Most batteries in cars, trucks, motorcycles, and boats, as well as solar electric back-up systems, continue to be the lead-acid batteries. You all know them. They can last a very long time, if they are cared for properly. That means:
- They must be kept at full charge
- They must be watered regularly (if not the sealed type)
- Their terminals/posts must be kept free of corrosion.
But I am sure almost all of us have mistreated them at one time or another.
From a prepper’s point of view, you need to know about batteries well enough to have them available and fully charged in an emergency. Batteries will keep your house lights on and even your refrigerator going, among other things.
Besides a basic lead-acid battery, you will also need an inverter that hooks up to the 12-volt battery or batteries directly and converts the DC power to 110 AC. Inverters are available in all sizes, from 200 to 5000-watt capacities. Harbor Freight is a good place to look for them locally at reasonable prices.
Just 400 watts will lift a garage door and power almost all electronics. Five thousand watts (if you have enough batteries) is probably enough to power your whole house via cheap extension cords and power strips (but not the ideal approach, which is quite a bit more costly).
Most of us really don’t understand the way batteries work and don’t want to.
I still get a little mixed up about volts versus amps. We just want them to work when we need them. And we throw them away (or recycle them), not knowing most can be recharged in some way.
I started experimenting with small-scale backup solar electric systems that use oversize lead-acid, wet-cell DEEP CYCLE (marine) batteries over 25 years ago. I wanted to have some power grid independence. (I first started with an RV setup that allowed for “boondocking”.) And, boy, did I screw up some batteries! Until recently, I just put them in a dead battery “graveyard”.
The usual reason for my screw-ups has been that charging was inadequate due to not enough amperage from my solar panels (resulting in too low voltage under the necessary 12-volt threshold for utility).
I had a small solar electric system for many years, which had two deep cycles being charged by one 100-watt PV panel. I had ignored it for some time as I’d developed a stronger system using one 180-watt panel and didn’t really need it. It languished in an outside cabinet. The batteries slowly lost their charge and started to sulfate. At that point, I considered the graveyard as they registered only 10 volts. And a couple cells looked dead.
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These ten-year-old batteries from Costco looked like new from the outside (as they were kept clean).
Normally Costco would take back any battery whether new or old, and give you a refund—except that in my case, Costco no longer carried their Kirkland brand and had replaced it with Interstate (but the same size batteries).
Somewhere I had read or heard that you could actually restore deeply discharged, sulfated, and almost dead lead-acid batteries.
Since these new batteries were selling for almost $100 apiece now, I figured the two deep cycles I had could be part of a smaller backup system that I planned to use when PG&E might shut off our power for up to five days in California if we were threatened with a wildfire. Yes, you read that right.
In anticipation of that, I had not only backup solar electric (using deep-cycle batteries) but various portable power sources (with small plug-in inverters), and in a worst-case scenario, I had a 100-foot extension cord I could run across the street to an AC outlet off my neighbor’s natural gas-powered Generac generator! Nice to have neighbors like that!
I got my initial encouragement that I could restore my two lead-acid batteries from a couple of YouTube videos. They suggested that what you needed to do was drain the batteries of their electrolyte—the battery acid that goes bad over time, starts eating away at the internal plates, and needs to be replaced, assuming the issue is that there hasn’t been enough charging, which it almost always is.
The videos clearly showed what you needed to do, and the answer was cleaning out the built-up metallic oxides that had liquefied and replacing the contaminated electrolyte with a solution of Epsom salts and distilled water. No promises were made on how long these supposedly restored batteries could last, but one video guy said maybe two to four years.
While this is an “it depends” solution, I thought it was worth giving it a try if you are handy, have time on your hands, and like a challenge. It certainly is cheap since Epsom salts, the baking soda, and the water you need to use to clean out the batteries cost only pennies. And elbow grease of course. I don’t have all that much time (we run a home-based B&B), but I’m handy and up for a challenge.When I say that restoring dead batteries the YouTube way is dangerous, it is only if you don’t pay attention to the suggested procedures. You need to wear waterproof gloves, in case your hands come into contact with battery acid, and a pair of goggles in case the battery “erupts.”
