction sheet for the battery switch again. Since it is meant to combine, maybe it'll shed some light on it.

I sure appreciate your thoughts on this.

Sunbeam
 
Adding the fuse in the ACR's ground wire is a good idea, but I don't think that's the cause of the problem. Fuses are for useful protection from faults, but they do nothing to prevent them.

But, you just stated something that made me stop and reconsider the ACR as the root cause... Everything was good for months, and then this problem cropped up. ... ... ... hmmm ... ... ... Makes me think something may in fact be wrong with the ACR itself, and not the external wiring. I don't exactly know what all's inside of one of those things (and I'm not cutting mine open to find out!), but I do know that there's more than tiny fairies monitoring voltages and flipping switches. There's certainly electronic circuit boards and such. And, all kinds of mayhem can be unleashed when that stuff goes wonky. (I may have a pretty good handle on electricity, but can you tell I don't know much about electronics? :? )

Anyway, I'd like to hear what BlueSea has to say about it...
 
Okay, well since you didn't immediately think that missing fuse on the ACR ground wire was the cause (and I'm not sure), I think I'll still call Blue Sea in the morning. I'll explain about that missing fuse just so they know, in case it's a clue.

By the way, I just looked at the original diagram that the electrical tech wrote up for my system, and I see that on it, the "main breaker" is on the "downstream" side of the switch (i.e. towards the helm) vs. the upstream side where it ended up in the Safety Hub. Maybe that was to prevent what you were thinking about with the "combine" setting on the switch. I think somehow when I agreed to the suggestion of the Safety Hub, that changed. Maybe I need to just change some things around now to make it "proper." I don't mind doing that at all once I figure out how it should be.

On the ACR: Just to clarify, the time period I've been using it for hasn't quite been months - just because this trip on Powell was my first real trip, save for one afternoon "sea trial" on Lake Crescent. But, it did work fine for the first three weeks of this trip, which was 24/7 living aboard/motoring/anchoring, so a fair bit of use. I actually more than doubled the hours on the boat from when I bought it! (Was 52; now around 135.)

I hear what you are saying about how "black boxes" are different than straightforward electrical.

Sunbeam
 
Sunbeam":ofk16kwx said:
Hmmm, that doesn't sound good. I take it this is regardless of the inline fuse in the positive wire to the trim tab relay? (20 amp, as suggested by Bennett.) And of course there is no separate fuse (well, except the one we put in now for testing) on that helm feed wire. I was thinking it was protected by the main fuse, but maybe with the "Combine" function these things are negated?
Click to expand...
Ahh... I missed that somewhere along the way. So, yes, your trim tab wiring should already have adequate protection.

Still, my concern remains valid for the main wire running to the helm. Looking at my diagram, imagine the switch in the 'combine' position (all three switch legs closed). In that case, current can flow from the start battery to the 'start side' of the switch, across the cross-link to the 'house side' of the switch, and then to the positive bus, and up to the distribution block at the helm without going through a fuse. And the same path would be available for current originating at the motor(s). So, with the switch in the 'combine' position, there is no circuit protection for that long wire up to the helm.

Also, a similar path could be created (even if the switch was turned off) if there is any possibility of a fault in the ACR that would internally connect terminal 'A' to terminal 'B'. Again, I don't have a clue about the inner workings of an ACR, but I wouldn't want to find out the hard way if such an internal fault was possible.
 
Pardon my naive question, but I also wondered about the placement of the 30 A fuse. I also would have expected it to be downstream of the switch, with the switch within 7 inches of the battery, and the Safety hub right next to the switch. Placing it between the positive terminals of the two batteries when the switch is set in to Combine mode means if there is a current flowing from one battery to the other, as would be the case if one battery is more fully charged than the other, then that fuse is exposed perhaps to a heavy current.

Is that possibly the problem?

What bothers me about moving the safety hub past the switch is that then the bilge pump circuit(s) will not be energized when the switch is off. I believe you want them energized (and fused) all the time, yes?

Is that Safety hub intended for a two battery system? If so, do the instructions for installation say to put it between the on/off switch and the battery?
 
These sound like good questions that I need to find out the answers to. I couldn't figure out for sure by reading the instructions for the individual components, but I was just looking at some "sample systems" that Blue Sea shows on their website. I *think* they show the Safety Hub between the battery and the switch (like mine) but I'm not completely sure because (of course) none of the examples are just like mine. But.... see this one for example (the safety hub is a 150 not a 100 like mine so it looks slightly different, plus the whole thing is more elaborate). On the other hand, you can't really see what's going on inside the switch, in terms of what is where so maybe there is something I'm not seeing.

http://www.bluesea.com/systems/43/Batte ... _SubSystem

I now have a list of things to ask the good folks at Blue Sea tech help about, thanks to you all :thup As you say, there are many ways to accomplish it - I just need to know that I have what I think I have (or if not, change it). Glad I have things mounted in such a way that I can switch them around without too much agony.

