Energy Wars

AnchorDragger · Sep 3, 2012

"If I build the boxes and have the cabinetry done I'm probably looking at 3.5 grand or more..."

That much money would buy a lot of dry ice.

Rick486 · Sep 14, 2012

Rick D said:
My whine:

It used to be so simple in my first four boats: take everything to the boat in coolers. Get good, clear block ice, fill up the frig with the ice and the food, put something on top of the food and shut the lid. This would generally last for four days to a week depending upon all the usual factors. We would listen to the VHF (when there was VHF!), stereo (when there was stereo!) and sometimes a little TV (there was TV!), and use lights when we weren't using our oil lamps. It was rare the battery required charging and the first two boats had outboards anyway and had no way to recharge.

So then to the first boat with refrigeration in a well insulated box. It had a freezer but we didn't use it generally. At first we continued using the ice and with occasional use of the refrigeration, we got a week out of it. Later, it became nearly impossible to get good clear block ice, and the chipped packed stuff is awful. So, we used the refrigeration twice a day for about four hours. I ran the engine every other day for an hour. Stock dumb alternator.

OK, so then I learned from the AB refrigeration technicians that it is more energy efficient to have the refrigeration turned on full time and simply turn down the thermostat to save amps. I also changed the batteries out to Group 31's and added a separate start battery.

So, now in 1999 I moved up to my 1994 Hunter 40.5. When I recommissioned it, the service manager talked me out of a generator after pointing out that my use would not require it and it would just add weight and complexity. He suggested two banks of golf cart batteries, a Balmar 100 amp alternator, smart regulator & inverter/charger. The 40.5 has a separate large frig & freezer, each with its own compressor. The boat also had a nice TV, video tape player and all the other amenities of the era.

Soooo, the first thing I find is the power draw is such that I need to run the engine twice a day. The prior owner did not use the freezer as a freezer much, but my wife finds it very useful since we use the boat for long periods both at and away from the dock. Thanks to early discussions in the Hunter Forums and Rich Stidger, I learned about adding gasketing to better seal the lids which made a noticeable improvement.

Then I purchased three flexible 22 watt solar panels which I put on the bimini at anchor. This permitted me to cut down the engine run time to once a day, but still needing the occasional two. I was relying on my panel volt meter. I learned from these forums how inaccurate it could be, so I installed a Heart battery monitor. It really was off!

At a Yanmar seminar, I found out how damaging it can be to run the engine with only the alternator load, at least frequently. By this time, the full-time seasonal live aboards in the anchorage had changed to using portable generators, but they were very noisy. Then the Honda EU series came out and I purchased one.

The EU2000 works great. It takes between an hour and two per day depending on the season (remember the solar panels) and our energy appetite. However, it does drone on and I would like to cut down the run time. So, I changed all the lights (including running lights) to LCD. I changed the TV's to energy efficient ones (although we rarely watch anything more than an hour and usually less).

More recently, I added four fifty watt solar panels for a total of 266 watts of solar and a MPPT charge controller. I just came back from the island after eight days in the anchorage and this is what I found:

1. The significant solar charge was limited to 10:00 - 4:00 PM (Southern California August). Even with semi-articulating panels, it fell off rapidly before or after.
2. The theoretical output is about 19 amps. I was hoping for 12. I got maybe 9-ish.
3. So, I was only putting back about 10-15 net amp hours during the day.
4. I used about 60 amps overnight without the frig & freezer being opened and nothing else on. Add to that about 30 during the other hours the panels are not providing power and I'm still an hour to an hour and a half to charge the batteries (500 amp hours) to 80% given a power share setting of 20 amps on the panel which produces 66 amps charge from the Honda.

OK, so I'm still not happy.
So now what? The first thing I thought was that the batteries are getting weak-kneed since they are just wrapping up three years and that's about all I have ever gotten. So, I brought a good 130 amp load tester since I didn't own one and I'm sure not going to haul the batteries out to be tested. I'll test them before my next trip and replace if necessary.

What else? Well, the obvious thing is to better insulate, or re-insulate the frig & freezer. I already replaced the frig unit with a Sea Frost slim holding plate system and it's more energy efficient. I suspect the foam insulation has gotten damp and that will significantly reduce the insulation value. I'm thinking of going with closed cell foam which would keep moisture intrusion away but the cost of labor to tear out and reassemble the cabinetry would be on the order of several thousand dollars. Still, it is something to consider.

