Battery Care and Maintenance

    After more than 3 decades as the owner and operator 
of an automotive electrical business, and dealing with 
every conceivable battery issues over those years, I 
think I can safely say that I’m somewhat of an expert 
on the subject. In this article I’m going to lend some 
of those years of experience to everyone and hopefully 
clear up some of the mysteries of battery care and 

Storing electrical energy is everyone’s concern 
whether they are in a car, RV, on a farm, or maintaining 
a life style off of the grid. Over the years I’ve heard 
of all kinds of mixed up facts and fiction about 
batteries and battery care. In this article I’m going to try and set the record straight once and for all on the different types of batteries, battery maintenance and what you should know.

Flooded type
Cars weren’t always equipped with a 12 volt battery, actually the first production cars were almost always 6 volt and a lot of them were positive ground cars rather than the negative grounded cars (and RV’s) of today. Why the switch to 12 volts vs. the 6 volts? That was mainly for the added strength (electrical push) you could get from a 12 volt battery vs. the 6 volt for starting the vehicle (especially in cold weather). The switch to all negative ground leads had more to do with WWII. During those years the plastic coated wires were perfected and they could do away with the woven fabric coatings that was used on everything. The woven fabric wires had a tendency to absorb moisture and eventually would have this galvanic effect of corrosion throughout the entire length of the wire. Engineers found out that if they would use a positive grounded system the effects of this corrosion were greatly reduced. Switching to the plastic coated wire eliminated all those concerns. (Not all woven fabric wire cars are positive ground vehicles, but all positive grounded vehicles are likely to have used woven fabric wire)

    A 12 volt battery as it is called is not really 12 volts, but should fall somewhere between 12.4 and 12.6 volts when fully charged. As a rule of thumb, if you test a battery and the voltage level is below 9.6 volts, it’s probably not a good candidate to recharge at all (depending on its age – which we will get into later). The typical 12 volt battery in use is what is referred to as a ‘flooded’ battery. That is to say, it has a liquid solution of sulfuric acid and water separating each cell.  

    There are two basic types of flooded batteries on the market. One that you can add water to the individual cells and one that you can’t. The water level needs to be maintained to keep the battery at its peak performance level. The level is checked by taking the caps off and looking straight down into each of the holes. There is a collar about a half an inch down in each cell opening. This collar is the water level line. Always keep it filled to this point and no higher. 

    The sealed 12 volt battery or sometimes referred to as a ‘maintenance free’ battery generally will have a small window with a little ball in it. The ball mysteriously changes from red or yellow or green. This is actually a cheap version of a hydrometer (battery acid measuring tool) green is the color you want to see in the window. (If you’ve ever shook one of these batteries you can jiggle it around enough to see the other colored balls in there). The problem with this so called ‘maintenance free’ battery is that you are only looking at one cell in the battery. So, it is NOT a good indication of the entire battery condition… just that one cell. 

AGM battery

    The AGM (Absorbent Glass Mat) batteries are quite similar to the standard flooded battery, but different at the same time. The AGM was developed in the early 1980s as a sealed lead acid battery for military aircraft, vehicles and UPS to reduce weight and improve reliability. The sulfuric acid solution is absorbed by a very fine fiberglass mat and held there rather than sloshing around as in the flooded battery. Making the battery virtually spill-proof.

    The leading advantages of an AGM battery is that it can charge up to five times faster than its flooded type battery counterparts. It also has the ability to act like a deep cycle battery and be depleted up to 80% from fully charged and recharged without any significant loss in energy storage capabilities. (A flooded type battery can’t go below about 50% of its charge level without a significant loss of storage capacity.)

    Because of the AGM’s reduced acid spilling characteristics in odd angles, accidents, their performance in cold weather conditions, and an overall lower weight in comparison to the flooded batteries. They’re a great replacement battery for off road and RV use. They can also be mounted in some rather strange configurations and angles too. Which makes them ideal for tight spaces and odd battery configurations.

Lithium Batteries – the wave of tomorrow’s energy sources

    Lithium –ion batteries are everywhere. They power our laptops, cell phones and most every small item electronic device including some vehicles on the road today. The electrodes of a lithium-ion battery are made of lightweight lithium and carbon. Lithium is a highly reactive element, meaning that a lot of energy can be stored and released as needed. This translates into a very high energy compaction for lithium-ion batteries. 

    There is no liquid acid solution as in the other two sources of energy storage. But, the charge rate is much slower. (Nanotechnology engineers are working on that issue) However, they will hold their charge level with very little drop in rate over a period of time as the flooded or AGM will. They also can be molded into any shape or size you can think of. The output rate is very stable and can last for a much longer run between recharging compared to the flooded or AGM battery.

That is not to say that lithium-ion batteries are flawless. They have a few disadvantages as well:

They are extremely sensitive to high temperatures. Heat causes lithium-ion battery packs to degrade much faster than they normally would.
If you completely discharge a lithium-ion battery, it is ruined.
A lithium-ion battery pack must have an on-board computer to manage the battery. (This makes them even more expensive than they already are.)
There is a small chance that, if a lithium-ion battery pack fails, it will burst into flame.

Charging and Life expectancy 

    Each of the three types of batteries I’ve mentioned have some great qualities and some not so great qualities. One of the big concerns is the recharge rates and how long can each of them last. 

Flooded battery

    The good old fashion 12 volt flooded battery is the most common and of course the one that is widely understood as far as the needs for recharging. Most companies that build inverters and converters start by building one for the flooded type battery market. This could be for use with a generator or from solar panel energy sources. The average life span of a flooded battery can be anywhere between 3 to 5 years. 

