Battery desulphator for off grid installation

[la7qz]

Hi

I'm looking for a battery desulphator for a yacht installation. At the moment I'm running four Trojan T-105 batteries wired for 12V, but may add more batteries later. It seems a few of the desulphators out there are meant for smaller banks.

Please note that there is no mains power available (other than from inverters running off the same battery bank), so I need something that will power itself off the batteries it is working on.

Owen

Yacht "Magic"

St Maarten

[bob g]

do yourself and your batteries a favor and learn how to charge your batteries properly, and forget the magic that is promised by desulfators.

my opinion only

bob g

[shay]

you are doomed and forced to junk them or learn to extend their lives. How about suggesting how to keep them in great shape? Is there something we've missed?

[shay]

are powered from the batteries themselves and a renewable energy engineer told me they do work!

[la7qz]

Hi

My batteries are charged "properly" by a combination of 310W of solar power, a 400W wind turbine and (very rarely) the engine alternator.

Regulation is by a Tristar 60 configured as a dump load regulator and dumping into a 600W 12V heating element in the hot water tank. The set point of the Tristar 60 is 14.4V, 0.2V higher than the engine alternator which is set at 14.2V since I don't particularly want the dump load regulator load up the alternator. Everything works just fine and most days I am dumping power for a couple of hours in the middle of the day. On days with lots of wind and sun, I'm even heating water with the excess energy, but the main reason my dump load is in the hot water tank is to avoid heating the boat.

I believe I do know how to charge my batteries.

What would you do different?

Apart from possibly adding a solar regulator instead of letting the dump load regulator take care of everything, I can't think of a thing to change. Adding a solar regulator would mean I loose the water heating of course.

I do not have an AC generator or access to grid power.

Owen

[bob g]

i have little doubt that a desulfator works, what is in question to me is:

1. which ones work, and
   
2. how do they work, and
   
3. it has never been proven that they do anything that proper charging
   
   

doesn't do better in the first place.

any time a supposed engineer states some claim about desulfators i become automatically suspect, usually he is selling them.

the bottom line is

understand what what sulfation is, and the fact that it is a normal function of

discharge. also bear in mind what you need to have for a charging capability for the size of battery bank  you want to work with, and don't use a desulfator to do

what proper charging is meant to do.

in other words if you need a desulfator you are doing something wrong to start with.

your either being sold something you don't need, or you are not charging your batteries properly because you have too large a bank, or too small a charging capability.

nothing wrong with using a desulfator to recover a battery (attempt) that will not recover by normal means, but in my opinion they should never be used as a standard part of a charging system.

i could go on for days on this subject if you like?

bob g

[bob g]

looks to me like you are doing everything just fine as is without

buying into the desulfator hype.

there is nothing a desulfator is going to do for you that you are not doing

correctly now.

do a periodic equalization charge and call it a day.

your voltage setpoint of 14.4 is just fine for a working set of batteries

just keep the water level up properly and my bet is you will get as good of life

from those batteries as anyone under the same scenario.

btw, provided you are not in extremely hot climates, where you might want to taper back a bit.

bob g

[ghurd]

I agree.

There are some papers at Sandia.  Somewhere.

PWM solar charging is as good as a desulfator.  I saw a Very old 100AH battery brought back to functional with a PWM SG-4 and 40-50W panel. Never would have believed it.

Another paper or 2 had short term tests that implied PWM dump control had the same effect.

The TS-60 runs at 300-350Hz.  It is probably doing the same or better than a self powered desulfator.

I often wondered if a single phase alternator would not do the same thing because it charges in pulses.

G-

[Opera House]

Whether or not desulphators work, I wonder why there haven't been posts saying that thing destroyed my equipment.  I've seen posts claiming 60V pulses.  That is fine if the battery is stand alone disconnected from a system.  I wouldn't want one connected to a functioning system without an inductor to filter the pulses from other electronics.

[la7qz]

Hi Ghurd

Just one little thought here.

Since I am running the TS-60 as a dump load regulator, none of my charge is going through it to the batteries, so if my batteries see the 300-350Hz pulses, that is only as a load, not as high voltage pulses going into the battery which the desulphators claim.

Anyway, looks like the general opinion here is desulphators may be useful for bringing back damaged batteries, but are not needed in a properly functioning installation.

