I believe the attached image to be the same configuration alternator as I have now. The second attached image is where (I suspect) the B+ Sense attaches to the B+ Output on the alternator, and then goes to charge the batteries (charging will be bypassing the starter, directly to fused batteries). The capped connection being B+ Sense, and upcapped and disconnected being the B+ Output.
If this is correct, does this mean my alternator has a built in charge regulator, and I should disconnect the Sense from the Output, and run the Sense directly to the battery? Or, is the Sense cable used to run to an external charge regulator.
It is not in my budget right now to purchase a charge regulator, during this project, so if one is required, can I leave it connected the way it is now, or can I completely disconnect the B+ Sense without damaging anything, alternator or battery?
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
The only issue I have with your responses is that with 1) a very accurate voltmeter and 2) a very accurate current draw, the totalizer summing 3) amphours consumed should be accurate as well, as this number is merely the product of the first two. I agree wholeheartedly that unless the total available amphours of any specific battery is accurately known (by your 20 hour test plus entering the Peukert and all those other minutiae into the monitor defaults) there is no way the LinkPro can calculate either an SOC percentage OR an estimated hours remaining to the next charge. My point is that simply knowing the first three items is way more valuable information than I've ever had before.
—
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
I'm not following your post. My question is regarding the alternator configuration charging the batteries. I'm inquiring on the configuration of my alternator. 1) Whether it has a built in charge regulator. 2) If no, would I damage the batteries or alternator disconnecting the B+ Sense from the charge circuit? or 3) Should I leave it connected as is (B+ Sense, to B+ Output, to house bank?
If it does contain an internal charge regulator, I would like to utilize it the best possible way. I have 2- 200 A/hr house batteries I will be paralleling and fusing connected directly to the alternator.
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
[quote=rtrinkle]Larry, I'm not following your post. ..... .[/quote]
Robert -
I think Larry was responding to an earlier post (#51) in the thread by Rodd Collins, a/k/a Maine Sail, hence your confusion.
[quote=rtrinkle] I'm inquiring on the configuration of my alternator. 1) Whether it has a built in charge regulator. 2) If no, would I damage the batteries or alternator disconnecting the B+ Sense from the charge circuit? or 3) Should I leave it connected as is (B+ Sense, to B+ Output, to house bank?
If it does contain an internal charge regulator, I would like to utilize it the best possible way. I have 2- 200 A/hr house batteries I will be paralleling and fusing connected directly to the alternator.[/quote]
With again the caveat that I'm not expert on this (and hope that I'll be corrected by wiser minds on the subject if I'm wrong): You absolutely need to have the B+ Sense connected somewhere to the circuit, because without that you have no regulation at all of the charge. You need this regardless of the size of your battery bank; that's how regulators do their job.
If nothing else, you could leave it jumpered over to the B+ output terminal as it apparently is now, from your pictures and description, Since assumedly your plan is to run the alternator output direct to the house bank (or the ACR) with a nice fat new cable (I think you indicated 1 ga), I imagine the voltage drop won't be very significant.
There was some dialog on this between Maine Sail and me a few years back in a different thread here: www.catalina36.org/comment/48484#comment-48484 :
[quote=Maine Sail][QUOTE=Chachere;14776]Maine - This may be a stupid question, but, hey, I'm not proud: As noted in an earlier post in this thread, I recently rewired so that the output of the stock Motorola 55 amp alternator (with its stock internal regulator) on our M25 is now directly fed to the house bank (rather than goes through the 1-2-both switch). Is there something that should be done with the "sensing" -- or it that a non-issue in this context?[/QUOTE] Not stupid at all. With an internal regulator all you can really do is sense the alt. Some of the Moto alts are key excite and some self excite. The best you can do to avoid VD is to run larger + and - wires to the bank. People ALWAYS forget the neg wire and just assume the case ground or factory neg wire is doing its job, usually not. See this for more on that: [B][URL="http://forums.sbo.sailboatowners.com/showthread.php?t=143814&#post942773"]Chronic Under Charging? - Check for Voltage Drop[/URL][/B][/quote]
See also http://forums.sbo.sailboatowners.com/showthread.php?t=143814&#post942773
But to get more accurate voltage regulation, as I understand things it might be better to connect the B+ sense connected by its own wire (12 ga probably enough) to the house bank to get more accurate sensing of the voltage being actually delivered at the battery (versus at the B+ Output of the alternator). As I said, wiser minds may correct me on this.
