Zombie Batteries

Zombie Batteries that won’t die

Zombie Batteries was going to be the title of this post. I wanted the title to be “Zombie Batteries that didn’t die” or something like that. Someday I will have batteries that won’t die. Dead is dead, and dead is what I had. Zombies come back to life, my batteries didn’t come back to life. I hoped that my batteries wouldn’t die. In fact, I went to extraordinary efforts to keep them alive.

The short story is that my batteries died and we had to replace them. The longer story is how I tried to make them zombie batteries. The even longer story is how I will try again (with the new set) to make them zombie batteries and perhaps they will never die.

Lots of batteries

We have fifteen big batteries, nine lithium, four AGM batteries, and two chassis batteries (otherwise known as engine start batteries). Starting last week the engine start batteries are new. If you want to include the car, we have sixteen big batteries. Now they all are in good shape.

Zombies come back, after death, most typically in B-rated movies. For the last two months, I have been trying to breathe new life into my engine starter batteries. Ultimately I failed, or rather the batteries failed, and now they are gone. You would think that a battery of this size and weight would live a long life but sometimes they die and that would be the end of the story.

Some modern lead-acid batteries are not as robust as some others and they are certainly not as robust as my lithium batteries.

DHC Tester on my car battery. Factory spec CCA is 640 and my reading was 635. Happy-happy.
DHC Tester on my car battery. Factory spec CCA is 640 and my reading was 635. Happy-happy.

I have friends that know how to make batteries last a very long time and I called on every resource to try and make my battery last a longer life. So really the story is about how lead-acid batteries die and how to make zombie batteries that just won’t die. All batteries die eventually. I have been working on this story (really working on my batteries) since last April. Last week I gave up, actually, the batteries gave up, one too many times they failed and now they are gone.

Battery Guru’s

You would think after writing several articles on batteries I would have this down to a science. I think I am above average in the battery info department. So as a review, here are links to some of the articles.

Most all these articles compare Lead-Acid batteries to Lithium batteries and we have both. Our huge lithium battery bank is working great. We still have our lead-acid AGM house batteries and they are surprisingly strong. Really we ask very little of them and they have passed all tests both on a daily basis in my RV and as compared to other house batteries.

Engine Batteries

The batteries that failed are our three-year-old engine start batteries. Here is the story about the first sign of trouble in May 2020. Unable to Depart

Our RV was new (to us) and sat in one place during the first part of the COVID virus lockdown for a long time. After sitting, the RV wouldn’t start and the batteries were the fault. Dead. So I recharged them seriously for hours and hours and finally, the next day, I got the RV to start. At that time we didn’t have our big lithium battery bank. So driving a couple of hundred miles and then camping in a deserted casino parking lot was a little risky.

I put my phone inside my engine compartment and had to use a voice command to take this picture of my batteries. It doesn't look too bad from this angle.
I put my phone inside my engine compartment and had to use a voice command to take this picture of my batteries. It doesn’t look too bad from this angle.

Our campsite was in a tiny Nevada town. Here is the campsite review of the Tonopah Banc Club Casino

We didn’t have any problems for the next year. In the Unable to Depart story comments, Scott Hellman told us about the PulseTech battery charger that he uses to do some fancy stuff (I will describe it in detail later) to make his batteries last for a very long time.

Occasional Boost

Over the course of the year, I gave the engine start batteries an extra charge a few times. The reason was I knew that our battery tender wasn’t working when we were boondocking and we did quite a bit of boondocking. We were using our new lithium battery system (no solar) to operate for the entire year. When we were boondocking our trickle charger wasn’t hooked to a bus that would allow it to work. So I topped them off a little a few times before starting the engine.

The DHC tester attached to my AGM batteries. These are zombie batteries.
A DHC tester attached to my AGM batteries. Notice the orange clamp on the hot wires, this is how I kept the RV working while I had removed these batteries from the circuit for testing and recharge.

Starting in March this year I noticed that my engine batteries seemed a little weak. A different friend who just happened to work for PulseTech decided to help us out (thanks Smokey*). PulseTech (link at the end of this article) loaned me some commercial-level repair equipment to see if they could help me. This is the same company that Scott Helmann recommended in the Unable to Depart comments.


Starting when we were leaving Tuscon this year, I was giving the battery a little more love, stop after stop, and making plans to give them reconditioning charge later this spring. To recondition a battery you have to remove the lead sulfate buildup on the lead plates. This is where the PulseTech commercial charger comes into play.

The SC-2 Recovery Charger "boosting" my AGM batteries. Which wasn't needed, but they lent me the equipment so I used it.
The SC-2 Recovery Charger “boosting” my AGM batteries. Which wasn’t needed, but they lent me the equipment so I used it.

What is Lead-Sulfate?

