Battery/starter voltage question
 

I had my battery checked today after some warning signs in recent months (11.5-12v shown on cigar lighter voltmeter and Traction Not Available messages on occasion at start, plus a couple of slow cranks.) Voltmeter shows consistently 14.1-14.4 or 14.5 when running with no electrical load. The battery is an Interstate AGM appropriate for a x308 and is two years, eight months old. The car generally gets weekend use, though I’m trying to use it more these days. Approx 47k miles

The battery tested OK by the shop’s standards, showing 12.22V while off and well over 14 when running. The shop declined to do a warranty replacement but did point to their test meter showing the starter highlighted in yellow at 11.5 volts as opposed to a standard (by their way of telling it) of 12 volts. (At this shop the tech told me with a battery replacement they’d have to “reset” the ECU. Say what? I think that’s BS.)

So, here’s question: If my starter is putting out/receiving/or whatever 11.5V and presuming it should show 12V, what are the potential causes? Weak ground? Weak starter? If the starter, it spins up nicely and gives no indication I can see of being on the way out. Does it even matter? Should I care?

I am more interested in what the heck is going on than the cost of the battery ($270 at this joint, $170 at Costco with a different warranty structure.)

Thanks in advance for any further education in the ways of this beast. I need to add, I am in a garage-less townhouse and to use a battery tender would have to run a cord across a common sidewalk. Not the most conducive situation for using a battery tender. I’ve thought of the solar ones, but they put out so little amperage I’m not sure they’re worth the hassle.

Eliot, if the car is garage kept, I’d highly suggest getting a “battery tender” and keeping it plugged in all the time you’re not driving it. I’d recommend getting this one below. It’s a charger and maintainer and works on AGM. Amazon link below.

https://a.co/d/1Ue4USr

Some newer cars need a ECU reset. Not sure about Jags, but your 'old ' car doesn't.

If you had a place to use a battery tender, I'd suggest that followed by a test of battery health using a capacitance tester.
Those devices measure resistance & compare spec CCA vs actual CCA. If the ratio is < 80% it calls the battery bad.

I recommend CTEK MXS 5.0
https://smartercharger.com/collectio...s/ctek-mxs-5-0
$95 Amazon

or
CTEK MULTI US 7002 which can also supply power during a battery change.
https://smartercharger.com/collectio...-multi-us-7002

SOLAR BA9 battery conductance tester

Given your lack of a garage:
1. Find a spot where you can park next to an electrical outlet, place your (new) CTEK in the trunk & let the (Outdoor) extension cord connect with the trunk closed/locked. the soft, rubber gaskets will not be damaged & neither will the extension cord when the trunk is closed on it. I have done this many times since my Jag is parked on my driveway bc my garage is full of 2 newer, much more expensive cars.

https://www.harborfreight.com/50-ft-...nge-62941.html


Remove the battery & bring it in your home, preferably on a balcony or yard so, it will be outside. Charge with CTEK. Then test with battery tester. If you do not have a yard or balcony next to an open window but, it is winter & very cold so probably not practical. Must have ventilation when charging a battery!

You will lose some settings, leaving the car w/o a battery for hours. There are devices that use a 9V battery & connect to 12V outlet or OBD2 diagnostic port that retain computer settings but I have never used.

If your fully charged battery fails the capacitance test, show the results to the place you purchased the battery since it is AGM, get a free replacement.

I would change mechanics, since resetting the ECU seems like B.S.

If you have to buy a new battery I recommend AGM H8, 95Ah, 900 CCA manufactured by Clarios (Formerly Johnson Controls).
They make the exact same battery for many retailers under different names.

Warranty is usually 3 yrs but Walmart sells EverStart Platinum AGM $180 with a 4 yr. Replacement warranty.
You can order online with free shipping, if your local stores do not carry or carry an 850 CCA version NOT made by Clarios.

Other brands made by Clarios:
Everstart for Walmart
Varta (Used by Porsche)
Die Hard (Now sold by Advance Auto Parts)
Champion (sold by Pep Boys, (now discontinued)
Duralast (sold by Auto Zone)
AC Delco (Sold by Amazon)
Interstate (sold by independent garages and Costco)
Motorcraft (Ford)
SuperStart (O'Reilly Auto Parts)
Legend (NAPA Auto Parts)
There are undoubtedly more I have not listed.


If all the above is too much trouble, you can try to take a ½ hr. Freeway drive to, hopefully, charge the battery & then stop at an auto parts store that does free battery testing & will give you a printout. (Call 1st to verify free capacitance test with printout)

AutoZone
https://www.autozone.com/lp/free-parts-testing#

I think PepBoys also does this & probably others as well.

(I attached pic or that battery)

Good luck!




https://cimg4.ibsrv.net/gimg/www.jag...33ebb637b3.png

A2B: Alas, no garage or driveway, just a townhouse and would have to run an extension cord to the car over the shared sidewalk. I could probably hook it up for a few hours at a time a day or two a week.

