Short Battery Tutorial

sunking

Unfortunately there is not a good Topic to file this under, so please feel free to move this topic on Batteries.

Thought I would take a few minutes to share some of what I know about batteries after working some 35 years with them professionally in the utility and Telecom sectors. I have worked extensiveness with most of the the really big name manufactures, some you might have never heard of like C&D, Exide, Enersys, Rolls-Surette, Concorde, US Battery, and even Trojan.

The golf cart world still primarily uses the Flooded Lead Acid (FLA), and a few use Absorbed Glass Mat (AGM). Stay away from Gel batteries. All three are lead acid batteries that have been around for over 100 years and the technology is very mature.

Lead acid batteries fall into 3 main categories of application of SLI (Starting Lighting, & Ignition), Hybrid which have many Marketing names like Golf Cart, Floor Machine, RV, Marine, Leisure, and the list goes on. Last but not least a true Deep Cycle. Each has its own application and is built for such.

SLI aka Craning or Car/Truck batteries are built to deliver very high quick short burst of Cranking Currents, and then be recharged very quickly by the engine alternator. To achieve that objective requires a battery with very low Internal Resistance referred to as Ri. To construct such a battery requires the manufactures to use multiple thin, closely spaced, sponge like texture plates to maximize surface area ans thus lowering Ri. However if pushed into cycle service is very short lived of 50 cycles or less if you are lucky. If you were to drop in SLI batteries in your cart, initially you would love them because they can deliver tremendous currents without a lot of voltage sag which means great acceleration and start up torque. But just after a few cycles you will notice that surge fading fast, and dead soon after when the plate material is all corroded and laying in the bottom of the battery jar. So SLI is off the table.

True Deep Cycle batteries are at the other end of the construction spectrum. They are constructed from heavy thick plates, and much heavier than there SLI cousins for a given volume. This enables them to be cycled many many times. However there is a trade-off of Internal Resistance is much higher than their SLI cousin. That means they cannot deliver high amounts of current without significant voltage sag. Typically you want to limit maximum current draw to about C/8 hour discharge rate where C = the battery rated Amp Hour capacity at the 20 hour discharge rate. Example an 80 AH deep cycle can only deliver 10 amps without significant voltage sag of 5% or less. Again not something you want to use in your cart. If you did you would notice slow acceleration from low torque because the battery cannot deliver the high currents required at low RPM’s in a series DC motor. Once up to speed though it is OK and you would get longer battery life.

That brings us to Hybrid Batteries. Hybrids are a compromise between SLI and Deep Cycle. They are made with heavier thicker plates than SLI, but not as heavy and thick as Deep Cycle. They have higher Ri than SLI, but lower than Deep Cycle. They will last longer than SLI in a cart, but not as long as deep cycles. The Hybrid is the battery of choice for your carts. An contrary to what you might believe or been told, the Trojan T-105 and its brothers in 8 and 12 volt versions are Hybrids, not Deep Cycle. If you do not believe this fact then take a look at the Trojan T-105RE and T-105 Spec sheets. RE means Renewable Energy and is a true deep cycle. Note the weight and warranty. The T-105RE is 5 pounds heavier ( more lead inside) and carries a longer warranty of 24/60 vs 12/24 for the T-105.

How do you get the most out of your batteries? Answer is simple; understand how to care for your batteries so you know what shortens the cycle life and what extends the cycle life. First step is know how to read manufactures date codes. Trojan has two date codes. First is the Birth Code or day it was assemble. Second is the day they added acid and charged the battery. So when you buy a new set, check the date code, you want less than 6 months since it was first charged up.

Charge and Discharge is one of the most critical aspects to battery cycle life. In a nut shell, the less you discharge the battery, the longer it will last. What I mean by that is how deep you discharge the battery, and how quickly you get it fully recharged. For example if you look at any battery Cycle Life vs Depth of Discharge (DOD) you will notice if you use only 20% of the capacity you will get on paper around 3000 to 4000 cycles. Take it down to 50% DOD and cycle life drops to 1700 cycles, at 80% it falls down to 500 cycles, and if you push your cart home, only a few hundred cycles.