Owen

[scottsAI]

La7qz,

According to Trojan, the flooded cells should be equalized, from the link:

http://www.trojanbattery.com/pdf/UsersGuide_English.pdf

Equalizing Final charging voltage is 14.7 (bit low to me) to 16.2v

Charging to 14.2 is not enough to equalize the battery. At 77F. Temp comp voltages.

From experience couple years without equalizing the batteries capacity begins to drop.

With daily charging to 14.2 volts will take longer. 14.2 is 95% full charge, from chart.

Experience suggest no less than twice a year to 4 times if deep deep cycling is done often.

Over doing the equalizing charging is bad, same as over charging a battery, yet if done with the right mix keeps the battery healthy. Its like working out, OK to have evaluated heart rate, not good to do it all day!

Skip the desulphators. Equalizing works, questionable if desulphators work.

Have fun,

Scott.

[bob g]

pardon my crude reply, i got distracted and after rereading i figure

maybe i should rephrase things

my point was to just use proper charging principles which it appears you have a good

handle on, i was not trying to suggest you are difficient in any way.

i get all wound up at times when i see the subject of desulfators come up, often times they are hyped as being the best thing since sliced bread, or "no proper system i without a desulfator" which is BS of the first order.

anecdotal evidence aside, i have been debating the merits or rather the lack thereof for many years now of desulfators.

still waiting for a double blind test by sandia or some other unbiased lab to do some real tests and compare the results to standard 3 step charging regimes with periodic equalization.

so far the best i have found is sandia labs stating "maybe they work" or "they work to some degree, in certain applications" but...

no difinitive results as to what is happening inside the cell, what is actually happening to the sulfate crystals (which one shouldn't allow to form in the first place), whether they are actually broken back down or simply dislodged from the plates, or what combination?

so far it appears to me a variation of "create the crisis, provide the solution"

wherein the folks that sell these things have identified the problem and purport to have the only solution.

excellent marketing strategy, but is the solution necessary? or even desirable?

bottom line is learn what your batteries needs are, their proper care and feeding, and one likely will never need to buy any of this stuff anyway.

it would appear the OP has a good understanding of what his batteries needs are.

rant over

bob g

[ghurd]

Another paper or 2 had short term tests that implied PWM dump control had the same effect.

I assume there is a buss bar.

There are still pulses.

Ignoring the windmill, the battery will see pulses of 18A charging and 32A discharging.

If the windmill was making 25A while the panel was making 18A, the battery would see pulses of 43A charging and 7A discharging.

I do not believe the self-powered units can actually achieve strong enough pulses to make high voltage at the battery terminals, let alone down in the plates.

It would take a substantial jolt to make 60V (O.H.'s number) claimed pulse into a battery.  If it could do it into the buss bar, then there would be posts about smoked equipment.

G-

[dnix71]

I have used a 12v Sulfarid and a 24v Sulfarid for over a year.

I can't say good or bad, because my batteries were new. The 24v is on my Currie ebike,

the 12v on my off-grid 12v hybrid marine/deep cycle setup (4 batteries in series).

The 12v setup in on solar only and hits 14.2-14.5, depending on the sun, each day while I'm at work.

They do draw a little power, but not enough to drain overnight. The ebike desulfator is only hooked up when charging. I tapped the battery pack and added a standard female auto power outlet on a pigtail and wired a male power outlet to the desulfator.

[Flux]

I have seen little evidence that desulphators remove sulphate. There is some evidence that large pulses ( either charge or discharge) are beneficial so the pwm dump load probably works as well as a pwm charge control.

Sick batteries seem to suffer from other defects and sulphate is only one of them . I suspect that the pulses cure some of the other problems and establish a circuit back to the active plate material and once this is done the normal charging process can resume. If these things really did remove sulphate the sg would rise with them in use. Even those who seem to find that they work for them don't report any rise in sg.

I also have serious reservations about stinging a battery with 60v pulses with other loads connected. Fortunately the first stage of most equipment is a big electrolytic capacitor, if not most things would be killed.

Flux

[wpowokal]

For flooded batteries installed on a yacht I suspect the electrolyte would be sloshing around somewhat. To me this would extend the period between equalizing as one of the main reasons for equalizing is to stir up the stratified electrolyte.

