Challenges Keeping Batteries Up at Anchor

[Kings Gambit]

So, I have four fairly new (< 6 mo) 6-volt batteries wired in series/parallel to form my house bank, plus a separate starting battery. The house bank has a theoretical 470 ah. There is also a battery monitor but probably not a very good one, and two 85-watt solar panels. Under the protocol I believe I was introduced to in this forum the useful "tidal range" of the house bank is between about 85% and 50% SOC assuming one does not wish to "murder" the batteries in the manner described by Maine Sail in his previous posts. So, 0.35 x 470 = 164.5 ah to work with. My daily needs appear to be near 50-60 ah (the fridge alone is near 30 @ 4 amps x 1/3 hr/hr x 24 hr = 32 ah). The Espar heater runs at 40 W; so, 40 W/12 v = 3.3 amps. Runs of 5 hr/day = 16.5 ah/day. Put the rest in the miscellaneous category for now. Due to high cliffs around there was only 7 hr of direct sunlight on my best day last week, generating 30 ah of charge from BOTH panels; only 4 days not clouded over, so maybe 120 ah total there. The rest of the charging had to come from the diesel. When we pulled up to come home yesterday the monitor read 53% SOC. That adds up to about 340 ah [120 + (0.47 x 470)]. Could my diesel running on average about 2 hr/day with 55-amp Hitachi alternator (output at 14.20 v) supply the difference, i.e., 55 ah demand/d x 8 d = 440 ah demand, then minus 340 ah = 100 ah?

In any case, the estimated 8-day demand of 440 ah divided by 220 ah = twice what I could generate on site, which ultimately brought the batteries to 53% SOC. Moreover, the admiral would have been much happier if we had run the Espar nearly continuously. Another few days of overcast, and we'd be running the diesel 4 or more hours per day to keep up the charge. How do others solve this problem short of the installation of a generator? Having a larger bank just kicks the can down the road.

 

[justsomeguy]

Move away from those cliffs?

 

[dlochner]

Are your panels wired in series or parallel? Is there any partial shading from the mast, rigging etc?

If the panels are wired in series and one of them has partial shading, it will reduce the total output of the panels, so instead of 14 amps in direct sunlight, you may only see 7 or 8 amps.

Check Maine Sail's discussion of Hitachi alternators and regulators for advice on your Hitachi alternator.
http://forums.sailboatowners.com/index.php?threads/musings-regarding-external-regulation.125392/

 

[Brian D]

I would start by using a fuel based heater vice electrical based heater. Some fuel based heaters can generate a lot of heat, but also fumes if not vented properly. That should save in your electrical budget if possible. Might be the admiral doesn't want fuel based heating.

 

[Kings Gambit]

Are your panels wired in series or parallel? Is there any partial shading from the mast, rigging etc?

If the panels are wired in series and one of them has partial shading, it will reduce the total output of the panels, so instead of 14 amps in direct sunlight, you may only see 7 or 8 amps.

Check Maine Sail's discussion of Hitachi alternators and regulators for advice on your Hitachi alternator.
http://forums.sailboatowners.com/index.php?threads/musings-regarding-external-regulation.125392/

Parallel; thanks for the reference to MS.

 

[Kings Gambit]

I would start by using a fuel based heater vice electrical based heater. Some fuel based heaters can generate a lot of heat, but also fumes if not vented properly. That should save in your electrical budget if possible. Might be the admiral doesn't want fuel based heating.

One of the other boats there had that; so, I'm looking into it as well. Thanks for reminding me about it.

 

[David in Sandusky]

The Admiral and I use comfortable, warm clothing, and a thick fluffy quilt in the cool ends of the season. But keeping the Admiral happy is always the #1 Goal!

I also recommend unloading your refrigerator by freezing some of your food supplies, and considering a modern high R factor cooler for some food.

We have no problem going 4 days using our built-in ice box, with home frozen ice, frozen meat, and maybe a frozen chili dinner. This is even easier in chilly water and air, which both reduce heating of refrigerated items.

dlochner has already proposed a path that will make your diesel charging cycles more effective.

