battery desulfator?

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battery desulfator?

September 29, 2013, 05:06:13 pm

I'm pretty sure one of my coach batteries has a bad cell that shorted out and boiled off a lot of water in all the cells of both coach batteries, which of course are connected in parallel. The cranking battery is completely unaffected and still works like new. Both coach batteries are unable to hold a reasonable charge for any length of time now. I realize the battery with the shorted cell is useless, but I'm wondering if I can save the other coach battery with a desulfator? All the batteries are less than two years old so there may be a prorated warranty on them if I can find a dealer. The manufacturer's phone number is on the batteries and I'll call them tomorrow probably. All the batteries are ordinary 12 volt 8D lead acid cranking batteries. I stopped at O'Reilly Auto Parts but they didn't have a desulfator and weren't sure if they could order one. They told me to go to NAPA tomorrow to see if they could get one. Do you folks think a desulfator will be able to save the battery that doesn't have the shorted cell? Where can I get a desulfator? Perhaps the manufacturer will give me a prorated warranty on both batteries and I can get one new 8D that's designed for an RV instead of cranking a diesel. I presume one RV battery would last about as long as two cranking batteries and would weigh half as much. I'm currently between jobs but I expect to be employed as soon as next week, so I'm looking for an inexpensive repair. I'm currently plugged into 50 amp shore power for $15 per night, which is unusually affordable.

Re: battery desulfator?

Reply #1 – September 29, 2013, 05:31:12 pm

Amazon.com wizbang desulfators

Re: battery desulfator?

Reply #2 – September 29, 2013, 05:44:21 pm

Scott,

Crank batteries are designed for short, heavy discharge. House batteries are designed for slower, light discharge. You are best to put group 31 in the crank position and 8D in the house position.

As for resurrecting a battery with a desulfator - it depends upon how badly it is damaged. It surely is worth a try. If you vented some of the electrolyte out, then the show is over. I bought desulfators from eBay:

http://www

.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313.TR9.TRC1.A0.Xwizbang+desulfator&_nkw=wizbang+desulfator&_sacat=0&_from=R40

Some folks are using one per each 8D battery.

Re: battery desulfator?

Reply #3 – September 29, 2013, 05:56:31 pm

Was impressed with the East Penn / Deka factory rep at the Grandvention with his overall experience right up to the question about the Desulfator, where he was caught in the headlights like a deer. Had zero recommendations about it, I was surprised, maybe his job is selling new, not extending the life cycle

Re: battery desulfator?

Reply #4 – September 29, 2013, 05:59:43 pm

I have never seen Desulfators at NAPA or O'Reilly, probably because most folks do not know what they do and so there is not enough demand for parts stores to stock them. I purchased Wizbank desulfators for $20 from eBay.

If your batteries are flooded (removeable caps to add water), then check each cell with a hydrometer.

You indicated that:
"all batteries are ordinary 12 volt 8D lead acid cranking batteries".

If you are using starting batteries for the house battery bank (ie deep cycle service), they will only last for two years because they are not built for deep cycle service. I know someone who did not manage their golf cart batteries (deep cycle type) and used them near discharged for one year. The batteries were destroyed even though they were deep cycle batteries.

A desulfator will help with a deep cycle battery which has been heavily discharged, however, it will require about six months for desulfation to be completed. A desulfator will also help with a cranking battery that has been heavily discharged, however, a cranking battery will suffer more severe damage. If your coach batteries will not hold a charge for long and they are start batteries, junk them and buy two six volt golf cart batteries from a golf cart supply or an 8D (depending on price).

A real deep cycle battery (golf cart or 8D) will last eight times longer in deep cycle service then a start battery.

A cheap pretend deep cycle battery (ie Walmart or Costco) will last four times longer in deep cycle service then a start battery.

A high quality Gel deep cycle battery will last 12 times longer in deep cycle service then a start battery.

An 8D flooded deep cycle battery will cost circa $250 while an 8D Gel will cost $450. Two golf cart batteries will cost circa $200 and you may find some near new golf cart batteries for less because golf season is near the end in parts of the country.

Re: battery desulfator?

Reply #5 – September 29, 2013, 06:25:12 pm

Interesting:

Answer To The Question: Battery Desulfators - Do They Work? - Blog | Impact

best, paul

Re: battery desulfator?