Differences in sg would indicate the need for equalizing in this installation, I have no doubt Owen knows how to look after his system.

Battery technology has been around a long time, but despite the makers best information/intentions once they are installed, each installation has it's own characteristics which the owner needs to learn and manage.

allan down under

[scottsAI]

Sloshing does not equal mixing it up, better than nothing. Equalizing bubbles up from bottom to top, seriously mixing it up!

Clearly Owen is competent in taking care of his battery, yet why is he asking about desulphators??

Owen did explain what he was doing, equalizing was missing from the mix, also noticed by Bob g.

There is no battery magic, each instillation is different yet, a battery is a battery is a battery, common care and feeding must be observed to protect investment in battery.

Some battery owners believe they should only use the upper 10% of their battery (wrong), just because someone has a battery does not make them an expert, regardless of how long.

BTW, reading on fieldlines, less than 10% battery owners have or use SG, nothing was mentioned in Owen's post about taking any readings...

Waiting for SG reading to drop is bad form (yet in the manual), learn your system, equalize before much drop in SG. Limit equalizing to two to 6 times a year. Frequent Deep discharging may dictate equalizing Monthly (few hard rules... it depends). Like in a forklift battery. Forklift battery chargers do not equalize the battery, yet they last 5 years or more.

Have fun,

Scott.

[bob g]

its both disheartening and encouraging to follow this thread.

on the one hand there seems to be continued support for desulfators as the "must have" tech item which i find disheartening, and on the other hand

(not so much in this thread, but the fact that the subject continues to come up)

there seems to be a growing group of folks that understand what batteries really need, care and feeding and all that.

Scott mentions the lack of folks using hydrometers to chart their cells specific gravity, which i don't understand at all why this is so hard for folks to get on board with. perhaps it is all the advertizing hype from charger/inverter/controller manufactures that have folks believing that if the "green" light is on their propreitary microcontroller "controlled" charger with their megacode top secret algorithm is taking care of business without human intervention.

yes it amazes me how few folks own and actually use a good quality temp compensated hydrometer, chart their batteries, have a suitable charging capability for the batteries they are using, let alone ever do an equalization charge.

don't get me wrong, this is not meant to be condescending, but rather a call to sit up and do better.

i know of a few folks that have several thousands of dollars invested in huge battery banks that are just fine with using a 5 dollar voltmeter and a 10 dollar cheap ass charger thinking that their battery is doing just fine. Then when faced with being offered a free decent quality temp compensated hydrometer they refuse it, while stating "my engineer friend tells me i don't need it".  

of that group, i wonder how many end up moving to the subgroup that is touting or questioning the use of a desulfator a few months down the road when the battery starts to get sick.

on the topic of sloshing around,

most stationary deep cycle batteries should not be sloshed around at all, reason being?  the normal sulfation due to discharging the battery forms a soft layer on the plates,, sloshing dislodges some of this layer and it settles to the bottom of the battery where it will never return its acid to the electrolyte as designed.

the end result is a reduction in active material, reduction in acid, which lowers specific gravity, and reduces capacity, and over time shortens the life of the cell.

even deep cycle traction batteries which are hardened with the addition of antimony

or calcium so that they can stand up to being shaken/sloshed will loose some of the soft sulfation, just less of it.

bottom line, there is nothing good to be said for sloshing  around a good battery.

sometimes i come down pretty harsh on this topic, my hope is someday, someone

will get his back up in the air enough to go out and prove using scientific method

that these desulfators not only work, but are beneficial, and do not damage or shorten the life of the cells.

notice i use the term "scientific method" as opposed to "anecdotal evidence"

i really am a bit slow to warm up to "an engineer says it is so" or "abc company states..."

