Best practice for desulfation battery bank

[phantomracer]

Originally Posted by Maine Sail

It will be fine for short periods & equalizing I would not personally use it as a maintenance charger..

Thanks.. any suggestions on a better unit?

[a64pilot]

Originally Posted by phantomracer

not crazy about lugging a generator to and from the boat each time i want to charge the battery...and having gasoline on board makes me nervous as well.. plus dropping another $1500 .. just easier/cheaper to take it into the dock time to time

Yes, the little Honda's are not ideal, I have two and just put in a 3.5 KW NexGen because I disliked the Honda's, not that I love a generator, just my electrical plans sort of require one as I plan on having an AC high output watermaker, and that means a generator.
Everything is a compromise, even deciding to forego refrigeration so you can live with a simple battery bank is a compromise.
But assuming you like me want to have some modern conveniences, your going to have to get the power from somewhere to properly charge your batteries often or accept a short life span from them, and you have decided not to go the Solar route. So that leaves from what I can tell three other methods, a dock, your main propulsion engine, or a generator of some kind.
From my very limited knowledge it seems we need to fully charge our batteries to 100% at least weekly to get a good, full life out of them, and to get from 85% to 100% takes hours, regardless of how good the charger is.
So that leaves either a generator or a dock as your source as in my opinion running your main engine as a battery charger is abusive to it, and is bad in the long run.

[phantomracer]

yup its a balance for sure! As the engineer in the movie Apollo 13 says 'Power is everything'

In the end my system will be a compromise for sure..and will take effort to make it last.

After going half a season with the system as is, I recognized something is wrong. learned a lot in this thread.. for better or worse, the efoy is the best compromise for the heart of the system. Will get a small panel to help during the day, and will try and get to a dock to equalize the batteries time to time

If we were more hard core cruisers, I would certainly get a more appropriate solar set up along with the efoy to augment the system

[sailorboy1]

Originally Posted by a64pilot

So that leaves either a generator or a dock as your source as in my opinion running your main engine as a battery charger is abusive to it, and is bad in the long run.

No it doesn't! My boat sits out on a mooring all week by itself with the refrigerator running and my 290W solar panel fully charges the batteries 80% of the days and even completes its' cycle of maintaining 2 hours at absorption charge before going into float. And I'm just 20 miles up the coast from the OP.

[phantomracer]

Originally Posted by sailorboy1

No it doesn't! My boat sits out on a mooring all week by itself with the refrigerator running and my 290W solar panel fully charges the batteries 80% of the days and even completes its' cycle of maintaining 2 hours at absorption charge before going into float. And I'm just 20 miles up the coast from the OP.

I think he meant ME when he said 'your' (as I am reluctant to put a space station size panel on my boat)

[sailorboy1]

Originally Posted by phantomracer

I think he meant ME when he said 'your' (as I am reluctant to put a space station size panel on my boat)

I don't know what a space station size panel means. I can't even see my panel mounted above the bimini. But you haven't said what your normal daily power use is to even begin to size a solar system.

But solar or wind is really the only good answer for a boat out on a mooring left alone most of the week.

But when it comes down to it you have gotten 5 years out of your batteries while really taking bad care of them. I feel that is pretty good and if you really start looking at the costs of some of things on this thread you will find that they are going to cost as much or more than the replacement batteries. My 4-6V batteries cost me $439 4 year ago. That's currently $109/yr. If they last another 4 years the cost would be $54/yr. Spending lots of money on a boat to save $54/yr is a lost cause.

If you have 6V wet cells golf cart batteries it always seems to me that some people spend more money on things to extend their life than the batteries are even worth.

[svlamorocha]

Originally Posted by Maine Sail

The problem is that the Efoy will turn off once the target voltage is attained, where a decent solar controller does not. The Efoy does not reach target voltage then limit the voltage to that point and hold it there it simply gets to target voltage and shuts off entirely until the voltage falls to 12.3V.

Maine Sail
I understand and agree with everything you say, except that SOME of the EFOY literature User_Manual_EFOY_600_2200_WEBopt3.pdf says that the thing has a proper 2-stage regulator that maintains the absorption voltage, as opposed to an on-off logic. See text below that describes an absorption period of "up to 3 hours".

5.4
Automatic Operation
Automatic operation will begin the moment that you connect the unit to a battery. The unit will monitor battery voltage by itself.
The fuel cell switches on automatically if the battery voltage falls below 12.3 V. The battery is then charged until the deactivation threshold, 14.2 V, is reached. Note: To guarantee optimal battery maintenance, it is important that the charge current is not stopped abruptly when the deactivation threshold is reached. For this reason, the EFOY continues to charge for up to 3 h after the deactivation threshold set is reached (by default, 14.2 Volt is preset). The recharging period depends on the battery voltage and the electricity consumption.
The device goes through a cold start phase of about 20 minutes before reaching its full rated output. In normal operation the current generation is interrupted briefly a few times a second.

[phantomracer]

Good point..Its more than cost, its about having power when you need it.. ensuring the fridge stays running, and have power for everything else when i need it. It just feels like I am constantly coming up short on power. If I can get ahead of the curve by improving the system and treating it better and fixing the method that I am using, it would be great.

frigoboat guestimates the refrigeration is about 25 or so ah a day. no idea if this is real life or not. Just a figure they say is 'typical'. Other than the bilge pump, that is all that is running when the boat is unattended.

Just not going to permanently mount panels on my boat. I will give up the refrigeration before I would mount panels.

Might try a small portable panel to take the edge off and assist during the day, and taking it to the dock more regularly to charge it with a charger..