FYI, the link may be bad, it goes to something called “super deals,” not any Amazon site.

Iconoclast and everyone else: thanks for all the good info, links, etc. and education about manufacturers. The battery list is great. What I have is an Interstate H8 G-49 AGM bought at the place that did todays testing.

I like the suggestion of just recharging the battery on my porch, though I don’t know what settings I would lose if I had it out 5-6-7 hours. I suspect the car would have to relearn my driving habits or something, but I presume it would restart without issue if it were out for several hours being recharged then reinstalled. I could always also top it off a couple times a week in my parking lot as I do have a long enough cord from the days I thought I actually had an interest in cutting grass! And I go someplace once a week where I could probably find power to run a charger while I’m in a gathering for a couple of hours.

I also have some Auto Zone and Advance Auto places around I can use for objective testing. There are a couple of Walmarts near me, as well as a Costco. I can just get an Interstate replacement at Costco for $170. The shop I got it from wants $270. Warranty structure is different. And the Walmart version’s warranty is outstanding. Maybe the Walmart unit is the way to go

I do need to clarify that the place I had test the car today is a local chain of tire/service centers from which I bought the battery. The first one died because of a massive parasitic drain. I got that fixed (bad switch LF door), and then a replacement battery under warranty.

I was also very curious why the testing shop’s meter said there was a voltage issue with the starter, 11.5V against the alleged standard of 12V. So far no one has hazarded any guess why the testing shop would tell me that. For honest-to-goodness work I use an Indy garage I trust.

Thanks to everyone who has taken the time so far (9pm EST) to offer guidance. What a great community.

"the starter highlighted in yellow at 11.5 volts" - is this the voltage measured on the battery while cranking the engine?

Otherwise, you should not allow the battery voltage to drop to 11.5-12V (just about 30% of charge) as this will cause accelerated battery sulfation and irreversible loss of capacity. Even the 12.2V measured at the shop is somewhat low, 60% of charge.

To keep the battery healthy and lasting long, it should be kept at near fully charged (~12.6 V) most of the time, if possible. If you don't use the car daily, you should either install a battery cut-off, have it connected to a trickle charger or charge it frequently. I have a battery cut-off and use it frequently. I have absolutely no issues caused by the battery disconnections/reconnections (1999 Daimler Super V8).

My XJR sat for about 7 months with a battery showing under 1.2v (yes one point two, it really had totally died). When I finally replaced the battery the car fired up like it'd last ran yesterday. So I wouldn't worry about that side of things.

To close this out, and thanks again to Iconoclast, I got a Walmart EverStart H8 Group 49 AGM battery today, but upon arriving home after installing it in the store parking lot, realized I got the 850 CCA version, not the 900 CCA version which was not stocked at this place. At least this battery had a 1/24 date on it. DUH. I suppose I could see about returning the 850 after ordering a 900, but I’m not sure it is worth the hassle, nor do I know their return policy. I’ll look that up and see what the story is.

I will say the one store near me with an auto service operation was singularly useless, which led me to pick up the in-stock battery at a regular Walmart closer to me.

So, at this price, no big deal unless someone sends me a flame of a note saying I’ve totally screwed this up!

Car starts, runs. What’s not to like.

As long as you keep it fully charged, no problem. Do you have a battery maintainer?

I don’t have a maintainer. Easy to get one, but as noted I have to lay an extension cord across a common area sidewalk to charge it in place, or take it out and stick it on my porch for a few hours while it gets topped off. At my age lifting one of these batteries out of the trunk is a little awkward, but I could consider it “resistance training” and credit to my old fart goal of 150 minutes of exercise weekly!

If I had to do that (charging) considerably less with the 900CCA battery I might be inclined to make the swap. Further investigation tonight suggests that I can order the larger battery online for home delivery, and return the 850 to the store. I’m doublechecking that in person at the store tomorrow.

There's not much difference between the two, and no matter which one you have maintaining a full charge is important. It takes more than a short trip every few days to do that. If you don't have a multimeter get one and check that the battery is at least 12.6V. You can check it at one of the bulkhead fuse boxes in the engine compartment.

Perhaps a solar photovoltaic-powered maintainer is a viable solution for you. I use a lithium portable power station because my car lives inside a subterranean garage without available shore power.

OK: proper Walmart EverStart 900CCA AGM on order for home delivery next week. Walmart store confirms it will provide full refund on the 850 unit when returned. Additionally, I ordered the CTEK MXS 5.0, also arriving next week. I have one place I go where I can plug the car in for a couple of hours a week if needed. I’ll first experiment at home what schedule is good, either with a cable across the common sidewalk or the battery out on my porch. As I approach 75, it would be nice if batteries were a little lighter! The Walmart staffer who helped me heft the 850 battery into a cart remarked that I must have a pretty big truck to take such a battery!

Thanks to the community for all the great guidance. Oh yeah, the CTEK phone customer service folks were absolutely outstanding.

