Decreasing charge time of FLA house bank

[haveaday]

Originally Posted by ramblinrod

Agreed, but 4 times daily A-hr consumption (for FLA) is ideal, and the OP is under this.

The main issue, RUNNING TOO MUCH REFRIGERATION.

Best solution, when away from shore power, shut down all but the most efficient single fridge/freezer combo. If you hafta walk 20 feet for another beer, it will likely do you some good, if you are used to needing 4 refrigeration systems aboard when tied to a slip! ;-)

PS, I think the OP is way underestimating other overnight loads. An incandescent anchor light alone = 12 hours X 1.2 A = 14.4 A-hrs.

A 12" MFD for anchor alarm can easily = 12 hours X 2.5 A = 30 A-hrs. Much better to run an anchor alarm app on a mobile device that will likely be on anyway.)

I think, based upon the snide reply, you misunderstand the use case. The boat has four refrigeration units. One 24" undercabinet refrigerator, one 24" undercabinet freezer, one 15" undercabinet refrigerator and one 3 cu ft unit on the flybridge. We are a family of four currently in the Bahamas for two months and living aboard and cruising full time for a year. The walk for beer changes not at all with shutting down refrigeration units. Beer is in a cooler in the cockpit. Shutting down a refrigerator means spoiling food. Others have suggested that the manufacturer's design of running household 110v units on an inverter is inefficient. I'm highly inclined to agree with that but unsure about my appetite for the investment to remedy that at this time.

Additionally, among cruising boats we've encountered, our refrigeration load isn't that high. Many have a larger fridge in the galley and hence are able to eliminate one other unit but at minimum we mostly see three refrigeration units on board. Frequently one in the galley, a freezer in a lazzarette or other space and a small fridge on the flybridge or other location. Many add an icemaker bringing the compressor count back up to four.

As I indicated I do plan to swap out the incandescent anchor light. I've metered the MFD and it is using .8 amps with the display dimmed down. It's a newer unit with an LED backlight and relatively efficient internals. I've not had high enough reliability with apps in terms of both false alarms and the alert getting muted, etc. I find the MFDs are more reliable and have a louder dedicated alarm.

[Pizzazz]

Just to reiterate my suggestion above, make sure that you can supply high current to your batteries in bulk charging first. Then you would know if you have a charging problem or not.

If you need to run that much refrigeration then that is fine. The electrical system should support you lifestyle not the other way around. If you have so much refrigeration I would not bother changing to LED, it will not make a difference. If you use your plotter for the anchor alarm just Jim it overnight and the current consumption will drop to close to zero.

Lastly, battery capacity of 4x daily consumption means 75%-99% charging profile which is slow by definition. Try not charging every day but every other day and see if your charging times improve. Then you would know where the problem is.

[haveaday]

Originally Posted by Pizzazz

Just to reiterate my suggestion above, make sure that you can supply high current to your batteries in bulk charging first. Then you would know if you have a charging problem or not.

If you need to run that much refrigeration then that is fine. The electrical system should support you lifestyle not the other way around. If you have so much refrigeration I would not bother changing to LED, it will not make a difference. If you use your plotter for the anchor alarm just Jim it overnight and the current consumption will drop to close to zero.

Lastly, battery capacity of 4x daily consumption means 75%-99% charging profile which is slow by definition. Try not charging every day but every other day and see if your charging times improve. Then you would know where the problem is.

Thanks, I didn't lose track of your suggestions and appreciate the direction. I think that I've been able to verify that. When I connected to shore power yesterday I was able to see the inverter deliver just shy of 100a of charge. The batteries weren't very deeply discharged so the acceptance stage was very short. Helpfully right now the power is out in Treasure Cay where we are so I'll have the opportunity to test some more.

Also, I found the voltage on the generator to be a little low. I adjusted that up to just over 240 and seem to be seeing better results now. At the end of acceptance I'm seeing the bank coming over 14.4v.