 

[Kings Gambit]

The Admiral and I use comfortable, warm clothing, and a thick fluffy quilt in the cool ends of the season. But keeping the Admiral happy is always the #1 Goal!

I also recommend unloading your refrigerator by freezing some of your food supplies, and considering a modern high R factor cooler for some food.

We have no problem going 4 days using our built-in ice box, with home frozen ice, frozen meat, and maybe a frozen chili dinner. This is even easier in chilly water and air, which both reduce heating of refrigerated items.

dlochner has already proposed a path that will make your diesel charging cycles more effective.

Bought the admiral a PolarTech base layer, flannel warm layer and Musto shell; Cashmere neck scarf, smart wool socks, and gloves made in Newfoundland!! It helps, some; but there has to be heat as well to enjoy the time out. We do that with the fridge; I'd really like to stock w/non-, or minimally perishable, food items.

 

[Maine Sail]

The house bank has a theoretical 470 ah. There is also a battery monitor, but probably not a very good one,

Unless you actually know the capacity of your bank through physical Ah capacity testing your Ah capacity is indeed "theoretical".. Please ignore your battery monitor for SOC unless it is a SmartGauge or unless you've run a 20 hour test and properly programmed the monitor..

and two 85-watt solar panels.

170W is better than nothing just be sure your absorption voltage and absorption time/duration are 14.7V - 14.8V and 4+ hours.

Under the protocol I believe I was introduced to in this forum the useful "tidal range" of the house bank is between about 85% and 50% SOC assuming one does not wish to "murder" the batteries

It's not really a "protocol" so much as a reality. Discharging below 50% SOC, in the real world, tends to murder batteries very rapidly. The shallower you discharge the better off you'll be but the larger a bank you will require.

Recharging to more than about 85% SOC without 6-10+ hours per day of uninterrupted charging at a sufficient charge rate, is just very difficult to achieve due to CAR or the declining charge acceptance rate once you push into the low to mid 80's as a percent of charge.

Keep in mind that you can not continue this 50% - 80-85% routine indefinitely, especially in warmer climates, but for short week-long jaunts it is acceptable. All lead acid batteries need to get to 100% SOC as often as is humanly possible or they lose capacity faster. I like to see every third day, as a bare minimum to 100% SOC, but I know this is not realistic for many cruisers. Using ICE (internal combustion engine sources) to bulk charge is a necessary reality for most cruisers.

So, 0.35 x 470 = 164.5 ah to work with.

In theory yes, in reality perhaps not. If you don't know the physical capacity of the bank it is better to err on the side of caution. You will also experience PSOC walk down meaning each day you'll need to run the engine or chargers for a bit longer to achieve the same SOC as the day before. If you charge for exactly 1 hour per day your usable capacity will continually walk down as sulfate builds up on the plates between full recharges.

My daily needs appear to be near 50-60 ah (the fridge alone is near 30 @ 4 amps x 1/3 hr/hr x 24 hr = 32 ah). The Espar heater runs at 40 W; so, 40 W/12 v = 3.3 amps. Runs of 5 hr/day = 16.5 ah/day. Put the rest in the miscellaneous category for now. Due to high cliffs around, there was only 7 hr of direct sunlight on my best day last week, generating 30 ah of charge from BOTH panels; only 4 days not clouded over, so maybe 120 ah total there. The rest of the charging had to come from the diesel. When we pulled up to come home yesterday the monitor read 53% SOC. That adds up to about 340 ah [120 + (0.47 x 470)].

I am going to make this very easy:

DO NOT DISCHARGE YOUR BANK BELOW 12.2V

If you find your discharging duration to 12.2V is too short, then you simply need to add more charging time. It really is this simple..

If you want the batteries to last longer don't discharge below 12.3V. By starting charging at 12.2V you will soon develop an idea of how much charging you need each day to make it through each night.

Could my diesel running on average about 2 hr/day with 55-amp Hitachi alternator (output at 14.20 v) supply the difference, i.e., 55 amp-hr demand/d x 8 d = 440 ah demand, then minus 340 ah = 100 ah?