CCA won't matter to how long it works when the car is parked, the measurement you need to compare is the amp/hrs. I'm damn sure when I went looking for a battery for my XJR last year the spec was 800-850CCA, so the one you've got is easily powerful enough.

CCA is Cold Cranking Amps, so the max power output of the battery at peak demand. Amp/Hrs is how much electric the battery stores, measured in either how many Amps drain will empty the battery in one hour, or how many hours a 1 Amp drain will empty the battery in. These two are the same figure so it can be read either way.

Another way of looking at it is if it was a tap running of a tank in the loft then CCA is the highest pressure at the tap & Amp/Hr is how long till the tank is empty.

FWIW,

The Clarios H8 AGM batteries such as Everstart are 900 CCA & 95 Ah.
All the H8 AGM, 850 CCA batteries, including the Everstart ones (NOT made by Clarios) are 92 Ah.

If you do not have a helper to test your alternator voltage as one person revs the engine to 2500 RPM & the other person uses a multimeter under the hood…

“Innova Equus Battery Alternator Tester 3721” $20
• Easily plugs into vehicle’s cigarette lighter or power receptacle to monitor battery and charging system voltage
• Designed for 12-volt negative ground systems
• LCD displays measured voltage with a bar graph to indicate battery charge level
• Color-coded LEDs quickly identify battery’s charge status
• Head pivots for easy viewing and angle adjustment


https://cimg7.ibsrv.net/gimg/www.jag...d03e7c7b57.png

And now I’m totally closing out this thread. I installed the wiring for a CTEK MXS 5.0 charger (4.3 amps) today just before installing the new H8 G-49 Walmart AGM EverStart battery, which weighed a mere 58 pounds. That battery, by the way, appears only available online for home delivery. Look for the one that describes itself as the BOX version, otherwise you will get the very slightly smaller capacit unit. Read the item description if you are unsure. The bigger battery is 900CCA, the smaller one I bought in a store first then returned was 850CCA and the 850 number in the online description text is the giveaway. Iconoclast noted in a PM to me that some stores stock the 900CCA unit, while others like mine only carry the 850 and online they have the same part number. I put the 900 battery on the charger for about a half hour before I installed it, and will probably hook the charger up tomorrow or the next day for a much longer period, until I see the lights get to the final position, i.e. fully charged.

The hardware for the O-ring type wiring apparatus was too short to reach the spare tire tie-down bar which has been recommended as a sufficiently separated location from the positive terminal, or even stretch to the negative terminal. I attached the ring to a right side body sidewall ground that I think I saw used as a grounding location in pictures I saw from someone else’s job. Of course, I couldn’t find the original post.

I’m attaching a few shots of the installation. No one should panic when you see red on the ground wire. That is insulation from the positive wire that stayed with the negative wire as I pulled them apart to give me enough length to work with. This isn’t exactly a small battery! Because the original vent elbow had long since parted company with the car, I bought a Dorman 924-254 Battery Exhaust Vent Tube: kit from Advance Auto. https://shop.advanceautoparts.com/p/...E&gclsrc=aw.ds The original rubber venting tube was still in place, so all I needed was the plastic elbow and the plug for vent on the opposite side of the battery (negative side). The second plug is a little tab attached to the red cover for the positive terminal present when the battery is delivered or installed. I think the Dorman kit was $14. I have no clue where I could have found the elbow unit alone.

I thank everyone who offered advice and moral support as I did this little project.
https://cimg9.ibsrv.net/gimg/www.jag...f240a3ec1.jpeg
Wide shot of the connections
https://cimg1.ibsrv.net/gimg/www.jag...ed39235b8.jpeg
Positive lead
https://cimg4.ibsrv.net/gimg/www.jag...812452e90.jpeg
Negative lead to right side body ground. Don’t panic, the red color is insulation that came off the positive lead as I pulled them apart. As shipped, the leads did not stretch from the + terminal to - terminal.
https://cimg6.ibsrv.net/gimg/www.jag...a39eeeaa5.jpeg
Finished product.

Great thread, guys, and thank you for reporting your success, Eliot!

For those who just can't park their car close enough to an AC outlet to use a conventional battery tender, I have had pretty good luck with a Schumacher solar-powered battery maintainer that I bought from Amazon. It has done pretty well at keeping a battery charged for up to a month unless it's been a rainy-cloudy month. I tried the 2.4 watt version first but it just couldn't keep up, but this 4.8 watt version is pretty good:


https://cimg2.ibsrv.net/gimg/www.jag...4f11d5485f.jpg




Cheers,

Don

Don, Did you buy: “The Schumacher SPC-7A Charge Controller is recommended for extra overcharge protection (sold separately)”


If not, will this overcharge the battery?

Yes, I did buy a Schumacher charge controller - I do not know if it is strictly necessary, but I have always used it just in case. Thanks for asking - I thought about mentioning this but must have used the wrong keywords when I was searching for it so I could include it in my previous post, and then I forgot to follow up. Thank you for actually reading the link I posted. Maybe I should have done that!

Here's the link to the controller:


Cheers,

Don