Sunbeam
 
One quick solution to the fuse placement issue would be to swap the SafetyHub and the positive bus in the diagram. The bilge could run off of the positive bus, and the trim tabs and helm power could then be fused off of the SafetyHub, downstream of the switch.

Or, move the Safety Hub to where the positive bus is, delete the positive bus altogether, and run the bilge pump off of the hot terminal of the 'house side' of the switch.

More than one way to skin a cat...
 
Sunbeam":3q65tkfh said:
C-Nile":3q65tkfh said:
After my boat accident, I drove the boat back to port for the twenty-mile trip on my kicker engine...
Click to expand...

I've been meaning to tell you that I've been using a tip that you gave out when telling about that event. Because my Honda 8D kicker has a tiller - and is installed to starboard - apparently it's not easy to install a tie bar to the main. I had that in the back of my mind as a slight negative (although of course I can run it back in the cockpit like a skiff), and then I read your tale of that day, and how you were able to effectively run back under kicker by fixing it in the "straight ahead" position and using your main as a rudder while steering from the cabin/helm. (I should have thought of that as when running small sailboats with outboards we'd just leave them pointing straight ahead and steer with the tiller).

Anyway, I tried it with my Honda kicker on the maiden voyage in September, and, voila!, it worked like a charm. Did the same thing today while running around on the kicker getting the "good" fuel into it. So thanks for that :thup And glad to hear you are good as new again.

Sunbeam
Click to expand...

Your welcome Sunbeam. On my CD 16, lashing the kicker was not as effective due to the weight distribution and length of the boat in that it was very unresponsive in turns. With our length boats, it is really surprising how responsive this set up is. I am glad it works on your boat as well.

Rich
 
Okay, just got off the phone with Blue Sea's very friendly and helpful tech support. AK Angler, your drawing worked a treat, allowing them to quickly see just how everything was set up, without a long, drawn-out description (such as I subjected everyone here to :wink:).

So first we concentrated on the mystery fuse-blowing problem. They could not see any reason why my wiring/set-up should cause such a problem. They also couldn't see any reason why the ACR "should" act that way (it is basically just two automotive relays inside a box), but then they did agree that it does seem to be doing so.

They did ask if we had tried one thing that sounded logical and that we had not thought of to try: That is, combine the batteries manually (with the battery switch) and then "un-combine" them manually (i.e. without the ACR doing it) to see if the fuse then blew. My buddy ran out and did that while I stayed on the phone with Blue Sea. He ran several cycles and ... nothing blew.

Without missing a beat (and even though this is apparently not a "known" failure mode of the ACR), the tech person offered to send out a new ACR to me for free. Even offered 2nd Day air when I said we were going to be leaving the area and might have to wait quite a while to be "settled" at another address. That is fantastic customer service. There was no hint of "Gee, this has never happened before (and thus you, the customer, are the weirdo and we, the company are superior)." That attitude always galls me (especially when I often find out later - thanks to the Internet - that no, I'm not the only person who had X problem). Not a whiff of that from Blue Sea :thup

Next I related my questions about where the Safety Hub is, what might be able to happen when the batteries are manually combined, and a couple of other minor things. I bridged the idea of moving the Safety Hub to the other side of the switch. Some things the tech person mentioned in no particular order (and hoping I understood them and can convey them properly):

1) As far as ABYC recommendations, there is a "grey area" in fusing for the combine function. This has to do with emergency/combine engine starting, and how it is hard to have a fuse large enough for that but small enough to work within a given system. Not that I am looking for loopholes, but he just mentioned it.

2) The tech person did mention that it would be possible (and maybe common for some installations) to have a very large (100 amp, say) fuse in the Safety Hub that would cover the "manual combine" function anyway; but then agreed that that would make the rest of my wiring (e.g. to helm) problematic to protect, so probably not the way to go on this boat. We will, however, figure out what sort of load the Yamaha main engine might draw when starting, to see what we are dealing with in that area. Perhaps my future upgraded helm wiring (say to allow a 50-60 amp fuse) might cover it anyway. This may be moot if we move the Safety Hub -- at any rate we now have more tools to use to figure out the best way to proceed.