You might also look at https://www.catalina36.org/forum/technical-discussion/why-do-i-need-exte...
Hope this is of some use.
—
Matthew Chachère
s/v¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Yup. Agree with Matt. The sense is feedback to the regulator about battery voltage. The sense placement becomes a factor when the output of the alternator experiences significant voltage drop before reaching the batteries. If drop is not a factor, then connecting sense directly to the alternator output lug is fine. The sense draws very little current, so 12ga wire is fine regardless of connecting sense a few inches over to the alternator output lug, or running sense all the way to a battery or an isolator.
Speaking of isolators, a good example of sense options with fixed regulators. Here, alternator output would connect to the isolator common lug and sense might go to the isolator house battery lug. The regulator would sense that the house battery voltage was persistently lower than target voltage and would boost the alternator output to compensate for diode drop. Another common technique for isolators is to insert a diode in series with sense and just connect sense to alternator output. Essentially doing the same thing, i.e. encouraging the regulator to encourage the alternator to boost output to compensate for resistive loss.
—
Nick Caballero
Retired C36/375IA Mk II Technical Editor
The only issue I have with your responses is that with 1) a very accurate voltmeter and 2) a very accurate current draw, the totalizer summing 3) amphours consumed should be accurate as well, as this number is merely the product of the first two. I agree wholeheartedly that unless the total available amphours of any specific battery is accurately known (by your 20 hour test plus entering the Peukert and all those other minutiae into the monitor defaults) there is no way the LinkPro can calculate either an SOC percentage OR an estimated hours remaining to the next charge. My point is that simply knowing the first three items is way more valuable information than I've ever had before.
[/quote]
Yes you have a lot more information than you had before!
Ah counters count Ah's VERY accurately! This is easy.
*The problem is that what they count as removed & returned may not have any good relevance other than a very big "ball park" in relation to the battery in terms of SOC...
*Take the 375Ah battery used in my article for example.
>If we discharge it from full at 18.75A & 77F and remove 187.5 Ah's we are at 50% SOC. Easy and accurate Ah counting if the bank was actually 375 Ah's.
>If we now discharge that same battery at 4.86A at 77F if becomes a 486Ah battery, not a 375 Ah battery so your -187.5 Ah's is not the 50% SOC one might assume it is. Instead of being at 50% SOC you are really at 61.4% SOC an 11.4% variance in just one cycle by not computing for Peukert.. This is the point where I get complaints that the alt won't stay in bulk etc. etc. because the actual SOC is higher than it is assumed. This is safe for the battery, for a while, but leads to inefficient charging.
>Now what if the battery temp drops and you still discharge 50% of the "rated" Ah capacity based on the -Ah's screen?
>What if the Ah counter hits -0.0 Ah's? You're "full" right? Probably not...
>You now discharge again based on the Ah counter reading -0.0Ah's as "full" but you only put back 100% of what you removed and it really takes 130% of what you removed to actually be "full"....
>So again you discharge to an assumed 50% SOC based on the -Ah's screen... Now where are you, SOC wise, without accounting for Peukert, charge efficiency or battery temp at discharge....???
>What if your solar system tricked your monitor into resetting when the -Ah's screen still read -45Ah's....?
Again, these devices provide excellent information, count Ah's extremely accurately but the information they provide & count is rarely in-line with your battery, unless they are used & set up properly....
Mods:
Can we please leave these posts until we have a good way to move them... My last post took considerably time to respond to and was removed due to thread drift. This stuff is all relevant in the context of this thread, despite it drifting a bit......
Robert, somehow this thread was hijacked (alas, I was probably one of the hijackers) onto the topic of battery monitors. Nick is planning to separate those posts from your topic and make a new battery monitor thread.
Sorry to derail your starting battery thoughts, but I *was* responding to an earlier Maine Sail post. Apologies.
—
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
Yup, I tried to separate out the contents yesterday, but the new system only allows me the complete reassignment of all threads to another forum. I've got a message off to investigate this. Stay tuned.
