Need more power, new batteries?

[sunchaser]

Does a boat with a genset and a good AC battery charger like the OP really need a large alternator? If Seevee arrives at his achorage with fully charged batteries (I'm assuming), doesn't that mean that his alternator is sufficient?

+1

This is precisely how our vessel operates. Two 90 amp alternators neither with a Balmar nor Leece Neville tag. Works fine for us and the 8 US made Trojan 105s.

Seevee is close to a good setup, just have a compatible BMK installed to manage the energy use. Magnum makes wonderful BMKs.

 

[Heron]

FWIW.....

 

[O C Diver]

+1

This is precisely how our vessel operates. Two 90 amp alternators neither with a Balmar nor Leece Neville tag. Works fine for us and the 8 US made Trojan 105s.

Seevee is close to a good setup, just have a compatible BMK installed to manage the energy use. Magnum makes wonderful BMKs.

I may have missed something, was under the impression that he had only one 80 amp alternator as in a single engine.

Ted

 

[dhays]

Does a boat with a genset and a good AC battery charger like the OP really need a large alternator? If Seevee arrives at his achorage with fully charged batteries (I'm assuming), doesn't that mean that his alternator is sufficient?



BTW, I understand the benefit for those without generators as an alternator might be their only charging source. Is there something I'm missing? If my alternator is able to keep up with my DC needs while underway without taking anything away from my batteries, isn't my alternator good enough?

Most of my days under way from anchor to anchor are 6-8 hours. I usually run the genset for a couple hours in the morning and in the evening. The time running the boat usually tops up the batteries. As was mentioned, an 80amp alternator won’t be providing 80 amps except when the batteries are pretty low.

Since I added a 365W solar panel, I have found that the batteries top up very quickly when under way. If I am not going anywhere, if I run the genset a couple hours the solar will top up the batteries during the day.

My biggest drain overnight is my wife’s CPAP which runs off the inverter and then the 12v fridge and separate 12v freezer.

 

[FF]

Showing 14+ V on a volt meter on engine shutdown shows the batts are still charging , not fully charged.

After a SOC meter shows the charges in and discharges out , a 3 or4 stage volt regulator would be next purchase.

Of course solar is always a big help.

Even a smallish 75W panel is great to get to 100% charge , the requirement after every deep discharge.

 

[Seevee]

I have kind of lost track of the facts behind this thread. This is what I think I know:

1. 390 AH house bank of AGMs
2. Charged with a genset driving a 125a amp Magnum? inverter/charger
3. Daily AH demand is 155 amp hour, of stuff that will run every day not matter what. Two 12v fridges are the biggest. Must be large with two 120V?? fridge and freezer, coffeemaker, other appliances run off inverter Only coffeemaker, microwave and computer charging run off the inverter, normally
4. At end of day/overnight no genset running period, voltage (resting?) is 11.0.
First thing in the morning, it reads about 12.2 or 12.3
5. Morning genset running charges house bank to 14.5+V. Dont believe that's right, it will charge with that much, but the battery reads 12.6 after a full charge with no load.
6. OP spends as much as 6 days at a time at anchor

Next steps- Install a battery monitor ($250 or so) and determine 24hr DC load. Or spend a thousand $ or two and double battery capacity. Or maybe try running genset morning and night to keep from discharging existing batteries too low- try it.

David

Dave,

I've filled in the above.
I do have a battery monitor.
The issue is that after coffee making in the morning, the battery sometimes shows well below 11v. I probably had something else on that one of us forgot to turn off. If we did our due diligence and turned off EVERYTHING that would could other than the main fridge, we could probably have the morning coffee, and heat a cup before heading out and be ok. But want a bit more.

Goal is to increase capacity, that's the jest of this post, and what are some good battery options.

After hearing all the comments, solar might be the thing to do, even though it would be expensive. Looking into where I could build a support to mount those solar panels, and someone mentioned flexible panels. Gut feeling, I'd look seriously at putting a hard top on for the solar. Would significantly improve the flybridge and would get rid of every spec of eisenglass (hate the stuff), and canvas....(hate that, too). Would be expensive, but no more replace the fabric and eisenglass, give a much better cover and have a spot for all the solar I'd want.