3) But they could see why I (actually AK Angler and Astoria Dave!) was asking. We discussed possibly moving the Safety Hub to the other side of the switch (and then using some other fuse block on the battery side for the bilge pump leads). Although, by the way, having the Safety Hub where I do is a common recommendation/installation on "in the water" boats, as outlined on their site -- so it's not always just weird or wrong.

4) I mentioned that when I first put the system in, my house battery was within a 7" cable length of the Safety Hub, so I did not need any circuit protection on the wire (as per ABYC); but then when I had to change start battery sizes, I switched the position of the two batteries (physically), and so now I have a longer cable leading to the Safety Hub from the house battery. The reason I mentioned it is that if the SH were no longer providing that "within 7" fusing, then maybe one of its functions was no longer a "plus" on this side. He then told me about an exception in ABYC that I did not know (or forgot?). That is that one can have up to 72" of cabling before the fuse if it is encased in protection. I have around 27" and it is easy to get to and to see, and is a clear run, so I will put a casing around it. (I like Blue Sea's terminal fuses, but I can't fit one due to height constraints; I was going to put an inline fuse/block in, but now I guess I don't have to.)

So, the plan is to first get the new ACR and put it in with all else "as-is." Then we will recreate the "click over to isolate" moment a few times and see if it still blows the fuse (let's hope not!).

In the meantime we'll be noodling over the best way to arrange or re-arrange my components (Safety Hub, fuses, bilge pump wires, helm fuse blocks) and then order some Blue Sea goodies of one sort or another and get things polished and tidy.

I'll update as we go.

Sunbeam
 
BlueSea did the job for you. Good. I will be very interested in the outcome when you plug in the new unit. Keeping my fingers crossed!

Sounds like you have gleaned a lot of solid information for configuring your wiring, etc., in a safe, approved fashion. Thanks to your careful, persistent attention to the mysterious 30 Amp fuse fracas. :thup 8)
 
Maybe. I am missing something since I am looking at the diagram on the i pad. The ACR should be wired directly to the house battery, not thru this switch or the safety hub.
The diagram shows that when the ACR relay is closed the current goes thru the fuse on the safety hub to the house battery. This could blow the fuse, as the batteries combine.
Also when the ACR relay is closed, then the positive buss is directly connected to the start battery as well as to the house battery, and thus the positive buss is not fused properly. There is no fuse to the trim tab relay.
If the switch is put on combine, then any current from the house battery to the engine start battery will flow thru said 30 amp fuse. If you were to fuse the engine start, it should be 500 or so amps.
 
thataway":2u9baz2a said:
Maybe. I am missing something since I am looking at the diagram on the i pad. The ACR should be wired directly to the house battery, not thru this switch or the safety hub.
Click to expand...

Hi Bob,

The way you describe is the typical way. The reason Blue Sea suggested I wire the A and B leads from the ACR to the switch, is that if wired in the default way, then the ACR draws a constant load (even when battery switch is off). This is not a good feature for while the boat is stored. I want Off to mean Off.

So, when I first called Blue Sea (last January), they suggested this alternative as a legitimate option (wiring the ACR to the cold sides of the switch). So I changed it. Today when I spoke with them I asked them if this was what they had meant (to make sure I had wired it according to their specs), and they said yes. They also mentioned about not fusing (some ABYC exception/grey area) an "emergency" starting circuit... I guess I need to read the standard, because I'm not clear on this.

But, I do also see what you are saying. And I have no particular reason not to change things around; no need to "utilize" a grey area if there is way without one. Why live with that "grey area" if there is no need to? So, presuming I keep the ACR wired the way I have it, so there is no parasitic load (which is how I want it), then to avoid the problem you are speaking of, I need to move the main fuse to the "other" side of the switch (opposite the batteries). Is that right? If so, I don't see any reason why I can't do that. Is there a downside? If not, I think I will plan to do that, and figure out some other way/place to attach my "live" bilge pump leads. (Which I see AK Angler also suggested above.)

thataway":2u9baz2a said:
Also when the ACR relay is closed, then the positive buss is directly connected to the start battery as well as to the house battery, and thus the positive buss is not fused properly. There is no fuse to the trim tab relay.
Click to expand...

I do have a fuse to the trim tab relay (inline 20 amp fuse, as Bennett specified), but I think it's not shown on the diagram (we clarified that after AK Angler drew it). It's between the positive bus and the trim tab relay.

Appreciate the input, thanks.