I could add more solar, but it would mean an arch and I don't want it on full time. I don't want it for races, day sails or in the slip. I can store my four 50 amp panels in the dock box and the three 22 watt flexible panels in the aft cabin. Works out well. I do notice that most of the serious cruisers in the 40'+ range have north of 400 watts solar.

I could add a wind generator into the mix and it might be a good source of energy replacement while the panels are not producing. However, the halyard-hoisted ones are no longer available and the guys tell me that 5 amps is about what I should expect in real world conditions. Of course, the wind does not blow all night either.

So maybe I should have put the damn generator in to begin with? No, the service manager was right. Most of the time I don't really need it. Increasing the battery bank gets me nothing but more weight. So, I'm guessing that a battery replacement would make life better for a while and I'll keep considering other options. But, I'm not going to go back to block ice and shut off the freezer!

Sorry to disagree but here's my story. When I took delivery of my 44 DS 5 years ago it came with a Panda 6 kw generator. It runs great with no problems after 500+ hours. When cruising it runs 2-1/2 hrs a day when we are on the hook. It uses about .4 gal/hr diesel. We have a large fridge and smaller freezer. The freezer runs at 10 degrees F and the fridge at 40 degrees F. We keep ice cream and frozen food for weeks, run the TV and DVD, coffee maker, microwave, A/C when needed, heat when needed, always have hot water. We have 3 4D gels and 1 Grp 31 gel for start. The house bank never gets less than 50% SOC and is usually at more like 70 % SOC. No worries, no whirlygigs, no solar panels, no constant worry and re-engineering required. Rick, if you wanted a simple life you shoulda, and still could, gotten the generator.

Maine Sail · Sep 14, 2012

Rick D said:
Hey, Maine, do you think I did this right? The directions were replete with pages of cautions but almost devoid of instruction.

All the batteries checked out great! Hell, that sixty dollars saved me $500 if I believe it. It is a pretty beefy unit with heavy clamps and a dual 6/12 analog meter. Seemed to work well and I put it on one I know to be weak and that's just what I saw. I let the batteries rest off the charge without a load for half hour before testing.

To expand, this looks like a pretty dumb unit. All you do is hook it up and hold the switch for ten not to exceed 15 seconds. I checked each battery independently and several times. I am amazed they seemed to be good after three years (Sam's Club except for the start battery). I just equalized the battery bank last night and will be heading out soon for a couple of weeks, so I'll be exercising them pretty well again.

Rick,

The industry standard for load testing a battery is 50% of CCA applied for 15 seconds and temp compensated it should remain above about 10V.. These tests don't really show you capacity left just how much they can do for 15 seconds...

Stu Jackson · Sep 14, 2012

Rick486 said:
Sorry to disagree but here's my story. When I took delivery of my 44 DS 5 years ago it came with a Panda 6 kw generator. It runs great with no problems after 500+ hours. When cruising it runs 2-1/2 hrs a day when we are on the hook. It uses about .4 gal/hr diesel. We have a large fridge and smaller freezer. The freezer runs at 10 degrees F and the fridge at 40 degrees F. We keep ice cream and frozen food for weeks, run the TV and DVD, coffee maker, microwave, A/C when needed, heat when needed, always have hot water. We have 3 4D gels and 1 Grp 31 gel for start. The house bank never gets less than 50% SOC and is usually at more like 70 % SOC. No worries, no whirlygigs, no solar panels, no constant worry and re-engineering required. Rick, if you wanted a simple life you shoulda, and still could, gotten the generator.

Gee, running a generator 2 1/2 hours a DAY? That's "easy?" You could have reduced your run to time much less by using solar, too.

Rich Stidger · Sep 14, 2012

Stu Jackson said:
Gee, running a generator 2 1/2 hours a DAY? That's "easy?" You could have reduced your run to time much less by using solar, too.

Well, maybe reduced it some, Stu, but my refrigerator uses about 60AH/day, and the freezer about 90AH/day plus all of the other stuff- lights, AP, instruments, radar, etc. and I'm looking at the best part of 200AH for a day of sailing- no motoring. With my genset and two chargers (80A and 30A- both set for maximum boost on bulk mode) plugging away I think 2.5 hours on the generator is pretty reasonable. The average daily output on my Air-X wind generator is about 15AH unless the wind is howling at 25kt+. I have no solar, but unless you have a lot of big panels and a strong sun day, I don't think you are going to make a serious dent in the 200 AH replacement.