I think this points to two things:
1. The inverter is very picky about the incoming power and any anomolies result in it producing less charge. I have a call into the support people for the alternator and am still waiting on a call back. I'm not sure there's much they're going to be able to suggest but can't hurt to check.
2. The alternator hung off the engine for the purpose of charging the 12v house bank (the engines are 24v and charged from a separate alternator) is likely a piece of crap. It's supposed to be a 100a alternator but the combination of it and the regulator seem pretty poor.

I do indeed dim the plotter all the way down when it's used as an anchor alarm. I hear you on the very small percentage of power drain the anchor light represents. On the other hand, I've tried hard to eliminate or minimize every load I can easily impact. Can't see a reason not to chase this one down.

Ben

[Dave Lochner]

Originally Posted by haveaday

I think, based upon the snide reply, you misunderstand the use case. The boat has four refrigeration units. One 24" undercabinet refrigerator, one 24" undercabinet freezer, one 15" undercabinet refrigerator and one 3 cu ft unit on the flybridge. We are a family of four currently in the Bahamas for two months and living aboard and cruising full time for a year. The walk for beer changes not at all with shutting down refrigeration units. Beer is in a cooler in the cockpit. Shutting down a refrigerator means spoiling food. ............

Many of the those who have responded to your questions and concerns cruise in sailboats, not power boats. If I can make a generalization (yeah, I know, dangerous) sailors approach power needs from a different perspective than powerboaters.

As sailors our first inclination is reduce power consumption. Our second is to increase power production. One characteristic both groups do have in common is a strong desire to have our equipment working properly.

The issues that you have been having are taking a significant toll on your batteries, placing the batteries in a death spiral. Improving the charging system and having it function correctly is one part of the solution, however, at this stage it may not be sufficient.

The other half of the solution is to reduce power consumption. There are lots of ways to do that and doing so will help save your batteries and your money.

Refrigeration is a major power draw, you know that. And using an inverter to provide AC doesn't make it better. Many of use live on 1 refrigerator that is top loading and driven by 12v. Some of us do or have cruised using blocks of ice. So having 4 refrigerators seems a bit excessive, but its your boat, your money.

A few questions and suggestions to better manage power consumption, from someone who used to cruise with 2 group 24 batteries and no refrigeration, save for a block of ice.

How are you managing your refrigerators? Pick one refrigerator and use it as a day refrigerator. In the morning load it with everything you'll need for the day, drinks, meals, etc. Do not open any of the other refrigerators until the next day. This will reduce the running times for the other refrigerators.

Thaw frozen food in the refrigerator. The thawing will help to keep the refrigerator cool.

How many times a day do the kids hang in front of the open refrigerator door? This ain't home in Chicago with a big power plant.

Especially for the flybridge unit, make sure it is shaded. For the under cabinet units improve the insulation or at least hang a blanket over the front to help keep it cooler.

Are all the lights LEDs? If not, change them. Do the kids turn off lights when they leave a cabin? Do they need all those lights on? What appliances are being used and left on?

Take a good look at your energy consumption habits. How can you reduce consumption? Your batteries will thank you.

I hope you get the power issues resolved and enjoy the rest of your Great Loop trip.

[haveaday]

Dave,

Thanks for your thoughts and I think you are exactly right about the different mindsets that come from different backgrounds. I don't think there's a right or wrong here and realize I may be in some minority in the population represented here. I have taken quite a few steps to reduce power consumption along the lines you have mentioned. All the lighting on the boat is LED, we shutdown everything not needed, etc. You make some good suggestions with regards to the refrigeration and ways to further increase the efficiency. I like the day fridge unit and we will take steps to incorporate that. We've added some insulation around the back sides of the fridges where the sun hits the outside of the boat and the heat transmits. As we continue to cruise and if any issues are encountered with any of the existing units I will move to dual voltage units.

I think you are right that we are hard on our house bank. Given the size and cost of that bank I'd like to take reasonable steps to improve it's health. On the other hand as a family we probably aren't willing to shut down one or more of the fridges and so if part of the price of that is shorter life on the batteries we're probably willing to live with that.

I would like to thank everyone for your input, challenges to the decisions we've made and suggestions. My family and I have adjusted to living on board and it's possible there are further adjustments to be made. Some of those might take time to soak in for some or all of us.