—
Nick Caballero
Retired C36/375IA Mk II Technical Editor
Thanks for all the comment , and validating my thoughts. We are heading to the boat to de-winterized it, and I will get a better look at the alternator. I plan on connecting b+ sense directly to the battery with the same gauge wire connecting b+ sense to b+output. Will be using 1/0gauge wire from alt to battery. I'll keep you posted as the project continues.
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Update - So the 1/0 battery cable fished fine from the engine to the house battery compartment. I placed the starting battery in the fwd settee, however, I could not get the 1/0 AWG cable to run to the fwd settee. It kept getting stuck in the conduit behind the starboard bulkhead. It was a tight fit to get the cable in the conduit. Also tried to run it underneath the conduit with some flexible conduit. Still would not go through. Any thoughts on this? I have tried running the cable in both directions with no luck.
I have my ACR mounted in the house battery compartment. I need to run 3 cables (2 Pos, and 1 Neg) from the fwd settee to the rear settee. 1st Pos is for ACR, 2nd Pos is for starting circuit. Anyone got any ideas?
I'm running the alternator to the fused house bank. The ACR to the house bank and starting battery. The starting battery to the combiner at the chart table.
I picked up some 2 ga and 4 ga cable if I can't get the 1/0 to pass from aft settee to fwd settee. Would either of these suffice if I can't get the 1/0 ga to pass through?
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Robert -
I haven't tried fishing a cable through that area (although others have apparently done so), but what about the idea I suggested in an earlier comment above (see www.catalina36.org/comment/57114#comment-57114 )
that you might want to consider the alternative of putting the start battery in the little compartment behind the upper seat back cushion of the aft starboard seat, just above the existing battery compartment, as Soko did: https://julandra.shutterfly.com/195 (link is external) Would seem like an easy and much shorter cable run....
—
Matthew Chachère
s/v¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Yes you can move the v-sense to the battery bank. I do however urge caution with this because I have seen numerous internal regs continue to draw a few mA even with the key/excite in the off position. This is why I generally say not to do it, especially if I suspect the owner would not know how to check for a parasitic draw....
This parasitic draw is fine when you are on-board and using the boat but if left on a mooring on on the hook for a while unattended this can create an issue as the v-sense remains connected even with the batt switch off....
Also with internal regulators it is sometimes very difficult to get the negative sense side of that circuit to the bank. Positive v-sense is fine but it still only represents half the system wiring drop.
Can it be done? Yes, but you should confirm there is no parasitic draw on the v-sense wire when the ignition key is in the off position before doing so. If you really want to get all techie you could insert a relay in the v-sense wire that is opened and closed with the ignition key but at that point, in terms of time consumption, you would probably be better served with an external regulator...
[quote=Maine Sail]Yes you can move the v-sense to the battery bank. I do however urge caution with this because I have seen numerous internal regs continue to draw a few mA even with the key/excite in the off position. This is why I generally say not to do it, especially if I suspect the owner would not know how to check for a parasitic draw...[/quote]
I suspect the parasitic draw would occur even with the v-sense connected to the B+ output on the alternator, then B+ output directly connected to the battery?
[quote=Maine Sail]This parasitic draw is fine when you are on-board and using the boat but if left on a mooring on on the hook for a while unattended this can create an issue as the v-sense remains connected even with the batt switch off....[/quote]
Can the parasitic draw be checked with a multimeter using the snap around non-contact ammeter?
[quote=Maine Sail]Also with internal regulators it is sometimes very difficult to get the negative sense side of that circuit to the bank. Positive v-sense is fine but it still only represents half the system wiring drop.
Can it be done? Yes, but you should confirm there is no parasitic draw on the v-sense wire when the ignition key is in the off position before doing so. If you really want to get all techie you could insert a relay in the v-sense wire that is opened and closed with the ignition key but at that point, in terms of time consumption, you would probably be better served with an external regulator...[/quote]
If there is an issue I will probably keep the v-sense connected the way it is. I am using a 1/0 ga. cable between the alternator and the battery. Its about a 15' run of cable. So I would suspect very minimal voltage drop.