Bob 04 H260 · Sep 15, 2012

solar panels

In the last article I read by Nigel Calder he now recommends solar panels be connected in parallel not series.

He says if they are in series to increase voltage and limit the I*2R drop any partial shading on just one cell can reduce the output of all the panels.

The shading of one cell will only effect the output of the one panel if they are wired in parallel.

He is rewiring his boat to parallel and expects a big increase in output.

I think he says some panels are more susceptible to this than others. I also read this in sales literature that some panels are better suited for sailboats as the output will not go down as much if one cell is shaded.

Also panel output goes down as temperature goes up, so they need to be mounted with good air circulation under them.

Bob

Rich Stidger · Sep 15, 2012

How I measure deep-cycle capacity

Rick,

This is a bit of work and it takes some time but I think it gives a good measure of the capacity of the battery.

The rated AH of the battery should be based upon a 20A load if the batteries are rated according to industry standards. So if you have a 500AH bank and you place a 20A load on that bank, you should be able to run that load for 25 hours and the battery voltage will then be 10.5V (1.75V per cell).

Note that Reserve Capacity (RC) is not the same as the AH capacity. The RC is the number of minutes that the battery will supply a 25A load without the voltage dropping below 10.5V.

So what I do to measure the capacity of my batteries is to perform the following test. I test each battery separately- in my case that is four 6V golf cart units, but for your case you might test the entire bank to get an overall answer. I charge the batteries until they are fully charged as measured by both terminal voltage and specific gravity. Note that after charging the batteries need to rest for 24 hours without any loads in order to get an accurate measurement of terminal voltage. Attached is a chart that relates specific gravity to state of charge (SOC).

Then I apply a 20A load to the battery. I use a few car headlights to produce this load. I run this load for until the battery is about 50% SOC. I measure the starting current of the battery after the first 5 minutes and then the ending current before removing the load with a ammeter. Then I remove the load and let the battery rest for 24 hours. I then measure the voltage and the final specific gravity of the battery after the rest period.

Now it is time to calculate:

The initial specific gravity will yield the initial SOC. It may not be 100%; it might be only 96%. That's OK.

Then I take the current at the start of the test (after 5 minutes) and the ending current and average the values. Assuming a straight line (this is not quite true, but close enough) this gives me the average current for the time period. In your case for a 500AH bank, if you run this test on the entire bank instead of the individual batteries, I would run the test for about 12 hours - 12hr x 20A=240AH, or about half of your nominal capacity.

The reason that I measure the beginning and ending load current is so that I can calculate the number of AH that were actually withdrawn. If you have a battery monitor you can use that reading instead of doing the following calculation.

Since the voltage will decrease over the time of the test, the current will not remain at 20A for the entire 12 hours. So if the initial current was 20A and the final current was 16A, then I assume that the average was 18A for the 12 hours or 18x12=216AH withdrawn.

Now I determine the SOC from the specific gravity at the end of the test and I subtract it from the SOC at the beginning of the test. This tells me the chemical condition of the battery after removing the 216AH.

From the test data, and in a perfect world with the battery bank having a full 500AH capacity, this would translate to 216/500= 43% used or 57% SOC. If the beginning SOC was only 96%, then the final SOC should be 53%.

I now compare the calculated SOC (53%) with the SOC as indicated by the final specific gravity measurement. If they agree, then the battery bank has its full 500AH capacity. If they disagree, then the difference is the amount of loss in capacity.

For instance, suppose the calculated SOC was 53% as above and the final specific gravity showed the SOC to be 40%. Then the bank has lost 13% of its original capacity.

Attached are three documents that pertain to testing and battery condition. Not light reading, but good references.

BTW, you need a quality hydrometer to accurately measure the specific gravity of the cells. The $5 units that you can commonly purchase are not good enough. I use a unit and thermometer manufactured by Francis L. Freas Glass Works. They used to do direct mail order and I presume that they still will do that.

http://www.freasglass.com/

Now aren't you sorry you asked?.......

Maine Sail · Sep 15, 2012

Rich Stidger said:
Rick,

This is a bit of work and it takes some time but I think it gives a good measure of the capacity of the battery.

The rated AH of the battery should be based upon a 20A load if the batteries are rated according to industry standards. So if you have a 500AH bank and you place a 20A load on that bank, you should be able to run that load for 25 hours and the battery voltage will then be 10.5V (1.75V per cell).

Note that Reserve Capacity (RC) is not the same as the AH capacity. The RC is the number of minutes that the battery will supply a 25A load without the voltage dropping below 10.5V.