AGM battery

    The AGM battery has a slightly different charging requirement. If you are switching from the ‘flooded’ type battery to all AGM batteries make sure the charge rate is proportional to the needs of the AGM style battery. Failure to do so can weaken the lifespan of your AGM batteries. (It’s not the first time I’ve heard the story that someone spent money on AGM’s and didn’t like it, and went back to flooded batteries. When what most likely happened is they didn’t update the charging system to accommodate the AGM batteries.) The average life span of the AGM batteries are around 6 to 10 years. 

Lithium- ion battery

    The lithium-ion battery is a combination of carbon and lithium that forms a sort of paste. This battery type has the ability to deliver full volume of energy over a long period of time. Unlike the two previous battery styles that will slowly weaken their electric field and reduce the overall stored voltage a lithium-ion battery maintains basically the same level for a long long time. But, as with many other new technologies, the recharge rate is quite different and has its own set of problems. Such as the speed at which it can be recharged and at what level of charge can be used from the charging station. 

    There are some risks from explosions and fires from over charging or smashing/crushing (in an accident perhaps) because of the extreme amount of energy that is stored in these lithium-ion batteries. Also, a lithium battery that is allowed to drop to just over 50% of its capacity usually means the battery is done for and cannot be recharged safely or adequately. 

    The longevity of the lithium battery is based on hours of use. Which can only be determined by what they are being used for. Obviously, if they are used more often they would naturally wear out faster. Lithium-ion batteries do age though. It has been reported that a lithium battery only last two to three years if they are sitting on a shelf unused. On average, with continual use, they will last 3 to 5 years.


    I’ll stick with the maintenance on the battery and surrounding areas of the battery enclosures. The charging side of it the business is for a later discussion. Frist thing to keep in mind, all batteries, maintenance free or not are vented to the atmosphere in some way or another. That means that some of the vapor produced from the reactions of chemicals inside of the battery need to be dissipated. These ‘vapors’ are basically hydrogen gas and can be extremely flammable in a closed off area. Be sure to wear protective gloves, glasses, and clothing when working around a battery. Have the area well ventilated to remove any of these gasses that are present. 

    The furry looking growth you see on the metal surfaces is some of that vapor that has condensed and is now eating away at the various metal parts. It needs to be rinsed off and then cleaned with a baking soda and water mixture (Usually about 3 tablespoons to a quart of water). Use a soft bristle brush to scrub the areas where the growth has hardened. Be sure to remove every bit of it or it will recollect back on those very same spots. 

    Once the area is cleaned separate the battery terminals and lines from the battery posts. Remove the battery tie down straps and the batteries. Continue cleaning as needed. Any painted surfaces that have been damaged need to be repainted before everything is reinstalled. 

    Examine all the connections for deterioration and deformed connectors, replace anything that is questionable. Have the battery or batteries, tested before reinstalling. (Note: a reading of 12.4 to 12.6 is a fully charged battery, but this is not an indication of the potential of the battery. That can only be measured with the proper battery testing equipment and not a multi-meter)

Reinstall everything and secure it all in place. I like a bit of bearing grease on the terminals to increase the chances the vapor won’t collect on those surfaces.

The wives tales and misnomers 

    No matter where you go, or who you meet somebody has come up with a better mousetrap. So it is in the battery business. Here’s a few of my all-time favorite ideas and gimmicks that are common around the battery box:

Those little red and green pads you put on the battery terminals. 
Yes, they do have a chemical agent that helps prevent the acid from building up on the terminals, but I’ve found more than a few of them that prevented the battery terminal from fully seating on the post. Other times the oily concoction on these things seem to get everywhere. Personally, if you believe a little green and red pad is going to allow you to forget about opening up that battery box and checking on your battery condition… think again.
Corrosion spray 
 Oh brother, what a waste of money. First off, read the ingredients. What is the primary component – Uhm, it’s baking soda. Why not just buy some instead. It’s cheaper and has a lot more uses than that can ever will. Besides, most of the time when you go to use the can the second time the nozzle is clogged with the baking soda.  
The red protective spray for battery terminals. 
Would ya please take this stuff and pitch it into the nearest recycle center for me. This stuff is absurdly useless in my opinion. Yes, I’m sure it has some properties that make it the greatest thing since slice bread for battery terminal corrosion prevention, but if you’ve ever been around this stuff the dye they use in the spray doesn’t wash off. You’ll be wearing this stuff for days. Been there done that. I still prefer good old bearing grease if you want some basic protection followed up with a monthly check on the battery conditions.
You can test the output of the charging system by lifting the battery terminal off while the engine is running. 
If you’re doing this… you need to be removed from under the hood and placed in the trunk. Don’t do it! Today’s vehicles run on computer impulses and these impulses are minute and it doesn’t take much for the computer to see a drop in output and then tell the alternator to step it up. Which, could raise the alternator output to some extremely dangerous levels and burst the very computer that told it to raise the charge rate. Just don’t do it.
Distilled water
 Yes, distilled water is fine in a battery, and is probably better than from the hose. But, honestly I don’t think the amount of city water poured into your battery that you would normally be adding is going to change the battery potential in any way shape or form. 
Dielectric grease on the terminals
 Really? Is that what you think it is for? Yes, I’ve seen it done. Dielectric grease is an electrical ‘Vaseline’ to aide in terminal connections and to help seal out moisture. Effective on a battery terminal … sure… necessary… nope. Regular old fashion Vaseline works better and far cheaper too.