Equalizing and desulphitating batteries, comments and experiences

I'd be interested in hearing the members thoughts on equalizing and desulphitation of batteries. Do you, don't you, how often, how long, etc.

I have a Magnum 2 KW inverter charger, and a start/house bank of 2 -*8D lead acid batteries about 2 years old. The Magnum remote has an equalizing setting but I have never*used it.

Thanks

Steve Willett

Spend some time on Google and look up lead acid battery equalization and US Navy.

Depending on your installation and the type of charger and the cell voltage reached you can either extend your battery life or greatly shorten it.

Doing nothing is not a great idea if battery life is important but doing it wrong might cost even more. The charger manufacturer doesn't know how your boat is wired or how far the battery is from the charger and may not know the cell temperature or gassing rate so thinking that selecting "equalize" without monitoring what is actually happening in the cell makes the process a real crap shoot.

I will second that.

My neighbor decided to use the equilize feature on his new charger, didn't read the manual first*and ruined two 4D batteries.* It is usually not an automatic feature and requires you to monitor and test the cells with a hydrometer.* Also be sure and research your battery manufactures recommendation for your type of batteries too.*

Most of the modern chargers do a very good job maintaining batteries.* Allowing the batteries to float with no charge applied (rather than trickle charge) and bringing them up to full charge*on a preprogramed schedule.* Left alone, mine will float the batteries for 20 days.* On the 21st day it will perform a self test and bring the batteries up to a full charge, (around 14.5 volts) and then allow them to float again.*

My batteries are lead acid and were*seven years old this fall. *I will change them out in the spring even though they test good and start the diesels just fine.**

It all comes down to how big is your charger vs how big is your battery bank?* Without getting too technical, your charger should be capable of charging at rate of 10% of your battery capacity.* 500 AH = 50 Amps charge or 1000 AH = 100 amps chaqrge** This is not a rigid rule, but it*won't get you in trouble. That been said, equalizing on a monthly basis is a good thing.* Equalization is another word for over charging.* If done with a proper size charger will be good for your batteries.* Tempurature compensation is a good thing too, to avoid problems.* One sure way to ruin your batteries is to chronically under charge them, another way way is to chonically 'cook' them.* When you equalize, you over charge your batteries for a limited amount of time.* Too much of a good thing, isn't.* Batteries follow the universal law of nature, The faster they go, The faster they go.* This rule works for batteries, engines, and life in general.* Moderation is the key to longevity.* So back to the rule that charger capacity = 10% of battery capacity, the real number is 5 to 20%, but remember the universal law, the faster you go the faster you go.* So, all things being equal, if your charger capacity is 5% of your battery bank, you will experience far better battery life than with a 'Too Large charger.* This is assuming that there is adequate time for both to get to 'Full Charge'

*

*

"That been said, equalizing on a monthly basis is a good thing."

That is the usual opinion ,

Its my belief that IF one has the ability to return to 100% charged daily (not usual on a cruise with anchoring) or on a slightly used boat a bit higher charge voltage , 14.4 will do what equalizing is hoped to do with no danger.

The problem is the discharge to 50% or 40% SOC , and waiting days to recharge. This will sulfate the battery .

The 14.4 will bring it back to 100% but may nor help the sulfation a bit.

Most long term cruisers will size the batt set to operate between 85% and 50% , and allow some extra as the batt set dies from not seeing 100% often enough. Solar is a big help in stuffing in that last 15% that is slow to push in.

Go cruising and a good medium priced set of golf carts like Trojan will go 3+ years.

Sit in the slip , and 7 years is easy with some attention.

You pay for EACH discharge cycle in battery life.

I've used a couple of Battery MINDers http://www.batterystuff.com/battery-restoration/12-volt/*for years. I use one on the thruster bank and the other I alternate between the house bank and starter bank. My AGM's lasted 7+ years using this. I've also brought back batteries from the dead that I picked up in the parking lot. Takes a while though. Wouldn't be without them.

Ping desulfators will void the warentee of Trojans.