Lead sulfate is a crystal that is created during the discharge of a lead-acid battery. If you have ever seen a white powder on the top of a car battery this powder (toxic) is lead sulfate. Lead sulfate is a combination of the lead in the battery and the sulfuric acid electrolyte in the battery. In a perfect world, all the lead sulfate would disappear again during recharge. Since we don’t live in a perfect world, this doesn’t completely happen and you get a deposit of lead sulfate on the lead plates in the battery. Only “clean” lead plates in contact with the electrolyte can be used during discharge to release the stored energy.

The DHC tester on my AGM batteries showing 100% state of health. Happy-happy.
The DHC tester on my AGM batteries showing 100% state of health. These are zombie batteries. Happy-happy.

Lead sulfate is like skin cancer on the lead plates inside your battery.

PulseTech reconditioners

The PulseTech company makes devices that pulse energy into a battery to cause lead sulfate to detach from the lead plates inside the battery into the acid solution and eventually fall to the bottom inside of the battery case.

How it works

In a lead-acid battery, during normal operation, lead sulfate deposits start clouding the lead plates inside the battery. The lead sulfate deposits inhibit the normal interaction between the electrolyte and the lead plates and gradually, over time the amount of exposed lead is decreased and this results in a weaker battery.

The DHC tester attached to my RV start batteries. I have at least a dozen pictures like this one -- none of them good.
A DHC tester attached to my RV start batteries. I have at least a dozen pictures like this one — none of them good.

A PulseTech charger pulses the battery with electricity in such a fashion as to cause the sulfur to fall off the lead plates. The pulse of electricity hits the battery 25,000 times a second. Long duration use can not only inhibit the lead sulfate build-up but reverse and “clean” the lead plates. If you didn’t have lead sulfate attached to the lead plates then the battery would last for many more charge/recharge cycles.

Two-month project

To test or recondition the battery in my RV you have to remove all the electrical cables from the battery to connect the tester and charger. Removing my electrical cables from my battery is a royal pain. Not only are there multiple wires that need to be removed but also I had four fuel lines running across the top of the batteries that were in the way. You also have to be camping with electrical hookups to source the power for the reconditioner.

So every time we had a campsite with electricity for the last two months I tried to reconditioned my battery and I even saw some improvement on one of the start batteries. The state of health went from 849 to 903 cold-cranking-amps on the battery located on the driver’s side of the RV. However, the battery on the passenger side of the RV showed no improvement.

The brand new battery is rated at 950 cold-cranking-amps. They are about 30% bigger than your average car battery and I have two of them thus rated at 1900 cold-cranking-amps when working together. It takes a big jolt to start this big engine.

Reconditioning worked

On one of my start batteries reconditioning worked. On the other battery, it did not work.

Before and after each recovery attempt I had to disassemble all the wires on my batteries.

My view of the top of my RV engine start batteries.
My view of the top of my RV engine start batteries.

Before each recovery attempt, I fully charged the batteries and then let the surface charge dissipate. Then I tested the cold-cranking-amps and recorded all the results in a spreadsheet. After this, I charged the batteries using the recovery charger. After running the recovery charger for three days, I again let the surface charge dissipate and repeated the capacity test again.

All batteries eventually die and even though I was trying to create a zombie battery the battery on my passenger side never showed improvement. It would not recover. Test after test the result was that the battery was either in the “caution” range of the scale during testing or in the “bad-replace” scale of the testing. Since I ran the recovery process over and over again. The problem wasn’t an issue of lead sulfate film but rather it was a dead battery.

How did my battery fail?

Even after a full recharge, the charge would not hold in the battery for more than two days. The voltage would drop gradually until the point the battery would not start the engine. This happened twice, both in the same week. Full charge one day, started the engine on the next day, completely failed on the third day.

Why did my battery fail?

I don’t know why the battery failed, to find out I would have had to take it apart and this would have involved a saw to cut the battery apart to find out. Since this is a “maintenance-free” battery I couldn’t even find a way to test or see the fluid level inside the battery even after they were removed.

My RV batteries with the cables removed and the tester clamp installed. Another bad test -- this time it was because of my error. Can you spot the error?
My RV batteries with the cables removed and the tester clamp installed. Another bad test — this time it was because of my error. Can you spot the error?

How do lead-acid batteries fail?

The first and most common failure is discharge cycles that leave lead sulfate on the lead plates. If lead sulfate was prevented from attaching to the lead plates then lead-acid batteries would last three times longer. Lead sulfate attached to the lead plates kills nearly 80% of all car batteries.

Lead sulfate also creates resistance during the recharge. Resistance creates heat and heat can warp the lead plates. If this happens then the battery is dead-dead.

How to make zombie batteries that just won’t die-or rather die after a long life.

PulseTech makes the recovery charger that I was trying to use to fix my battery and the process worked on one of the engine start batteries. The best plan is to prevent rather than repair. If I would have started a prevention process in early 2020 I am nearly certain that I would have the same batteries and they would have been fine today. So now I am going to introduce you to what I call battery life extenders.

Good food and exercise

PulseTech also makes a line of what I am going to call life extenders for batteries. It is better and easier to extend the life of a lead-acid battery than it is to repair a lead-acid battery. If you never let lead sulfate attach to the lead plates, then you wouldn’t have to remove it.

