Battery Charging

[Monterey385]

If you want to test what your regulator is willing to put out if the regulator allow it to, then run your house bank down to about 60% & check current flow when charging begins.

Thank you for this ... it actually coincides with a thought I had earlier ... I think what I'm going to do when I get to the dock is to make sure I can get a full charge using my dockside electric. Then, once I know I have a full charge ... put the system under total load at 17 amps with no charging source and actually take voltage readings on the hour down to about 60%. At that point, fire up my engine and take clamp readings by the alternator and the battery while running the engine at about 2,000 rpm.

This should get me the data I need (assuming this clamp rookie can get solid readings on his ammeter).

In addition I plan to get the model of the regulator on my alternator as its unclear to me whether Catalina upgraded the regulator when they upgraded the alternator to the 120Amp version.

If I can pull all of this off next weekend I'll post the results.

As usual, in my limited time on weekends, this group has been fantastic in helping me to speed my understanding and break this down into a manageable issue.

Have a great week all and thank you,

 

[Monterey385]

@Monterey385 If you're not completely confused by now, you should be.

Ha Ha! Actually this is making more sense by the hour ... and yes, I will dust off the references to Ohms Law ... that's a great suggestion along with John's post on the clamp portion of my multimeter ... its been a very educational afternoon. A month ago it was HVAC ... now Electrical ... all in a day's work -

 

[Mark Maulden]

Still don’t know regulator you have (unless I missed it somewhere)..take the alternator off the boat and take it to a rebuild shop and have it tested. If you have an external regulator, take it with. This gives you a starting pt. Past that, its batts, connections, and wiring...Also, take some time and find some online courses in DC power..once you understand how things work and how things are measured, it will start to make sense..if your big 120a altwrnator is still internally regulated, I would suggest looking into an external regulator assuming ships wiring is up to par..

 

[JimInPB]

... I think what I'm going to do when I get to the dock is to make sure I can get a full charge using my dockside electric. Then, once I know I have a full charge ... put the system under total load at 17 amps with no charging source and actually take voltage readings on the hour down to about 60%. At that point, fire up my engine and take clamp readings by the alternator and the battery while running the engine at about 2,000 rpm.
...

Just checking here,
You want to get down to 60% state of charge, not 60% of full battery voltage. Voltage & % charge do not track on a 1:1 ratio. If you are down to 60% of voltage, your battery is way lower than you ever want it to be. You are doing serious damage to the battery at that point.

 

[Monterey385]

Just checking here,
You want to get down to 60% state of charge, not 60% of full battery voltage. Voltage & % charge do not track on a 1:1 ratio. If you are down to 60% of voltage, your battery is way lower than you ever want it to be. You are doing serious damage to the battery at that point.

Understood … I've got halfway modelled at between 11.9 and 12.0 volts for a deep cycle battery at approximately 75 degrees F ambient temperature. Let me know if this is materially different than what you would use as the 50% cutoff.

 

[Maine Sail]

Understood … I've got halfway modelled at between 11.9 and 12.0 volts for a deep cycle battery at approximately 75 degrees F ambient temperature. Let me know if this is materially different than what you would use as the 50% cutoff.

Under average house loads (20-30% of the 20 hour rating) your cut off should be 12.15V to 12.2V....

You don't need to draw your bank to 50-60% DOD to test the alternator. Simply flip on the inverter and turn on the hair drier. Now put your clamp meter on the alternator B+ cable.. This will immediately full field the alt. I would be surprised if a Catalina 385 did not have at least a 1 kW inverter...

 

[Monterey385]

Under average house loads (20-30% of the 20 hour rating) your cut off should be 12.15V to 12.2V....

You don't need to draw your bank to 50-60% DOD to test the alternator. Simply flip on the inverter and turn on the hair drier. Now put your clamp meter on the alternator B+ cable.. This will immediately full field the alt. I would be surprised if a Catalina 385 did not have at least a 1 kW inverter...

I do have an 1800W inverter and while I have no hair … my wife certainly has a hair dryer. So this test will quickly test the alternator (thank you!). Part of my plan (in addition to confirming the alternator was able to put out the full charge capability its rated for) was to also get a sense as to how much of my batteries' capacity remains as they are now going on 3 years old (however I've tried to care for them well). Other than drawing down to 50% with a stable load and taking voltage measurements q30 min or q60 min, is there another way to assess what the amp-hour storage capacity of the batteries are?

Since I'm now talking with the master … if you have any posts that cover this I would welcome any references you can point me to.

Thank you,
Kev

 

[jssailem]

Kev,
You really need this link. https://marinehowto.com/
It is where you can gain great insight from MaineSail.