 

[ranger58sb]

Gut feeling, I'd look seriously at putting a hard top on for the solar. Would significantly improve the flybridge and would get rid of every spec of eisenglass (hate the stuff), and canvas....(hate that, too). Would be expensive, but no more replace the fabric and eisenglass, give a much better cover and have a spot for all the solar I'd want.

FWIW, likely you know this, having a hardtop and having Eisenglass (whatever real brand) are two separate things. You likely can take your "glass" off right now, if you want; it's very likely not structural.

Another FWIW, you probably know, clear see-thru stuff is MUCH better than old ratty scratched see-thru stuff. And then Makrolon or EZ2CY or similar can be even MUCH better than that.

We don't have a lower helm and find we prefer at least our forward enclosure panels to be installed all the time. We take the aft panels off as soon as weather permits in late April/Early May, and then put all that back on usually in October. Makes a nice difference in how open the bridge feels when those aft panels are off...

-Chris

 

[DavidM]

Seavee:


So with the new details in your post above, I don't see what the problem is, certainly not lack of battery capacity with only 155 AHs being drawn from a 380 AH bank.


In the morning the resting voltage is 12.2-12.3. That is about 40% discharged, so no problem there. After genset charging (and presumably after the genset is shut off and at rest) the batteries read 12.6. That is a little low for AGMs which means they are not fully charged, maybe to 90%. This is to be expected with genset charging for only a few hours. I bet your Magnum is still in absorption mode when you turn off the genset, right?

So what you really need is some way to easily top off your batteries during the day. Only charging them to 90% or so for a week at a time isn't good for them. You need to add about 40 amp hours during the day. Other than mounting you can add a couple of hundred watts for about $300 in parts, maybe $400 for flexible panels. That should easily top off those batteries.

I would do this before adding any more batteries, which from the data given above you don't need to keep the batteries charged above 50%.

David

 

[Seevee]

Seavee:


So with the new details in your post above, I don't see what the problem is, certainly not lack of battery capacity with only 155 AHs being drawn from a 380 AH bank.


In the morning the resting voltage is 12.2-12.3. That is about 40% discharged, so no problem there. After genset charging (and presumably after the genset is shut off and at rest) the batteries read 12.6. That is a little low for AGMs which means they are not fully charged, maybe to 90%. This is to be expected with genset charging for only a few hours. I bet your Magnum is still in absorption mode when you turn off the genset, right?

So what you really need is some way to easily top off your batteries during the day. Only charging them to 90% or so for a week at a time isn't good for them. You need to add about 40 amp hours during the day. Other than mounting you can add a couple of hundred watts for about $300 in parts, maybe $400 for flexible panels. That should easily top off those batteries.

I would do this before adding any more batteries, which from the data given above you don't need to keep the batteries charged above 50%.

David

David,

Sounds pretty good to me. The 155 AHs is the bare minimum I need, but there can be other things, fortunately most are used when underway... electronics, charge up the computers, etc. The issue I have is that when I crank the coffee maker with 12.2 it drops about .5 to .8 volts, and if I crank the micro to heat something, it can kick off with low battery.

I'd like to be able to not run the genny in the morning when I'm just doing coffee and a light breakfast and get the engine going before the voltage drops too low, and later in the day, use the genny for charging, dinner, etc.... run for 2 to 5 hrs depending and have a good charge for the night.

I get up before sunlight at times, so the solar won't help until the sun shines.

Gut feeling, I could use the solar AND a greater battery bank capacity. Now you have me spending even more money...... <g>

 

[Seevee]

FWIW, likely you know this, having a hardtop and having Eisenglass (whatever real brand) are two separate things. You likely can take your "glass" off right now, if you want; it's very likely not structural.

Another FWIW, you probably know, clear see-thru stuff is MUCH better than old ratty scratched see-thru stuff. And then Makrolon or EZ2CY or similar can be even MUCH better than that.

We don't have a lower helm and find we prefer at least our forward enclosure panels to be installed all the time. We take the aft panels off as soon as weather permits in late April/Early May, and then put all that back on usually in October. Makes a nice difference in how open the bridge feels when those aft panels are off...