I am putting PulseTech life extenders on every lead-acid battery I own.

My car battery with PowerPulse installed. Anyone who ever held a wrench can install this unit. It is silly simple.
My car battery with PowerPulse installed. Anyone who ever held a wrench can install this unit. It is silly simple.

I am using two different pulse tech products to accomplish this goal. The first is called the PowerPulse and the second is called the SolarPulse. You already knew that solar would have something to do with this… didn’t you.


On my car, I have a PowerPulse device attached to the start battery. This device uses a little of the battery’s energy to condition the car battery 24 hours a day. Since the tester showed that my car battery was fine. The PowerPulse should keep it fine and prevent lead sulfate from building on the plates. Independent case studies document that using the PowerPulse on a car battery (frequently driven) can triple the life of the battery thus extending my car’s expected battery life from about three years to nine years.

I also have a PowerPulse attached to my AGM batteries in the RV. They too were healthy and get a daily charge being used and recharged all the time. Hopefully, this pulsing should also triple the life of my AGM batteries.

A different DHC tester attached to one of my 6-volt AGM batteries.
A DHC tester attached to one of my 6-volt AGM batteries.

As a point of concern, the PowerPulse uses a little of the battery’s power to perform the pulsing. You need to recharge this battery frequently or the PowerPulse can discharge a battery.

PowerPulse can recondition

The PowerPulse product also can remove some lead sulfate already attached to the lead plates over time but it is not nearly as fast as the commercial reconditioner that PulseTech loaned me. I won’t belabor the point but remember Scott Hellman has lots of history using PulseTech products to repair massive numbers of batteries for the South Dakota National Guard. For me, my best test results will be in about five years. Then I will have zombie batteries.

Here is an article about Scott’s testing lithium batteries. Destructive Lithium Battery Testing

In the future, I will condense a couple of emails between Scott and me that describes Scott’s battery results in the South Dakota National Guard. For now, I am just going to say — Scott is the expert at creating zombie batteries. Thank you Scott for directing us to PulseTech products.


My brand new engine start batteries installed last week also are getting a PulseTech charger. In this case, the charger is a SolarPulse. My engine start batteries only get charged when the engine is running so instead of attaching a PowerPulse to the engine battery, I put a SolarPulse to the task.

As I said before that my engine was delivered from the factory with a trickle charger that worked when the RV was plugged into shore power this charger helped keep the engine battery charged. The SolarPulse should replace the trickle charger for daily recharging and at the same time pulse the energy in the battery to prevent lead sulfate from destroying the battery. The picture at the top of this post is my SolarPulse panel for my RV engine start batteries.

On new Tiffin and Newmar RVs, PowerPulse is already being installed at the factory. I saw a picture of Bob Tiffins car collection… PulseTech products scattered everywhere. Bob already knows how to create zombie batteries.

As far as the engine batteries, I would encourage Tiffin to switch to the SolarPulse (or I have a different PulseTech idea for new Tiffins).

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Thank you again for the assistance from PulseTech and Smokey. *We knew Smokey for about two years before we found out that he was associated with PulseTech.

Thanks also to Darby at DHC Specialty for providing the testers used to evaluate our batteries. Here is a link to the main battery tester I used. DHC BT-400

Here is a direct link to the company. PulseTech

Here is a direct link to the products I use. PowerPulse, SolarPulse, SC-2 Extreme

Here is a link to the items on Amazon. We do not get income or commissions. The links are provided only to help our readers. PowerPulse, SolarPulse

4 thoughts on “Zombie Batteries that won’t die”

  1. I maintain by coach batteries by using a Pulse Tech Xtreme charger- Its on a digital timer and powered by the solar DC /AC system on my RV. I replaced my original trickle charger or battery maintainer with the Pulsetech Xtreme just over 5 years ago and the batteries still test with in 50 CCA of what they were when I put them in (they were used batteries when I installed them). The charger comes on for about 3 hours a day in the afternoon after my Lithium batteries are normally all topped off.

    Never had another problem again ever once I updated my system!

    1. Sadly, the Pulse Tech Xtreme charger is a discontinued product. I will update my recommendations to include their new charger as soon as it becomes available. Of course, I am looking forward to using it as well.

  2. Motorhome newbie here. My chassis battery is dead. It was charged and now dead again. It’s a good battery. What inside my coach pulls from this battery? What can I get to keep it charged? Coach is parked for the season but if I need to move it I don’t want to wait 3 hours for it to charge. What kind of charger do I get and do I leave it on full time? I appreciate the help you can give me.

    1. Sharon — how do you know the battery is good? How long was it between charged and discharged? How do you know that something wasn’t draining the battery? These are not easy questions to answer. You will need a charger and need to get it full. Something between 2 and 6 amps. The smaller the number the longer it will take to get it full.

      Then you will need to measure the voltage and then disconnect the battery. After three days, if the voltage has dropped to below 12 volts then you can assume the battery is bad.

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