Short answer NO... You are being grossly optimistic about the capabilities of your internally regulated Hitachi. You will be lucky to see 20-30A out of it once it warms up and this will be at a voltage that spells murder for your batteries. 14.2V +/- .3V is usually the Hitachi spec at 68F/20C... As that alt heats up it reduces voltage thus drastically limiting current output and chronically undercharging your bank. 20-30A is a charge rate of about .043 -.064C or approx 4% - 6% of bank Ah capacity and absurdly under powered for a deeply cycled 470Ah bank.. These batteries can easily be bulk charged at .25C or about 115A. This means a 140A to 160A alternator to deliver 115A when hot...

Automotive Alternators vs. Deep Cycle Batteries (LINK)

In any case, the estimated 8-day demand of 440 amp-hr divided by 220 amp-hr = twice what I could generate on site, which ultimately brought the batteries to 53% SOC. Moreover, the admiral would have been much happier if we had run the Espar nearly continuously.

Again keep it simple charge when you get close to 12.2V and charge long enough to make it though the night or modify your usage or get better charge equipment...

Another few days of overcast, and we'd be running the diesel 4 or more hours per day to keep up the charge.

Yes with the crappy Hitachi alternators you would need that...

How do others solve this problem short of the installation of a generator? Having a larger bank just kicks the can down the road.

• Larger Solar Array

• Proper Charging Voltages (14.7V to 14.8V absorption)

• Proper Absorption Duration (3-4 hours at 14.7V - 14.8V for solar at a bare minimum)

• An Alternator with external regulator sized at 25-30% of Ah capacity when HOT (your Hitachi alternator is a joke for your type of use)

• After each week long jaunt fully charge then equalize the batteries

• Conduct ICE bulk charging early in the day, preferably before 10:00 am, then minimize power use and let solar get the bank as full as it can.

Very few of my world cruising customers (24/7/365 cruisers) use a genset.

 

[jssailem]

I like the Wallas heater for low Ah use and diesel fuel heat.
Reviews say it is a little slow to feel the heat in the cabin. Maybe 15 minutes. So I get up early, start coffee, start heater. Toasty warm for breakfast. Have not had any issues with fumes smell.

 

[Kings Gambit]

Unless you actually know the capacity of your bank through physical Ah capacity testing your Ah capacity is indeed "theoretical".. Please ignore your battery monitor for SOC unless it is a SmartGauge or unless you've run a 20 hour test and properly programmed the monitor..




170W is better than nothing just be sure your absorption voltage and absorption time/duration are 14.7V - 14.8V and 4+ hours.



It's not really a "protocol" so much as a reality. Discharging below 50% SOC, in the real world, tends to murder batteries very rapidly. The shallower you discharge the better off you'll be but the larger a bank you will require.

Recharging to more than about 85% SOC without 6-10+ hours per day of uninterrupted charging at a sufficient charge rate, is just very difficult to achieve due to CAR or the declining charge acceptance rate once you push into the low to mid 80's as a percent of charge.

Keep in mind that you can not continue this 50% - 80-85% routine indefinitely, especially in warmer climates, but for short week-long jaunts it is acceptable. All lead acid batteries need to get to 100% SOC as often as is humanly possible or they lose capacity faster. I like to see every third day, as a bare minimum to 100% SOC, but I know this is not realistic for many cruisers. Using ICE (internal combustion engine sources) to bulk charge is a necessary reality for most cruisers.




In theory yes, in reality perhaps not. If you don't know the physical capacity of the bank it is better to err on the side of caution. You will also experience PSOC walk down meaning each day you'll need to run the engine or chargers for a bit longer to achieve the same SOC as the day before. If you charge for exactly 1 hour per day your usable capacity will continually walk down as sulfate builds up on the plates between full recharges.





I am going to make this very easy:

DO NOT DISCHARGE YOUR BANK BELOW 12.2V

If you find your discharging duration to 12.2V is too short, then you simply need to add more charging time. It really is this simple..

