I'm in the middle of Wisconsin. As for dollars, the web site owners do compensate me for every answer of value I submit. I used to get a portion of donations, but I don't know if that is still the case. Regardless, donations are greatly appreciated by the site owners as it is expensive to run a web site. I really like it that donations are not required.
I have a web site of my own and I just got another bill. I'm in the process of moving it to another company or just discontinuing it due to the cost. It jumped this year to over $500.00. I just spill automotive electrical information for students and instructors. I don't sell anything and I have never made a single penny on advertising.
As for batteries, I cover that on one of my web pages. To boil it down to the basics, the lead flakes off the plates over time. There is no way to avoid that, but the manufacturers know how quickly that will occur, and they use that information to provide the longest warranty period possible because that translates into more dollars they can charge for that battery. There is an area in the bottom of the battery's housing where that flaked-off lead accumulates. When it builds up high enough, typically after five years, it will short the negative and positive plates in that cell together. At that point the battery must be replaced. It will crank the engine very slowly, if at all, and if it does, it is usually too slowly for the engine to start. Even a jump-start might not work at that point because the shorted cell is still shorting out the jumping battery.
A battery can also fail before that lead builds up in the bottom of the housing enough to short the plates. The lead needs to be suspended on the plates, in the acid, to work. When half of it flakes off, the battery may still crank the engine just fine, but not for as long. A better example is when you leave your head lights on, (in the days before we had computers that turned them off for us). A fairly new battery would run those lights for about two hours before it was run down to the point it wouldn't crank the engine. By the time it's three years old, it might only run those lights for an hour, due to the less lead in the plates and therefore less room to store electrons, but it can still provide short bursts of very high current to crank the engine. I just went through this a few days ago with my van. I use a little power inverter to run my laptop when I sit in a parking lot using someone's wireless internet. Last spring I could run it for two hours or more, then start the engine and drive home. Last week it was down to less than a half hour, then, when it suddenly got cold the next day, it wouldn't even crank the engine fast enough to start. Electrical power can only be stored in a battery, and that is done chemically. Chemical reactions always slow down as temperature goes down, plus, cold engine oil gets real thick making the engine harder to crank. We need more cranking power and we're trying to get it from a battery that is weaker. That is why most battery damage occurs in hot weather, but it shows up in cold weather.
Here's the clinker. To be able to offer the longer warranty, which will cost extra, that area in the bottom of the housing that collects the flaked-off lead needs to be bigger. That means there's less room for the plates, so they have to be smaller. That isn't such a concern today when fuel injected engines start right away. Back in the '60s and '70s, with carburetors that were out-of-adjustment, it wasn't uncommon to grind on a starter for much longer before the engine finally started, especially on cold winter days. We needed batteries with plenty of lead in the plates to give us that longer cranking time.
You have to decide if the longer warranty is worth the extra expense. Only a very low percentage of any batteries fail during the warranty period. Instead, look at the length of the warranty as an indicator of how long you can expect that battery to last. Often they will fail with just a coupe of months left in the warranty. I've always been suspicious that was planned because the only way to collect on that is to receive a tiny discount on the cost of a new battery, ... From the same manufacturer. I look at it as a low-cost way to get you to buy another one of their batteries. Of course, to be fair, there are a lot of batteries that last considerably longer than their warranty period.
A few years ago I bought the cheapest Carquest battery I could find. That lasted over eight years, but now I found a better alternative. We have a battery store in my town that sells "reconditioned" batteries, but they don't advertise that, or tell you about them. You have to know about them and ask for one. One time they told me they were called "reconditioned", but they simply had been sitting on the shelf for over a year and they wanted to get rid of them. Another time they told me, as I had originally suspected, someone bought the battery, took it home and installed it them self, then found out it didn't solve the problem and they returned it. Technically it is now a used battery and can't be sold at full price.
Currently this store is selling their reconditioned batteries for $30.00 exchange. I always have a bunch of old batteries laying around. They buy them for six bucks each. Each time I need a battery, I take them six bad ones, make an even exchange, and only have to pay the sales tax.
You can also get some good deals at the larger salvage yards. The smaller yards typically buy the older cars where people keep the batteries, or they're on their last legs. The large yards buy late model insurance wrecks that are often one to three years old. They will often have more fairly new batteries than they know what to do with. My local yard sells them for $19.99.