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Matthew Chachère
s/v¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Thanks, Maine -- as I wrote in my earlier comment, I was hoping that "wiser minds may correct me on this"!
—
Matthew Chachère
s/v¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Any further ideas on the cable size? I can't seem to pass 1/0 cable to the starting battery. So thinking of using 2ga or 4ga for the charging circuit and starting circuit. I suspect the starting circuit would draw more current than charging. Ideally, I would use the largest cable possible for each circuit.
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Robert,
4 ga seems a bit small to me, but that's just my gut talking, with no empirical evidence to back it up. As Matthew suggested, I'm wondering why you don't put the starting battery in the compartment just above the house bank as I did. With a saber saw and a few minutes I had the opening big enough to fit the battery, and EVERYTHING is hidden by the backrest cushion. Shorter wire runs, and no conduits to worry about. Just a thought.
Tom,
I am actually thinking of putting it there. Did the cutout of the compartment take away from the support behind the cushion any? Do you have any pictures of the install? I suppose you drilled holes in the bottom of that hidden compartment to run the cables down to the battery compartment? One last thing, is there a place to purchase the trim that goes around the cutout behind the cushion?
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Robert,
The cutout did not take away from cushion support. I did that project well before digital cameras, and I do not have any pix of the install. From memory, I think I had to make a small wooden platform for the battery box to sit on, because the depth of the compartment was not quite enough (by depth, I mean the distance between the seatback and the hull), so I had to raise it up a bit. Yes, the wiring simply went down thru the bottom of the compartment into the battery compartment. I've seen the trim in several places since, but I can't remember exactly where. Should not be hard to find. Hope this helps.
Sounds like a plan. I would rather have it there, it would save on storage space. What gauge wires did you use for the starting and charging circuits? Do you think 2 ga would be plenty? My ACR is mounted in the main battery compartment, and the starting circuit will run behind the electrical panel, then following the OEM cables under the deck to the engine.
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Here is a thought. The space right behind the nav seat would be a good spot to put a battery. Lower center of gravity and it would not seem to be to difficult to build a box to contain. Wire run would be short as well and easy access.
—
Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine
That is a good thought too. I removed my swinging nav seat and built a compartment and shelves under the nav table. I look at that spot as well. Thanks. Since I'm using AGM batteries, I don't need to worry about keeping them completely upright.
With AGMs, they can lay on their side, correct?
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
I have installed the battery, ran the cables, and crimped them as necessary. Everything looks good so far. I'm still waiting for the terminal block fuses, and the battery monitor to come in, so not everything is hooked up yet. However, I did disconnect the alternator from the starter, re-terminated the sense+ and ignition switch wire to the starter and cleaned all the connectors. Here are some pics of that work. When I am completely done, I send more picture and finalize this project.
Thanks, again for all the great advise and wisdom shared on this post. I couldn't have done it without all your support. I think the end result will be a cleaner, better regulated, starting and charging circuits.
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Final installation.
I want to thank all of you who have posted ideas, comments, and information regarding this project. I have learned a lot about my electrical system through your words of wisdom, and articles you all have recommended. Again, thank you all. I am very happy with the outcome.
During the installation, I was also found some discrepancies in the electrical system, some of which you all pointed out, some found on my own. These discrepancies have been corrected, and the system appears to be working great. Please see the pics for the install.
I placed the starting battery on the shelf under the chart table I built last spring, and relocated the rarely used items normally stored there to the cubby hole behind the starboard aft settee, so it was a much easier and shorter cable run, yet still well hidden, easy to access, and well protected in the strapped down battery box. The red box to the left, inside the distribution panel is the on/off switch for the starting battery, it is accessed through the locker over the aft settee. I used Matthew's schematic for the circuit. The house banks are paralleled together, alternator feed directly to the house bank.
When installing the shunt for the monitor, the cable leading from the old shunt to the Neg bus bar parted from the terminal lead. I was able to clean the wire strands, repack and crimp again to repair. If I didn't find that, eventually the cable would have separated from the terminal on its own, and I would have lost all electrical. Of course that would have happened at the worst possible moment. So I went back and checked all other previous connections.
—
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
I read this great article relating to alternators and charging, but need a bit of clarity on the alternator configuration. http://www.pbase.com/image/158792518#comment_list.
