Electrical Question on a 1,2,3 switch

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Bob S

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Sep 27, 2007
1,813
Beneteau 393 New Bedford, MA
Twice this season I've had the 150 amp Blue Seas fuse on the house bank blow while sailing. I draw about 5 amps for the chartplotter, depth and radar. The battery monitor read 94% charged. Yet when I tried to start the engine it just barely turns over. I switched to battery #2 my reserve and it wouldn't start it either. A further check shows the battery monitor blank and the fuse blown. The first time I had a spare fuse aboard, replaced it and all was good for 4-5 weekends. Last weekend it happened again. This time I didn't have a spare so I pilfered the one on the reserve bank.

What I found confused me:

Without a fuse in the reserve battery I still got power to the DP. I don't believe I should. I will be down to the boat Sunday and want to remove all the wires attached to the back of the switch and check which post should be #1, #2 and both. The back of the switch is lettered not numbered so I might actually have it wired wrong. Any suggestions? Can I take a continuity check between the posts using a multimeter? How would I know which post is which?
 

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Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
1,2,B switch wiring

Bob, this one's simple: forget the continuity nonsense. Take all the wires off the switch, but clearly LABEL them before you remove anything. Since your DP seems to work, the DP wire should be off the C post, right? So the other two posts have to be one or two. Connect your house bank to one of the posts and put some lights on and switch the switch to position 1 or 2. If they work, you know what post it is. Simple. You could also do this with a simple test light, grounded to the negative bus of the panel and check the poles with different 1 or 2 switch positions.

You should also go back to your wiring diagram, which was correct, and trace each and every single one of those wires to assure you have them hooked up properly. In all the years I've been doing what we did together (designing Bob's system) I have not heard of fuses popping as you've described. Mine have been in and working since 1998.

Keep us posted.

Stu

PS This has been happening and you didn't tell me sooner?!?
 
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Feb 6, 1998
11,760
Canadian Sailcraft 36T Casco Bay, ME
Twice this season I've had the 150 amp Blue Seas fuse on the house bank blow while sailing.

Bob,

A 150 amp fuse is on the border for a peak starting load. Peak starting loads can be very easily be in excess of 150 amps for a brief second or so which could blow the fuse.

You need to know what your starter draws before sizing a fuse and we now know it draws just about 150 amps though this may be due to a weak or bad ground or a bad connection causing higher than normal load to the fuse. I would go to a 200 amp min and then check your grounds and make sure they are clean as well as what Stu suggested..
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
I'm not home by my wiring schematics, but I would think if you have a 150 fuse that feeds the circuit breaker panel, you do not want to power the starter off that line/fuse. True, 150 is marginal for a starter, then add some house load and no wonder it blew. Use a second fuse to power the starter load. My slip-neighbor, JIMM, has the C30, and I don't think we found his the way you describe yours.
 

Bob S

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Sep 27, 2007
1,813
Beneteau 393 New Bedford, MA
Thanks for the suggestions.

Stu, I will do as you suggest. Look at my attached schematic, if I removed the fuse from the reserve bank then there should not be power to the DP when the switch is in position 2, yet the green light is illuminated when in #2. That got me confused.

Maine, I'll increase the fuse size.

Ron, the starter comes of the "C" post so it can be started from either the house or the reserve banks. Do i need another fuse in that line?
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Right, Ron. He has separate feeders to the starter and DP. The fuses are at the banks.

Bob, you do not need to or want to fuse switches. What you have is just fine. ? attached? I have your diagram, assume nothing's changed?
 

Bob S

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Sep 27, 2007
1,813
Beneteau 393 New Bedford, MA
Stu, look closer at my original post. There is a pdf there.
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Bob, OK, will do, currently entertaining friends who sailed their C34 down from Vancouver, BC on their way to Mexico.

Patience my friend. I'll compare it to your older one, too.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
I'm suffering from two problems. I've been on vacation for three weeks, and my small laptop only gets dialup of about 20/22 Kbps Here on the Delaware shore. I'll look closer when I'm at home Sunday, but I thought from the PDF that house and starter current went thru the same fuse.
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Old & New are Functionally the Same

so the wiring diagrams should work, only thing missing, old & new, is the (+) connection from the C post to the DP.

My conclusion is that what you drew is correct, so what you installed ain't the same.

Check the wiring.

As drawn it's fine.

As installed, hmmmm??????

