Desulfating Batteries

[JDT]

Posted a few weeks ago about how long batteries last. Someone suggested I desulfate my batteries. I did some research on this and am a bit confused. I read about desulfating 12 volt batteries with a high charge rate, which I guess means getting a charger of some kind. Not sure how it works for the 6 volt. Also, the 12 volt starting batteries are the sealed type and not sure if this makes any difference. Maybe someone can give me some instructions on how to do it.

I am very close to getting new batteries but if desulfating works maybe could delay until next year.

Also, I read in Motorhome Magazine a few months ago that I probably don't have the correct converter/charger to prevent sulfation. Mine charges at 13.8 volts I think and the article said it needs to go up to 14.4. What kind of converter would do this?

[BryanL]

Sulfation is what happens when lead acid batteries discharge. It the creation of lead sulfate crystals on the plates. Recharging the battery will decompose almost all of this stuff back into sulfuric acid and lead. If batteries are not completely recharged, these crystals can grow and harden and be very difficult to decompose. That is what happens as the battery ages as the stuff builds up and reduces the battery performance. Canadus has a good rundown with pictures.

There was an article in Home Power magazine about ten years ago about one technique to break up lead sulfate crystals. BatteryMINDer (see the articles) products use that technique. There are websites with instructions about how you can build your own. It works kinda' like the singer who can break a glass by singing the right note.

Another method is that used by the Chargewizard type converters. When in storage mode, that will bump the charge voltage for a few minutes every now and then. It works by keeping the electrolyte mixed and keeping the battery at a full charge. It is best for inhibiting sulfation accumulation and buildup in the first place.

One of the best things you can do for your batteries is to get a converter that is a smart multiple stage charger and has a battery maintenance mode that inhibits sulfation. This is why the WFCO and Chargewizard based converters are popular upgrades.

The reference to 14.4 is to a good initial charge voltage for your 12v battery bank. When the current at that voltage drops to an amp or two, a smart charger will drop the charging voltage down to 13.8 volts or so to finish up the charge. When that is finished the charger should then transition to a float voltage with a sulfation inhibiting technique for proper storage maintenance.

Note that proper charging of the batteries is not the same as proper storage maintenance. A proper charge will reverse almost all of the sulfation that occurred during battery discharge and get the battery back to a full charge. Proper storage maintenance will keep the battery charged and attempt to break up any remaining sulfate crystals or at least prevent them from growing.

You may have 6v batteries wired to produce 12v. They act just like a 12v battery. If you have a 24 volt or other non 12v system, you will need to make sure your charging and maintenance equipment is designed for the system voltages you use.

[JDT]

BryanL, thanks for the information. I do all my own maintenance and some repairs on my coach but I must admit this subject is not my strength.

I have 4 Interstate U2200 6 volt batteries for the house side and a Magnum Energy ME2012 converter/inverter which has bulk, absorption and float modes. According to the book bulk is 14.6 volts, absorption 14.6 and float 13.4. Since I keep it plugged in to 50 amp all the time I thought it would take care of the batteries, and it has to certain extent since they are 6 years old.

What I did not know is it also has an equalize mode at 15.5 volts that is manually operated. The manual is rather confusing but I figured this out by searching some previous threads. I set it to do this this morning and could immediately hear the batteries making a gurgling sound. The equalize charge will last for 90 minutes based on the amp hours of my batteries being less than 400.

My question now is how often if I do this? If I don't get my voltage up I will buy new ones for an upcoming 3000 mile, 3 week trip. Even though I think 6 years are great in spite of my ignorance, I want to take proper care of new ones. Also, I assume keeping it plugged to my 50 amp shore power all the time is helpful in keeping the batteries properly maintained.

Lastly, is there something I can add to the converter to automatically do this when needed or is it just something I have to remember to do at certain intervals?

[BryanL]

re: "What I did not know is it also has an equalize mode at 15.5 volts that is manually operated"

You generally do not need this in typical RV use. It is an intentional overcharge whose purpose is to try to get all of the cells in your battery to an equal full charge. In doing that, it may overcharge some of the better cells causing them to loose electrolyte or suffer other damage. The voltage for this 'equalize all cells' charge may be a bit high for appliances in your RV as well. A proper equalization charge also requires careful monitoring of electrolyte during the process and this means exposure to sulfuric acid which requires significant care. (note that my view on equalization charging in RV's is somewhat controversial as can be seen in another thread)

Typical RV use generally discharges the batteries to a moderate state every now and then followed by a good charge with plenty of time followed by a few weeks of storage and maintenance charge. That sort of use will usually get all of the cells in the battery fully charged so special equalizing charges aren't necessary.