I believe the attached image to be the same configuration alternator as I have now. The second attached image is where (I suspect) the B+ Sense attaches to the B+ Output on the alternator, and then goes to charge the batteries (charging will be bypassing the starter, directly to fused batteries). The capped connection being B+ Sense, and upcapped and disconnected being the B+ Output.
If this is correct, does this mean my alternator has a built in charge regulator, and I should disconnect the Sense from the Output, and run the Sense directly to the battery? Or, is the Sense cable used to run to an external charge regulator.
It is not in my budget right now to purchase a charge regulator, during this project, so if one is required, can I leave it connected the way it is now, or can I completely disconnect the B+ Sense without damaging anything, alternator or battery?
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Rod, no sweat.
The only issue I have with your responses is that with 1) a very accurate voltmeter and 2) a very accurate current draw, the totalizer summing 3) amphours consumed should be accurate as well, as this number is merely the product of the first two. I agree wholeheartedly that unless the total available amphours of any specific battery is accurately known (by your 20 hour test plus entering the Peukert and all those other minutiae into the monitor defaults) there is no way the LinkPro can calculate either an SOC percentage OR an estimated hours remaining to the next charge. My point is that simply knowing the first three items is way more valuable information than I've ever had before.
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
Larry,
I'm not following your post. My question is regarding the alternator configuration charging the batteries. I'm inquiring on the configuration of my alternator. 1) Whether it has a built in charge regulator. 2) If no, would I damage the batteries or alternator disconnecting the B+ Sense from the charge circuit? or 3) Should I leave it connected as is (B+ Sense, to B+ Output, to house bank?
If it does contain an internal charge regulator, I would like to utilize it the best possible way. I have 2- 200 A/hr house batteries I will be paralleling and fusing connected directly to the alternator.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
[quote=rtrinkle]Larry, I'm not following your post. ..... .[/quote]
Robert -
I think Larry was responding to an earlier post (#51) in the thread by Rodd Collins, a/k/a Maine Sail, hence your confusion.
[quote=rtrinkle] I'm inquiring on the configuration of my alternator. 1) Whether it has a built in charge regulator. 2) If no, would I damage the batteries or alternator disconnecting the B+ Sense from the charge circuit? or 3) Should I leave it connected as is (B+ Sense, to B+ Output, to house bank?
If it does contain an internal charge regulator, I would like to utilize it the best possible way. I have 2- 200 A/hr house batteries I will be paralleling and fusing connected directly to the alternator.[/quote]
With again the caveat that I'm not expert on this (and hope that I'll be corrected by wiser minds on the subject if I'm wrong): You absolutely need to have the B+ Sense connected somewhere to the circuit, because without that you have no regulation at all of the charge. You need this regardless of the size of your battery bank; that's how regulators do their job.
If nothing else, you could leave it jumpered over to the B+ output terminal as it apparently is now, from your pictures and description, Since assumedly your plan is to run the alternator output direct to the house bank (or the ACR) with a nice fat new cable (I think you indicated 1 ga), I imagine the voltage drop won't be very significant.
There was some dialog on this between Maine Sail and me a few years back in a different thread here: www.catalina36.org/comment/48484#comment-48484 :
[quote=Maine Sail][QUOTE=Chachere;14776]Maine - This may be a stupid question, but, hey, I'm not proud: As noted in an earlier post in this thread, I recently rewired so that the output of the stock Motorola 55 amp alternator (with its stock internal regulator) on our M25 is now directly fed to the house bank (rather than goes through the 1-2-both switch). Is there something that should be done with the "sensing" -- or it that a non-issue in this context?[/QUOTE] Not stupid at all. With an internal regulator all you can really do is sense the alt. Some of the Moto alts are key excite and some self excite. The best you can do to avoid VD is to run larger + and - wires to the bank. People ALWAYS forget the neg wire and just assume the case ground or factory neg wire is doing its job, usually not. See this for more on that: [B][URL="http://forums.sbo.sailboatowners.com/showthread.php?t=143814&#post942773"]Chronic Under Charging? - Check for Voltage Drop[/URL][/B][/quote]
See also http://forums.sbo.sailboatowners.com/showthread.php?t=143814&#post942773
But to get more accurate voltage regulation, as I understand things it might be better to connect the B+ sense connected by its own wire (12 ga probably enough) to the house bank to get more accurate sensing of the voltage being actually delivered at the battery (versus at the B+ Output of the alternator). As I said, wiser minds may correct me on this.