[Added] Ron: nope, Bob has separate fuses, the reserve bank is on the left, house bank is in the middle, separate fuses, and the alternator output is also fused at the house bank.
 
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Bob S

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Sep 27, 2007
1,813
Beneteau 393 New Bedford, MA
You're right Stu, I'll add the connection from the C post to the DP. I've been thinking about why the green indicator light would be on even though the fuse was removed from the reserve. I have the echo charger attached directly between post #1 & 2. We motored about 5 hours on the return trip and the monitor showed the bank @ 100% and the echo charger indicator light was green. It's possible there was enough power coming across the post to illuminate the light? I am pretty sure it's wired as drawn and all wires were labeled as I installed them.
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Echo Charger and #2 Fuse

Bob,

I think we have to go back to the basics here. You seem to have two issues: one - the fuse blowing; two - power source with the Echo Charger (EC)

1. The fuse blowing is an issue and I have no idea why. The C34 wiring diagram that we worked off, and modified for you, shows the fuse sizes and I trust Jim's sizing of the fuses - he knows his stuff. OTOH, Maine Sail has a good point and you wouldn't go wrong to increase the size of the fuse as suggested - wouldn't hurt. What you said in your original post was "the fuse blew while sailing." Huh?!? What you didn't say was when the fuse blew. When you started the engine? And why didn't the engine start on either battery? There's something else going on here that we need to track down and think some more about. I just don't have the answer yet. Assume you've checked all connections and lugs, which should be new since you just did this work recently, right?

2. Echo Charger: Remember when I recommended that you put a shut off switch in the ground leg of this puppy? If I didn't, I am sure I sent you a link, most likely this one: reply #15 at === http://c34.org/bbs/index.php/topic,4949.15.html Alternatively, to test your theory out, just disconnect the ground wire, assuming the instruction manual for the EC says it's OK to do that, like our combiner. The fact that you were in a charging mode that combined the banks with the EC is a giveaway and most likely the answer to your panel light. Your two banks were combined, BUT ONLY THE SWITCH determines where the power to the DP is coming FROM. But, again, I'm still suspicious because what you didn't say in your last post was what position the battery switch was in. We NEED that information to understand your quandary. Fill in the blanks, please.:):)

We'll get there.

Stu
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Echo charger added note for Bob

Add to last post: are your sure the EC is working properly. It should shut itself off and disconnect the banks after the charging period is over.
 
Sep 12, 2009
2
sanibel 18 Smyrna,DE
is the echo charger working properly?

if neither battery would start the engine and one fuse was blown why didn't the reserve start the engine? I would check the condition of both battery banks and see if the echo charger is sending power between banks all the time. Trying to charge a dead or nearly dead battery and start the engine should blow the fuse.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
Agreed, in the original post, it sounded like the fuse blew when just sailing along (but I doubt that) but Bob later states (I assume) it blew when he tried to start the engine; correct? I'm back at home and on the big screen, and now the fine print shows up as more than a red or black dot. Bob will add the "C" to DP wire in his scematic, he says. I assume all other power-feed wires and fuses are shown. Bob never states a "both" position on the switch, but I assume there is one, but maybe not? Do you know the amp rating of the switch?

Z:) I also assume the "20-amp shore power" is the output of an inverter/charger powered by shore power, and not AC wired right to the DC components? (Regardless, there should be a smaller (30-amp) fuse close to the battery-source-end of the wire protecting those #10 wires. That would mean putting it next to the battery post. Just thought I'd mention it so maybe he could show that for clarity.

I see it that , given his stated problem, Bob needs to do one or both of two things: increasing fuse size (as allowed by wire size) or increase wire size to allow larger fuses....

Y:) With due respect to MS on fuse size, I see from the power post to B1 is doubled-up #4 wire, and the amp rating for #4 is 160, so Bob really should not go (much) higher than a 150 fuse. The fuse has to be rated for the smallest wire in the circuit. (Minute point, but the insurance company can have a field day with the oversight.) The "reserve" battery to B2 could go to 200 amps with the #2 wire. Both ratings assume his wire is 105C-rated.

X:) Even so, if the fuse to either of the banks is increased, I see a doublle connection will be on the "C" as connecting the starter #4 to a fuse higher than #4 rating. Change that C to starter wire to a #2 AT LEAST.

