I believe my battery is out, I will test after work to be positive.

Anyhow I was wondering if anyone was running an aftermarket battery? Would something fix in the stock box, or would I have to remove the box.

Looking at possible an Optima red top...

 

Are you in the US?..If yes, Pepboys has a an exact replacement physically and higher CCA to boot, 84 months, first 3 years, free replacement..It's a Bosch.

 

Yes, i'm over in Texas. I'll give Pepboys a shout once I get off work!

Currently I have the stocker charging just to see if this is the exact issue, I don't believe the starter is the problem as it has not been hanging up at all.

 

Wishy, as long as the new battery fits into the factory box, has the same posts, and has the same (if not more) cold cranking amps (CCA), then you will be just fine. All batteries in the US are made on 1 of 2 assembly lines (either Exide or Johnson Controls). So, picking a battery is kinda a mute point as most batteries are identical to the other except for the sticker on the outside of the plastic box. Yes, the Optima Redtops are of a different design, but, from watching other people have them, they don't perform any better or last longer than a standard lead acid battery. The only benefit the redtops have is if you need to mount the battery on its side or upside down.

Chris "Thermo" Coleman

P.S. I know nothing about batteries. I just work around one capable of powering a small town. The battery is capable of easily pulling 10,000 amps. Nothing much.

 

Like I said, the Bosch is an exact fit

 

Thanks for the info! I ended up going to a local O'Reillys and they had one. It fit the box, has more cold cranking amps, 86 bucks out out to door. 2 yr replacement and 72 month pro-rated.

 

I don't have firsthand experience with Optima red or yellow tops, but the blue tops for marine/deep cycle application have way outperformed wet cell types in both bassboat and drag outboard applications. This isn't really germane to Jaguar applications, but here's my two cents.

I've had one in my bassboat for 5 seasons, and it sits all winter long. At the first twist of the key in the Spring, it cranks right over. This is pretty amazing since I used to go through wet cell batteries at the rate of one every two seasons, and I could usually count on it being dead or too low to crank or even charge at the beginning of Spring.

Also, in the summer, the blue top will run a 1400 watt stereo for two hours while the boat is beached, at low to moderate volume, then start the boat again without effort. As I said, this battery is now over five years old.

I think the vibration resistance of the compacted spiral cell technology has something to do with it, and of course the no-maintenance, sealed design.

On the other hand, my serious bass fishing buddies HATE the Optimas for trolling motor applications. They say they run flat in 1/2 the time of a good wet cell, much as Thermo was saying. I know one seriously pissed fisherman in Tennessee who lost a tournament because of running an Optima.

Bear in mind these comments are about the blue tops, but the experience probably closely relates to the yellow-tops also.

My XJS seems to operate in current-deficit mode whenever the climate control blower is running. That thing must pull some serious amps, especially with its resistors for the various fan speeds. Talk about an inefficient way to slow down a motor! That's why the silly thing has a 50A fuse, I am guessing.

For this reason, I am considering a yellow top Optima in replacement of the current Interstate wet cell, which is on last legs anyway.

 

If you want to know anything about batteries, let me know. I am all too familiar with spiral wound and lead acid batteries. I used to work around batteries capable of powering small towns. Anything you want to know, I will be able to explain to you.

 

Thanks Chris! Does the spiral type have a higher internal resistance than the wet cell types? Is this what explains the spiral cell's seeming ability to hold a charge longer, or is this because the electrolyte cannot evaporate whilst in storage?

Lou

 

Hey Thermo,

You would certainly know the answer to this: Are the X-Type batteries maintenance free? In the Passport to Service to my 2005 X-Type 3.0, I see a service item every 10K miles to check the batter electrolyte level and top up with distilled water as necessary. When I look at the actual battery, it seems to be maintenance free.

Just wondering if its really necessary to top up the battery on our cars? If so, how do you actually do it?

 

BlackJack, the reason why the spirals can hold a charge longer is not so much because of internal resistance (this is actually a bad thing for batteries to have lots of), but it is more because the chemicals in a lead acid battery are able to move around and are not quite as stable as the spiral batteries. So, as the acid breaks down over time, this causes the lead acid battery to self discharge where the spiral batteries have a more stable chemical in them, therefore the chemical reaction that produces the electricity doesn't take place until an electrical load is called for.

Of note, if you compare a lead acid battery to a spiral wound battery (same physical size), the lead acid battery will have a high stored energy (amp-hour rating). What this means to people that use batteries as the sole means of electricity can get more run time out of a lead-acid battery than a spiral wound battery. If I remember the numbers correctly, the spiral wound batteries have a 60 amp-hour rating, where the same size lead acid has an amp-hour rating of 80 normally. Granted, this rating really is only applicable to deep cycle/marine grade batteries. For what should be in our cars (ie, a starting battery, completely different monster than a deep cycle/marine grade battery), the amp-hour rating is kinda a useless number except for when you are having problems starting the car, then those few extra amp-hours can come in handy.

Matt, the battery in your car could be either. A battery that requires some maintenance will be fairly obvious. If you look at the top of the battery, if you see 1 or more caps that can be pulled off, then you have a battery that requires maintenance. If the top is solid, then you have a maintenance free battery. In a lot of cases, it will say on the battery some where that it is maintenance free. If you do have a battery that requires maintenance, all you really need to do is look in the openings and make sure that the tops of the plates are not poking out the top of the fluid level. If they are, stop by the auto parts store and pick up a little bit of sulfuric acid. Add enough to get about a 1/4" above the plates. It won't take much.