Reply #6 – September 29, 2013, 06:35:02 pm

I don't have a mailing address anywhere near where I am currently, so I was hoping to purchase a desulfator locally. I'm only interested in 12 volt batteries because I want to have the option of disconnecting a bad battery and continuing to use the other one. Ideally I'd like to have only one 12 volt coach battery. If I have two batteries connected in parallel and one of them goes bad it will ruin the other one, which is what happened here and it's a shame. One battery would weigh half as much as two batteries. I use very little electric power and I was able to run several days on batteries even without deep cycle batteries. I presume one deep cycle or gel cell or other type of RV battery will run as long as two cranking batteries in parallel.

Re: battery desulfator?

Reply #7 – September 30, 2013, 03:57:20 pm

NAPA doesn't have a desulfator either. Are there any 6 volt batteries that are the same size as an 8D? I was considering golf cart batteries but they all appear to be too tall to fit in my existing battery box. It's difficult to find an accurate amp hour figure for 8D cranking batteries. Deep cycle 8D batteries appear to average around 250 amp hours. I'm guessing a cranking 8D battery will have about half the amp hours as a deep cycle 8D. Does anyone know for sure if this is true? I think I'll probably install a single deep cycle 8D if it has about the same amp hour rating as a pair of cranking 8D batteries. I would lose about 150 pounds and I'd never have one bad cell destroy two batteries again. I'm not sure which type of deep cycle battery I need. It will probably depend on which type is most compatible with my existing charger. I need to find out if my charger is adjustable for different types of batteries and the voltages they require.

When I bought my coach the previous owner had just installed three new 8D cranking batteries in order to sell the coach quickly. I should have sold off two of those batteries on Craigslist and put the money toward a deep cycle 8D... Just thought I'd mention this in case anyone else reading this is in the same situation and is capable of learning from another's mistakes instead of learning the hard way.

Re: battery desulfator?

Reply #8 – September 30, 2013, 05:33:24 pm

If you are normally connected to shore A/C power and seldom use your coach battery, you do not really need an 8D sized battery (160lbs). You could get a size 31 or 27 or 24 deep cycle (65lbs) from a solar supply or a battery dealer.

Re: battery desulfator?

Reply #9 – September 30, 2013, 05:41:19 pm

I do a lot of boondocking, which is how I discovered my batteries were dead. I'm currently plugged in to shore power but I want to be able to disconnect and dry camp again, so replacing my battery is currently at the top of my repair list... unless I can find a desulfator and it actually restores one of my batteries.

Re: battery desulfator?

Reply #10 – October 03, 2013, 02:57:42 pm

I called the battery manufacturer and was told they have a one year free replacement and two year prorated warranty. The batteries are close to two years old now and the prorated warranty pays so little at this point that it would be cheaper to buy new batteries without using the warranty. I was told that all 8D batteries are deep cycle no matter what the sticker says. They're basically like marine batteries in that they have good reserve capacity and good cranking amperage. Do any of you know if this is true? He said when you buy a deep cycle 8D they just charge you more money for a battery with a different sticker on it. He said desulfators do work, but they're for batteries that have sat for a long time without use. He said my batteries have been used a lot so they probably won't respond to a desulfator. I just ordered one from eBay anyway and I'm gonna have it shipped to the visitor center where I'm camped out currently. I'm sure it'll be useful for other batteries even if this one is beyond help. He told me to take my batteries to a battery shop or auto parts store and get them tested to see if anything can be done for them. He seemed surprised that the good battery didn't recover when I charged it. He said 8D batteries are very tough to kill. He told me dead 8D batteries will bring about $30 at the parts store but if I take them to a salvage yard where they buy scrap lead I'll get almost enough out of two 8D batteries to buy a new one... so that's what I learned today and it was probably worth the phone call... oh, and he said they have 8D AGM deep cycle batteries on sale for $250 right now, but he's in Florida and I'm in New Mexico so it won't help me, but for some of you snowbirds in FL it would be a good deal

Re: battery desulfator?

Reply #11 – October 03, 2013, 03:54:55 pm

Scott, if possible, put on the desulfators, stay plugged in as much as possible and give them 6 months

Re: battery desulfator?

Reply #12 – October 03, 2013, 08:12:33 pm

I only ordered one desulfator. I'm almost certain one of the batteries has a cell that shorted out, so that battery is probably trashed. I'll put the desulfator on the other battery as soon as it arrives, which could be Monday according to eBay. I have no choice but to stay plugged in unless I buy a new battery, which I don't have the money for at the moment due to a recent job loss. I can stay plugged in here for $10 per night for up to two weeks I'm told. It'll be interesting to see if the desulfator can improve the battery. It's nearly useless currently. It has just enough power to keep the gas refrigerator lit an hour or so while I'm in the store buying groceries... so I guess I should be thankful for that huh?