Bear in mind any fuse is sized to protect the wire. Any "lesser-size" wire additionally connected off of a larger wire would have its own, "lesser-sized" fuse. Obviously Stu has put some work into this, but as I see it, I would:
A:) Coming right off the "reserve" battery. there should be a LARGE fuse- say 200 amps since he is limited by having only #2 wire off the battery. THIS fuse protects THIS wire.

B:) Coming right off the "C" post, there should be a fuse rated to the size of his wire that goes to the DP (1?? amps).

C:) Since the starter and DP wires are both on the "C" post, they both draw through the fuse of whichever battery C is selected to (150 amps at present, and that's why he blows the fuse). If the switch is on the house bank, he is still limited to 150 amps by the fuse AND wire. If he is on the "reserve" battery, he is limited to 150 amps (at present), but could improve this quickly by changing that battery fuse to 200. I know STU will STEW, but this "reserve" battery could be his engine start battery if no other wiring changes are made. Sorry Stu.

D:) Since my neighbor has the C30, we have also dealt with low starting power. 2 house batteries under the stbd settee. It is a long wire run from the house batteries, but if your reserve battery is under the quarterberth, it's a cheaper, shorter to run a new #2 (at least).

Bob, to answer your question about a starter fuse, it is a matter of personal opinion, but I think manufacturers are not putting fuses in the starter circuits- like my new Beneteau- for the exact reason we see Bob's post. Let's not all go off on a new tangent about this, please, but start a new thread if you choose to re-hash any theories.


I know squat about echo chargers, but shouldn't it's charging source be wired right to the alternator wire so as to lessen wire runs and additional connects- both sources of voltage drop?

Bob, that's a great schematic. Looks like the pro one in my owner's manual! I've spent alot of time on this response and checking source books. Alot of bouncing from Pdf to email, also. Once I post this response and see it in one continuous screen, I may find updates or changes may be needed, but the O's play at 1:00, then the Redskins at 4:00.
 
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Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
Back to you, Ron, welcome home

These are my comments on Ron’s post. Thanks for the effort, Ron, good material. Stuff I agree with has been deleted, like most of your great suggestions! Thanks, again.

Bob never states a "both" position on the switch, but I assume there is one, but maybe not? Do you know the amp rating of the switch?

--- Ron between 1 & 2 IS the BOTH post of the switch. Three switch connections, four switch positions including off. The power from the switch goes FROM the C post TO the objects it serves (based on the switch position 1-2-or B), in this case the DP and the starter. It’s a standard Catalina Perko-type, most likely 250/350A (continuous/momentary. It’s adequate for the intended use.

I also assume the "20-amp shore power" is the output of an inverter/charger powered by shore power, and not AC wired right to the DC components?

--- Of course.

(Regardless, there should be a smaller (30-amp) fuse close to the battery-source-end of the wire protecting those #10 wires.

--- There IS a fuse between the Power Post PDP and the house bank on the diagram. The charger is internally fused. We’ve had this discussion over on our C34 Message Board, and our resident expert on TrueCharge units says outside fuses are pretty unnecessary but helpful because access to the fuses inside the TrueCharge are hard to get to unless you know the “secret handshake!”

I see it that , given his stated problem, Bob needs to do one or both of two things: increasing fuse size (as allowed by wire size) or increase wire size to allow larger fuses....

--- I’m gonna completely ignore the main fuse size discussion and wire sizing match you suggest. I think it’s overkill and unnecessary. I do not think the fuse or wire sizes are an issue in Bob’s problem and would recommend he leave them alone and fix whatever starting and EC problems he may have first. Other comments on location are:

Even so, if the fuse to either of … Any "lesser-size" wire additionally connected off of a larger wire would have its own, "lesser-sized" fuse. Obviously Stu has put some work into this, but as I see it, I would:

-- The doubled #4 are two paralleled wires. Yes, you could argue that the individual #4s should be protected, but they're simply like having one #2 (let’s not argue about the equivalency here, Ron, it’s the concept – he saved pulling new wire by paralleling two existing wires. I did it, too, in my boat).

A Coming right off the "reserve" battery. there should be a LARGE fuse- say 200 amps since he is limited by having only #2 wire off the battery. THIS fuse protects THIS wire.

--- There IS a fuse there. Did you miss seeing it?

B Coming right off the "C" post, there should be a fuse rated to the size of his wire that goes to the DP (1?? amps).

--- Not necessarily. Each individual circuit is fused or breakered on the DP panel. Most Catalinas do NOT have fuses on the D.C. side between the 1-2-B switch and the panel. Fusing between switches is unnecessary.