Late night TV is full of advertizing for everything from weight loss to male enhancement, and there are all sorts of "doctors" making claims, and "anecdotal"

evidence, but there is always some micro print at the bottom of the screen.

and we all remember fuel line magnets  

bob g

[shay]

With so many variables it is hard to inter-relate on desulfation. The comment I made on the engineers opinion was from a personal discussion and not commercially motivated. The first part is there are several variables in lead acid batteries. Cheapo deep cycle lead acids/golf cart , car batteries, high quality lead acid deep cycle  batteries, etc. Without specifying it may or may not be important considering how specific one wants to be (I know that sounds squirrely). The size of the bank in reference to the amps available to charge it is the next problem. Large battery capacity with light charging yields sleepy batteries. Small battery bank with large amp charging requires regulation while the other may not and how that problem is handled is important. I like a bank that is gassing, hissing and popping once a month but usually this only occurs at the equinoxes here at Morus Springs (unregulated system). The matter of temperature compensating a hydrometer is relatively insignificant in the cheapo deep cycle lead acid catagory. Cell dissimilarity is the main use of the hydrometer and a bad cell in an array is very important to get that battery out of the array. Equalization for me is 15 to 15.5 volts on a 12 v system for one afternoon. No mention was made on frequency of the pulses from the desulfator but at last count the resonant frequency of the battery is supposedly around 3.5 MHz. Rectifying 60 cycle ac has been used to 'jolt' batteries back to life. Exfoliation of the plates is part of the degrading process of a lead acid battery. I've seen horizontal flakes of plate on the tops of some of my cheapo golf cart deep cycles. My answer is to zap the battery, sometimes to double the normal voltage for minutes to churn things up and get those pieces to the bottom of the cells (not until the side of the battery is warm). In the old days batteries would be lifted out of the electroyte to clear the debris in the bottom of the cell to get the maximum life out of the plates. So, I like sloshing, bubbling, wide awake batteries. Should you have a sleepy system it might be possible to desulphate those batteries. The difference between 'soft' sulfate and 'hard' sulphate makes a big difference in recovery time with a cheap low power desulphator. High power desulfation is not for sissies and I suggest a power shutoff/interlocked shelter for the battery if you are really shaking one up. One bad connection can touch off the hydrogen if the ventilation is poor. Cells can lose electrolyte fast under these conditions and an arc internally will throw hot acid through the broken case. I cull the lead acid array and rate good, fair, and poor every few months even if no evidence of a bad cell is apparent (they are always slightly to moderately dissimilar after a few months)). Cells electrolyte levels that stay high are sleepy and those that boil out/electrolyse to gas are active. I try to keep sleepy with sleepy (and they will wake up) and active with active and they will settle down. Lead acids are a pain, so we are adding redundancy with NiFe cells soon. Being able to combine different inverters, different solar panel banks, different arrays of cells, to different circuits in the homestead, different diversions when there is a surplus is a lot of fun :-) Almost as nice as being on a boat!      

[Madscientist267]

Umm...

First, high temp anything is a bad thing. No need, just causes damage.

Second, high current pulses, yes. But at 3.5MHz? Coughing violently...

I am getting excellent results with pulses in the order of 5-10C at no more than 100Hz, at about a 0.04 - 0.05% duty cycle (frequency/duty cycle depends on the phase of SOC).

Within 3 cycles, a battery is back to reasonable health, a fourth or fifth bringing them as good as they're going to get. This takes quite a while to do, depending on the depth of sulfation, sometimes weeks and even months.

"Shaking them up" as you put it will only do damage. You can't brute force sulfation out of a battery, you have to coax it out. Also, gassing is minimal if the desulfation process is being done right.

The concept behind the pulses is that the sulfate acts like the dielectric in a capacitor. It insulates against current flow, and since it is a coating all around the plates, the way to beat it is with pulses that can transcend the dielectric, until the sulfate has been turned back into active material. The pulse hits the plates, then disappears, and the charge dissipates as surface charge within the sulfate. Over and over and over again, until its contiguous material.

Doing things the way you're talking about doing them, you'd need more than a bomb shelter, you'd need the EPA to come and pick up your molten mess when you're done blowing them up.

Getting the battery to handle extremely high current pulses isn't the problem. It's designing a pulse switch that can handle the transient current flow...

Sorry if this seems sharp, but when I read things like "", and "", I have a tendency to worry about people's knowledge of what is really happening (or supposed to be happening)... HOT acid? An internal arc can (and has) ignited the hydrogen under the right circumstances; this can happen during "normal" use if there is a weak cell... but under no circumstances should the acid ever be HOT, and especially not during desulfating!!

I just hope I live a fair distance from anything that you're desulfating with talk like that. In a word? Scary.

Steve