[sailorboy1]

Originally Posted by phantomracer

Good point..Its more than cost, its about having power when you need it.. ensuring the fridge stays running, and have power for everything else when i need it. It just feels like I am constantly coming up short on power. If I can get ahead of the curve by improving the system and treating it better and fixing the method that I am using, it would be great.

I think your main problem and is that you don't really know what your power demand is. Am I wrong in assuming you don't have a battery monitor or really anything to monitor you batteries other than a voltage meter?

I would say other that needing to do a full charge and equalization you probably need a battery monitor (and it needs to be properly programmed and setup).

If your refrigerator really is only 25 ah/day all you need is a 60W panel, that's pretty small.

[svlamorocha]

Originally Posted by phantomracer

frigoboat guestimates the refrigeration is about 25 or so ah a day. no idea if this is real life or not. Just a figure they say is 'typical'. Other than the bilge pump, that is all that is running when the boat is unattended.

Frigobota has no idea of the dimensions and R-value of your fridge, hence they cannot make a reasonable estimate of duty cycle and your Ah draw per day.

They can tell you what will be the instantaneous current draw given the "correct" load of refrigerant, the temperature and the speed of the compressor.

http://www.saltservice.net/files/44446309.pdf

Ifyou do not know the R-value of your fridge box then it is safe to assume that it is bad enough to have the compressor running all the time in order to get decent fridge temperature. That would mean a daily consumption closer to 100Ah than 25Ah, unless the low-voltage cut-off is triggered..

I bet you will be surprised if you actually measure how much energy the fridge consumes per day. The return on spending $55 on one of these may be good:

http://www.amazon.com/Watts-Meter-An.../dp/B001B6N2WK

I have used one of those to get real data on fridge consumption, solar panel output, etc.

[phantomracer]

Originally Posted by sailorboy1

I think your main problem and is that you don't really know what your power demand is. Am I wrong in assuming you don't have a battery monitor or really anything to monitor you batteries other than a voltage meter?

I would say other that needing to do a full charge and equalization you probably need a battery monitor (and it needs to be properly programmed and setup).

If your refrigerator really is only 25 ah/day all you need is a 60W panel, that's pretty small.

Yes. you are correct. I mentioned this earlier in the thread. I plan on installing a balmar SmartGauge in the near future

[Maine Sail]

Originally Posted by svlamorocha

Maine Sail
I understand and agree with everything you say, except that SOME of the EFOY literature Attachment 105827 says that the thing has a proper 2-stage regulator that maintains the absorption voltage, as opposed to an on-off logic. See text below that describes an absorption period of "up to 3 hours".

5.4
Automatic Operation
Automatic operation will begin the moment that you connect the unit to a battery. The unit will monitor battery voltage by itself.
The fuel cell switches on automatically if the battery voltage falls below 12.3 V. The battery is then charged until the deactivation threshold, 14.2 V, is reached. Note: To guarantee optimal battery maintenance, it is important that the charge current is not stopped abruptly when the deactivation threshold is reached. For this reason, the EFOY continues to charge for up to 3 h after the deactivation threshold set is reached (by default, 14.2 Volt is preset). The recharging period depends on the battery voltage and the electricity consumption.
The device goes through a cold start phase of about 20 minutes before reaching its full rated output. In normal operation the current generation is interrupted briefly a few times a second.

My info came from their applications engineer after regular tech support could not answer my questions. Admittedly that conversation was perhaps 1.5 years ago. IIRC the engineers name was Rick or Rich. My question to him was can the unit modulate it's output current and does I'd do any form of voltage regulation for a proper absorption cycle.

What I posted is what I was told and I kept quite good notes... One can only hope they have updated their charge process. Perhaps Phantom can observe the behavior on his and see what it actually does?

[svlamorocha]

Originally Posted by phantomracer

Yes. you are correct. I mentioned this earlier in the thread. I plan on installing a balmar SmartGauge in the near future

The SmartGauge is a nice piece of kit but it will not tell you what your power demand (A and Ah over time). It will only tell you State of Charge as in % full.

[sailorboy1]

Originally Posted by svlamorocha

The SmartGauge is a nice piece of kit but it will not tell you what your power demand (A and Ah over time). It will only tell you State of Charge as in % full.

And it will cost more than a set of new batteries for the OP.

[phantomracer]

Originally Posted by svlamorocha

Frigobota has no idea of the dimensions and R-value of your fridge, hence they cannot make a reasonable estimate of duty cycle and your Ah draw per day.

They can tell you what will be the instantaneous current draw given the "correct" load of refrigerant, the temperature and the speed of the compressor.

http://www.saltservice.net/files/44446309.pdf

Ifyou do not know the R-value of your fridge box then it is safe to assume that it is bad enough to have the compressor running all the time in order to get decent fridge temperature. That would mean a daily consumption closer to 100Ah than 25Ah, unless the low-voltage cut-off is triggered..

I bet you will be surprised if you actually measure how much energy the fridge consumes per day. The return on spending $55 on one of these may be good:

http://www.amazon.com/Watts-Meter-An.../dp/B001B6N2WK

I have used one of those to get real data on fridge consumption, solar panel output, etc.

I agree 100%. They have no idea what my fridge is pulling.

When the box isn't opened, the compressor rarely comes on. When it does, it barely registers on the (analog) amp meter (yes i need something better) as the compressor runs very slowly but over a longer period of time. The controller on the unit is very energy efficient...best rated in Practical Sailor (FWIW)

Overnight, if it comes on once during the night, thats a lot. The box is not nearly as good as virtually any modern ice box, thats for sure, but it isn't terrible.

I will look at that meter..