The one "maintenance item" I tend to do to all starting batteries is I do a partial discharge. What I normally end up doing is while I am waxing the car, I have the windows down and play the stereo for an hour or so at a moderate volume. What you are attempting to do is drain the battery at a rate of about 10 amps. What this does is it knocks the "moss" off that grows inside the battery. Don't be thinking of the gray stuff that grows on trees. It is more a protrusion that extends from a battery plate. By doing a discharge like this, you are getting rid of that moss, which will prevent a cell from shorting out, killing the rest of the battery. The trick is you don't want to discharge the battery too far as starting batteries do not like to be discharged. You want to reach a point where the battery is just able to turn the motor over and get it to start the vehicle. Then you can drive the vehicle for 15-20 minutes and that will recover the battery. I managed to get 10 years out of a factory battery by doing this.

 

Thanks Thermo. One clarifying question. The Jag manual says top up with distilled water. Is that sufficient or is there a strong case for topping up with sulfuric acid instead?

If the level's down, it seems like the water has evaporated, leaving the battery more acidic. Wouldn't adding more sulfuric acid screw up the balance of the solution?

Lastly, sorry for the naive question, but does sulfuric acid come in liquid form?

 

Matt...

Pure H20 (distilled water) has a specific gravity of 1.000..during the many charging and discharging process the battery goes through, it loses only the water through electrolysis..meaning it separates into the Hydrogen and oxygen components as a gas..Sulfuric Acid (S04) combines when mixed with water to form H2SO4, this brings the specific gravity of the combination known as Electrolyte to 1.300...The acid stays in the battery container during electrolysis..so topping up with distilled water is all you have to do periodically if it is not a maintenance free type battery (open cell container)..So yes, in most wet cell battery applications the Sulfuric acid is in liquid form.

 

Colt, fantastic answer. Thank you! My battery has a couple of caps on it, but doesn't say maintenance free anywhere. Per the service manual, I'll plan to top it up with distilled water every 10,000 miles as required.

 

Matt, the reason for loosing level in the battery is a 2 fold process. You normally loose some through heavy charging/discharging cycles. What happens is the current flowing through the battery is strong enough that it rips the hydrogen and oxygen apart that are forming water and the gases then leave the battery. The other way to loose level in the battery is through bouncing the battery around and having some acid leave the maintenance caps. This is normally seen as a white powder that forms on the battery terminals (also note that if you have a bad seal on the battery, the acid can come out in other locations).

So, with that being said, to do things right, you should actually measure the specific gravity of the liquid in the battery (tool can be bought at any auto parts store for like $5) and see what the specific gravity is. If you are down around 1.280 with the level low, then adding sulfuric acid would be recommended. If you are up around say 1.320, then adding distilled water is the better way to go. if you are in between, you need to add a little bit of both. The acid comes in a liquid form at the auto parts stores.

Please note that we are adding distilled water, not tap water. Tap water has impurities in it and this is bad for 2 reasons: 1) the impurities are conductive and with them in the solution, can cause the battery to self discharge faster; 2) the impurities can imbed themselves in the lead plates, leading to increased battery resistance and leading to other issues.

 

Not to dispute what you said, ....But the acid in solution with the water when (FULLY CHARGED) will give the SG of about 1.300.....true, any lose of acid could only be the result of being spilled or sloshed out..but highly unlikely in these cars, unless you do a lot of off roading..again unlikely....so to only add acid would be a mistake if the SG was down to around 1.100 or 1.200..this only means that the Acid is absorbed by the lead plates (Pb) of the cells and needs charging to drive it out of the lead back into solution with the water, hence bringing the SG back into range of about 1.300 or fully charged.

 

Colt, you do make a good point. I was making an undisclosed assumption that the battery was at full charge. I did that not to make the topic of the specific gravity that much more confusing. You know that when you start talking about if the battery is in a partially discharged state, the level is low, ........ the specific gravity can be all over the place. I was just keeping it fairly simple for the "backyard mechanic".

 

Aah, then we are on the same page...Cheers

 

Colt and Thermo, thanks.

I checked my battery this morning. It's an Interstate MTP-91 that's about a year and 10,000 miles old (dealer replaced the battery during my pre-purchase inspection because the OEM battery was cracked). I pried the caps off - the plates are clean, there's no white residue anywhere, and the electrolyte level is at the full mark in all but 2 of the cells. Even in those two cells, the level's still pretty close to full.

I'll plan to check the electrolyte level every 10,000 miles per Jaguar's recommendation - at the next checkup, I'll pick up a hydrometer to check the specific gravity as well. For what it's worth, my Popular Mechanics Complete Car Care Manual (a highly recommended resource for all shade tree mechanics) has this to say...reinforcing what both Thermo and Colt said:

"A better check is to use a hand held hydrometer...Open the battery up and look inside. The electrolyte should come up to the bottom of the filler cap or at least near it. If the level is down, especially if the plates are exposed, add water. Always use distilled water in a battery. There's never any need to add additional electrolyte. Batteries will normally consume water, but the sulfuric acid component of the electrolyte remains behind and never needs to be replenished."