 

[Monterey385]

Kev,
You really need this link. https://marinehowto.com/
It is where you can gain great insight from MaineSail.

Didn't realize that was Maine Sail … thanks John … I scanned it on my phone the other day and made a note to review it in detail later this week.

 

[jssailem]

Yes Kev. A great resource. Also a great place to buy certain replacement/upgrade parts for your boat. You have a lot of fun detail reading to do.

 

[Monterey385]

UPDATE:
I confirmed this weekend that the Alternator is outputting what looks like 120-140 Amps and I think I've traced my "problem". Yesterday, I fired up every DC draw I have on the boat and shut off the battery charger once I had the batteries fully charged. At 1046 the voltmeter read 12.6. At 1200, it read 12.2, 1300 12.1, 1400 12.0, 1500 11.9 and 1555 it read 11.9. The full amperage draw fluctuated during that time between 14 and 20 amps (Refrig and Freezer were cycling on and off during the test). I have two house 4D batteries each with theoretically 205 AH or 410AH between them. If I understand my voltage tables, I should have been able to pull a 20 amp draw for 10 hours before I reached the 50% mark and instead I only made about 5 hours to that point.

The batteries are 3 years old so I'm thinking that they are aging and losing their storage. However, I can't shake the feeling that my system hasn't been optimally configured. My two house batteries are wired into the 1-2-All battery switch in parallel on Battery Input 1. My dedicated start battery is wired to Battery Input 2. I was advised I should use Battery position 1 at all times but that the Engine Start battery will be kept charged and will automatically come into play when its time to start the engine.

Having traced the wiring, I don't think what I was told was accurate. If I understand my Blue Sea switch documentation properly, when I've had the battery switch set to 1, I have been using my house bank in parallel for both house loads and to start the engine. While it has always worked, I'm wondering whether this process has served to rob my house bank of necessary storage capacity. Catalina's documentation actually recommends this approach in writing but then has two 1-2-All switches in their schematic for a starting engine. I only have one 1-2-All switch and an Engine On/Off switch. I think, if I understand Catalina's schematic properly, if I had the Engine Start battery on a second 1-2-All switch, and the house bank on its own 1-2-All switch with one output from the house 1-2-All connected to battery 2 on the Engine Start 1-2-All switch, I would have an isolated engine start system that could tap into the house bank if necessary but the house bank could be fully isolated from the engine start.

Even more perplexing is that my battery charger is supposed to be able to charge all three batteries regardless of what position the battery switches are. However when I flipped my 1-2-All from 1 to All, the Battery Charger lit up and has been running at 20-30 Amps for the last couple of hours. Its a ProNautic 12.30.P and its reporting that it is running in Conditioning mode ... thus I'm wondering whether it needed to condition the Engine Start battery once I switched to All?

Bottom line, since I doubt this system was configured with a best practice in mind, is there a best practice for connecting 2 house batteries, an Engine Start battery with either 1 or 2 battery switches and a single Battery Charger?

 

[dlochner]

Bottom line, since I doubt this system was configured with a best practice in mind, is there a best practice for connecting 2 house batteries, an Engine Start battery with either 1 or 2 battery switches and a single Battery Charger?

Yes there is a best practices. See the second post from MaineSail on this thread https://forums.sailboatowners.com/index.php?threads/practical-battery-questions.192337/#post-1470990 (the diagram is also posted elsewhere, I could find this one quickly.)

Where does the alternator output go? From alternator to a battery switch? the starter? a positive busbar? the house battery?

 

[Monterey385]

Dave:
Thanks for the quick reply. Truth be told, I'm not entirely sure where the Alternator output is going. I have taken a series of pictures and when I get home I'm going to try to upload some of them. However what I see is a sea of red wires in several places and as such as you can probably imagine I have placed on the "to do list" the tracing of each one of the wires. My hunch is I will likely be swapping out the Engine On/Off switch for a second 1-2-All switch but before I change anything I want to make sure I understand how I am connected now. For instance, I see clearly that I have a yellow connection between the negative poles of my two house banks but I don't see the positive poles connected in parallel. I think the fact that the positives are connected on the same pole of the 1-2-All switch that is serving as the positive connection for the parallel setup but I can't figure out if that is a best practice or not. The behavior of the battery switch position and my battery charger also made no sense to me. We have a trip planned in several weeks and while I don't want to mess with anything that is working properly, I also want to make sure that it is working properly. As a backup plan, I'm considering finally breaking down and buying the Honda 2K I've been thinking about for a while but if I don't need to, I'd rather hold off for another year.

When I'm done, every one of these wires is going to be labelled clearly ... that may end up being a winter project but the DC systems are critical to have clearly outlined.