You might also be concerned about getting shocked working around electricity, but believe it or not, it’s never happened to me. You can touch a battery’s terminal with a bare finger (or, for that matter, one wire, whether negative or positive) as long as you don’t touch both at the same time and stand barefoot in a puddle of water. But be cautious when taking a battery out of a vehicle since there are metal parts nearby. Just disassemble the terminals one at a time and keep your tools in a safe place, away from any hot wires.
Fear of being shocked must keep many away from batteries and maintaining them properly. It’s really sad and ultimately expensive.
Now, onto the procedure:
#1. What you first want to do is drain the batteries of the existing electrolyte. This was the really hard part as the deep cycles I have are rather heavy, and you need to turn them upside down and place them over a bucket.
#2. Then you need to pour a solution consisting of 10 ounces of baking soda diluted in a gallon of regular water into the battery orifices, one at a time, with a funnel. That’s when you will get an “eruption,” although I don’t think it’s very dangerous since most of the acid is gone by now.
#3. When you pour the baking soda solution out, you will see how black the water has become, which is the bad oxides that have built up within the case and on the plates. I did this three times with each battery, and black continued to foul the water. Obviously, there was a lot of bad electrolyte there.
#4. On YouTube, one guy at that point rinsed the inside of the batteries with a hose nozzle with its jet setting. I just poured regular water into the holes to give the plates a final “rinse” then turned the batteries upside down again.
#5. Then I started adding a warmed up solution of Epsom salts (12 ounces to one gallon of distilled water) into the holes until the plates were covered in each battery. (No more eruptions, FYI!)
#6. I then put the caps back on securely.
I put my automatic battery charger connections on one battery and plugged it in. On the 2 amps setting, I immediately got a “fault” reading and knew no electricity was going into the battery but wasn’t sure why. So I looked it up on Google and learned that unless a battery is at or near 12 volts, automatic chargers won’t work; you need to use a manual charger or at least a trickle charger.
Well, I didn’t have either, but I did have two cheap float chargers and the charging power of the 100-watt panel that was still active on the roof (the one that couldn’t keep the two batteries charged over time). I connected the float charger and solar charger with its charge controller to one battery.
Two days later, the battery reached 12 volts, and the automatic charger no longer went into fault mode when I attached it. SUCCESS! Now I just needed to get the battery up a little higher, say 13–14 volts, which I knew would be more than enough to keep it fully charged even without constant attention.
The other battery, on my other float charger, at that point had only reached into the 11-volt range, but it didn’t have both a float charger and solar charger on it.
FYI, neither of the batteries ever went below 10 volts after being drained, doused, and refilled; I wasn’t expecting that. I just assumed they would “die” without fluids. They didn’t. So while one might have considered them “dead,” they were far from that.
Another day later both batteries were well above 12 volts, and after attaching my 400-watt inverter, which also has a fault mode that screams when there isn’t enough voltage, it was generating AC power again! Frankly, I was amazed.
I don’t know how long at this point the batteries will stay chargeable since they obviously have both experienced damage to their plates. After all, they were ten years old! If they don’t stay chargeable, I probably wouldn’t repeat the experiment. But for now, they are backup batteries for an outage, and I will keep them both on a float charger in readiness. The float chargers take very little electricity. I remain mystified that common Epsom salts can substitute original battery acid—and for pennies.
I had fun with this project (except for the lifting of the batteries) and already had all the equipment on hand to make it doable. Float chargers (Centech) are only about $10 at Harbor Freight. Next I will look into lithium ion batteries, which I know will be more expensive but probably even more durable. They are in my hybrid EV, a Toyota Prius Prime, and can be recharged thousands of times.
For more information on how to restore batteries, you can check out this video.
William Seavey wrote two more articles for our website. Some of his books on DIY projects can be found at williamseavey.com. To see what he has developed as a solar backup power strategy, see powerfromsun.com.
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