You might also look at https://www.catalina36.org/forum/technical-discussion/why-do-i-need-exte...
Hope this is of some use.
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Yup. Agree with Matt. The sense is feedback to the regulator about battery voltage. The sense placement becomes a factor when the output of the alternator experiences significant voltage drop before reaching the batteries. If drop is not a factor, then connecting sense directly to the alternator output lug is fine. The sense draws very little current, so 12ga wire is fine regardless of connecting sense a few inches over to the alternator output lug, or running sense all the way to a battery or an isolator.
Speaking of isolators, a good example of sense options with fixed regulators. Here, alternator output would connect to the isolator common lug and sense might go to the isolator house battery lug. The regulator would sense that the house battery voltage was persistently lower than target voltage and would boost the alternator output to compensate for diode drop. Another common technique for isolators is to insert a diode in series with sense and just connect sense to alternator output. Essentially doing the same thing, i.e. encouraging the regulator to encourage the alternator to boost output to compensate for resistive loss.
Nick Caballero
Retired C36/375IA Mk II Technical Editor
[quote=LCBrandt]Rod, no sweat.
The only issue I have with your responses is that with 1) a very accurate voltmeter and 2) a very accurate current draw, the totalizer summing 3) amphours consumed should be accurate as well, as this number is merely the product of the first two. I agree wholeheartedly that unless the total available amphours of any specific battery is accurately known (by your 20 hour test plus entering the Peukert and all those other minutiae into the monitor defaults) there is no way the LinkPro can calculate either an SOC percentage OR an estimated hours remaining to the next charge. My point is that simply knowing the first three items is way more valuable information than I've ever had before.
[/quote]
Yes you have a lot more information than you had before!
Ah counters count Ah's VERY accurately! This is easy.
*The problem is that what they count as removed & returned may not have any good relevance other than a very big "ball park" in relation to the battery in terms of SOC...
*Take the 375Ah battery used in my article for example.
>If we discharge it from full at 18.75A & 77F and remove 187.5 Ah's we are at 50% SOC. Easy and accurate Ah counting if the bank was actually 375 Ah's.
>If we now discharge that same battery at 4.86A at 77F if becomes a 486Ah battery, not a 375 Ah battery so your -187.5 Ah's is not the 50% SOC one might assume it is. Instead of being at 50% SOC you are really at 61.4% SOC an 11.4% variance in just one cycle by not computing for Peukert.. This is the point where I get complaints that the alt won't stay in bulk etc. etc. because the actual SOC is higher than it is assumed. This is safe for the battery, for a while, but leads to inefficient charging.
>Now what if the battery temp drops and you still discharge 50% of the "rated" Ah capacity based on the -Ah's screen?
>What if the Ah counter hits -0.0 Ah's? You're "full" right? Probably not...
>You now discharge again based on the Ah counter reading -0.0Ah's as "full" but you only put back 100% of what you removed and it really takes 130% of what you removed to actually be "full"....
>So again you discharge to an assumed 50% SOC based on the -Ah's screen... Now where are you, SOC wise, without accounting for Peukert, charge efficiency or battery temp at discharge....???
>What if your solar system tricked your monitor into resetting when the -Ah's screen still read -45Ah's....?
Again, these devices provide excellent information, count Ah's extremely accurately but the information they provide & count is rarely in-line with your battery, unless they are used & set up properly....
Mods:
Can we please leave these posts until we have a good way to move them... My last post took considerably time to respond to and was removed due to thread drift. This stuff is all relevant in the context of this thread, despite it drifting a bit......
-Maine Sail
https://www.marinehowto.com/
Robert, somehow this thread was hijacked (alas, I was probably one of the hijackers) onto the topic of battery monitors. Nick is planning to separate those posts from your topic and make a new battery monitor thread.
Sorry to derail your starting battery thoughts, but I *was* responding to an earlier Maine Sail post. Apologies.