Re: battery desulfator?

Reply #13 – October 03, 2013, 08:29:50 pm

desulfator will help, but will take 6 - 12 months to recover battery as much as it will recover.

Re: battery desulfator?

Reply #14 – October 03, 2013, 08:59:30 pm

Scott, I got along with one, 8D Lead Acid interstate battery from Sam's Club for several years. Cost was only $158. We boon docked for up to one week on that one battery running the generator for a couple of hours every other day. We were very conservative with our electrical use and did not use an inverter at all so if you can determine which of the two house batteries is bad you can probably get along with the other one just fine even if you are boondocking.

Re: battery desulfator?

Reply #15 – October 03, 2013, 09:18:54 pm

Has anyone had any experience with the liquid chemical desulfator?

Re: battery desulfator?

Reply #16 – October 03, 2013, 10:53:53 pm

Hi Scott,

Nobody talks about how long it takes for a desulfator to work...it could be weeks to never depending upon the condition of the battery. That was an interesting recent posting that described the difference between the two types - frequency and spike. By the time people decide to try use one, it may be way too late to be of much benefit. Possibly the best use of a desulfator is to have it on the batteries from day one. Good luck.

Re: battery desulfator?

Reply #17 – October 04, 2013, 01:00:46 am

I wanna know for sure if all 8D batteries really are deep cycle, like that battery dude told me on the phone today. I've never heard that one before. It would be in his best interest to keep that information to himself if true. He said the only difference between a deep cycle 8D and a cranking 8D is the price and the sticker they put on it. This guy sells both types so he has no incentive to tell me that. I would expect he'd want to sell the more expensive deep cycle battery... hmmm... I can get a new cranking 8D for about $200 at a local auto parts store right now. If the desulfator works it won't matter though cuz I'll just keep the battery I've got, and get rid of the bad one of course.

Re: battery desulfator?

Reply #18 – October 04, 2013, 02:40:33 am

With all this renewed interest in battery desulfators, now would be a good time for me to retest my house batteries

If you search this forum for nanopulser you will find my findings from two and a half years ago. At that time, I connected a nanopulser to my house batteries and ran before and after load tests. The results were inconclusive. Now the original batteries are going strong and ten years old. I plan to rerun the tests and see how my batteries are doing after 2+ years of constant nanopulsing.

Stay tuned.

Re: battery desulfator?

Reply #19 – October 04, 2013, 01:04:04 pm

When do you need to use a desulfator? Should they be used all the time? Or how about just during the winter in storage?

On new batteries to prevent sulfation? Or just on older batteries?

On both house & chassis batteries?

Does each battery need its own individual desulfator?

Re: battery desulfator?

Reply #20 – October 04, 2013, 02:07:09 pm

Based on what I have read I think I can answer the last two questions. You do need a separate desulfator for each battery, and the desulfator should be connected directly to each battery's terminals with very short leads. According to what I've read the effectiveness of the desulfator is diminished if the leads are too long. There's no difference between the cranking battery and the coach battery(s) so a desulfator should work on any of them. I doubt the desulfator needs to be on the battery all the time, maybe just a few months, and I doubt it would do much for a very new or very old battery... but I just started researching this the other day and my desulfator hasn't even arrived yet so I have no firsthand experience yet.

Re: battery desulfator?

Reply #21 – October 04, 2013, 02:17:46 pm

In my opinion, the long answer for RRadio is:

In my experience, few RV techitions and fewer battery dealers know what a desulfator does. Also, a person may know very little about batteries even though they sell them - there is no requirement for a person to pass a knowledge test to sell batteries - they just have to be able to breath and talk.

In your memo was: "I was told that all 8D batteries are deep cycle no matter what the sticker says". At his point in the conversation, I would discount anything more that this person says. The designation "8D" refers to a size, the dimensions and weight and has nothing to do with "start duty" or "deep cycle duty". Interstate, for instance makes 8D flooded batteries designated for "start service" and others designated for "deep cycle" service.

A "marine battery" designation is a marketing tool, it helps to sell batteries which are over priced. The "Marine battery" label does not mean it is a deep cycle battery, but instead that it has two types of connectors on it, a start battery post and a bolt.