-Chris

Chris,

Thx for the info. I know there's better products than eisenglass, probably worth looking into, but hard to be just good quality glass.

I envision a hard top, with a reverse raked for better sun/rain protection, 3 real glass windows that swing in and up, so I can operate in rain without going downstairs. The sides would be the mesh, which I currently have and really like.

And the solar on top.

 

[sunchaser]

Chris,

Thx for the info. I know there's better products than eisenglass, probably worth looking into, but hard to be just good quality glass.

I envision a hard top, with a reverse raked for better sun/rain protection, 3 real glass windows that swing in and up, so I can operate in rain without going downstairs. The sides would be the mesh, which I currently have and really like.

And the solar on top.

Geez, a much more cost effective thing to do is add the big alternator as others have suggested. A hard top is big bucks. Why the reluctance to run your genset in the morning? It is already installed.

What size charger do you have to juice up batteries when genset running?

 

[Seevee]

Geez, a much more cost effective thing to do is add the big alternator as others have suggested. A hard top is big bucks. Why the reluctance to run your genset in the morning? It is already installed.

What size charger do you have to juice up batteries when genset running?

Sun,

No issue running the gen if I'm not disturbing someone else. But often anchored and there's a bunch of sailboats around so just don't like to crank up at 6am for my morning coffee. In fact, I'll often dinghy over to them and ask if they mind if I run the gen for a bit in the morning or evening, and so far, no one has been an issue, but just don't like to crank it up too early. And right now, the most power I have left in the morning is barely enough for one pot of coffee.... maybe.....

Genset produces 125 amp charger thru the inverter.

I know hard top is big bucks, but add up just the cost of replacing the crapy isinglass and canvas and I've over half way there. And now I've got MUCH better shade, can eliminate that damn isenglass and have a place for the solar panels.

 

[dhays]

And right now, the most power I have left in the morning is barely enough for one pot of coffee.... maybe.....

Propane stove and a pour over?

 

[O C Diver]

Seevee, you're probably tired of reading my posts, so I'll keep this short.
If you don't want to start the generator in the morning, you need more batteries.
Regardless of battery storage you need to be able to produce more power than you consume because of loses in charging and discharging batteries. Think you need to first resolve how you will produce enough power to handle consumption and complete recharging of the battery bank.

Ted

 

[FF]

"I've filled in the above.
I do have a battery monitor."

A SOC meter or a volt meter as "battery monitor"?

The SOC meter will watch your batts and learn their capacity as the charge and discharge , and as they age and loose capacity.

You will be able to see the amps going in or out and the rates for either.

10V in the AM just means the batts are door nail dead and give no indication if 10 amps or 200 amps discharge killed them.

Usually batts that have been drawn to 10V are at the end of their life cycle and need replacing .

 

[Maerin]

"I've filled in the above.
I do have a battery monitor."

A SOC meter or a volt meter as "battery monitor"?

Usually batts that have been drawn to 10V are at the end of their life cycle and need replacing .

^^^^^^ ++1


Nothing kills a battery faster than a DEEEP (read:dead) discharge. Repeated deep discharges damage exponentially. Don't take my word, check the manufacturers' ratings on cycles vs. depth of discharge.


Battery monitor, a voltmeter is not. If you're using a voltmeter to determine battery state, you're only guessing. Your posts don't give any indication of SOC, only voltages, which are practically meaningless under anything but laboratory controlled conditions. 1st step in moving forward is to get an accurate assessment of what's going on, >> SOC meter that counts amps. If you make changes based on info provided by a voltmeter, you're going to be making MORE changes.

 

[FF]

One thought to improve charging might be to put a good truck 135A alt on a belt on the noisemaker.

Many noisemaker engines are sourced from yard equipment , so a dual belt pully may be a cheap, simple bolt on.

A 135A unit with a 3 stage V regulator would charge far faster than most 120v batt chargers.

Attempting to heat anything with a house resistance element is a HUGE! load on a battset.