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
Yup, I tried to separate out the contents yesterday, but the new system only allows me the complete reassignment of all threads to another forum. I've got a message off to investigate this. Stay tuned.
Nick Caballero
Retired C36/375IA Mk II Technical Editor
Thanks for all the comment , and validating my thoughts. We are heading to the boat to de-winterized it, and I will get a better look at the alternator. I plan on connecting b+ sense directly to the battery with the same gauge wire connecting b+ sense to b+output. Will be using 1/0gauge wire from alt to battery. I'll keep you posted as the project continues.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Update - So the 1/0 battery cable fished fine from the engine to the house battery compartment. I placed the starting battery in the fwd settee, however, I could not get the 1/0 AWG cable to run to the fwd settee. It kept getting stuck in the conduit behind the starboard bulkhead. It was a tight fit to get the cable in the conduit. Also tried to run it underneath the conduit with some flexible conduit. Still would not go through. Any thoughts on this? I have tried running the cable in both directions with no luck.
I have my ACR mounted in the house battery compartment. I need to run 3 cables (2 Pos, and 1 Neg) from the fwd settee to the rear settee. 1st Pos is for ACR, 2nd Pos is for starting circuit. Anyone got any ideas?
I'm running the alternator to the fused house bank. The ACR to the house bank and starting battery. The starting battery to the combiner at the chart table.
I picked up some 2 ga and 4 ga cable if I can't get the 1/0 to pass from aft settee to fwd settee. Would either of these suffice if I can't get the 1/0 ga to pass through?
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Robert -
I haven't tried fishing a cable through that area (although others have apparently done so), but what about the idea I suggested in an earlier comment above (see www.catalina36.org/comment/57114#comment-57114 )
that you might want to consider the alternative of putting the start battery in the little compartment behind the upper seat back cushion of the aft starboard seat, just above the existing battery compartment, as Soko did: https://julandra.shutterfly.com/195 (link is external) Would seem like an easy and much shorter cable run....
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Yes you can move the v-sense to the battery bank. I do however urge caution with this because I have seen numerous internal regs continue to draw a few mA even with the key/excite in the off position. This is why I generally say not to do it, especially if I suspect the owner would not know how to check for a parasitic draw....
This parasitic draw is fine when you are on-board and using the boat but if left on a mooring on on the hook for a while unattended this can create an issue as the v-sense remains connected even with the batt switch off....
Also with internal regulators it is sometimes very difficult to get the negative sense side of that circuit to the bank. Positive v-sense is fine but it still only represents half the system wiring drop.
Can it be done? Yes, but you should confirm there is no parasitic draw on the v-sense wire when the ignition key is in the off position before doing so. If you really want to get all techie you could insert a relay in the v-sense wire that is opened and closed with the ignition key but at that point, in terms of time consumption, you would probably be better served with an external regulator...
-Maine Sail
https://www.marinehowto.com/
[quote=Maine Sail]Yes you can move the v-sense to the battery bank. I do however urge caution with this because I have seen numerous internal regs continue to draw a few mA even with the key/excite in the off position. This is why I generally say not to do it, especially if I suspect the owner would not know how to check for a parasitic draw...[/quote]
I suspect the parasitic draw would occur even with the v-sense connected to the B+ output on the alternator, then B+ output directly connected to the battery?
[quote=Maine Sail]This parasitic draw is fine when you are on-board and using the boat but if left on a mooring on on the hook for a while unattended this can create an issue as the v-sense remains connected even with the batt switch off....[/quote]
Can the parasitic draw be checked with a multimeter using the snap around non-contact ammeter?
[quote=Maine Sail]Also with internal regulators it is sometimes very difficult to get the negative sense side of that circuit to the bank. Positive v-sense is fine but it still only represents half the system wiring drop.
Can it be done? Yes, but you should confirm there is no parasitic draw on the v-sense wire when the ignition key is in the off position before doing so. If you really want to get all techie you could insert a relay in the v-sense wire that is opened and closed with the ignition key but at that point, in terms of time consumption, you would probably be better served with an external regulator...[/quote]
If there is an issue I will probably keep the v-sense connected the way it is. I am using a 1/0 ga. cable between the alternator and the battery. Its about a 15' run of cable. So I would suspect very minimal voltage drop.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Thanks, Maine -- as I wrote in my earlier comment, I was hoping that "wiser minds may correct me on this"!