Thanks
Ben

[ramblinrod]

Originally Posted by haveaday

The boat has four refrigeration units. One 24" undercabinet refrigerator, one 24" undercabinet freezer, one 15" undercabinet refrigerator and one 3 cu ft unit on the flybridge.

Thanks for the refrigeration info.

If you consume 300 A-hrs overnight, with a 100 A charger you'll need to run it about 12 hours/day to keep your batteries charged.

Which is perfectly fine if that is what you want to do.

If you don't want to run the generator that much...

Reduce the amount of perishables stored, and then shut down the 15" under-cabinet and the flybridge fridge when away from the slip.

This will reduce your energy consumption to about 150 A-hrs per day when on the hook.

Run 400 W of solar charging.

You should be able to run your generator for about an hour in the morning, and have batteries topped by sunset.

If you don't want to run the generator more during the odd cloudy day, make it 600W of solar charging capacity.

[Pizzazz]

Originally Posted by ramblinrod

Thanks for the refrigeration info.

If you consume 300 A-hrs overnight, with a 100 A charger you'll need to run it about 12 hours/day to keep your batteries charged.

Which is perfectly fine if that is what you want to do.

If you don't want to run the generator that much...

Reduce the amount of perishables stored, and then shut down the 15" under-cabinet and the flybridge fridge when away from the slip.

This will reduce your energy consumption to about 150 A-hrs per day when on the hook.

Run 400 W of solar charging.

You should be able to run your generator for about an hour in the morning, and have batteries topped by sunset.

If you don't want to run the generator more during the odd cloudy day, make it 600W of solar charging capacity.

Again, this is not needed in this application. If you consume 300Ah a day, you need to run a 100A charger for slightly over three hours to replenish the energy if you run your batteries in bulk mode (20-80% state of charge). You will halve the battery lifetime but your quality of life will improve.

You can replace a 800Ah battery bank for $800. On the other hand running the genset for an extra 9 hours a day just to squeeze in the last 20% is crazy in my opinion.

My advice would be to go and talk to a forklift operator, how they use and charge their batteries. You may be surprised.

Solar will not move the needle in such an application and especially on a powerboat. One 100W panel will generate 25-30Ah on the average. You need four panels to balance one hour of engine charging (in bulk). I would not do it but some people swear by solar.

[ramblinrod]

Originally Posted by Pizzazz

If you consume 300Ah a day, you need to run a 100A charger for slightly over three hours to replenish the energy if you run your batteries in bulk mode (20-80% state of charge).

The OP is using 300 A-hrs overnight. That's ~ 600 A-hrs / day. So with 25 A-hrs of constant load, the 100 A charger only has 75 A left for charging batteries.

To replenish in bulk mode, maintaining a 50-80% discharge cycle will take 4 hours minimum. Without regular recharge to 100%, this will kill the bank in about 2 years.

Solar will not move the needle in such an application and especially on a powerboat.

Power or sailboat makes no difference. The batteries don't know what kind of boat they're on.

Option A: Leave as is.

Run the generator 4 hrs/day, and replace 24 batteries in 6 years.

Option B: Leave as is.

Run the generator 12 hrs/day, and replace 8 batteries in 6 years.

Option C: Add 600 W solar, reduce energy consumption to 150 A-hrs per day, cut the house bank capacity in half.

Run the generator 1 hr/day and replace 4 batteries in 6 years.

Add in the hernia operation due to slugging all those batteries and/or replacement generators to and from the boat, and hearing aid costs (Option A or B) and ol' RamblinRod's recommendation (Option C) looks dang good. ;-)

[smac999]

Originally Posted by haveaday

Oh and I should have mentioned that right now according to the BMS I am putting 61 amps of charge into the battery bank and the bank is at 14.42v.

Ben

You need a clamp meter to measure the charger out put. (If it doesn't tell you on own screen.

Your 100a charger might be putting out 100a. But if you are using 40a. (Lights etc). Then you are only charging 60 into the battery. This would mean the charger is fine. But you are simply using too much. And your chargers are too small.