Sunbeam
 
Sunbeam,

I think where some of the confusion comes from is that the wiring diagram's don't show all of the fuses that you say you have.

Bill Kelleher
 
Hi Bob,

I'm not one to stick my nose in where it's not wanted, but I thought I'd offer a few thoughts...

thataway":31n4cfez said:
The diagram shows that when the ACR relay is closed the current goes thru the fuse on the safety hub to the house battery. This could blow the fuse, as the batteries combine.
Click to expand...

It seems to me as long as the fuse in the safety hub that the house switch is connected to is 30A or greater, this would not be a problem. The 'weak link' in the system would be the ACR 30A fuse (as long as any problem is downstream).

thataway":31n4cfez said:
If the switch is put on combine, then any current from the house battery to the engine start battery will flow thru said 30 amp fuse. If you were to fuse the engine start, it should be 500 or so amps.
Click to expand...

If the switch is on combine, then no current should flow through the 30A fuse - as there is a path of lower (near zero) resistance through the switch between both batteries. All of the current will flow through the "combine" function of the switch since the cables are much larger than the 30A fused wires and the ACR relays have some (more) resistance.

JMHO,
Ray
 
Bill K":1fkpbybm said:
Sunbeam,

I think where some of the confusion comes from is that the wiring diagram's don't show all of the fuses that you say you have.

Bill Kelleher
Click to expand...

Well blame me for that, not AK Angler. That said, I think the only fuse that is within the diagram's "area" and not shown is the inline fuse to the trim tab relay. I think we discussed it after the drawing was made; I may have left it out of my system description because we had eliminated the trim tabs as a possible cause; but of course now we are onto just critiquing my electrical system, beyond the "mystery" problem. That's fine by me as I now plan to make some changes (but first absorbing all this and formulating a plan).

The other part of the diagram that doesn't show everything is where the wires lead off up to the helm (there are many fuses there); but that was also probably not considered germane to the mystery.

I'll see if I can annotate the diagram and re-post it.

Edited to add: Here we go...

My_electrical_system_10_2013_AK_Angler_annotated.jpg

Sunbeam
 
Something happened to me year's ago. One day, my car would not start. The battery was fine, and there was no visible signs of corrosion. The (hot side) battery cable looked fine on the outside, but when I checked, the wire was corroded a few inches inside the cable. The starter could not get sufficient current to crank the engine over.

Is it possible that you have a problem with one of your cables? Internal decay or a defect could cause it to heat up under load and possibly blow a fuse.

Rich
 
Sunbeam,

Re-looking at your diagram, it seems to me that if EITHER of your batteries, start or house, were very low, then the instant that either the ACR or the COMBINE switch joined them together, then a HUGE amount of current would be sent through the safety switch fuse as the good battery tried to transfer energy into the depleted battery (the physics tries to make this happen instantaneously).

In the case of the ACR, it is designed per the installation instructions such that the wire, likely 16ga, offers quite a bit of resistance to this in order to limit the current, and the 30A fuses in those wires (I assume you have them) would protect the wires themselves. When ACR-combined, though, there are then THREE fuses in series connecting the two batteries together.

[EDIT]
2 issues -
1) Looking back at your pictures, I don't see any fuses in your ACR wires that join the batteries. These are recommended by Blue Sea in the installation instructions (http://assets.bluesea.com/files/resourc ... 170140.pdf). This means that in all of the dissimilar batteries cases, the 30A safety fuse would be the only thing trying to limit surge currents. This fuse would definitely open if the batteries were far apart is charge when the ACR closed.
2) I was working from memory on other installations for the ACR - the wire sizes (16ga, etc.) are a function of the charging currents available in your system. The wire (and fuse) sizes are recommended in the installation link above.

The fuses in the ACR lines are the same value as the safety switch fuse in your case, so in the case of an immediate spike/surge that did run through the ACR wires, the weaker of any of those three would blow first. Could it be that the the safety switch fuse was just a bit shy of the two ACR fuses when the ACR combined? Maybe test a 40A fuse in the safety switch and see if one of the ACR 30's then blows first?

Alternatively, in the case of the master switch COMBINE (again with dissimilar battery levels), then the 30 safety switch fuse is the only one in the way of this large current surge, which could blow immediately.

This, again, is ONLY for the case that one or the other battery is very low compared to it's companion.

It also might make sense to take static voltage measurements on the two batteries at a time of similar occurrences (engine just having run, etc.). Or, also, after both have been resting for some time to see if there is a weak cell, etc. in one or the other of them.

Just some more thoughts.....
 
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