There are a few Chrysler models that have gone to the really miserable side-post batteries that GM refuses to give up on, but I think your Jeep uses the better top posts. If so, when you look for a replacement battery, look at which corner the positive and negative posts are in. Match the new battery to that to be sure the cables will reach. Anyone at a battery store or salvage yard will know right away or they will pop your hood and look to be sure. You can replace the battery yourself, but there are some things you must be aware of. First of all, many of the computers have memories that will be lost. For example, you'll need to reset the clock and your favorite radio stations. Any diagnostic fault codes stored in the Engine Computer will be lost. That isn't a big concern, and will have occurred anyway during the current repair work. Fuel trim data will start to be rebuilt as soon as you resume driving. That takes just a few minutes and you are likely to not even notice the less-than-perfect engine performance.
What DOES worry me is there are some European import cars that have multiple computers that lock up when the battery is disconnected or run dead. That requires a very expensive tow to the dealership. GM copied that idea since they are the top manufacturer at coming up with innovations that benefit them at the expense of their customers. (Chrysler has always been the leader, since the '50s, at developing innovations that really benefit car owners, but that's a story for a different time). To avoid these problems, there are a number of "memory saver" devices on the market. Most of them plug into the cigarette lighter and use a 9-volt transistor battery to keep the computer memory circuits powered up. I use a small battery charger hooked right to the battery cables, but there are certain precautions that must be observed when doing that. I do have a 2014 Dodge truck that was smashed, and my friend rebuilt in his body shop. We did need to disconnect the battery a few times, and there was not a single indication that was done other than the incorrect clock, so I might be worrying you about nothing. You can ask your mechanic if any computers need to be unlocked after reconnecting the battery. If he says "no", you can overlook this entire paragraph.
Along with the location of the two posts on the battery, the positive post is always larger in diameter than the negative post. Use your wrench to loosen and remove the negative cable first. We do that one first only because if you slip and the wrench contacts the clamp and the body sheet metal at the same time, nothing will happen. The two are actually connected together by the smaller wire on the negative cable. If you do the positive cable first and the wrench makes contact with another metal part, there will be huge sparks, and the wrench can actually get welded in place and become red hot enough to melt and bend! Remove the positive cable last. That way, if the wrench makes contact with a metal part, nothing exciting will happen. No current can flow and cause sparks once the negative cable is already disconnected.
There will be either a bolt to loosen to loosen the hold-down bracket near the bottom of the battery, in front or in back, or there will be a strap-type bracket over the top. Once you get the new battery in, be sure whatever is used to hold the battery in place is tightened properly. If it is not, the battery will vibrate excessively. That will aid the lead in flaking off the plates, and will shorten the battery's life.
Use a post cleaner to scrape the inside of the cable clamps and the outside of the posts so they're clean and shiny and make good contact. Don't get so carried away that you grind off so much that the clamps can't be tightened enough. What you don't want to see on the contact areas is a hard black coating. That is one type of corrosion that prevents a good connection.
As a point of interest, don't let anyone sell you a pair of "juicy rings" that slide over the posts to prevent corrosion. What I have found is when a lot of the lead has flaked off the plates, as in when the battery is near the end of its life, the little lead that is left has to absorb the full charging current flow, and that makes the plates get hotter than normal. The heat causes increased gasing and bubbling of the acid, and those bubbles reach the underside of the top of the housing. From there, the acid that has splashed onto the case works its way over to the posts where it sneaks through the mechanical joints and collects right under the cable clamps. That is what causes the white corrosion that looks like cauliflower. If that corrosion hasn't shown up yet on an old battery, those juicy rings aren't going to do anything. If the corrosion has shown up, the battery can be expected to fail within the next six months, and the juicy rings aren't going to change that. When I saw that corrosion on a customer's battery during other services, like oil changes and alignments, I would include a written warning on the repair order, to expect a failure soon. Some people thought I did something to their battery to cause the failure, and that's how I knew it was going to fail.
Reconnect the positive cable first, then the negative one. The positive post, as I mentioned, is larger, it has a plus sign molded into the top right next to it, and often there will be red paint on the top of the post. The negative post is smaller, has a minus sign next to it, and when used, will have green paint on top. If you mistakenly try to put the negative cable on the positive post, it won't fit unless you spread the clamp open. That is the first clue you're about to do the same damage that is being repaired now. If you put the positive clamp on the negative post, it will be too loose.
My experience has been that computers with "customer preference" settings retain their programming when the battery is disconnected. Those settings include things like horn chirp when locking the doors with the remote, speed-activated door locks, and things like that. Tire size is programmed into the Transmission Computer so the speedometer will be calibrated correctly. That should not change, but to be safe, observe if you're going faster or slower than everyone else. I check my vehicles with the remote radar signs the cops set out periodically. Those seem to be pretty accurate.
Wednesday, November 23rd, 2016 AT 6:00 PM