Today I learned quite a few things about lead-acid batteries and had some long held beliefs destroyed.
This all began when my golf cart charger wouldn't charge the batteries. I disconnected them and tested voltages on each and found 2-3 volts on each.
My cart has 8 6VDC deep cycle lead-acid batteries for an output of 48 volts.
That was last fall and I assumed either my batteries were junk or the charger died...so I walked away and figured I'd save up for new batteries IF I decided to keep the thing.
Today I decided to do some more investigation and removed all the battery caps n peeked inside. To my horror I saw dry plates in all 8 batteries.
I decided to fill one battery with distilled water to see how low it was. 3 cells took just under 1 gallon of water! The other 7 batteries took about the same amount.
Now we come to misconception #1. All my life I have believed that when wet cell batteries are charged and get hot, the sulfuric acid (Electrolyte) and hydrogen escapes and causes terminals to corrode, steel to rust and burns on your skin. I learned that this isn't exactly true.
When a battery is charged, the sulfate in the active material of the plates is driven back into the electrolyte.This reduces the sulfate in the plates and increases the specific gravity of the electrolyte, an electro-chemical process which continues until the charging cell voltages reach 2.50 to 2.70 volts per cell.
When being charged under normal conditions the typical automotive battery will not emit any detectable liquids or gasses except for water (H2O). When a battery is charging, the electrolytic breakdown of the water in the electrolyte produces oxygen on the positive plates and hydrogen on the negative plates. This is normal.
However,if a high charging rate is continued after the battery has been brought to its gassing voltage (2.50 to 2.70 volts per cell), the gassing becomes excessive, and abnormally larger amounts of hydrogen and oxygen gases are produced. The best indication of excessive gassing is a very noticeable “bubbling” action of the electrolyte and high electrolyte temperature.
Also, when a battery is being charged with a current and voltage at a rate it can absorb, it should only see a 10 to 20 degree F. rise in temperature when fully charged from a completely discharged state.
So, when a battery is taken past it's gassing point, hydrogen, water vapor and oxygen are created and once the battery case becomes pressurized to a certain point, and electrolyte temperatures are elevated, these gasses are released. Those wet acid spots on the top of your battery are a result of this.
Partial Misconception #2: You must only add distilled water to a battery with low electrolyte levels.
Generally, a certain amount of water loss is normal in all batteries, and it should be replaced with “pure” tap water or distilled water. In some areas around the country, tap water may contain chemicals or other impurities harmful to batteries. If you know your local water at the tap is 'pure' you can use it. When in doubt, use distilled water.
Misconception #3: Adding water to a lead-acid battery dilutes the sulfuric acid and makes it weaker.
Not true unless there is a tip-over/spill or battery case leak. In most cases, when the water in the battery is boiled off or 'Gassed', the water is released leaving the sulfuric acid behind. By itself, the acid cannot function as an electrolyte and the cell(s) will no longer accept a charge. When water is added, it mixes with the acid and electrolyte is created.
So, after educating myself on all things Battery, I charged the batteries in isolated pairs of two. My automotive charger is a 12v only model, so two six volt batteries in series act like a single 12v unit
After getting the pairs to 70% of their full charge I re-connected the cables and hooked up the dedicated Lesteronics charger and it came to life. I learned that many cart chargers will not begin to charge the batteries unless a minimum voltage is present. In the case of my Lester, this minimum voltage is 4 volts.
The charger ran for about 2 hours and shut off. After confirming the batteries were cooled down, I took the cart for a spin and darn near rolled it in a sharp turn.
I decided to share what I learned and un-learned today as this applies to our FSJ batteries and even moreso to those rigs with higher current demands and higher output charging systems that use wet cell batteries. Accordingly, the AGM and Gell Cell batteries also suffer from overheating/overcharging.
Charge On Brothers!