I know STU will STEW, but this "reserve" battery could be his engine start battery if no other wiring changes are made. Sorry Stu.

--- No stewing here:), Ron, you’re right:), it’s simply an operational issue.;) We agree with Maine Sail that the reserve bank should be just that, and use the house bank for everything. BUT, he still can use 2 to start his engine and switch to 1 anytime EVEN WITH THE ENGINE RUNNING without hurting anything, because his alternator output goes to the house bank. Simple!

D Since my neighbor has the C30, we have also dealt with low starting power. 2 house batteries under the stbd settee. It is a long wire run from the house batteries, but if your reserve battery is under the quarterberth, it's a cheaper, shorter to run a new #2 (at least).

--- I believe this is the biggest perpetrated nonsense ever foisted upon the boating community. This crud about putting a battery closer to the starter is idiotic. The extra ten feet of wiring simply makes for a longer run of #2 wire. What’s the big deal? Yes, #2 wire is pretty expensive, but the voltage drop table say it’s good for 16 feet at 3% and 40 feet at 10%. Geez. My start bank is forward of my galley, the wiring is still the old #4 through the 1-2-B switch and my engine starts up every time.

I know squat about echo chargers, but shouldn't it's charging source be wired right to the alternator wire so as to lessen wire runs and additional connects- both sources of voltage drop?

--- OK, then let’s quit while we’re ahead here. It actually is wired just as you suggest, it is just placed at the other end of the same wire thru the PDP (Power Post to house bank and #2 red to reserve bank).

but the O's play at 1:00, then the Redskins at 4:00.

--- Go O’s and Skins!

Thanks again, Ron, we’re pretty much on the same page. We’re all waiting to hear back from Bob, guessing he’s out on the boat tracing stuff down in response to our earlier discussions. Let’s stay with him here, always something to learn.

Stu
 
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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
While I did not actually direct the switch questions to BOB, I assumed he would respond since it is his boat and switch to look at and reply with an answer that is factual and not a guess on anyone else's part. Stu, when you said, "most likely..." that tells me that you DO NOT know the amperage for sure, and thus you should not have answered that question. Leave it to BOB, please. I would appreciate it if people would not answer instead of whomever has been asked- the boat in the original post. I stated "assume" and ended with a question mark with the anticipation BOB would give us the correct answers. Most people would say 1-2-B-off switch, and I wanted it clarified from BOB. There are, in fact, battery switches that DO NOT have the "both" position, which pretty much says they are nothing more than a SPDT switch. I had such a switch on a trailerable boat and I see alot of them in the second-hand shops- mainly because the new, better, switches have the "both" and "off" positions. "C" does not mean BOTH batteries are on, but means either battery can feed C, obviously dependant on the switch selection. And to me, 1-2 switch does not tell me that both can be on/off, though I assumed it could be. Usually it doesn't hurt to ask.

You are wrong, Stu, there should be a (30 amp in this case) fuse in each and every charge conductor that goes to a battery. As I said and is common knowledge (or should be), these fuses are there to protect the wires, not the electrical devices. Unless your C34 expert is smarter than the way my new boat came wired, and the instructions that came with my TruCharge, you should not quote him. You and I have gone around before about miss-information from those C-sites you quote so often. Otherwise, there is the risk of putting the full 150-amp power on that little #10 AND into the charger and starting a fire way before that 150 blows.

As far as the "C"-to-DP fuse, I quote from the "Boatowners Illustrated Electrical Handbook" 2nd edition (McGrawHill): quote" A Distribution Panel or switchboard should be protected at it's source of power (battery, battery switch, or starter solenoid) by either a fuse or trip-free circuit breaker of capacity not exceeding the capacity of the panel or the ampacity of the feed connectors" end of that quote. BOB needs a fuse sized to the rating of the conductor, or of the DP itself. Additionally, I would question if his circuit breaker panel (DP) is rated 150 amps, but it could be. Maybe Catalina didn't use to fuse the DP lead, but I wonder if they do it on new ones? Anyone care to FACTUALLY- NOT GUESS- and verify yea or nay? Beneteau calls that a "mega fuse".

As for the #4 from "C" to the starter that is presently fed by a 150 fuse, in another chapter on overcurrent protection, quote:"branch circuit breakers and fuses should be rated at or less than the ampacity of the smallest current-carrying conductor in the circuit." End of THAT quote. BOB, you need to either put a fuse in that conductor right at "C" or increase the size of it to #2.