Equalization of cell charge levels may be called for when the batteries don't go through a vigorous discharge recharge as a routine thing and don't have the opportunity for a proper full charge to occur. You really should know what you are doing when you put an equalization charge on your batteries. It should be partnered with careful hydrometry and that means full hazmat precautions and lab practice.

re: "is there something I can add to the converter to automatically do this when needed or is it just something I have to remember to do at certain intervals?"

If you have a modern converter like the chargewizard types, all you should have to do is to keep it plugged in and then monitor electrolyte levels every few months. Typical wet cell lead acid batteries should last about 5 years if you treat them right.

The Magnum Energy ME2012 looks to be a nice converter, inverter, and charger. It claims a Battery Saver (tm) feature which implies some sort of battery maintenance mode but I can't find out what it does in a quick search. I'd find out what that does and, if its just a float or trickle charge, I'd add a BatteryMINDer type desulfator to the mix to use when the rig is between uses.

Quote:

Even though I think 6 years are great

That says you are doing things right as that is a good life for wet cell lead acid batteries.

One of the difficulties with battery life is figuring out when enough is enough. Batteries degrade over time. RV's need significant reserve capacity to avoid frequent discharges below 50% state of charge. That means that a battery bank capacity can drop to 60% to 80% of its original value over a few years and not be really noticed most of the time. Like with cars owners that find out they need new starting batteries on the first cold snap, the RVer may only really get the word about needing new batteries when he really needs to push what he's got.

[bachler]

Having Owned 7 motorhomes, purchased 100s of batteries.Here's what I found out. In our 2000 winne; Ultimate advantage I replaced the batteries In 2001 large deep cl. We have a 1500 watt inverter Use the micro, W, TV, VCR, Well in 2009 I took the barreries out, And took them to the factory were they build them. It's DYNO, in SEATTLE Wa. He checked them With the load. witch in itself is scarie, then hydro;test the reading was the same as the new batteries, His words were Use a good barrery charger, it will keep the batteries at 14.4 Volts. they need to be recharged right away and NOT STORED IN A DISCHARGE STATE:; And the converter in a motorhome will not charge the batteries, His words were You will Die before the battery will be charged; I installed good battery chargers in our prior motorhomes and our batteries have allways lasted over 8 years,;; These are just the facts;; Life is good

[BryanL]

can't let that pass! ;-) let's see, hundreds of batteries, that must mean more than 300. In banks of 8 typical of a large moho, that means something more than 35 replacements. Over 8 years must mean 9 or 10. If we add that up, it comes to the implication you must be more than 350 years old. Talk about experience!

I think I'll take a reputable vendor's idea of battery life as a bit more reliable. Check the NAWS FAQ as an example.

[walt2137]

Jim check out this web site I have used the power plus PP12 L for about 8 yrs with good success.
Pulsetech - ReNew-IT Pulse Technology

[bachler]

Quote:

Originally Posted by BryanL can't let that pass! ;-) let's see, hundreds of batteries, that must mean more than 300. In banks of 8 typical of a large moho, that means something more than 35 replacements. Over 8 years must mean 9 or 10. If we add that up, it comes to the implication you must be more than 350 years old. Talk about experience! I think I'll take a reputable vendor's idea of battery life as a bit more reliable. Check the NAWS FAQ as an example.

My Friend I am Over 70 years old Have . had 37 tractors at one time & 7 MH> over the years. And had 49 employees working for me. Must of them had common scence. Once in a while I would get a Smart One;; Oh there is other equipment that uses batteries . not just MH. BUB:

[JDT]

Did the equalizing yesterday and checked the batteries with my meter today. Prior the equalizing the reading was 13.02 volts. Now they read 13.48. Both readings were with it plugged into my 50 amp power. May need to check it with it not plugged in but it's been too dang hot to be outside for long. We'll see.