 

[dlochner]

I think the fact that the positives are connected on the same pole of the 1-2-All switch that is serving as the positive connection for the parallel setup but I can't figure out if that is a best practice or not.

This is not a good set up for the batteries. There should be one entry point for the electrons passing through the battery and one exit point. Here's an excerpt from MS drawing showing batteries properly wired in parallel.

Note that there is one red wire going from the positive terminal to the switch and one black negative wire going from the negative terminal to a shunt (cropped from photo). The type of battery doesn't matter, in this drawing it is an AGM bank, however the same wiring would be done for a flooded lead acid battery.

When I purchased my boat 5 years ago, I think the batteries were wired as you suspect yours are. I ended frying 2 GC and ended up with 4 new batteries. There were too many wires going in too many directions to keep track of them. Their now sitting in a box in my basement.

 

[Monterey385]

This is a picture of the House bank connections and the starting battery with the house bank ...

 

[Monterey385]

Here is the back of the 1-2-All switch and the Engine On/Off switch

 

[dlochner]

From the battery, it appears that there are 2 leads from B+ one to the bow thruster and one to house. There also appears to be a couple of lighter wires, 8 or 6 gauge attached to the batteries, are those from the charger or alternator?

On the upper 1-2-B switch there are a mess of wires. On the upper post, there is one cable, from the Start Battery? On the lower post there are 5 wires and cables. One from the Battery Bank, one for the bilge alarm, then 2 more smaller wires and one cable. One cable is clearly labeled H the other cable is not as clear. Then there is the smaller cable that goes to the circuit beaker, is this for the windlass?

On the common post for that switch, there is a large cable that goes to the on-off switch. It is then joined with 2 other cables and one cable on the other post. What are those other cables, charger and start battery?

Also, there are too many connections on that #1 post. By my count there are 5, 4 is the limit. It is a bit hard to see, however, it appears the bilge alarm wire is at the bottom of the stack. The heaviest current draws go on the bottom, the lightest ones on top.

As near as I can tell, if the battery switch is set to 1 everything runs off the start battery. The current flows from the start battery through the switch to the lower 2 pole switch where there are the feed to house panel, a charging (?) cable, and the feed from the 1-2-b switch. If the On/off switch is off, there is no power to the starter, the engine won't start.

If the 1-2-B switch is set to 2, then everything runs off the house batteries. Current flows through the switch to the On-off switch and then to the DC panel and the charger? alternator? If the On/off switch is off, there is no power to the starter. Very confusing.

A much simpler system is Battery ---> On/Off----> Blue Seas 5511e <------On/off switch ------ House battery.

Blue Seas 5511e -----> starter
\-------> House

This system lets you isolate the house and start batteries and when necessary combine them without getting involved with 1-2-both switches.

Hope this helps and perhaps Maine Sail will weigh in.

 

[jssailem]

My suggestion, start at the alternator and follow the Positive output (should be a red wire) as far as it goes.
What Dave is saying: the alternator Positive wire should go to the Positive on the house bank battery. This helps to get everything your alternator is putting out into the battery.

 

[Monterey385]

Here is what I think happened .. we ordered the boat with the optional starting battery but I think it shipped from the factory without the option and the dealer added the starting battery. I think this might be the explanation for the stack of wires on Input #1 of 1-2-All switch. The schematic for the starter battery option shows two 1-2-All switches but I have the switch combination for the standard configuration. To make matters more confusing in the text they describe a switching approach that uses one 1-2-All switch with the House bank in parallel and the dealer seemed to follow this approach but did it backward from the text.

I do have to trace the alternator and charger wires to get them clearly identified. I believe the two black marks are each H’s for House. The handwriting at the bottom of the text is from the dealer.

 

[dlochner]

The schematics are helpful.

Where are the charging sources, battery charger and alternator connected? Is the alternator a stock internally regulated alternator?

The 2 house batteries are wired independently of each other and while the batteries are in a parallel circuit in the "both" position, the batteries are not paralleled. Having one large house battery bank is better for the batteries than 2 smaller battery banks. There is more useable power and the batteries last longer.

When properly wired in parallel, batteries last longer because they are maintained at a higher state of charge and are discharged less deeply. Consider this given a 100 amp hour battery with a 10 amp draw for 3 hours. That's 30 amp hours drawn out of the battery or about 30% of the batteries capacity, the SOC is then 70%. However, if you have 2 100 amp hour batteries wired in parallel and take the same 30 amp hours out, the SOC is only 85%, 200 -30 = 170 amp hours remaining. The actual math is a bit more complicated, however, this is accurate enough to illustrate the effect.