The Diesel Page

2020 Battery Selection and Maintenance

By Jim Bigley

Battery selection and tray maintenance are important to both provide the most reliable vehicle operation and to maintain the structural integrity of the battery mounting hardware. The above photo was taken in late 2011 during a battery replacement project I was involved in with my 2001 GMC. The original batteries had provided reliable leak-free and corrosion-free service for 10 full years at that point, and you can see in this photo that the tray is still in great shape. A good scrub using soap and water, followed by a quick touch up using some rattle-can black paint made the battery trays look nearly as good as new (where the paint had worn a bit just from the weight of the batteries) - I didn't even have to remove the trays from the truck. However, be prepared... the photo appearing below of the very same battery tray after an additional 9 years might not be suitable for sensitive viewers.

On the left in this 9 year old photo is one of the original ACDelco 78-7YR maintenance-free batteries that were installed in my 2001 GMC at the GM assembly plant in the year 2000. The original maintenance-free batteries never leaked acid during their 11 years of use. Shown on the right in the above photo was a new replacement (in 2011) ACDelco 78-7YR, which is not maintenance-free. I've had great luck with AC-Delco batteries through the years. Aside from long life, the maintenance-free batteries have never created a corrosion problem in my truck's battery trays or surrounding underhood structures. They are often my first choice when comparing price, long life and corrosion-free service. Unfortunately, the only AC Delco 78-7YR model batteries that were available at our local ACDelco store in 2011 were the removable cap type - not maintenance-free. Going against my better judgment, I decided to accept this type of battery because it would allow discussing whether "maintenance-free" batteries or "serviceable" (removable cap type) batteries might be the best choice for owners living in climates warmer than Montana. What a horrible mistake that was.

I knew that the cap style batteries I installed 9 years ago had the potential to vent acid, but I'd hoped that battery technology had evolved to a point that precluded any sort of problem with actual acid leaks... I went against my instincts and decades of prior experience when I settled for new batteries having serviceable caps (not maintenance-free). Because of the way the batteries fit into the truck, you can only see a fraction of each tray, and the optimist in me didn't want to assume the worst... Not till removing the batteries did I see the full extent of the damage. I can't help feeling like AC Delco had let me down. Luckily, the acid caused corrosion problem was limited to the trays and did not reach the cab or any other steel structure.

The solution to this problem began by soaking the trays overnight in a bucket of water and a mixed-in half box of baking soda. Once the battery trays had been acid neutralized, I used a wire brush wheel on my electric drill and a hand disc sander to remove all the loose crud, then soaked the battery trays in a solution of POR-15 rust remover. They came out of the rust remover solution looking a lot better, especially after another detergent washing, followed by more time spent with the wire brush wheel. Then, I painted the battery trays with POR-15 rust preventative paint. This should protect them for the life of the truck. While not shown, I also used my drill and wire brush wheel to clean all of the individual nuts and bolts. Most of them were then painted using either black or silver rattle-can paint to make them look good. During installation, I applied a little chassis grease to each of the bolt threads to help keep them rust free.

POR-15 paint is incredible stuff. The paint kit thoughtfully came with rubber gloves, but "real men" don't wear protection. I quickly discovered in 1999 that dried-on POR-15 paint wouldn't dissolve in acetone or lacquer thinner, so I had to wear the paint off my hands. Of course, it's the same color as the grease on a diesel engine, so I looked like a diesel mechanic for quite some time. As a result of that experience I used nitrile gloves during this paint project. The above image was snapped from the Amazon web site in early November of 2020. I prefer glass canning jars (pint or half pint) to store the POR-15 paint long-term. Just use a new rubber sealed replacement cap/lid every time the jar is opened (the original POR-15 can can't keep the paint fresh after it's been opened once). You could wrap the glass jars with several layers of duct tape if you're worried about dropping it. The POR-15 gloss black paint I used for my GMC battery trays in 2020 came from the very same batch of paint I bought for my 6.5TD Power Project in 1999. Even after more than 20 years of storage, the liquid paint was still as good as new. The overnight cure time I remember was not affected.

Over this past year I found numerous retail outlets that sold genuine maintenance-free (non removable caps) series 78 batteries that I prefer. I found them at Wal-Mart, at CostCo, at Home Depot and as shown here, even at NAPA. All were priced within dollars of each other (about $100 each). Our local NAPA had two of these in stock, and being local to me, they offered an easy return of the old batteries. By the way, the old batteries were still perfectly good - in so far as keeping a charge and providing quick starts... I just wanted to get rid of them because of the damage they did to my truck.

I don't see myself buying batteries having removable/serviceable vent caps for my trucks again.     TDP
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Guide to Diesel Pickup Battery Selection and Maintenance - Copyright 2020