Battery Maintenance: Flooded Cell Lead-Acid

[jimh]

I was doing a some maintenance on one of my cars this weekend, a 2011 model year sedan. I noticed that the positive battery terminal had accumulated quite a bit of blueish-white powder around it. I investigated and spent some time cleaning the power.

The blueish-white powder is probably formed as a reaction from some battery venting of acidic electrolyte reacting with the metals of the battery post. I vacuumed most of it away. Then the old-fashioned remedy of mixing some baking soda in water and rinsing the connection removed most of the remaining traces. Then I soaked up all the soda-water I could, vacuumed up the rest, and gave the terminal a good spray with WD-40 (or Water Displacement formula 40).

Although I have owned this car for over five years (since November 2010), I had not looked closely at the battery. It is still the original battery, and I was a bit surprised it was a flooded-cell, vented, lead-acid battery. I guess I shouldn't have been surprised as that is probably the least expensive battery to furnish with a new car. I was expecting a maintenance-free or valve-regulated lead-acid (VRLA) battery.

This battery has been in service for about 67-months, and I have never checked the electrolyte levels. I pried off the caps and peered into the cells, using a flashlight to illuminate them. The electrolyte was down in level just slightly. I topped off the six cells with distilled water. They only needed perhaps an ounce or two of water to bring them back to full.

I was surprised by several things about this battery, first:

--that is was a vented flooded-cell design; I was not expecting that; next,

--that in 67-months it had hardly lost any electrolyte, and finally,

--that it has grown a rather impressive crop of blueish-white powder on the positive terminal

I should mention that I have looked at the battery in the past. I had sprayed both terminals with CRC TECHNICIAN GRADE BATTERY TERMINAL PROTECTANT, which gives the terminals a coating of a dark red viscous liquid. The negative terminal was in perfect condition; only the positive terminal had the blueish-white powder coat.

The car has about 47,000 miles. If you figure an average speed of about 35-MPH, that suggests about 1,300-hours of operation. And many start cycles. It gets driven daily. Let's figure 67-months × 30-days-per-month = over 2,000 days. And figure at least two engine starts per day, so about 4,000 engine start cycles. In other words, a lot of running time and a lot of start cycles, far more than a boat battery would tend to get in the same time--at least far more than my boat would get.

Also, on this car, the lighting load on the battery is crazy. When you turn the ignition key, about a dozen lamps illuminate. The car body has all kinds of little running lights that come on. The interior has all sorts of little lamps. At first I thought the lamps had LED bulbs, but I see, again probably to save money, that those lamps are all using incandescent bulbs. There is plenty of lighting drain to keep the battery working hard. And the battery is not very big. It's a mid-size sedan and space under the hood is limited. The battery is smaller than the usual GROUP-24 you used to see in your older car.

I was impressed with how well the battery has held up. There has never been any indication of a problem with cranking. However, I have a general rule about batteries and Michigan winters. I usually get a new battery before the sixth winter. This one has been through six winters already. I will probably replace it this fall, just as a precaution. But, for an old technology and very simple lead acid battery, it has been very reliable.

[Don McIntyre - MI]

Would be interesting to see the results of testing with a load meter.

[jimh]

You mean the "load meter" at the battery store that will show it needs replacement? :-)

Today I checked the battery in the Suburban. It is only two years old, and it is a Walmart-branded, Johnston Controls, vented, flooded-cell, lead-acid battery. It needed about an ounce of water in each cell, too. It probably was not filled to the top before--that's my guess. This battery has side-mount terminals used on most GM cars. There was no sign of any blueish-white powder anywhere. The actual terminals are well-sealed by stiff rubber cups that are part of the battery lead terminal attachments. That is a good design. I gave them a refresh of the CRC Battery Terminal Protectant spray.

Tomorrow the boat comes out from the storage warehouse. The boat batteries are sealed AGM batteries. They've been sitting since October with no load and no recharging. First priority will be to check the terminal voltage and let the float charger work on them for a while.

Boating season is almost here: I can tell because hockey season is almost over.

[ConB]

The original battery in my last pickup truck went 10 years and140,000 miles. My present SUV battery did at least as well. Northern Michigan winters but both vehicles spent the night in a cold garage.

Con

[Oldslowandugly]

My batteries that are left outdoors lose little [electrolyte] over the winter. The boat batteries I store in the basement near the furnace lose [electrolyte] as it is very dry down there. On my top post batteries I smear some Lanocoat corrosion inhibitor on the posts and clamps and I never get any crusty corrosion. Side post models are supposed to be immune but still get some. I find adding some Lanocoat or anti-seize on the battery cable bolt threads is all that is needed for those. Baking soda and water is still the best cleaner and is very safe to use.

[jimh]

As I recall my longest-lived battery went about 85-months. It had an 82-month pro-rated warranty. I guess the manufacturer knew how to make batteries and how to warranty them.

[jimh]

I got my boat from the storage warehouse. The two AGM batteries had the following terminal voltages, after sitting without any re-charging for about eight months:

--cranking battery, a Sears-branded Marine Diehard Platinum AGM that was new in 2010: 12.47-Volts

--house battery, a private-label-brand 70-Ampere-hour AGM that was new in 2009 and was in service on a large UPS for about three years: 12.27-Volts

According to my data on state of charge as a function of terminal voltage, those voltages represented a discharge percentage of 30-percent discharge and about 45-percent discharge. When I powered-on the dedicated 120-VAC charger, it would only go into Float Mode to recharge. After about an hour of float charge, both batteries had terminal voltage of over 13.1-Volts.