So what I do to measure the capacity of my batteries is to perform the following test. I test each battery separately- in my case that is four 6V golf cart units, but for your case you might test the entire bank to get an overall answer. I charge the batteries until they are fully charged as measured by both terminal voltage and specific gravity. Note that after charging the batteries need to rest for 24 hours without any loads in order to get an accurate measurement of terminal voltage. Attached is a chart that relates specific gravity to state of charge (SOC).

Then I apply a 20A load to the battery. I use a few car headlights to produce this load. I run this load for until the battery is about 50% SOC. I measure the starting current of the battery after the first 5 minutes and then the ending current before removing the load with a ammeter. Then I remove the load and let the battery rest for 24 hours. I then measure the voltage and the final specific gravity of the battery after the rest period.

Now it is time to calculate:

The initial specific gravity will yield the initial SOC. It may not be 100%; it might be only 96%. That's OK.

Then I take the current at the start of the test (after 5 minutes) and the ending current and average the values. Assuming a straight line (this is not quite true, but close enough) this gives me the average current for the time period. In your case for a 500AH bank, if you run this test on the entire bank instead of the individual batteries, I would run the test for about 12 hours - 12hr x 20A=240AH, or about half of your nominal capacity.

The reason that I measure the beginning and ending load current is so that I can calculate the number of AH that were actually withdrawn. If you have a battery monitor you can use that reading instead of doing the following calculation.

Since the voltage will decrease over the time of the test, the current will not remain at 20A for the entire 12 hours. So if the initial current was 20A and the final current was 16A, then I assume that the average was 18A for the 12 hours or 18x12=216AH withdrawn.

Now I determine the SOC from the specific gravity at the end of the test and I subtract it from the SOC at the beginning of the test. This tells me the chemical condition of the battery after removing the 216AH.

From the test data, and in a perfect world with the battery bank having a full 500AH capacity, this would translate to 216/500= 43% used or 57% SOC. If the beginning SOC was only 96%, then the final SOC should be 53%.

I now compare the calculated SOC (53%) with the SOC as indicated by the final specific gravity measurement. If they agree, then the battery bank has its full 500AH capacity. If they disagree, then the difference is the amount of loss in capacity.

For instance, suppose the calculated SOC was 53% as above and the final specific gravity showed the SOC to be 40%. Then the bank has lost 13% of its original capacity.

Attached are three documents that pertain to testing and battery condition. Not light reading, but good references.

BTW, you need a quality hydrometer to accurately measure the specific gravity of the cells. The $5 units that you can commonly purchase are not good enough. I use a unit and thermometer manufactured by Francis L. Freas Glass Works. They used to do direct mail order and I presume that they still will do that.

http://www.freasglass.com/

Now aren't you sorry you asked?.......

Guys,

I will respond with much more info later when I have some time. We are off sailing.

A few things though for now:

#1 For a 20 hour capacity test to be even close to accurate the battery MUST be drawn down at the 20 hour draw for the SPECIFIC battery. A 500Ah battery bank would be drawn to 10.5V at a 25A rate NOT 20A!!!

A 100Ah battery would be draw at 5A NOT 20A. A pair of 6V 225Ah in series batteries would be draw at 45A NOT 20A...

To figure the load that needs to be applied you divide the 20 hour Ah capacity by 20.

So 100Ah battery divided by 20 = 5A

A 125Ah battery divided by20 = 6.25A

It is best to test the individual batteries in the bank separately so you know the individual condition of each battery.

#2 To get an accurate calculation the bank capacity the battery must be drawn to the complete cycle depth per industry standards of 10.5V.

I built a home made capacity tester using a Victron BMV-600 and Omron ice cube relay to terminate the test at 10.5V. In conversing with Nigel recently we both discovered we built the exact same tester.

#3 The load needs to remain as constant, at the 20 hour draw/load, as is humanly possible. I use a number of bulbs and dedicated load chips that can be switch on or off to maintain the exact load even as the voltage falls. Other than a $4k constant load device this is as close as it gets.

#4 You do not need SG or voltage, other than the 10.5V cut off voltage, to perform this test. You will know when your battery is "full" by measuring the accepted current. The battery monitor will keep track of voltage and shut off the test when the battery hits 10.5V and show you exactly how many Ah's were produced before the bank hit 10.5V...