If you want the batteries to last longer don't discharge below 12.3V. By starting charging at 12.2V you will soon develop an idea of how much charging you need each day to make it through each night.



Again keep it simple charge when you get close to 12.2V and charge long enough to make it though the night or modify your usage or get better charge equipment...



Yes with the crappy Hitachi alternators you would need that...

• Larger Solar Array

• Proper Charging Voltages (14.7V to 14.8V absorption)

• Proper Absorption Duration (3-4 hours at 14.7V - 14.8V for solar at a bare minimum)

• An Alternator with external regulator sized at 25-30% of Ah capacity when HOT (your Hitachi alternator is a joke for your type of use)

• After each week long jaunt fully charge then equalize the batteries

• Conduct ICE bulk charging early in the day, preferably before 10:00 am, then minimize power use and let solar get the bank as full as it can.

Very few of my world cruising customers (24/7/365 cruisers) use a genset.

Thanks, I'll get to work on this for the next time!!

 

[Maine Sail]

I like the Wallas heater for low Ah use and diesel fuel heat.
Reviews say it is a little slow to feel the heat in the cabin. Maybe 15 minutes. So I get up early, start coffee, start heater. Toasty warm for breakfast. Have not had any issues with fumes smell.

The Wallas is a great little unit but the Espar is also excellent. When installed correctly they are very comparable noise wise too. Most Espars & Webastos are horribly installed and many are flat out installed unsafely.

We had friends on our boat in October, who also have an Espar, and they were shocked at how quiet ours was.

 

[Kings Gambit]

The Wallas is a great little unit but the Espar is also excellent. When installed correctly they are very comparable noise wise too. Most Espars & Webastos are horribly installed and many are flat out installed unsafely.

We had friends on our boat in October, who also have an Espar, and they were shocked at how quiet ours was.

Factory (Bavaria Yachtbau) installation on our Espar; so, can only hope it's in correctly. Have no problem with the sound; it's very quiet once it gets to the "maintenance stage." Can heat up the boat very quickly to much higher temps than we need. Runs off of the diesel fuel in the regular tank.

 

[Kings Gambit]

Move away from those cliffs?
View attachment 131562

It's a pocket. The only way to escape is to put back to sea.

 

[Rick D]

Ergo, that's why you hear all those Honda 2000EU's run after the workers get off, especially in the winter. Just not enough sun and the wind is often much lighter in the winter too for the wind gen output. I have almost double the alternator output (Balmar) with a smart regulator and I get less than 70 amps out of a 90 amp unit. Happy New Year! I had several friends over there too. I understand it went from beautiful to stormy.

 

[Kings Gambit]

Yeah--the last few days--light east wind much of the time especially in the mornings, little direct sun, scattered showers with some hard rain. And--some would say---cold (55-61 deg much of the time,).

 

[Gunni]

As Maine says you are lucky if you even see 1/2 of that OEM Hitachi alternator. Maybe 20-25 amps at the wrong voltage. And all the while you are running/wearing a very expensive and important auxiliary Diesel engine to pump out that meager juice. Best value would be a 150 Amp Balmar high-output alternator that fits your existing mount and an external regulator with temp sensors. I have a similar set up to your house electric and once I swapped the Hitachi out for a Balmar I find that I can keep the house in good charge with maybe 45 minutes a day of engine run time. That often just means 20 minutes to get the anchor up, and 20 minutes to motor sail to my course. Throw in 20 more minutes to set anchor while charging in bulk phase and I am good for the night. I have a genset but find I don't need to run it nearly as often as I used to.

 

[Kings Gambit]

OK--thanks. I'll check 'em out.

KG

 

[Ralph Johnstone]

Every small saving counts. Are ALL your internal lights LED ? Anchor light as well ?

Also, put that useless Hitachi alternator to work by installing an external alternator regulator to get that 14.2V output up to 14.7V. Not the greatest but likely the easiest as you work up the cost ladder trying to match your supply to demand.

 

[Johnb]

Since your fridge seems to be more than half of all your load consider the use of "dry ice" to further save on the demand side.