In your memo was: "desulfators do work, but they're for batteries that have sat for a long time without use." Nope! He does not appreciate what a desulfator does. A desulfator is most effective at increasing battery life if it is applied when the battery is new and left on for the life of the battery. I have and use five desulfators, one which I built from parts ten years ago.

Your batteries may not respond well to a desulfator, not because they have been used, but because, when batteries are deeply discharged, the powder formed on the plates can/will dislodge and fall to the bottom of the battery. This forms useless lead sludge in the bottom of the battery while reducing the amount of lead available in the plates. A desulfator forces the powder back into solution that a charger does not.

In your memo was: "take my batteries to a battery shop or auto parts store and get them tested to see if anything can be done for them".
In my experience, very few battery shop workers can do a load test on a battery to determine it's ability to provide "deep cycle" service. For example, MOT told me that the coach batteries in my U320 were good for deep cycle service, but they were NOT and I replaced them. Solar Mike, who has his solar business at the SLABS in California asked me to do a 10 hour test on a battery. The ten hour test proved that his assessment (using a quick load test) was correct. The tested battery was, indeed, good for "deep cycle" service.

It is a myth that a deep cycle battery cannot be used as a "start battery". An 8D sized start battery will provide perhaps 2500 CCA, while an 8D sized deep cycle battery will only provide 1100 CCA.

My motorhome is a rolling example of using deep cycle batteries for starting because I do not have a start battery bank. I have three 8D deep cycle (sealed) batteries ganged together in a single bank, which provides both starting and deep cycle service. My M11 cranks faster then it did on three red top Optima start batteries (800CCA each).

Re: battery desulfator?

Reply #22 – October 04, 2013, 02:46:08 pm

Hi Wyatt,

As you posted earlier, starting with the boost switch on is not as effective as it might otherwise be, because the house batteries are so far from the starter batteries in most coaches (but not yours).

But going the other way, what do you think of me using the boost switch to connect the house and starter AGMs to reduce % battery draw down overnight? (I thot Red Tops were AGMs.)

Are your 3 8D's AGMs or GELs? I'll guess AGMs.

best, paul

Quote

My motorhome is a rolling example of using deep cycle batteries for starting because I do not have a start battery bank. I have three 8D deep cycle (sealed) batteries ganged together in a single bank, which provides both starting and deep cycle service. My M11 cranks faster then it did on three red top Optima start batteries (800CCA each).

Re: battery desulfator?

Reply #23 – October 04, 2013, 02:55:58 pm

BamaFan:

You need to use a desulfator during recharging after discharging a battery.
If you do not discharge a battery while keeping a trickle charger on it, a desulfator will not help much. For example, telephone companies use battery banks to provide continued service during a power failure. These batteries may be trickle charged for twenty years without ever being discharged. A desulfator would not be of much value for this use.

Desulfate new batteries if you discharge/recharge them. If you never discharge/recharge a new battery while trickle charging, a desulfator will not help much.

Desulfate old batteries to recover lost capacity only if they have been discharged/recharged or if they have NOT been constantly trickle charged.

Desulfators are effective on batteries being discharged/recharged. The deeper the discharge before recharge, the more valuable desulfation is.

If your start batteries are trickle charged at all times, then a desulfator will not help much. Start batteries are discharged only a little when starting, then recharged by the alternator very quickly. If your start batteries are not trickle charged all the time, they will discharge slowly over a few weeks and will not even start your engine. Desulfate to recover lost capacity.

When a battery is being discharged, a powder is forming on the plates. The deeper the discharge, the thicker the layer of powder. Recharging converts this powder back into solution, but, not all of it. Every discharge/recharge cycle leaves powder on the plates, which becomes thicker with each discharge/recharge cycle. Equalizing, is a controlled overcharge, which quickly converts the powder on the plates of an apparently fully charged battery back into solution. Desulfation does the same thing on a continuous basis without causing the damage which equalizing can.

The desulfators which I use are passive (draws power from the battery) and low power. Because they are low power and connected directly to the battery posts, there is no requirement to shield the devices which are powered by the battery (from the voltage spikes which a desulfator generates). A single powerful battery charger/desulfator could service an entire battery bank, however, it would require extensive voltage spike blocking so that damage is not done to the 12 volt items being powered by your batteries and so that your stereo does not add a squeal to your favourite tunes.

Re: battery desulfator?

Reply #24 – October 04, 2013, 04:36:49 pm

Wyatt,

Thanks for the education. This is a great help to a newbie.

Royce

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