What happens is 95% of all battery deaths are from sulfated battery plates. Remaining 5% I smostly corrosion of the plates as a result of overcharging. The result is high internal resistance. The symptom is classic most of you have experienced. See if this sounds familiar or not. Your batteries are dead, you put them on a charger and notice the charger shuts off quickly indicating the batteries are fully charge. You measure the voltage and everything looks good. Then you turn the cart on and it barely moves and you notice the battery voltage drops from say 50 volts down to 10 or 20 volts. Turn the power off and you notice the battery voltage rebounds back to 50 volts. Ever see something like that? It means you need new batteries; the ones you have are boat anchors.

What has happened is normal. When a FLA battery is less than 100% charged up lead dioxide turns into lead sulfate. Initially the lead sulfate forms soft crystals on the battery plates, and when you recharge it dissolves most of the soft crystals back into lead dioxide, but not all of them. As the battery gets deeper discharged the crystal formation accelerates and begins to harden. Below 50% SOc and crystal formation explodes and starts to harden very quickly. Once those crystals are hardened off, there is no way to dissolve them and it accumulates. That raises the internal resistance and leads to death of your battery. All you can do is slow it down, you cannot stop it.

Second thing else you can do to extend battery life is pay close attention to electrolyte level and keep the plates submerged. Use only distilled water to replenish lost water. Never use tap water. Last choice would be ionized water if distilled Is not available. One of the best investments you can make is an Automatic Watering system and learn how to use it. When in place it only takes a couple of minutes to refill the battery cells. Super simple and fast using something like a Trojan Hydro-Link system.

Keep it clean, tight, and lubricated. Sounds simple but most fail. Keep the batteries clean, check those connections, and keep an Anti-Oxidant on all connections. The best stuff you can buy is from Sam Chem called No-Ox-Id Special A formula. A $10-tube will last a lifetime. It is what industry uses exclusively. If correctly applied will stop corrosion in its tracks for up to 50 years. There is no better product money can buy.

Last topic is charging and corrective action. Since most of you use a standard golf cart chargers, not much you can do because they do not have the functions that allow you to extend your battery life like Float and Equalize. If that is the case all I can suggest is anytime you drive your cart for any reason, charge it back up. A FLA battery starts to degrade with anything less than 100% fully charged. If your cart sets for a couple of weeks without use, charge it up. Keep your batteries fully charged at all times.

Now if you want maximum battery life and have couple of hundred dollars to spend, buy an upgraded battery charger, one with Float and Equalize functions. In addition buy a good temperature compensated hydrometer. Take at least monthly hydrometer readings, and when the specific gravity gets out of tolerance, EQ the batteries. Such a charger never turns off if it has Float Mode. Such a model will use what is called a Bulk Mode Constant Current like every standard charger for fast charging, but once charged switches to a Constant Voltage Charge which remains until you disconnect it or turn it off. Flaot Chargers keeps your battery at 100% SOc ready and waiting to go. Again once you get into commercial and industrial battery plants; all use only Float Chargers with EQ. What is ironic is they are less expensive and are superior to what your standard golf Cart chargers are.

Hope you found this info useful and please feel free to ask questions.

BGW

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crash test dummy

great write up

all that and only 1 mistake

sunking

Prove it.

crash test dummy

that's the good thing about quotes... they preserve the original

gornoman

Fixed it for ya....

crash test dummy

Scott_nra

Very nice. THANK YOU from a Newbie.

oldcaptainrusty

Great info for a noob. This has answered a lot of my questions. Thanks

JaxUnicorn

Thank you for all the info! Any suggestions for 2 year old marine batteries where the water level dropped below the plates? I re-filled them with distilled water....but still nothing.

teecro

What else have you done besides replace the water? Have you hooked them up to a charger; and how did they behave? Despite the stories there really is no way to bring dead batteries back from the grave; sometimes heavy charging can have marginal luck but you have to be careful not to overheat the battery.