As for the paralleled #4 cables, I don't have to argue anything- only quote the text books. I had to go dig up what we refer to as the boater's bible, "Boatowners Mechanical and Electrical Manual". Nigel Calder convieniently has a sidebar on page 185 (of the 3rd edition), that, in addition to 2 other parageraphs on the subject, says: "What is not (his emphasis) acceptable is to provide a single fuse or breaker sized on the agggregate ampacity of the paralled cables. The reason is that if one of the cables is accidentally disconnected, the amp rating of the overcurrent protection device will now considerably exceed the ampacity of the remaining cables( s), creating a fire risk if there is a short circuit. (In fact, on my boat I plan to double a #14 instead of buying #12, but it will be fused per the #14. -Ron)

On the reserve battery fuse, I emphasized "large" to acknowledge that there IS a fuse there, and only that it could be switched out to the 200.

Among wire and fuse problems, it DOES seem Bob has a charging problem, but he needs to address the wire & fuses.

And Stu, #2 wire being $6.60 or more by now, it does add up to some people on a budget- and THAT's the BIG DEAL.

And Stu (any others?) I don't know why you can't understand that if Bob is running his boat lights and gadgets, then also turns on a 150-plus amp starter, why WOULDN'T that blow a 150 fuse? Figure the load as you always tell everyone.

For the record, #4 is 42,000 circular mills (area), #2 is 66,500, #1 is 84,000 according to the West book.
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
OK, I'm NOT "bob", but

the reason I answered, Ron, is that I worked with Bob over the course of a few months to design his system, and I know it as well as he does because I worked with him to develop his wiring diagram. That's why I responded, for Bob's information, to your very helpful post.

I look forward to hearing from him and see what he's found.

Additionally, I would question if his circuit breaker panel (DP) is rated 150 amps, but it could be. Maybe Catalina didn't use to fuse the DP lead, but I wonder if they do it on new ones?

The DP panel is only 30 Amps DC, and that'd be with everything ON, like pumps, anchorlight AND running lights, etc. Not sure where you get the 150 A "panel" from. This is just for clarification.

Don't disagree with much of anything else you wrote, other than the tone.
 

Bob S

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Sep 27, 2007
1,813
Beneteau 393 New Bedford, MA
I can see this has been an active post. There is a lot of knowledge shared on this forum and I thank everyone for that. I hope all opinions can be expressed freely and that it's up to me to digest them and use them. I truly appreciate all the advise I get from here.

Clarification:
It is a 1, 2, both, off switch. It is original Catalina DP and switch. It's funny but the original set up wasn't fused at the batteries and as I understand it most older boats are not but should be. The house bank consists of 2 new 130 ah batteries this season. The reserve battery is a group 24 60ah dual purpose WM and it was on the boat when I bought her Oct 07. I'm not sure how old it is.

All the wiring is as my schematic shows. Nothing was wired differently. All the terminals are new and clean. The echo charger is working properly. The DP panel light would not turn on when in switch position 2 as would be expected. That confused me before because it did light up after removing the fuse but that's because the EC was still sending power to the reserve battery through the switch even though the battery was disconnected. It makes sense to me now and I kind of figured that out before going there today.

The fuse blew when I tried starting her, not before because the chart plotter was active. I did state I had the Radar, Chartplotter and Depth instruments running but I neglected to say the Fridge was also on. Ron, the run from the house bank to the switch is only 6-8'. I can and will replace the paralleled #4's with a #2. Today I increase the fuse size to 200 amps.

I observed the monitor and I had 12.70v on the reserve battery and 12.75v for the house. I tried starting her on #2 (the reserve) and it turns over slowly. When I went below the monitor was reading 12.35v. The fluid levels was good. I think the battery is no good and won't sustain the load it takes to start the engine. What do you think? Nigel wrote" a battery that shows nearly full voltage when under no load but a steady falling voltage when a load is applied, the battery is short on usable capacity.

Question for the both of you. I used #4's on the ground side of this system. Is that a problem? Should I increase those to #2's also?

Thanks again,
Bob
 

Bob S

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Sep 27, 2007
1,813
Beneteau 393 New Bedford, MA
Although I show a shore charger, it has never been used. My only source of charging is the alternator. I'm on a mooring. It's not fused correctly I know. I did buy a 30 amp fuse for it but neglected to install it because I new I was never going to use it.
 
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