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Any further ideas on the cable size? I can't seem to pass 1/0 cable to the starting battery. So thinking of using 2ga or 4ga for the charging circuit and starting circuit. I suspect the starting circuit would draw more current than charging. Ideally, I would use the largest cable possible for each circuit.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Robert,
4 ga seems a bit small to me, but that's just my gut talking, with no empirical evidence to back it up. As Matthew suggested, I'm wondering why you don't put the starting battery in the compartment just above the house bank as I did. With a saber saw and a few minutes I had the opening big enough to fit the battery, and EVERYTHING is hidden by the backrest cushion. Shorter wire runs, and no conduits to worry about. Just a thought.
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
Tom,
I am actually thinking of putting it there. Did the cutout of the compartment take away from the support behind the cushion any? Do you have any pictures of the install? I suppose you drilled holes in the bottom of that hidden compartment to run the cables down to the battery compartment? One last thing, is there a place to purchase the trim that goes around the cutout behind the cushion?
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Robert,
The cutout did not take away from cushion support. I did that project well before digital cameras, and I do not have any pix of the install. From memory, I think I had to make a small wooden platform for the battery box to sit on, because the depth of the compartment was not quite enough (by depth, I mean the distance between the seatback and the hull), so I had to raise it up a bit. Yes, the wiring simply went down thru the bottom of the compartment into the battery compartment. I've seen the trim in several places since, but I can't remember exactly where. Should not be hard to find. Hope this helps.
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
Sounds like a plan. I would rather have it there, it would save on storage space. What gauge wires did you use for the starting and charging circuits? Do you think 2 ga would be plenty? My ACR is mounted in the main battery compartment, and the starting circuit will run behind the electrical panel, then following the OEM cables under the deck to the engine.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Here is a thought. The space right behind the nav seat would be a good spot to put a battery. Lower center of gravity and it would not seem to be to difficult to build a box to contain. Wire run would be short as well and easy access.
Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine
That is a good thought too. I removed my swinging nav seat and built a compartment and shelves under the nav table. I look at that spot as well. Thanks. Since I'm using AGM batteries, I don't need to worry about keeping them completely upright.
With AGMs, they can lay on their side, correct?
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
I have installed the battery, ran the cables, and crimped them as necessary. Everything looks good so far. I'm still waiting for the terminal block fuses, and the battery monitor to come in, so not everything is hooked up yet. However, I did disconnect the alternator from the starter, re-terminated the sense+ and ignition switch wire to the starter and cleaned all the connectors. Here are some pics of that work. When I am completely done, I send more picture and finalize this project.
Thanks, again for all the great advise and wisdom shared on this post. I couldn't have done it without all your support. I think the end result will be a cleaner, better regulated, starting and charging circuits.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Final installation.
I want to thank all of you who have posted ideas, comments, and information regarding this project. I have learned a lot about my electrical system through your words of wisdom, and articles you all have recommended. Again, thank you all. I am very happy with the outcome.
During the installation, I was also found some discrepancies in the electrical system, some of which you all pointed out, some found on my own. These discrepancies have been corrected, and the system appears to be working great. Please see the pics for the install.
I placed the starting battery on the shelf under the chart table I built last spring, and relocated the rarely used items normally stored there to the cubby hole behind the starboard aft settee, so it was a much easier and shorter cable run, yet still well hidden, easy to access, and well protected in the strapped down battery box. The red box to the left, inside the distribution panel is the on/off switch for the starting battery, it is accessed through the locker over the aft settee. I used Matthew's schematic for the circuit. The house banks are paralleled together, alternator feed directly to the house bank.
When installing the shunt for the monitor, the cable leading from the old shunt to the Neg bus bar parted from the terminal lead. I was able to clean the wire strands, repack and crimp again to repair. If I didn't find that, eventually the cable would have separated from the terminal on its own, and I would have lost all electrical. Of course that would have happened at the worst possible moment. So I went back and checked all other previous connections.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
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