[Denali]

Quote:

Originally Posted by JDT Did the equalizing yesterday and checked the batteries with my meter today. Prior the equalizing the reading was 13.02 volts. Now they read 13.48. Both readings were with it plugged into my 50 amp power. May need to check it with it not plugged in but it's been too dang hot to be outside for long. We'll see.

One thing to keep in mind when equalizing batteries is that you need to disconnect your 12 VDC circuits in the rig when doing that. The 15+ volt charging power can damage electronics such as thermostats, fridge control boards, etc.

In our coach, the only way to do that is to use the DC Coach Power switch near the entry door. The battery disconnect switch won't do it.

I equalized our original batteries a couple times a year. They lasted about four years and had been discharged down to 11.5-11.8 VDC (measured under load) hundreds of times while boondocking.

Last year I bought a BatteryMINDer® OnBoard Battery Restorer-Conditioner 12-Volt With Battery and Charging System Indicator | All | Battery Chargers by BatteryMINDers.com. I guess it will be a few years until I can judge whether it does the job as well.

[wa8yxm]

Quote:

Originally Posted by JDT Posted a few weeks ago about how long batteries last. Someone suggested I desulfate my batteries. I did some research on this and am a bit confused. I read about desulfating 12 volt batteries with a high charge rate, which I guess means getting a charger of some kind. Not sure how it works for the 6 volt.

I will make it easy for you: You do not have a six volt battery in your rig

You have a 12 volt.. Now this 12 volt, for ease in handling, has been broken into two parts... But it is still ONE 12 volt battery.. NOT two six volts.

So long as it is properly installed in the rig.

Now.. Just to add confusion (If you are easily confused stop reading now)

If you remove this 12 volt batteries's 2 pieces from the RV, disconnecting the jumper wire that joins them.. THEN.. you have six volt batteries

But so long as they are installed they are one 12 volt

Think of them that way.. and you will be sure how it works.

Cause it works just like a 12 volt battery, which it is at the moment.

[Luv2go]

Quote:

Did the equalizing yesterday and checked the batteries with my meter today. Prior the equalizing the reading was 13.02 volts. Now they read 13.48. Both readings were with it plugged into my 50 amp power. May need to check it with it not plugged in but it's been too dang hot to be outside for long. We'll see.

Jim, I think you're on the right track equalizing your batteries to desulfate them and get capacity back.

Do your batteries have vent caps and can you get to them? If so measuring specific gravity of the cell's electrolyte with a hydrometer is the best way to measure charge level. BTW, you do need to unplug and let the batteries settle a bit before you'll get an accurate reading with your voltmeter.

Look at your battery mfr website for specs on specific gravity vs charge level, here is a generic website if your mfr does not have a table. You should be able to use equalize mode until your batteries SG is correct, just check your electrolyte levels and add distilled water as necessary while you are equalizing.

It is possible that equalizing will not recover your batteries to your satisfaction, but it's cheap (just the cost of the electricity and distilled water), way cheaper than new batteries.

Good Luck!
Stewart

[AFChap]

Our Freedom inverter/charger has an equalizing mode that must be manually started ...and it will last apx 8 hours. Instructions indicate all water cells must be full AND the batteries fully charged (in float mode) before starting equlaizing. THE EQUALIZING MODE WORKS ONLY ON THE DEEP DISCHARGE HOUSE BATTERIES ... IT DOES NOT EQUALIZE THE CHASSIS BATTERIES.

As Denali indicated, all 12v loads must be removed. I do that by tripping the battery disconnect switch located at the entry door on our coach.

Our coach had been a dealer show coach for a year before we bought it, and no doubt treated less than perfectly. We noted the first few times we boondocked the batteries would be nearly dead after minimal use overnight. After equalizing, they had much greater capacity. Since then, I have equalized the house batteries about once a year. The original 2002 house batteries lasted until 2007.

[bcbounders]

Quote:

Originally Posted by Denali Last year I bought a BatteryMINDer® OnBoard Battery Restorer-Conditioner 12-Volt With Battery and Charging System Indicator | All | Battery Chargers by BatteryMINDers.com. I guess it will be a few years until I can judge whether it does the job as well.

I'd be curious to know how you're making out "a few years" later. Any indication the BatterMinder is helping?