After I installed my new Xantrex charger I ran through the equalization routine.* I did monitor the batts closely, checked the temps and specific gravity and kept detailed records over a number of days.* The specific gravity did come up in every cell of the 4 big (4D, I think) batteries.* The batts aren't like new, but they did get an extension on life.

I know, everyone seems to think Xantrex is junk, but mine seems to do what I need it to do, was easy to install and worked right out of the box with no fuss.


-- Edited by BaltimoreLurker on Tuesday 29th of November 2011 07:54:55 AM

BaltimoreLurker wrote:
*I know, everyone seems to think Xantrex is junk, but mine seems to do what I need it to do, was easy to install and worked right out of the box with no fuss.



-- Edited by BaltimoreLurker on Tuesday 29th of November 2011 07:54:55 AM

Click to expand...

I've*read that too and I've*used a Xantrex system for nearly 6 years now.* As far as service life*it has run flawlessly.* Doesn't boil the batteries, they use very little water and keeps them up to charge.* Battery life has been over 7 years so dont know the problem?*

My only gripe is it doesn't like generator AC when it gets a little off cycle.* But that may be a good thing, as it reminds me to keep my maintenance on the gen set up to snuff.*

LB

*

My first set of Trojan house batteries, charged via Xantrex, *lasted 8 years and were still going strong when I scrapped them. No equalizing or de-sulphating was*done**- as pointed out by RickB, I thought the risk reward not worth it*.

Have to ask, if they were going strong why did you scrap them? PM?

Good question Keith. The best answer I have is like so many things on a boat, batteries don't last forever. My cruising plans had me in far away places with*no access to*low cost but *quality batteries if one of my old ones gave up.

sunchaser wrote:
The best answer I have is like so many things on a boat, batteries don't last forever. My cruising plans had me in far away places with*no access to*low cost but *quality batteries if one of my old ones gave up.

Click to expand...

Exactly, same here.* Mine were seven years old this last summer and since I only*carry three 4D's I would hate to have a cell short out while at anchor in some remote hole in the wall place.* They appear to be fine*and perform great.**But in my experience,*batteries don't always just slowly fade away.**As batteries age the chance of having a catastrophic cell*failure*becomes more likely.* If*that happens the entire battery becomes a big chunk of dead lead.**It can be a long walk to the nearest battery service center.**

I have 3+ year-old golf cart batteries from Sam's Club (4 of them) and am in the market for a new charger (Iota... either 55A or 75A) that does have an equalize cycle. Is it too late to try and desulfate them now? I thought I would just refresh them, but if an equalization will haelp them, it might be nice to hang on to them for another season.

Gonzo* -* Do a load test and check SGs - these are easy tasks especially since you are electrical savvy. *Chances are your batteries may be just fine for a few years yet. As stated earlier in the thread, 8 years + is*attainable with no desulphate or equalization stuff.

GonzoF1 wrote:
I have 3+ year-old golf cart batteries from Sam's Club (4 of them) and am in the market for a new charger (Iota... either 55A or 75A) that does have an equalize cycle. Is it too late to try and desulfate them now? I thought I would just refresh them, but if an equalization will haelp them, it might be nice to hang on to them for another season.

Click to expand...

*That was when I decided to replace my charger system too.* The old charger was overcharging and trickle charging the batteries to death.* My father left it running for several months during the off season and cooked a two year old set of 8-D's beyond recovery.*

I bought and installed the Xantrex 40 amp charger with the remote monitoring panel shortly after that and have never had a problem since.* I usually*add about a*cup of distilled water to each battery in the spring and they are good for a year.*

For me, 75 amp charger would be*way too big and bigger is not always better.* Size your new charger to your battery bank. *I could have actually gotten by with the 20 amp Xantrex (has no cooling fan) runs quieter.* Something to keep in mind, I hear people complain about generator noise.* But that charger cooling fan is not fun to listen to while trying to sleep at night either!* While at anchor, running the*gen set during*meal preparation*keeps the batteries up and two refers cold. I*don't have that big of a battery bank either, just three 4-D's and I don't mess around with inverters.* Keeping things simple works for me.