Find another way to make coffee or run the noisemaker , not the inverter,

 

[DavidM]

For all of you who complain about the OP running the battery down to 10-11 volts, I am pretty sure that is not resting volts. Yes he has said 10-11 volts on this crazy thread, but I believe it was while powering his inverter and brewing coffee with an electric coffee pot plus fridge, freezer and ???. A 750 watt coffee pot will draw 75 DC amps and will drop the battery voltage another volt or so from its resting value.

He did say 12.2 volts at rest after drawing 155 amp hours from a presumably fully charged battery. That is what we should be focusing on, not the 10-11 volts.


Having said that, resting volts whatever they are is a very poor indication of SOC. His battery monitor if properly set up should give him that value.


David

 

[Donsan]

What engine do you have? If a Yanmar or Volvo, it is a fairly easy upgrade to a larger small case high output alternator like the Powermax PM125.

PowerMax Small Case

 

[O C Diver]

What engine do you have? If a Yanmar or Volvo, it is a fairly easy upgrade to a larger small case high output alternator like the Powermax PM125.

PowerMax Small Case

Guess that's a nice option (although very pricey for a 125 amp alterator) if it's plug and play in the existing bracket and belt configuration. Looks to be about $930 for a 125 amp alternator, 3 stage regulator and the alternator temperature sensor to keep from frying the alternator.

Ted

 

[FF]

A new truck large frame 135A alt is about $135, and has external leeds to handle the V reg of choice.

The drive pulley will be a few bucks more.

BUT you have to make your own bracket.

 

[Stu-L]

One simple thing to try is to look and see how your 6v are configured to make a 12 v system. One configuration is to take two 6v and wire them in series to get 12v and take another two 6v wire them in series to get another 12 v. Then the two 12 v and wire them in parallel. This give you 190 AH. I believe you have your bank wired this way getting 190 AH

To boost this take the first two 6v wire them in parallel. Take the second two of 6v and wire them in parallel. Then take the two 6v parallel configurations and put them in series. This will give you a 12v bank at 380 AH. when batteries are in parallel the AH is additive. (190 + 190 = 380)

 

[FF]

"This will give you a 12v bank at 380 AH. when batteries are in parallel the AH is additive. (190 + 190 = 380)"

Watch out for this fellow to offer a good deal on a bridge in Brooklyn!

Someone please do the math for him!

 

[bykpjfk]

First thing, I'm with the OP concerning agm's. I never want liquid/acid batteries again after experiencing agm's.
I have our 40' mainship equipped with 8 duracell GC2's from Sam's, cheapest $ per amp/hr. I have the fridge freezer operating on 12 volt from the main 12 volt panel, so basically runs from whichever starting battery is selected for the 12v panel. Both engines are equipped with balmar 70 amp alternators with external regulators, so starting batteries (also agm's) recharge quickly. Whichever engine is not feeding the 12v panel can be used to maintain the house bank while underway through battery combiners. My engines are 4 cyl yanmar, usually cruising at 1400 rpm's, so the balmars would never recharge a deeply discharged house bank. I use the genset for 2-3 hours in the morning to recharge batteries. Forgot to mention that I'm in Florida, and usually run a 6k btu a/c in the forepeak all night behind my 2500 watt inverter. Works great, but batteries need a good charge in the morning. BTW, kuerig style coffee maker use significantly less power for a shorter period of time.

When at dock, the 20 amp 3 stage battery charge keeps the 12v side happy, while the inverter/charger keeps the house bank/ac side happy.

 

[Maerin]

I have the fridge freezer operating on 12 volt from the main 12 volt panel, so basically runs from whichever starting battery is selected for the 12v panel. Both engines are equipped with balmar 70 amp alternators with external regulators, so starting batteries (also agm's) recharge quickly. Whichever engine is not feeding the 12v panel can be used to maintain the house bank while underway through battery combiners.

Just a thought, why power the "house" loads from the starting battery rather than the "house" battery? House battery would be better suited to those long duration, relatively low amp draw loads. Any time you have a battery switch that needs to be switched, you're introducing a failure point, either mechanical or memory. Along the same lines, would not the alternator do better connected to the house bank with a sense line to that rather than the start batteries that have a relatively short recharge time.