#5 Capacity and voltage or specific gravity are NOT one in the same. You can have a 100Ah battery showing perfect SG and OCV that has but a 30Ah capacity left in it. The only way to know capacity is to test it using the 20 hour capacity test. It is not advised to conduct this test very often because you draw the bank to 10.5V. When or if you do this test charge the bank back to 100% ASAP, preferably within an hour of the bank hitting 10.5V....

Rich Stidger · Sep 15, 2012

Thanks to Maine Sail for correcting the load currents for the 20 hour rate.

The lab-type test procedure is as Mainesail states- the load must be held constant for the entire 20 hours. However since without an investment in test equipment that most users are not willing to make, I maintain that my procedure will produce results to indicate if your batteries are healthy or on their last legs.

I do maintain that the specific gravity measurement is the most accurate way to determine SOC, and since it is not a good idea to completely discharge your battery to zero, I prefer to discharge to only 50% not to 100% per the battery spec. Is this a perfect test?- no, but IMHO it is close enough. 50% is the recommended maximum discharge level to provide for reasonable battery life.

Maybe some of the other posters will have another method that is simpler to use.

Bob 04 H260 · Sep 15, 2012

If I have a battery monitor and watch the battery voltage as I draw current from the bank of batteries that should tell me if I have a problem that needs testing or not ?

For example if I have a 400 hr bank and it is fully charged, and I can only draw 150 Ahrs out of it before the battery voltage drops to 10.5 V then I must have one or more bad batteries, and so they all need testing ??

Does having a bad battery in a bank ruin the whole bank fairly quickly ? or does it just kill them off slowly ?

Bob

Sumner · Sep 15, 2012

Rich Stidger said:
....Maybe some of the other posters will have another method that is simpler to use.

You and MS have provided some great info, thanks.

Me, I replace them when I don't think they are holding a charge and just not performing. Am I replacing them too soon or too late? Probably :cry:.

It was pretty evident with the battery that came in the Mac and the house batteries that were in the Endeavour at the time of purchase were shot as they also wouldn't hold even a fresh charge. Found a couple screwed up cells in them testing cell to cell with the volt meter. We will be replacing all 4 of them :cry:. I'm hoping that they then last as long as we have the boat,

Sum

[FONT=Arial, sans-serif]============================[/FONT]

Our Endeavour 37

Our MacGregor 26-S Pages

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

Rich Stidger · Sep 24, 2012

Rick- Do you mean that your solar supplies all of your refrigerator and freezer load and provides an additional 30AH/day, and you still need to put back another 60-70AH?

How many AH per day to you use anyway? It sounds like upwards of 240Ah/day!!

Sumner · Sep 24, 2012

Sounds like you have made some good progress :dance:.

Rick D said:
I think better insulation for the frig & freezer might help a lot for a lot of money.

I agree, insulation is key. I just posted the following on another forum and was in response to a question there so please forgive if you read it there already but it does show the benefits of good insulation....

=======================================

The power thing is totally going to depend on the insulation. How much insulation is your friend going to have top, sides and bottom? Most of the units below the Danfoss BDF50's seem to use between 3-4 amps when they are running the insulation is going to determine how much they run.

Our portable that we use in the MacGregor ....

...has a compressor/condenser that runs at 3 1/2 amps, but when the boat is 85 degs or so inside runs about 40% of the time, so about 34 amp/hours a day.

The fridge we made...

...for the Endeavour also runs 3 1/2 to 4 amps, but even thought it is 1 1/2 cu ft. larger, around 4 cu. ft., and has a freezer section seems to only run about 10-15% of the time with the same interior boat temps so less than 15 amp/hours a day. The key is...

...this one has lots more insulation compared to the portable (3 inches top, 4 on the sides and 7 and 9 on the bottom)

It uses the more efficient of the two Danfoss 35 compressors, the coolmatic 84, and with the evaporator is a couple hundred more than the Norcold, but we really like it and it is sized for a box over twice the size of our box so feel that we aren't working it very hard. So far we are very happy with the frig and the Coolmatic.

More on our fridge build and install here....

Endeavour 37 Interion Mods Index

...and good luck,

=============================

Rick D said:
BTW I get some 'pulsing' from the regulator. By that I mean it might move up to 10 amps and then drop to 6.5, but then step back up to 10 and hang there a bit. Is this something the MPPT controller is doing, or is it more likely the boat swinging and getting some shadowing?

I haven't noticed ours doing that, but the panels aren't ever really shaded,

Sum

Energy Wars

.

.

.

.

.

.

.

.

.

.

.

Attachments

.

.

.

.

.

.

.

.

.