LB

Yea... My 30A Newmar charger has pretty much been going non-stop for 3 years now on these batteries. That's why I am asking if my batts are toast. But thanks for the tips. I think I am going to back down to a 55A charger for now. See how much I am really going to use at anchor, and upgrade should the need arise.

Tom, Is there a load test method you would suggest is a better way to do onboard? Do I need to head over to Sears for a tester or could I pull them and take them to Auto Zone? And moreover, is load testing a deep cycle battery smart? I thought that would be just for starting batteries.

Tom-

Gonzo* -- I load test*and monitor*my Link. I will turn on several space heaters and draw down* to 1/2 the rated amp hours*following the volts* along the way. In my case I draw out 440 amps (12 volt system) which gets me down to about 11.7 to 12.0 volts. If you cannot draw out at least 1/2 of your amps while staying above 11.6 volts or so, your batteries may be problematic.

IF you really want the batts tested no auto shoppe has the proper equipment.

The folks that DO are in the business of electric GOLF CARTS , the tester is quite expensive , but they really need to know if a batt is discharged or dead.

Put them in your car and take them to be tested.

FF's suggestion is good, if you are with a strong back. My local yard has a "tester" they take to the boat, but at $90/per hour I do it only about every 3 years. My Link seems to closely duplicate the "tester."

If your electric system upgrade includes a new* Link or similar battery monitor, why not wait to replace the batteries and see what it tells you? You can measure*SG right now.

Will do... Thanks guys.

sunchaser wrote:
Gonzo* -- I load test*and monitor*my Link. I will turn on several space heaters and draw down* to 1/2 the rated amp hours*following the volts* along the way. In my case I draw out 440 amps (12 volt system) which gets me down to about 11.7 to 12.0 volts. If you cannot draw out at least 1/2 of your amps while staying above 11.6 volts or so, your batteries may be problematic.

Click to expand...

I'm not clear whether you are referring to voltage under load or resting voltage here but either interpretation is wrong.* Voltage under load will vary depending on the load so it is meaningless for SOC calculations.* Generally accepted numbers for resting voltage at 50% SOC are much higher than you are suggesting.* For lead acid batteries look for at least 12.2 resting volts @ 50% SOC and for gels a little higher.

One of the best summaries of battery information that I know of is here:

http://www.phrannie.org/battery.html

If you are discharging to 11.6 resting volts your batteries are effectively dead at that point.*

Bob

Good article, I've seen it several times before but didn't recall the detail of SG vs resting volts. Do you know if he*has updated it to*detail the inverter advancements during the past 15 years?

My comments were meant for under load, drawing 110V through the inverter and reading the Link*as close to 2500 watts are being drawn. My Link and Xantrex manuals are not in front of me but I seem to recall as much as a 0.5 voltage lower differential between max inverter*draw and resting voltage.

I'll watch the resting vs discharging volts*more closely next time I do a 50% draw down at anchor.

sunchaser wrote:
..........

Do you know if he*has updated it to*detail the inverter advancements during the past 15 years?

........but I seem to recall as much as a 0.5 voltage lower differential between max inverter*draw and resting voltage.

I'll watch the resting vs discharging volts*more closely next time I do a 50% draw down at anchor.

Click to expand...

I use that page as a battery resource - I doubt that the inverter information has changed but the inverter efficiency doesn't really change what is happening to the batteries.* I think you'll be surprised how much difference there is between the voltage with a ~1000-1500 watt load and the real resting voltage.* We routinely see over a volt difference with 3x8Ds under a 12-1500 watt load.*

Somewhere I've got life cycle expectancy charts which show the effect of lifetime discharge cycles.* In summary they show that if you can use the top 25-40% of the batteries you will dramatically extend their useful life c/w using the top 60 or 70% of the battery bank.* I have my Trimetric set to show 50% discharge when we've really got more like 60% of the bank left and we have a hard and fast rule that we never let it get to 50% - more typically we'll start the gennie at 60% indicated which is likely closer to 70% SOC.* Currently we're well into our 8th year on Lifeline AGMs with no measurable deterioration in their condition.