When I bought the car I asked if the battery had been serviced and the salesman said he did not know. It looks like this could be the original battery (2005 XJ8) so, is battery maintenance the same as any other car? What I'd like to do is disconnect and remove the battery, check the electrolyte, top up with distilled water, if necessary, and attach to the charger for 5-8 hours. Then reconnect the battery. Anything special I need to do? Any resetting of anything? Do I even need to do this? I've always been able to keep batteries 4-5 years by maintaining them. Let me know if I'm blowing in the wind with this. Thanks.

 

2005, the amount of maintenance that needs to be done to a battery is all dependent on the type of battery you have. Pretty much batteries are going to come in 2 styles, those with caps on the top and those that are sealed. If you have a sealed battery, there is not a lot that you can do to it, so, leave it be until it starts giving you trouble.

As for the batteries with caps on the top, those you need to check on the fluid level inside. Like you mentioned, if you can see the tops of the plates, you need to add some fluid. But, make sure you don't over fill as this can lead to other problems like the acid spilling out of the battery during hard braking/turning. This leads to rapid metal depletion in the area around the battery.

The other "maintenance" item I do to my batteries periodically is to do a partial discharge. This is a fine line here. Not discharging enough will do nothing for the battery. Overly discharging can damage the plates. So, unless you are willing to gamble a little bit, don't do what I am about say. To extend the life of the battery, you need to knock the "moss" (battery term, think of it as a growth on the side of the plates due to repetative charges and discharges from starting the car) off of the plates. You do this by doing a partial discharge. I normally do it by putting about a 10 amp drain on the battery (turning on your headlights makes a 10 amp discharge). You want to let the lights run for about 1 to 1.5 hours. Essentially you want to drain the battery to the point that it is just able to turn the engine over and get it to start. Then you let the vehicle run for about 15 minutes to put a quick charge on the battery and return the battery to near full charge. From there, the next time you drive the vehicle, it will finish returning the battery to 100%. I did this once a year on my truck and managed to get 10 years out of that battery. Just a warning though, when you are recharging the battery using the motor, this is somewhat hard on the alternator as you are pushing it towards its limits. So, if you can drive the car on the highway shortly after starting the engine to get the engine RPMs up and getting the field current down some.

If you want more info, just let me know. I used to work around battery systems that were powerful enough to run a small town for a few hours.

 

Hi, Thermo, thanks for the excellent write up sounds like many, many years of battery experience there. It's amazing that you were able to get 10 years out of a battery; best I've ever done is 5+.

My car battery has the removable caps so I can check the electrolyte level upon removal of the battery. I just wanted to be sure that when I re-install the battery in the car that I would not be dealing with any error messages or any other issues. Thanks again for sharing that info, Thermo, I found it interesting and you made it work, but without your experience, I don't think I would dare try that.

 

2005, it is just one of those things that I was taking what we did with the bigger battery and simply adapting it to our vehicle batteries. They use the same basic technology. It sounds more difficult than it sounds. Normally I would turn on the aftermarket stereo I had and let it play for an hour or so as I waxed the truck and then get in and let it run for 15 minutes or so to recharge the battery. To each their own.

The big thing that kills modern day batteries is doing a deep discharge on a non-deep cycle battery. This tends to hurt the plates and the battery isn't quite the same again. An example of this would be leaving the interior lights on to the point that the motor can't turn over and the interior lights are a very dim at best. You can normally recover the battery to a useable condition after 1 time of doing this. But, much beyond that, you are looking at many problems. If you ever want to know anything about the different types of batteries, let me know. There is some basic info that I can pass on to make sure you get the correct battery for your application and usage style.